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4 GYROCOMPASS SYSTEMS
Upon completion of this chapter, you will be able to do the following:
• Discuss basic gyroscopic and gyrocompass theory. • Identify the major components of the Mk 23 gyrocompass systems, and explain the procedures for starting, standing watch on, and securing the Mk 23 gyrocompasses. • Identify the major components of the Mk 27 gyrocompass system, and explain the procedures for starting, standing watch on, and securing the Mk 27 gyrocompass. • Identify the major components of the AN/WSN-2 stabilized gyrocompass set, and explain the procedures for starting, standing watch on, and securing the AN/WSN-2 stabilized gyrocompass set. • Explain the purpose of the synchro signal amplifier used with the various gyrocompass systems. • Explain the purpose of the ship’s course indicators used with the various gyrocompass systems. • Describe the entries to be made in the engineering logs, and the deck and watch logs to be kept when standing watch on gyrocompass systems.
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4.0.0 INTRODUCTION The ship’s gyrocompass and its associated equipment is an important part of an IC Electrician’s responsibility. Gyrocompass systems provide information that is used for remote indicators and various navigational, radar, sonar, and fire control systems throughout a ship. As an IC3, you will be responsible for starting, standing watch on, and securing the ship’s gyrocompass.
To understand how a gyrocompass operates, you should be familiar with gyroscopic and gyrocompass theory. A variety of gyrocompasses are presently in use throughout the Navy. In this chapter, we will discuss basic gyroscopic principles, and then we will develop the basic gyroscope into a basic gyrocompass. We will then discuss the operation of some of the more common gyrocompass systems installed on board Navy ships today.
We will also discuss the associated equipment used in conjunction with the gyrocompass systems. The topics include descriptions of the components and functions of the master compass, gyro control systems, follow-up systems, alarm systems, and starting control systems. In addition, we will also point out the significant differences among the various modifications and provide procedures for operating the gyrocompass in normal and auxiliary modes. 4-2 UNCLASSIFIED
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4.1.0 THE FREE GYROSCOPE A free gyroscope is a universal-mounted, spinning mass. In its simplest form, the universal mounting is a system that allows three degrees of freedom of movement. The spinning mass is provided by a heavy rotor. Figure 4-1 illustrates a free gyroscope. As you can see in the figure, the rotor axle is supported by two bearings in the horizontal ring. This ring is supported by two studs mounted in two bearings in the larger vertical ring. These two rings are called the inner gimbal and outer gimbal, respectively. The outer gimbal is then mounted with two studs and bearings to a larger frame called the case.
Figure 4-1.—The gyroscope. 4-3 UNCLASSIFIED
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The rotor and both gimbals are pivoted and balanced about their axes. The axes (marked X, Y, and Z) are perpendicular to each other, and they intersect at the center of gravity of the rotor. The bearings of the rotor and two gimbals are essentially frictionless and have negligible effect on the operation of the gyroscope.
4.2.0 THREE DEGREES OF FREEDOM As you can see in figure 4-1, the mounting of the gimbals allows movement in three separate directions, or three degrees of freedom: (1) freedom to spin, (2) freedom to tilt, and (3) freedom to turn. The three degrees of freedom allow the rotor to assume any position within the case. The rotor is free to spin on its own axis, or the X axis, the first degree of freedom. The inner gimbal is free to tilt about the horizontal or Y axle, the second degree of freedom. The outer gimbal ring is free to turn about the vertical or Z axis, the third degree of freedom.
4.3.0 GYROSCOPIC PROPERTIES When a gyroscope rotor is spinning, it develops two characteristics, or properties, that it does not possess when at rest: rigidity of plane and precession. These two properties make it possible to convert a free gyroscope into a gyrocompass.
4.3.1 Rigidity of Plane When the rotor of the gyroscope is set spinning with its axle pointed in one direction (fig. 4-2, view A), it will continue to spin with its axle pointed in that direction, no matter how the case of the gyroscope is positioned (fig. 4-2, view B). As long as the bearings are frictionless and the rotor is spinning, the rotor axle will maintain its plane of spin with respect to a point in space. This property of a free gyroscope is termed rigidity of plane.
Newton’s first law of motion states that a body in motion continues to move in a straight line at a constant speed unless acted on by an outside force. Any point in a spinning wheel tries to move in a straight line but, being a part of the wheel, must travel in an orbit around its axle. Although each part of the wheel is forced to travel in a circle, it still resists change. Any attempt to change the alignment or angle of the wheel is resisted by both the mass of the wheel and the velocity of that mass. This combination of mass and velocity is the kinetic energy of the wheel, and kinetic energy gives the rotor rigidity of plane. Gyroscopic inertia is another term that is frequently used interchangeably with rigidity of plane. Figure 4-2.—Rigidity of plane of a spinning gyroscope. 4-4 UNCLASSIFIED
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A gyroscope can be made more rigid by making its rotor heavier, by causing the rotor to spin faster, and by concentrating most of the rotor weight near its circumference. If two rotors with cross sections like those shown in figure 4-3, are of equal weight and rotate at the same speed, the rotor in figure 4-3, view B, will have more rigidity than the rotor in figure 4-3, view A. This condition exists because the weight of the rotor in figure 4-3, view B, is concentrated near the circumference. Both gyroscope and gyrocompass rotors are shaped like the rotors shown in figure 4-3, view B.
Figure 4-3.—Weight distribution in rotors.
4.3.2 Precession Precession describes how a gyro reacts to any force that attempts to tilt or turn it. Though vector diagrams can help explain why precession occurs, it is more important to know how precession affects gyro performance.
The rotor of a gyro has one plane of rotation as long as its axle is aligned with, or pointed at, one point in space. When the axle tilts, turns, or wobbles, the plane of rotation of the rotor changes. Plane of rotation means the direction that the axle is aligned or pointed.
Torque is a force that tends to produce rotation. Force acts in a straight line, at or on a point. Torque occurs within a plane and about an axle or axis of rotation. If the force acts directly on the point of an axis, no torque is produced.
Because of precession, a gyro will react to the application of torque by moving at right angles to the direction of the torque. If the torque is applied downward against the end of the axle of a gyro that is horizontal, the gyro will swing to the right or left in response. The direction in which it will swing depends on the direction the rotor is turning. 4-5 UNCLASSIFIED
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A simple way to predict the direction of precession is shown in figure 4-4. The force that tends to change the plane of rotation of the rotor is applied to point A at the top of the wheel. This point does not move in the direction of the applied force, but a point displaced 90° in the direction of rotation moves in the direction of the applied force. This results in the rotor turning left about the Z axis and is the direction of precession.
Figure 4-4.—Directio n of precession.
Any force that tends to change the plane of rotation causes a gyroscope to precess. Precession continues as long as there is a force acting to change the plane of rotation, and precession ceases immediately when the force is removed. When a force (torque) is applied, the gyroscope precesses until it is in the plane of the force. When this position is reached, the force is about the spinning axis and can cause no further precession.
If the plane in which the force acts moves at the same rate and in the same direction as the precession it causes, the precession will be continuous. This is illustrated by figure 4- 5, in which the force attempting to change the plane of rotation is provided by a weight, W, suspended from the end of the spin axle, X. Although the weight is exerting a downward force, the torque is felt 90° away in the direction of rotation. If the wheel rotates clockwise, as seen from the weighted end, precession will occur in the direction of arrow P. 4-6 UNCLASSIFIED
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As the gyroscope precesses, it carries the weight around with it so that forces F and F1 continuously act at right angles to the plane of rotation, and precession continues indefinitely. In other words, the rotor will turn to the right and continue turning until the weight is removed.
Figure 4-5.—Conti nuous precession.
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4.4.0 FORCE OF TRANSLATION Any force operating through the center of gravity of the gyroscope does not change the angle of the plane of rotation but moves the gyroscope as a unit without changing its position in space. Such a force operating through the center of gravity is known as a force of translation. Thus, the spinning gyroscope may be moved freely in space by means of its supporting frame, or case, without disturbing the plane of rotation of the rotor. This condition exists because the force that is applied through the supporting frame acts through the center of gravity of the rotor and is a force of translation. It produces no torque on the gyro rotor.
4.5.0 EFFECT OF EARTH’S ROTATION As just explained, a free-spinning gyroscope can be moved in any direction without altering the angle of its plane of rotation. If this free-spinning gyroscope is placed on the earth’s surface at the equator, with its spinning axis horizontal and aligned east and west, an observer in space below the South Pole would note that the earth rotates clockwise from west to east and carries the gyroscope along. As the earth rotates, rigidity of plane keeps the gyroscope wheel fixed in space and rotating in the same plane at all times. Figure 4-6 shows how this gyroscope would appear. Assume that the gyroscope is set spinning at 0000 hours with its spinning axis aligned east and west and parallel to the earth’s surface. At 0600, 6 hours after the gyroscope was started, the earth has rotated 90° and the axle of the gyroscope is aligned with the original starting position. At 1200 the earth has rotated 180°, while the gyroscope returns to its original position. The figure shows how the gyro completes a full cycle in a 24-hour period.
Figure 4-6.—Free gyroscope at the equator viewed from space. 4-8 UNCLASSIFIED
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4.6.0 APPARENT ROTATION OF THE GYROSCOPE An observer on the earth’s surface does not see the operation of the gyro in the same way as an observer in space does. On the earth, the gyro appears to rotate, while the earth appears to stand still. As the earth rotates, the observer moves with it, so the gyroscope seems to rotate around its horizontal axis. The effect the observer sees on the earth is called apparent rotation and also is referred to as the horizontal earth rate effect. If the gyro were started with its axle vertical at one of the earth’s poles, it would remain in that position and produce no apparent rotation around its horizontal axis. Figure 4-7 illustrates the effect of apparent rotation at the equator, as seen over a 24-hour period.
Figure 4-7.—Free gyroscope at the equator viewed from the earth’s surface.
Now assume that the spinning gyroscope, with its spinning axis horizontal, is moved to the North Pole (fig. 4-8). To an observer on the earth’s surface, the gyroscope appears to rotate about its vertical axis. To an observer in space, the gyroscope axle appears to remain fixed, and the earth appears to rotate under it. This apparent rotation about the vertical axis is referred to as vertical earth rate effect. It is maximum at the poles and zero at the equator.
When the gyroscope axle is placed parallel to the earth’s axis at any location on the earth’s surface, the apparent rotation is about the axle of the gyroscope and cannot be observed. At any point between the equator and either pole, a gyroscope whose spinning axis is not parallel to the earth’s spinning axis has an apparent rotation that is a combination of horizontal earth rate and vertical earth rate. 4-9 UNCLASSIFIED
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The combined earth rate effects at this point make the gyro appear to rotate partly about the horizontal axis and partly about the vertical axis. The horizontal earth rate causes the gyro to tilt, whereas the vertical earth rate causes it to turn in azimuth with respect to the earth. The magnitude of rotation depends on the latitude of the gyro.
Apparent rotation is illustrated by placing a spinning gyroscope with its axle on the meridian (aligned north-south) and parallel to the earth’s surface at 45° north latitude and 0° longitude (fig. 4-9). Figure 4-8.—Apparent rotation of a gyroscope at the North Pole. Figure 4-9.—Apparent rotation of a gyroscope at 45°N latitude.
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A gyroscope, if set on any part of the earth’s surface with the spinning axle not parallel to the earth’s polar axis, appears to rotate, over a 24-hour period, about a line passing through the center of the gyroscope and parallel to the earth’s axis. This apparent rotation is in a counterclockwise direction when viewed from south to north. The path that the north axle describes in space is indicated by the line EAWB back to E (fig. 4-10).
Figure 4-10.—Path of the spinni ng axis of a free gyroscope.
The effect of the earth’s rotation causes the north end of the gyroscope axle to rise when east of the meridian and to fall when west of the meridian in any latitude. This tilling effect provides the means by which the gyroscope can be made into a north-seeking instrument.
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4.7.0 MAKING THE GYROSCOPE INTO A GYROCOMPASS Up to this point, we have discussed the basic properties of a free gyroscope. Now, we will discuss how we use these properties, rigidity of plane and precession, to make a gyroscope into a gyrocompass. The first step in changing the gyroscope to a gyrocompass is to make a change in the suspension system. The inner gimbal that holds the gyro rotor is modified by replacing it within a sphere or case (fig. 4-11, view A), a necessary feature that protects the rotor. A vacuum is formed inside the sphere to reduce air friction on the spinning rotor. The next step is to replace the simple gyroscopic hose with what is called a phantom ring (fig. 4-11, view A). The difference between the simple base and the phantom is that the phantom is turned by a servomechanism to follow the horizontal plane of the rotor’s axle, while the simple base remains fixed in its position. The phantom ring allows the outer gimbal (vertical ring) (fig. 4-11, view A) the freedom to turn and to tilt. These modifications enable the gyroscope to maintain its plane of rotation as long as it spins and nothing touches it. We have modified the basic suspension system to enable us to convert the gyroscope to a gyrocompass. Now, we must make it seek out and point to true north. For the purposes of this explanation, true north is the direction along the meridian from the point of observation to the North Pole.
Figure 4-11.—A. Simple gyrosc ope. B. Modified gyroscope.
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To become a gyrocompass, a gyro must be modified so it can:
1. align its axis on the meridian plane,
2. align its axis nearly horizontal, and
3. maintain its alignment both horizontally and on the meridian, once it is attained.
In figure 4-11, view B, a weight (pendulous weight) has been added to the bottom of the vertical ring, which makes it bottom heavy, or pendulous. The weight exerts a force on the gyro whenever the rotor is not level with the earth’s surface.
In previous discussion, we talked about precession and vertical and horizontal earth rates. Now, we will see how we use the apparent rotation of the gyro rotor to make the modified gyroscope north-seeking. In figure 4-12, point A, the gyro axle is parallel to the earth’s surface; however, as the earth rotates, the earth rate effect causes the gyro rotor axle to tilt in relation to the earth’s surface, and the weight that we attached to the bottom of the vertical ring now applies a force to the bottom of the gyro. As we discussed earlier, precession occurs in the direction of rotation, but 90° away from the point of application; therefore, the weight applies a force to the bottom of the gyro but is felt about its horizontal axis, which causes the gyro to turn. As the gyro turns, the phantom follows the rotor axle. As you follow the gyro through one rotation on the earth’s surface, you can see that the gyro rotor follows an elliptical path around the meridian. It actually points north twice in the ellipse; in other words, it has become north-seeking. The period of oscillation is actually much less than the 24 hours required of an unmodified gyro; the actual time is determined by the speed and weight of the rotor and the size of the pendulous weight. The next step, logically, is to make the north-seeking gyroscope north- indicating.
As you have seen, we made the gyroscope north-seeking by adding a pendulous weight, which caused the gyroscope to oscillate about north. To make it north-indicating, we must somehow dampen these oscillations. To do this, we must add another smaller weight, Wz, on the cast side of the rotor. Both weights, W and W1, influence the gyro when it is not aligned with the meridian (fig. 4-13).
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Figure 4-12.—Effect of weight and earth’s rotation on the gyroscope.
Figure 4-13.—Gyroscope with weights on the vertical ring and sphere.
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When the gyro is started while pointed away from the meridian, the effect of earth rate causes it to tilt. As soon as it tilts, weight W causes precession; however, now the smaller weight, W1, also causes the gyro to precess towards a more level position, which limits the effect of precession caused by weight W. The excursions from level continue, but the dampening effect of weight W1 causes each successive oscillation to be reduced; the path of the rotor axle then will be spiral shaped (fig. 4-14).
Figure 4-14.—Effect of weights on the gyroscope.
As you can see, the only position of rest for the gyro axle is level and on the meridian. The free gyroscope has now become a gyrocompass, able to settle only on the meridian (pointing north) and level.
This is a very basic gyrocompass, and it really operates satisfactorily only on the equator and when mounted on a stable platform; however, the principles and basic concepts are the same for all gyrocompasses. 4-15 UNCLASSIFIED
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To make a basic gyrocompass function properly over a wide range of latitudes, we must stabilize it with respect to the earth’s surface instead of with the earth’s axis, and we must damp out the effects of the ship’s acceleration and deceleration. There are several methods used to do this. The method used depends on the type of gyrocompass. For further information on the method of damping used in the gyrocompasses installed on your ship, refer to the applicable manufacturer’s technical manual.
4.8.0 DIGITAL FLUX GATE MAGNETIC COMPASS SYSTEM (DFGMC) The MV103AC, MV103ACS and MV103DG Digital Flux Gate Magnetic Compass (DFGMC) Systems constitute an integral part of the ship’s navigation system. These systems were designed as a replacement for the wet globe magnetic compasses found on many older vessels. DFMGC systems are electronic compass systems, which use digital processing techniques to determine the heading of a vessel referenced to magnetic North. Magnetic heading data is displayed to the operator in numerical format on a liquid crystal display at the helm and may be sent to other equipment in the form of RS-232 or RS-422 serial data.
4.8.1 Equipment Description The basic DFGMC System consists of the (1A3) Sensor / Processor Unit, (1A2) Junction Box, (1A1) Main Display, (PS1) Uninterruptible Power Supply, plus associated power and signal cabling. System specific equipment may include the (1A6) Degaussing Interface Unit, (1A4) RS232/422 Display Driver, and (1A5) RS232/422 Remote Displays. All system components are shown in figure 4-15.
Figure 4-15.—DFGMC System. 4-16 UNCLASSIFIED
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Figure 4-16 shows the interrelationship of units in AC and ACS systems, including the optional (1A4) RS232/422 Display Driver and optional (1A5) RS232/422 Remote Displays.
Figure 4-16.— MV103AC and MV103ACS DFGMC System Block Diagram.
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Figure 4-17 shows the interrelationship for the units in the DG systems.
Figure 4-17.— MV103DG DFGMC System Block Diagram.
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4.8.2 Reference Data
PERFORMANCE: Accuracy: 1.0 o RMS error after calibration in free field Repeatability: 1.0 o Resolution: 1.0 o display; 0.1o digital output Field Strength Sensitivity: 6.5 to 65 Tesla Magnetic Dip Angles: 80 o magnetic inclination
ENVIRONMENTAL: Operating Temperature: -40 o C to +85o C (-20o C to +70o C for (1A5) RS232/422 Remote Display)
Storage Temperature: -62 o C to +74o C (-40o C to +125o C for (1A5) RS232/422 Remote Display)
Humidity: 0% to 100% ((1A3) Sensor / Processor only)
SERIAL DATA INTERFACE: (1A2) Junction Box RS232 or RS422 (depot selectable) using NMEA 0183 sentence structure
(1A4) RS232/422 Display Driver RS232 us ing NMEA 0183 sentence structure
POWER REQUIREMENTS: Input Power - Compass: +24VDC 6 VDC at 200 mA ((1A1) Main Display lighting at full brightness)
Input Power – (PS1) KH-1000B: 115VAC 60Hz, 2.2A startup, 1.8 A running
Input Power – (PS1) BH-2000: 115VAC 60Hz, 4.6A startup, 2.2 A running
Input Power – (1A4) RS232/422 Display Driver 115VAC, 60 Hz at 300mA (with 3 ( 1 A 5 ) R e m o t e D i s p l a y s a t t a c h e d a t f u l l b r i g h t n e s s
Fuse Rating – (1A2) Junction Box: 3/10A, 250 VAC, slow-blow
Fuse Rating – (PS1) Power Supply: KH 100B 2.5A, 250VAC (in); 3/10A, 250VDC, s l o w - b l o w ( o u t )
Fuse Rating – (PS1) Power Supply: BH2000 5A, 250VAC (in); 3/10A, 250VDC, slow- blow (out) 4-19 UNCLASSIFIED
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Fuse Rating – (1A4) RS232/422 Display Driver 1/2 A, 250VAC
DIMENSIONS AND WEIGHTS (1A1) KVH Main Display: 4.8"L x 3.6"W x 1.8"H / 1lb.
(1A1) AMSEC LLC Main Display 4.5” L x 3.5” W x 2.8” D / 1.1 lbs.
(1A2) Junction Box: 9.9"L x 4.0"W x 3.4"H/2.7 lbs.
(1A3) Sensor / Processor Unit: 6.3"L x 6.6"W x 3.6"H/3.8 lbs.
(1A4) AMSEC LLC RS232/422 Display Driver 8.9” L x 4.7” W x 2.5” D / 2.5 lbs.
(1A5) AMSEC LLC RS232/422 Remote Display 5.5” L x 3.5” W x 2” D / 1.1 lbs.
(1A6) Degaussing Interface 6.3"L x 6.6"W x 3.6"H/4.0 lbs
(PS1) Power Supply: KH-1000B: 11"L x 7"W x 5.5"H/15 lbs. BH-2000: 11 1/2"Lx 7 1/2"Wx 4 5/8"H/10.3 l b s .
4.8.3 DFGMC Operation The DFGMC is an “output only” type system and does not require any operator input for normal operation. When power is applied, the system automatically enters the Compass Heading mode. The Digital Display shows the present compass heading relative to magnetic north using the last calibration data stored by the system.
4.8.4 Controls Figure 4-18 illustrates MV103AC (1A2) Junction Box controls. Figure 4-19 illustrates MV103ACS and MV103DG (1A2) Junction Box controls. Use of these controls is further described in Section 2, Compass System Operation. The Main Power Switch located on the KH1000B Power Supply and the Alarm Override Switch on the BH2000 Power Supply are the only other controls on this system.
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Key Nomenclature Function 1 POWER Controls power to the DFGMC OFF: no power applied. ON: applies power to the DFGMC (no display lighting). LIGHT ON: applies power to the DFGMC and lighting to (1A1) Main Display. 2 DIMMER Controls (1A1) Main Display lighting when POWER switch is at LIGHT ON. 3 F1 3/10A Fuse under screw-off cap; protects the DFGMC from short circuits and overloads. 4 DECL Used to enter variation or declination to convert magnetic to true North. Also used to enter (1A3) Sensor / Processor alignment correction factor. 5 GPS/NAV Used to toggle between compass heading and GPS input display modes. GPS Input not used at this time. 6 RESPONSE Adjusts display response time (damping factor). SLOW: displayed value averaged over a 17-second period. MED: displayed value averaged over a 9-second period. FAST: displayed value averaged over a 3-second period.
7 SET CRS Used to enter a reference course or to enter and exit the calibration mode.
Figure 4-18.— MV103AC (1A2) Junction Box Controls.
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Key Nomenclature Function 1 POWER Controls power to the DFGMC. OFF: no power applied. ON: applies power to the DFGMC. 2 DIMMER Controls (1A1) Main Display lighting. 3 F1 3/10A Fuse under screw-off cap; protects the DFGMC from short circuits and overloads. 4 OFFSET Used to enter (1A3) Sensor / Processor alignment correction fact 5 RESPONSE Adjusts display response time (damping factor). SLOW: displayed value averaged over a 9-second period. NORMAL: displayed value averaged over a 3-second period. 6 CAL Used to select the type of calibration for the DFGMC. ON: Calibration is on. The display cycles “CAL” “CAL score” “heading”.
AUTO: Calibration is monitored and adjusted by the DFGMC as required. The (1A2) Junction Box will beep 4 times indicating a new calibration has been accepted by the DFGMC.
Figure 4-19.— MV103ACS and MV103DG (1A2) Junction Box Controls.
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4.8.5 Operating Procedures Compass Heading Mode - MV103AC When the DFGMC is powered up, the present declination value is displayed for two seconds, and then automatically enters the Compass Heading mode. The LCD area shows the present compass heading relative to magnetic North; no other symbols are activated. Figure 4-20 shows the LCD display at initial power-up in Compass Heading mode. The factory default declination value is 00o and the present heading is 270o.
Figure 4-20.— Compass Heading MV103AC.
Adjusting Display Response Damping - MV103AC The RESPONSE toggle switch (Fig. 4-18) selects any of three fixed values of display damping. The function of display damping is to average a number of headings over time to present a stable display to the operator. This function has no effect on the response time of the (1A3) Sensor / Processor electronics. When a damping time is selected, the LCD shows “d-1” (FAST position), “d-2” (MED position), or “d-3” (SLOW position) for two seconds. Selection of the response damping value is largely a matter of operator preference and the vessel’s operating condition. For example, when operating in rough seas or at high speeds where heading is apt to change rapidly, the operator may select SLOW which causes the display data to be averaged over a 17- second period. The heading continues to update at one-second intervals, but the display is the average of the most recent 17 seconds. Conversely, when operating in calm seas or slow speeds where heading changes slowly, the operator may select FAST, which causes the display data to be averaged over a 3- second period. MED averages the heading data at a 9- second interval. Response damping time may be selected at any time in the Compass Heading or Set Course operating modes. RESPONSE has no effect in the GPS mode.
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Compass Heading Mode - MV103ACS and MV103DG When the DFGMC is powered up, the system automatically enters the Compass Heading mode. The LCD area shows the present compass heading relative to magnetic North. No other symbols are activated. Figure 4-21 shows the LCD display in Compass Heading mode. The illustrated heading is 270o.
Figure 4-21.— Compass Heading MV103ACS and MV103DG.
Adjusting Display Response Damping - MV103ACS and MV103DG The RESPONSE toggle switch selects any of two fixed values of display damping. The function of display damping is to average a number of headings over time to present a stable display to the operator. This function has no effect on the response time of the (1A3) Sensor / Processor electronics. Selection of the response damping value is largely a matter of operator preference and the vessel’s operating condition. For example, when operating in rough seas or at high speeds, where heading is apt to change rapidly, the operator may select SLOW, which causes the display data to be averaged over a 9- second period. The heading continues to update at one-second intervals, but the display is the average of the most recent 9 seconds. Conversely, when operating in calm seas or slow speeds, where heading changes slowly, the operator may select NORMAL, which causes the display data to be averaged over a 3- second period. Response damping time may be selected at any time in the Compass Heading mode.
Calibration All magnetic heading sensors operate on the principle that a magnetized needle or card aligns itself with the Earth’s magnetic flux field. These devices are also influenced by nearby distortions or disturbances caused by magnetized or magnetizable materials or electrically generated flux fields. The DFGMC has the ability to compensate itself for these disturbances by executing on-demand or continuous self-compensation routines. “Auto-compensation”, or calibration, refers to a process in which the DFGMC assesses the local magnetic environment and applies correction factors through embedded software routines. 4-24 UNCLASSIFIED
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The DFGMC is calibrated at the factory during assembly. However, every vessel has its own magnetic characteristics, which require that the DFGMC be compensated after installation. In addition, auto-compensation should be done whenever the Processor Unit is replaced, if it is moved to a new location on the vessel, or whenever the vessel goes to an area where the magnetic environment differs. The MV103DG system also has the capability of maintaining correct compensation regardless of the status of the ships Degaussing System.
4.9.0 GYROCOMPASS SYSTEMS There are a wide variety of gyrocompass installed on Navy ships in the fleet systems today. Gyrocompasses are identified by the mark (Mk)–modification (Mod) system. The Mk number designates a major development of a compass. The Mod number indicates a change to the major development. The most common type of gyrocompasses found in the fleet today are the electrical gyrocompass systems, such as the Sperry Mk 23 and the Sperry Mk 27.
There are also other gyrocompass systems currently being installed on Navy ships today. These are the Stabilized Gyrocompass Set AN/WSN-2, Inertial Navigation Set AN/WSN-5, Ring Laser Gyrocompass (RLG) Inertial Navigation System AN/WSN-7B, and AN/WSN-7 RLG. Operation of the AN/WSN-5 is classified; therefore, only the AN/WSN-2, WSN-7 and 7B will be discussed in this training manual.
4.9.1 SPERRY MK 23 GYROCOMPASS SYSTEMS The Sperry Mk 23 gyrocompass is a small electrical compass that is used aboard many naval vessels to furnish heading data. On many of the small combatant vessels and larger auxiliary vessels, it is used as the master compass. On some of the larger combatant vessels, it is used as a backup compass. The compass is capable of indicating true north accurately in latitudes up to 75°N or S. The compass also can be used as a directional gyro when nearer the poles.
Unlike the mechanical gyrocompass, which uses weights that are affected by gravity to cause the desired period of damping, the Sperry Mk 23 gyrocompass uses a special type of electrolytic bubble level (gravity reference), which generates a signal proportional to the tilt of the gyro axle. This signal is then amplified and applied to an electromagnet which applies torque about the vertical and/or horizontal axes to give the compass the desired period and damping. The gyrocompass is compensated for speed error, latitude error, unbalance, and supply voltage fluctuations. An electronic follow-up system furnishes accurate transmission of heading data to remote indicators.
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The original Sperry Mk 23 gyrocompass (Mod O) has had several minor modifications and one major modification (Mod C-3). Only the Mk 23 Mod O and the Mk 23 Mod C-3 will be discussed in this training manual.
4.9.2 MK 23 MOD 0 GYROCOMPASS SYSTEM The Mk 23 Mod 0 gyrocompass system (fig. 4-22) consists of the master unit, control cabinet, speed unit, alarm control unit, a compass failure annunciator, and an alarm belt.
Figure 4-22.—Mk 23 Mod 0 gyrocompass equipment.
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Master Unit The master unit consists of a shock-mounted, oil-filled binnacle and the gyrocompass element. The master unit is designed for deck mounting and weighs approximately 100 pounds. The compass element is the principle unit of the compass system and is gimballed in the binnacle to allow ±45° of freedom about the pitch and roll axes. Drain plugs are located in the lower bowl for draining the oil.
Control Cabinet The control cabinet contains all the equipment required for operating and indicating the condition of the master compass except the visual alarm indicator and the alarm bell. The control cabinet houses the control panel, control amplifier, follow-up amplifier, and power supply.
Speed Unit The speed unit contains the necessary components to produce an electrical signal proportional to ship’s speed. Speed information is received from the ship’s underwater log equipment or is set in manually by the ship’s dummy log system. The speed range of the unit is 0 to 40 knots.
Alarm Control Unit The alarm control unit contains the necessary relays and components to actuate the lamp on the visual alarm indicator or the bell alarm when certain portions of the system become inoperative.
Compass Failure Annunciator The compass failure annunciator is a visual alarm indicator. It provides a visual indication of problems within the gyrocompass system. Under normal conditions, the lamp on the indicator is lighted continuously. When a failure occurs within the system, the lamp flashes or goes out. A test push button is provided on the annunciator. In some installations a type B-51 or B-52 alarm panel is used in place of the annunciator.
Alarm Bell The alarm bell is used with the annunciator to provide an audible indication of problems within the gyrocompass system. 4-27 UNCLASSIFIED
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4.9.3 OPERATING THE MK 23 MOD 0 GYROCOMPASS Instructions for starting and stopping (securing) the compass under normal conditions are on an instruction plate (fig. 4-23). This plate is located on the front of the control cabinet. There are two modes of operation, normal and directional gyro (DG). The normal mode of operation is used for latitudes up to 75°. The DG mode of operation is used for latitudes above 75°. Normally, the compass should be started at least 2 hours before it is needed for service. For additional information on starting the compass, refer to the manufacturer’s technical manual.
Figure 4-16.—0perating procedures for the Sperry Mk 23 Mod 0 gyrocompass.
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If it becomes necessary to stop the compass in a heavy sea for any reason other than failure of the follow-up system, the following procedure should be used:
1. Place the power switch in the AMPL’S position.
2. 7 Wait 30 minutes, and then place the operation switch in the CAGE position.
3. Place the power switch in the OFF position.
In case of follow-up system failure, place the operation switch in the CAGE position immediately and the power switch in the OFF position.
If power to the compass fails, place the power switch in the FIL’S position and the operation switch in the CAGE position. When the power is restored, restart the compass in the usual manner.
Setting Correction Devices Correction device settings for the Mk 23 gyrocompass include the manual speed setting on the speed unit, the latitude control knob setting on the control panel, and the latitude switch setting on the rear of the control panel.
When you operate the speed unit manually, adjust the speed settings to correspond to the average ship’s speed. Change the latitude control knob setting on the control panel when the ship’s latitude changes as much as 2°, or as ordered by the ship’s navigator. Throw the latitude switch on the rear of the control panel to the 65° position for normal operation when the ship’s latitude is above 60°. The position of the latitude switch is immaterial for directional gyro operation.
Indications of Normal Operation Normal operating conditions for the compass are indicated by the following:
1. The follow-up failure and corrector failure lamps on the control panel should be dark.
2. The master unit should be lukewarm.
3. The speed dial should indicate the ship’s speed for normal operation or zero for directional gyro operation.
4. The tilt indicator pointer should be oscillating evenly about the zero position.
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Watch Standing When you are assigned the gyrocompass watch, you will be required to maintain the gyrocompass log and to respond to any alarms associated with the gyrocompass system. The gyrocompass log contains hourly readings showing the conditions of the gyrocompass and the power sources available. During an alarm condition, the compass is no longer considered reliable.
4.9.4 MK 23 MOD C-3 GYROCOMPASS SYSTEM The Mk 23 Mod C-3 gyrocompass system is identical to the Mk 23 Mod 0 system with the exception that the Mk 23 Mod C-3 system uses solid-state devices in place of vacuum tubes in the control cabinet. In addition, two more units are used in the C-3 system. These two additional units arc the power supply unit and the power supply control unit.
The power supply unit and the power supply control unit, together with a 120-volt dc battery, are used to form a standby power supply for the compass. This standby power supply provides uninterrupted 120-volt, 400-Hz, 3-phase power to the compass for a limited period of time if the normal ship’s supply fails. If the normal ship’s supply fails, a red light located on the power supply control unit will come on. When the compass is being supplied power from the standby power supply, power will be cut off to some of the remote repeaters.
The starting and stopping procedures for the compass are basically the same as for the Mk 23. Instructions for starting and stopping the compass under normal conditions are given on the instruction plate (fig. 4-24) located on the front of the control panel. Make sure the ON-OFF switch located in the power supply control unit is in the ON position before starting the compass. For additional information on starting and stopping the compass, refer to the manufacturer’s technical manual.
Figure 4-24.—Mk 23 Mod C-3 control cabinet.
Watch-standing procedures are basically the same as for the Mk 23 Mod 0 gyrocompass system. 4-30 UNCLASSIFIED
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4.9.5 SPERRY MK 27 GYROCOMPASS SYSTEM The Sperry Mk 27 gyrocompass is a rugged, low-voltage electrical compass used as the master compass on small craft and as the auxiliary compass on larger ships. The Mk 27 gyrocompass is designed to operate on 24-volt dc or 115-volt, 60- or 400-Hz, single- phase power.
Figure 4-25.— Mark 27 Master Unit.
The Mark 27 Mod 0 Gyrocompass Equipment, shown in figure 4-26 and described in this manual, is small, compact, has a low power demand, and is capable of furnishing an accurate heading indication under the severe operating conditions encountered in small boats, amphibious vehicles and craft, submarines, and larger combatant vessels. The compass can be read directly or heading data can be transmitted to remote systems and indicators.
4.9.5.1 Design Features The Mark 27 Gyrocompass contains a gyroscope controlled in a manner to make it seek and continuously align itself with the meridian and thereby point to true north. The properties of the gyroscope in combination with the rotation of the earth and the effect of gravity produce this result. The Mark 27 Gyrocompass differs from previous gyrocompasses in that a gimbal system is used which reduces the complexity of the equipment.
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Figure 4-26.— Mark 27 Mod 0 Gyrocompass Equipment.
The gyrosphere containing the gyroscope rotor is immersed in silicone fluid, and is designed and adjusted to have neutral buoyancy. The weight of the gyrosphere in the fluid is canceled by the buoyant force of the displaced fluid. This feature is a distinct advantage in that (1) the weight of the gyrosphere is removed from the sensitive-axis bearings, (2) the gyrosphere and bearings are protected from excessive shock loads, (3) sensitivity to shifts of the center of mass of the gyrosphere relative to the sensitive axis are eliminated providing improved accuracy, and (4) the effects of accelerations are minimized because the center of mass of the gyrosphere and the center of buoyancy are made coincident. 4-32 UNCLASSIFIED
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The compass is compensated for the effects of varying latitude. In addition, a servo follow-up system is provided in the azimuth axis to keep the phantom yoke support aligned with the gyrosphere as the vessel turns; it also drives the compass card and any data transmission system that may be included. Provision is made so that the gyrocompass may be equipped with a step transmitter, a I-speed synchro transmitter, a 36-speed synchro transmitter, or any combination of these units. Either 60 or 400 cps heading data synchros can be supplied. The compass card is visible for direct reading, and has the normal sense of relative rotation for direct steering purposes. A built-in alarm is utilized to give a direct indication of failure in power supply or follow-up amplifier. Because of the low viscosity of the suspension and ballistic fluids, no heaters are required in the Mark 27 Gyrocompass.
4.9.5.2 General Description The Mark 27 Gyrocompass consists of three major assemblies: Master Unit, Electronic Control Assembly and Power Converter.
Master Unit The Master Unit consists of a shock-mounted, fluid-filled binnacle which houses the sensitive element. The unit is sealed and designed for deck mounting. To prevent damage when not in use, the sensitive element can be caged by depressing a button on the top of the unit. The viewing window for the compass card is oriented on the after side of the compass. The dial has dark-adapted illumination and its brightness is adjustable at the Electronic Control Assembly. This will be discussed in further detail later in the chapter.
Electronic Control Assembly The Electronic Control Assembly is a watertight, deck-mounted unit which houses the control panel, power supply, servo amplifier, latitude compensation circuit, and alarm circuit. The servo amplifier printed circuit board and the power supply section (except for the power amplifier transistors) are easily removable for maintenance. The power amplifier transistors are attached to the cabinet frame for adequate heat dissipation. The Master Unit and Electronic Control Assembly will operate directly from an external 24- volt d-c power source or from the Power Converter described below. The Electronic Control Assembly may be mounted directly under the Master Unit or remotely, although the assembly should not be separated from the Master Unit by more than an arm’s length to permit ease of operation during starting or adjustment of dial illumination. This will be discussed in further detail later in the chapter.
Power Converter The Power Converter is used for applications where the gyrocompass equipment must operate from a single phase 115-volt, a-c, 60 or 400 cps power source. The converter is housed in a watertight enclosure and its purpose is to convert a-c input power to 24-volt d-c for operation of the compass equipment. This will be discussed in further detail later in the chapter. 4-33 UNCLASSIFIED
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4.9.5.3 Operation These instructions will enable operating personnel to start and settle the compass in azimuth in a minimum of time under all sea conditions. Although operation of the Mark 27 Gyrocompass does not require continuous attention to the controls and adjustments, operating personnel should have a full knowledge of the meaning and purpose of the various indicating lamps, meters, switches, and alarms.
STARTING THE COMPASS Where practical, starting procedures should begin at least 2 hours before the gyrocompass is required for service.
• NORMAL SEA STARTING For use where roll and pitch are less than 10 degrees and compass has been stopped for at least 1 hour.
(1) Insure that the RPTR switch and the MODE SELECTOR switch are in the OFF position.
(2) Place MODE SELECTOR to SLEW
(3) CAGED lamp should be lighted. If lamp is off, push the cager button on the top of the binnacle to cage gyro and wait 5 minutes to allow ballistic fluid to stabilize.
NOTE: Compass will slew rapidly if gyro is uncaged.
(4) Use the TILT/AZIMUTH switch to slew the compass as close as possible to ship's heading. Pushing the switch in the + direction will make the compass card rotate counterclockwise; pushing in the - direction will make the card rotate clockwise. (Wait 5 to 10 seconds between reversals of the switch to allow the follow-up servo amplifier to stabilize.)
(5) Turn MODE SELECTOR to START. Wait 10 minutes for gyro to come up to speed. Then firmly push cager button on top of the binnacle to encage the gyro. CAGED lamp must go out or gyro has not been uncaged.
(6) Switch MODE SELECTOR to MANUAL LEVEL immediately after uncaging.
(7) Operate the TILT/AZIMUTH switch to bring the gyro to a level position as indicated by the LEVEL meter. Push the switch in the direction of desired pointer movement and hold it until the meter pointer has reached its center position. If it overshoots, reverse direction as needed until the pointer has been centered.
(8) Place MODE SELECTOR to RUN. 4-34 UNCLASSIFIED
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(9) Set N -S switch for north or south latitude.
(10) Set LATITUDE corrector control to ship's latitude.
(11) To operate repeater, place RPTR switch to ON.
NOTE: When step repeaters are used they should be synchronized to the compass card reading prior to turning RPTR switch ON.
(12) Adjust DIMMER control for satisfactory dial brightness.
• HEAVY SEA STARTING During the starting period when the gyro is caged, the eager mechanism will apply torques to the gyro if any rolling or pitching is taking place. When these motions are 10 degrees or more, they will cause the gyro to move away from the desired heading. This can increase the time required to settle the compass. The following procedure uncages the gyro before this movement in azimuth takes place and enables operating personnel to get the compass settled in a minimum of time.
(1) Insure that the RPTR switch and the MODE SELECTOR switch are in the OFF position.
(2) Place MODE SELECTOR to SLEW.
(3) CAGED lamp should be lighted. If lamp is off, push the eager button on top of the binnacle and wait 5 minutes for the ballistic fluid to stabilize.
NOTE: Compass will slew rapidly if it is uncaged.
(4) Use the TILT/AZIMUTH switch to slew the compass as close as possible to ship's heading. Pushing the switch in the + direction will make the card rotate counterclockwise; pushing the switch in the - direction will make the card rotate clockwise. (Wait 5 to 10 seconds between reversals of the switch to allow the follow-up servo amplifier to stabilize.)
(5) Place MODE SELECTOR to START
(6) Wait from 30 to 35 seconds only and then uncage the gyro by depressing the eager button. CAGED lamp must go out.
NOTE: The compass will move away from heading rapidly if a longer period is allowed between starting and uncaging. The compass should be uncaged if possible when the ship is at the center of its roll and pitch motions so the gyro will be released near a level position. 4-35 UNCLASSIFIED
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(7) Note the average position of the swings of the pointer of the LEVEL meter. If they average around zero, proceed to step 10. If they do not, operate the TILT/AZIMUTH switch to reverse the polarity of the average position and to make it about one-half of what is was. Push the switch in the direction of desired pointer movement.
(8) Watch the compass card for about 1 minute to determine in which direction it is moving with respect to the desired heading.
(9) If the card is moving toward heading, allow it to continue until it is within 2 degrees of the desired heading and then operate the TILT/AZIMUTH switch to level the gyro and make the average position of the LEVEL meter pointer zero.
(10) If the card is moving away from heading, reverse the polarity of the average pointer position by operating the TILT/AZIMUTH switch. Wait until the direction of the card movement changes and when it is within 2 degrees of the desired heading, operate the TILT/AZIMUTH switch to level the gyro and make the average position of the LEVEL meter pointer zero.
(11) Place MODE SELECTOR to RUN.
(12) Set N-S switch for north or south latitude.
(13) Set LATITUDE corrector control to ship's latitude.
(14) Wait 10 minutes from the time the compass was uncaged before placing RPTR switch to ON.
NOTE: When step repeaters are used they should be synchronized to the compass card reading prior to turning RPTR switch ON.
(15) Adjust DIMMER control for desired dial brightness.
• ROUTINE OPERATION Because operation of the compass is almost completely automatic, the only routine operating procedures that need to be performed are the following checks for each watch:
(1) Check setting of LATITUDE corrector control and reset to local latitude, if required.
(2) Check setting of N-S switch and reset to proper hemisphere, if required.
(3) Make normal azimuth checks on compass to determine accuracy of heading indication.
(4) Record LEVEL meter reading when compass is settled for reference. 4-36 UNCLASSIFIED
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• STOPPING THE COMPASS To stop the compass:
(1) Place RPTR switch to OFF.
(2) Place MODE SELECTOR to SLEW.
NOTE: When seas are rough, turn MODE SELECTOR to OFF. Wait 30 minutes and then cage the gyro.
(3) Push cager button on top of binnacle to cage the gyro. CAGED lamp should light.
(4) Place MODE SELECTOR to OFF.
• OTHER PROCEDURES The procedure to be used if the compass is dumped or must be started with the wheel running is as follows:
(1) If the compass should become dumped after the wheel has come up to speed, as indicated by a full scale LEVEL meter reading and a rapidly slewing compass, place the MODE SELECTOR in AUTO LEVEL. This will stop the slew and level the gyro, but will leave the compass at some heading other than the desired heading. To restore the compass to heading, perform steps (1) through (8).
(1) Place MODE SELECTOR to MANUAL LEVEL.
(2) Push cager button on top of binnacle to cage the gyro. CAGED lamp should light.
(3) Push the TILT/AZIMUTH switch in the same direction as that in which the card should rotate to return to the desired heading. Release the switch when the LEVEL meter indicates its maximum.
(4) Compass card will slowly rotate toward desired heading.
(5) Allow compass to rotate past desired heading by 2 or 3 degrees and immediately uncage the gyro by depressing the cager button on the binnacle. C AGED lamp should go out.
(6) Move MODE SELECTOR to AUTO LEVEL. This will approximately level the gyro.
(7) Move MODE SELECTOR to MANUAL LEVEL and operate TILT/AZIMUTH switch to center the pointer of the LEVEL meter.
(8) Place MODE SELECTOR to RUN. 4-37 UNCLASSIFIED
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• LATITUDE CORRECTION The tilt of the ballistic causes horizontal torques which precess the gyro in azimuth. Horizontal earth rate affects a gyro when located anywhere except at the poles. Horizontal earth rate likewise causes the gyro to tilt. The torque developed by the tilted ballistic will be just enough to keep the gyro precessing at a rate equal and opposite to the vertical component of earth rate. The higher the latitude, the greater must be the tilt of the spin axis to keep up with the higher vertical earth rate.
As a result of this tilt, the damping weight produces a vertical torque which causes the north end of the gyro axle to settle eastward from the true meridian in north latitudes, westward in south latitudes. This displacement from the true meridian, increasing with latitude, is called latitude error. In the Mark 27 Gyrocompass, latitude error is corrected by applying an opposing vertical torque to the gyrosphere of a magnitude to just cancel out the steady torque produced by the damping weight. The gyro settles with a tilt, but with no latitude error.
The E-core pickoff is used to produce this torque. A d-c current is introduced in one output winding of the E-core pickoff on the vertical ring. The magnetic field produced attracts the armature on the gyrosphere and a counteracting vertical torque is created.
Because the latitude error reverses sign between north and south latitudes, the d-c current is introduced in one output winding of the pickoff for north latitudes and in the other output winding for south latitudes. This reverses the direction of the corrective torque. The switching function is manually performed as an equipment control function. Magnitude of the torque is varied to agree with the latitude of operation.
4.9.5.4 Gyrocompass Equipment Detailed Description
Master Unit The Master Unit, shown in figure 4-27 contains the compass element. The two basic parts of the Master Unit are the binnacle and the base. The binnacle is shock-mounted in the base and the shock mounts are positioned to act through the center of gravity of the binnacle. The base is a casting which is fixed to the deck by four bolts with plus or minus 5 degrees of freedom in azimuth to permit accurate alignment with the ship.
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Figure 4-27.— Mark 27 Master Unit.
Binnacle The binnacle contains the compass element and is completely filled with flotation fluid. In addition to the sensitive element, it contains a bellows located inside the bottom cover, which accommodates the contraction and expansion of the fluid with temperature changes. Also on the binnacle are the card viewing window, the cager diaphragm, the binnacle electrical connector, and the evacuating and filling nozzles.
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Compass Element The heart of the compass is the compass element and it is shown in figure 4-28 as removed from the binnacle. It consists of the support plate, follow-up system components, compass card, phantom fork, vertical ring and gyrosphere.
Figure 4-28.— Compass Element.
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Gyrosphere - The gyrosphere, shown in figure 4-29, is the north seeking part of the gyrocompass. It derives its name from the fact that the gyro wheel is mounted within a spherical enclosure. The sphere is 6.5 inches in diameter; at running temperature, the specific gravity of the sphere is the same as that of the fluid in which it is immersed. Because the sphere is in neutral buoyancy, it exerts no load on the vertical bearings which, therefore, serve only as guides for the sphere. Flotation of the gyro in this manner not only reduces pivot friction, but serves to protect the gyro pivots from destructive shocks. The sphere has been evacuated and partially filled with helium gas. This gas serves to transfer the heat generated by the gyro motor windings to the surface of the sphere.
Figure 4-29.— Gyrosphere.
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Gyro Motor - Gyro motor B1101 is of symmetrical design to minimize weight shifts. It consists of an outer cylindrical aluminum flywheel into which is pressed the aluminum bar squirrel cage of the induction motor. This assembly is then secured to the two aluminum endbells, and the entire unit rotates on the outer bearing races fitted into the gyro endbells. This aluminum rotor is designed for maximum angular momentum, consistent with the flotation requirements. The ball bearings and inner races of this separable bearing are fitted on a fixed aluminum shaft which also carries the stator winding of the gyro motor. The stator winding is placed at the center, and the leads are brought out through a hole bored in one end of the shaft.
The preload is maintained by two threaded clamps, one on each end of the gyro rotor. In addition, the clamp presses a wick (held in a retainer ring) against the inner race of each bearing. The wick feeds oil to the bearings from a felt reservoir in the lower part of the gyrosphere. The outer race rotation results in a flow of oil from the inner race to the outer race where the excess oil is centrifugally thrown off. The excess oil collects on the inner surface of the sphere and runs down the inside of the sphere to the oil reservoir. By this means the required oil lubrication is achieved.
The gyro is a complete subassembly and is statically balanced as a unit. The stator winding on the shaft and squirrel cage on the gyro wheel constitute a 4-pole, 3-phase induction motor. The speed is about 11,800 rpm counterclockwise from the south end, and the motor uses 7 watts of electrical power.
Gyro Shaft Pillow Blocks - The gyro shaft is secured to the frame by two pillow blocks, as shown in figure 4-30. A pin, driven through a hole in one of the pillow blocks into a keyway in the end of the stator shaft, prevents rotation of the shaft. The pin does not go all the way through the shaft. After the gyro and pillow blocks are assembled in the frame, nuts are screwed on the threaded gyro shaft to position the shaft. These nuts hold the shaft stationary along the pillow block axis of the frame and provide a means of positioning the entire gyro and shaft to establish mechanical balance of the frame and motor assembly. The pillow blocks and holding screws are individually fitted to the frame and are not interchangeable.
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Figure 4-30.— Support Plate Assembly.
Electronic Control Assembly The electronic control assembly shown in figure 4-31, houses the operating controls, follow-up servo amplifier, alarm circuitry, power supply, latitude control circuitry, and gyrocompass control functions. It can be mounted directly under the gyrocompass to form a compact arrangement or conveniently nearby for easy access to both units. All internal components are easily accessible by removal of the chassis and panel combination through the front.
A plug-in connector on the rear cabinet frame connects external cables to the chassis and permits removal of the chassis from the cabinet. Cables to the Electronic Control Assembly are routed through three stuffing tubes on the rear of the cabinet.
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Figure 4-31.— Control Cabinet.
Servo Amplifier - The servo amplifier is an integral part of the follow-up system used for the Mark 27 Gyrocompass. The amplifier has the necessary voltage and the power amplification of the follow-up pickoff signal to drive the azimuth n1otor and n1aintain alignn1ent of the phanton1 yoke with the sensitive element. It also provides stabilization and quick response to the overall follow-up system. It uses other sources of signals to aid in leveling the gyrocompass or to slew it in azimuth during starting.
The servo amplifier is located in the electronic control assembly where necessary interconnections are made between the amplifier, signal source, and power supply. With the exception of the power output transistors, the amplifier components are mounted on a plug-in, subassembly board on the right side of the electronic control assembly as shown in figure 4-32 and easy access to all circuit points is possible by removal of the chassis from the front of the cabinet. The power output transistors are physically mounted on the rear of the cabinet frame which affords heat dissipation.
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Figure 4-32.— Electronic Control Chassis.
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The amplifier is the heart of the gyrocompass follow-up system. From the block diagram of figure 4-33 it can be seen that the amplifier consists of three basic circuits: a single- needed input stage, a driver stage, and a power output stage. Additional stages of demodulation and modulation are used to accomplish feedback.
Figure 4-33.— Servo Amplifier, Block Diagram.
The input stage provides amplification of the pickoff signal to control the push-pull driver stage. A driver is utilized for each half of the signal to provide sufficient voltage and power amplification for operation of the push-pull power amplifier stage. Stabilization of the follow-up system is derived from the feedback of a portion of the output signal. To provide rapid response, free from oscillation, this feedback voltage is demodulated and developed into a rate signal. The rate signal is then modulated and mixed with the pickoff signal to give the amplifier the required dynamic characteristics.
Power Supply - The power supply converts the normal 24-volt d-c shipboard power to voltages which meet the power requirements of the Mark 27 Gyrocompass. Where the shipboard power source is a-c power, the Mark 27 Power Converter is used to produce the 24 volts d-c for the input to the power supply.
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The power supply chassis is mounted on the left of the electronic control chassis in the Electronic Control Assembly cabinet as shown in figure 4-32 and is accessible without removing the chassis from the control cabinet. The power output and regulator transistors and zener diodes are mounted separately on the frame member at the rear of the cabinet and the cabinet is used as a heat sink. The chassis contains two circuit boards, three transformers, and other directly-mounted components. A terminal board on top provides connection points for the cable coupling the power supply to the transistors located on the rear frame member. A connector is provided to permit easy removal or replacement of the power supply.
4.9.6 AN/WSN-2 STABALIZED GYROCOMPASS SET The AN/WSN-2 stabilized gyrocompass set provides precision analog dual-speed roll, pitch, and heading signals to the ship’s navigation and fire control systems. The set uses an accelerometer controlled, three-axis, gyro-stabilized platform to produce vital heading synchro data and reference, nonvital heading synchro data, and both roll and pitch angle synchro data.
4.9.6.1 Equipment Description The AN/WSN-2 stabilized gyrocompass set (fig. 4-34) consists of an electrical equipment cabinet and five major assemblies. The five major assemblies are contained within the cabinet. These assemblies are the control indicator, control power supply, battery set, synchro signal amplifier, and inertial measuring unit (IMU).
Figure 4-34.—Stabilized gyrocompass set, AN/WSN-2. 4-47 UNCLASSIFIED
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4.9.6.2 Electrical Equipment Cabinet The electrical equipment cabinet (fig. 4-34) provides the mechanical and electrical interface for the five major assemblies. The cabinet also provides forced air cooling for the IMU.
The cabinet contains a wiring harness, alarm relays, power relays, electromagnetic interference (EMI) filters, an elapsed time meter, capacitor assemblies, and a blower for IMU cooling, and the IMU rack. A connector panel located on the rear of the cabinet provides the electrical cable interconnections for cabling to external equipment, including primary power.
Control Indicator The control indicator (fig. 4-35) is a hinged assembly located in the top of the electrical equipment cabinet. It is secured to the cabinet with quick-release fasteners. The control indicator contains all the operator controls and indicators for the gyrocompass set. The control indicator also contains built-in test equipment (BITE) for the major assemblies and subassemblies. BITE circuits identify equipment faults and provide visual indications of the faulty assembly or subassembly.
Figure 4-35.—Controls and indicators.
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1. BATTERY, STAT indicator 15. REF SP, OFF indicator 2. FAULTY, CTR indicator 16. MODE, NAV indicator 3. BATTERY, OPR indicator 17. MODE switch 4. FAULT, PS indicator 18. MODE, ALIGN switch 5. HDG FAIL indicator 19. PANEL potentiometer 6. FAULT, BFR indicator 20. ENTER LAT switch-indicator 7. ALARM indicator 21. DISPLAY potentiometer 8. FAULT, IMU indicator 22. Latitude thumbwheel switch 9. FAULT, AIR indicator 23. PWR circuit breaker 10. Display 24. SYN REF circuit breaker 11. DSPL Test push-button switch 25. FAULT, RESET push-button switch 12. DSPL SEL switch 26. FAULT, SET push-button switch 13. REF SP, OVRD LOG indicator 27. FAULT, DI indicator 14. REF SP switch Figure 4-35 (Cont’d).—Controls and indicators.
CONTROL POWER SUPPLY The control power supply (fig. 4-36) contains the control, computing, processing, analog/digital conversion, input/output interface, and power supply electronics for the gyrocompass set. The control power supply also contains capacitor assemblies, cooling blowers, BITE, and the battery charging electronics for charging the battery set.
Figure 4-36.—Control power supply. 4-49 UNCLASSIFIED
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BATTERY SET The battery set is installed in the electrical equipment cabinet (fig. 4-34). It is secured in the cabinet by quick-release fasteners. The battery set consists of a battery, isolation diodes, fuses, and sensing circuits. The battery consists of 60 sealed lead-acid storage cells. They are connected in series-parallel, five parallel branches, consisting of 12 cells per branch, to provide a nominal 24-volt output for approximately 30 minutes during normal power failure. The battery set weighs 70 lbs and requires careful handling by two persons when moved. The battery is under a continuous charge, provided by electronics in the control power supply. The fuses provide overload protection in the battery charger input circuit and the battery output. The sensing circuits consist of a high-voltage sensing circuit, a low-voltage sensing circuit, and a temperature sensing circuit. The output of these sensing circuits go to BITE circuits in the control power supply and are routed to BITE indicators on the control indicator.
SYNCHRO SIGNAL AMPLIFIER The synchro signal amplifier (fig. 4-37) is installed in the electrical equipment cabinet. It is held in the cabinet by quick-release fasteners. The synchro signal amplifier contains four synchro buffer amplifiers, an inverter power supply, cooling blower, and BITE.
The synchro buffer amplifiers provide the voltage and power levels for the gyrocompass heading, pitch, and roll synchro output signals. The inverter power supply converts the battery output to 115-volt, 400-Hz power and converts this to the proper dc levels for the synchro signal amplifier. The inverter power supply also produces ac power for the equipment cooling fans and a vital heading reference output for the gyrocompass set when normal single-phase, 400-Hz power is lost. The inverter power supply also contains BITE summary logic for the synchro signal amplifier.
Figure 4-37.—Synchro signal amplifier, exploded view.
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INERTIAL MEASURING UNIT The IMU (fig. 4-38) is installed in a special precision IMU alignment rack located in the bottom of the electrical equipment cabinet, behind an access cover. Access to the IMU is gained by removing the access cover. The IMU contains the gimbal assembly, the electronics necessary to maintain the gimbal assembly, and associated electronics necessary to interface with the control, computing, and processing functions of the control power supply. The IMU also contains BITE circuitry and indicators and houses temperature controlling electronics.
Figure 4-38.—Inertial measuring unit exploded view.
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4.9.6.3 FUNCTIONAL DESCRIPTION The primary function of the stabilized gyrocompass set is to produce precision analog dual-speed roll, pitch, and heading signals for use by the ship’s equipment. The outputs are available in all modes during normal operation and battery backup. When operating on inverter produced single-phase power, only vital heading and its synchro reference are available. For the stabilized gyrocompass to operate, it requires certain electrical inputs from the ship. These inputs are 115-volt ac, 400-Hz, single-phase synchro excitation; 115-volt ac, 400-Hz, 3-phase primary power; underwater log data with reference voltage; and 24-volts dc provided internally by the battery set and used during the loss of 3-phase input power.
4.9.6.4 SIGNAL DEVELOPMENT The roll, pitch, and heading (in some publications referred to as azimuth) located in the IMU gimbal are excited by 26 volts, 4.8 kHz when the gimbal is caged, or by 26 volts, 400 Hz during normal operation. Both resolver excitation levels are provided by the servoamplifier. Each resolver has two outputs, which represent the sine and cosine of the angular displacement of its respective rotor shaft. These outputs are sent back to the servoamplifier when the gimbal is caged. When the gimbal is uncaged, during normal operation, the outputs are sent to the resolver preamplifier.
The roll and pitch sine and cosine signals from the resolver preamplifier are amplified, buffered, and converted to standard three-wire format by the synchro signal amplifier. The data leaves the synchro signal amplifier as S1, S2, and S3 synchro data.
The heading sine and cosine signals from the resolver preamplifier are converted to true heading sine and cosine signals in the 1X and 36X true heading converters before being sent to the synchro signal amplifier and the analog/digital (A/D) multiplexer. The true heading sine and cosine data, like the roll and pitch data, are amplified, buffered, and converted to standard three-wire synchro data in the synchro signal amplifier. True heading data is subsequently sent out as S1, S2, and S3 synchro data.
The roll, pitch, and heading sine and cosine signals from the resolver preamplifier and the true heading sine and cosine signals from the true heading converter are also sent to the A/D multiplexer. The A/D multiplexer sends these analog signals to the A/D converter, where each sine/cosine part is converted to the tangent of the respective angle, in digital format. The tangent values of the roll, pitch, and heading angles are sent to the processor for use in program computations and data updates.
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4.9.6.5 MODES OF OPERATION The stabilized gyrocompass set has three modes of operation: automatic calibration (AUTO CAL), navigate (NAV), and directional gyro (DG). At equipment turn-on, there is a leveling sequence that provides for equipment leveling and initial calibration.
Leveling Sequence The stable element leveling sequence is initiated upon application of power to the equipment. This is accomplished by moving the MODE switch out of the POWER OFF position. The major elements of the leveling sequence are stable element caging, digital course leveling, tine leveling, gyrocompassing, and calibration.
STABLE ELEMENT CAGING.— Upon energizing and for 10 seconds thereafter, gyro spin power is inhibited by the software program and the stable element is caged. At the end of the delay, the gyros are energized with high spin power. The software program allows 60 seconds for the gyros to gain speed and then perform the gyro synchronization test. If the synchronization test is passed, the program examines the output of the X accelerometer (fig. 4-39) for minimum output, which indicates the platform is level. The software program then checks for proper temperature of the IMU. When the synchronization test, level check and temperature check are successfully completed, the stable element is uncaged and placed under gyro control. Gyro spin power is then set to normal low spin value.
Figure 4-39.—Inertial measuring unit. 4-53 UNCLASSIFIED
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DIGITAL COARSE LEVELING.— Upon completion of the caging sequence, all integrators and biases and the alpha (OC) angle (the alpha angle is the angular difference between the stable element’s [north-south] axis and true north) are set to zero, and digital course leveling is initiated. Normally, digital coarse leveling requires 1 minute. This time, however, may be lengthened by loop settling delays. Completion of digital coarse leveling is determined by the velocity error signal. When the absolute values of the velocity error signal represent less than 1/2 ft/sec, and 60 seconds have elapsed, digital coarse leveling is complete, and fine leveling is started.
FINE LEVELING.— At the start of fine leveling, as in digital coarse leveling, all integrators, biases, and the alpha angle signal are set to zero. Again, completion of the sequence is determined by the velocity error signals. When the absolute values of these signals represent less than 1/4 ft/sec and 6 minutes have elapsed, fine leveling is completed.
LEVELING COMPLETION.— At the end of the leveling sequence, the software program calculates the alpha angle, establishes an initial value for latitude, and initializes the two direction cosines (pitch and roll angles). If a latitude entry was made at the start or during the leveling sequence, that value will be the initial latitude; otherwise, latitude is set to zero degrees.
GYROCOMPASSING AND CALIBRATION.— A four-step, timed procedure accomplishes the gyrocompassing and calibration sequence. This sequence takes approximately 4 hours and must be completed before the gyrocompass is capable of providing full accuracy outputs. The software program estimates latitude if none was entered by the operator. In either case, latitude information will be updated at the end of the gyrocompassing and calibration sequence. At the completion of the sequence, the MODE NAV indicator light will come on, and the MODE ALIGN indicator light will go out, indicating the gyrocompassing and calibration sequence is completed. Table 4-1 details this sequence.
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Step Name Mechanization Functions Calibration Functions Time East Gyrocompass Slew Y-axis to -90 degrees None 0-6 minutes Settling Step None 2 minutes Coarse Gyrocompass Minibias X-axis 37 minutes Fine Gyrocompass Minibias X- and Z-axis and estimate latitude if no entry 20 minutes Slew Y-axis to +90 degrees Accelerometer bias data 6 minutes Slew Settle Estimate Y- accelerometer bias and remove platform tilt 2 minutes
West Gyrocompass Coarse Gyrocompass Minibias X-axis 27 minutes Fine Gyrocompass Minibias X-axis, minibias Z-axis, update latitude and compute X- axis bias 20 minutes
South Compass Slew Y-axis to 180 degrees None 3 minutes Slew Settle None 2 minutes Coarse Gyrocompass Minibias Y-axis 27 minutes Fine Gyrocompass Minibias Y- and Z-axis 20 minutes
North Gyrocompass Slew Y-axis to 0 degrees Bias accelerometers 6 minutes Slew Settle Remove platform tilt 2 minutes Coarse Gyrocompass Minibias Y-axis 27 minutes Fine Gyrocompass Minibias Y-axis, minibias Z-axis, update latitude and compute Y- axis bias 15 minutes
Table 4-1.—Gyrocompassing and Calibration Sequence
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Auto Cal Mode The AUTO CAL mode is used at latitudes below 85° north or south. The AUTO CAL mode is used at initial start-up and should be implemented at least every 90 days during continuous operation to ensure accuracy of outputs. Automatic calibration requires 24 hours to complete but will continue as long as the mode switch is in this position.
Setting the MODE switch to AUTO CAL at anytime after completion of the leveling sequence places the equipment in the AUTO CAL mode. This mode starts an automatic recalibration sequence to determine new gyro biases, accelerometer biases, and latitude corrections. These new values are automatically averaged with old values to accomplish equipment recalibration.
All gyro functions and outputs are maintained in the AUTO CAL mode. The outputs from the IMU resolvers, representing pitch and roll angles, are applied directly to the synchro signal amplifier. The synchro signal amplifier amplifies the resolver input information and transmits dual-speed synchro information to the ship’s equipment. Roll and pitch angle information is also sent to the A/D multiplexer.
In the AUTO CAL mode, heading is continuously slewed, completing 360° every 24 hours. The IMU heading signals are sent to the true heading converters. Also applied to the true heading converters is the alpha angle. In AUTO CAL it is set to a value representing 15° per hour. These two signals are combined in the true heading converter to develop true heading information. The output of the true heading converter is sent to the synchro signal amplifier for amplification and distribution to the ship’s equipment and is sent to the A/D multiplexer for use by the processor.
The digital display indicator provides for local display of the quantities shown in table 4- 2. Data for display is selected by the DSPL SEL switch.
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DSPL Sel switch position Data displayed Range Resolution Remarks LAT Latitude 0 to 90 degrees 1 minute Sign of latitude is not displayed; degree and minute marks are displayed
EM LOG LOG velocity 0 to 99.9 knots 0.1 knot leftmost digit is not used
HDG True heading 0 to 359.9 degrees 0.1 degrees
PITCH Pitch 0 to +/- 99.9 degrees 0.1 degrees Positive (bow down) sign is blank
ROLL Roll 0 to +/- 99.9 degrees 0.1 degrees Positive (starboard up) sign is blank
TEST Test Pattern. The program shall display all 0000’s, 1111’s through all 9999’s. The pattern shall change approximately each second.
Table 4-2.—Data Dis play Parameters Nav Mode The NAV mode, the primary operating mode, is mechanized the same as the AUTO CAL mode. In the NAV mode, the heading is not slewed and the alpha angle is held at zero; thus, the equipment becomes a north-pointing gyrocompass.
The NAV mode is the normal mode of operation and is used between latitudes 85° north or south. If the NAV mode is initially selected as the mode of operation, the alignment sequence must be completed before the gyrocompass is capable of providing full accuracy outputs. This sequence takes approximately 4 hours. The alignment sequence is completed when the MODE ALIGN indicator goes off and the MODE NAV indicator comes on.
DG Mode The DG mode is used at latitudes above 85° north or south. When the gyrocompass is operating in the DG mode, the stable element is dampened by velocity signals and allowed to wander in azimuth. Earth rate correction is made by torquing the stable element in azimuth. The alpha angle is held constant and grid heading, rather than true heading, is sent to the ship’s equipment. Otherwise, the equipment’s function is the same as for the AUTO CAL mode.
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4.9.6.6 SUPPORTING FUNCTIONS The major functions of the stabilized gyrocompass are supported by several supporting or subordinate functions. The supporting functions are described in the following paragraphs.
Latitude Set The entry of latitude data maybe made during the leveling sequence (except during the north and south gyrocompassing phases) and at anytime the system is NAV ready. The gyrocompass is ready to receive a latitude entry when the ENTER LAT switch indicator (Fig. 4-35) is on. The software program commands the ENTER LAT switch indicator on when power is applied and when the position of the MODE switch is changed. If the ENTER LAT switch-indicator is not on, entry can be accomplished by pressing the ENTER LAT switch indicator ONCE. The gyro compass will then be able to receive a latitude entry for 1 minute.
With the DSPL SEL switch set to LAT and the ENTER LAT switch indicator on (fig. 4- 35), latitude entry is made by setting the desired latitude (hemisphere, degrees, and minutes) with the thumbwheel switch, then pressing and releasing the ENTER LAT switch indicator. The ENTER LAT switch indicator will go off and the selected latitude will be displayed on the digital display.
Data Display Several pieces of data are available for display on the control indicator panel. The data available for display is latitude, electromagnetic (EM) log, ship’s heading, pitch, roll, and test (table 4-2). The desired data is displayed by setting the DSPL SEL switch to the appropriate position. Also, under software control, but not selectable, are the MODE, ALIGN indicator, and the MODE, NAV indicator. When the alignment sequence is complete, the software program turns the MODE, NAV indicator on, and the MODE, ALIGN indicator off.
Reference Speed Selection The software program controls the reference speed selection function. The REF SP switch is positioned by the operator to define to the software program the operational mode required. In the OVRD LOG position, the REF SP switch provides a ground via the dimming control circuit card to energize the OVRD LOG indicator. The REF SP OFF indicator is controlled by the processor.
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The ship’s EM log input is changed from synchro format to sine and cosine values by the Scott “T” transformers in the A/D multiplexer transformer. The EM log sine and cosine signals are selected by the A/D multiplexer and converted to a tangent value, in digital format, by the A/D converter. The EM log tangent signal is then applied to the processor. When the REF SP switch is set to OFF, the processor ignores the EM log inputs and the gyro operates in the free inertial state. When the REF SP switch is set to EM LOG, the processor tells the software program to implement gyro operation, damped by the EM log velocity information.
The EM log velocity information is monitored for reasonableness by the software program. When it determines that the velocity information does not meet the reasonableness test, the processor will command the equipment to ignore the velocity data and operate in the free-inertial state. The processor will also initiate a reference speed off signal, causing the REF SP, OFF indicator to light. The operator can override the reasonableness test by setting the REF SP switch to OVRD LOG. In the OVRD LOG position, the processor disables the velocity monitor and commands the software program to use the EM log velocity information for damping purposes. The REF SP, OFF indicator will go off, and the OVRD LOG indicator will come on, indicating the equipment is operating in a damped state.
When the REF SP switch is set to DOCK, the processor tells the software program to use a zero reference velocity for damping instead of the EM log velocity input.
Illumination Control Two circuits control the level of illumination of the control-indicator’s panel lighting and indicators. These circuits are illustrated in block diagrams in figures 4-39 and 4-40.
PANEL LIGHTING.— The control indicator panel lighting is controlled by a potentiometer marked PANEL. The PANEL potentiometer is excited by ±15 volts dc. The potentiometer adjusts a biasing level applied to the illumination sensing circuit in the dimming control circuit card. The output of the sensing circuit drives the dimming control amplifier. The output of the dimming control amplifier is an aboveground variable voltage determined by the position of the PANEL potentiometer. Figure 4-39 identifies the lights controlled by the PANEL potentiometer.
STATUS INDICATOR AND DISPLAY LIGHTING.— The control indicator’s status indicators and the digital display are controlled by the DISPLAY potentiometer. The potentiometer provides a triggering level input (0 volts to +5 volts) to a controlled-width blanking pulse circuit, located on the dimming control circuit card. The blanking pulse is applied to the indicator enabling logic, also on the dimming control circuit card. When the input to any indicator, controlled by the DISPLAY potentiometer, is determined to be correct by the display logic, the indicator is energized. 4-59 UNCLASSIFIED
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The period of the blanking pulse, established by the DISPLAY potentiometer, determines the illumination level. Indicators on the control indicator that are controlled by the DISPLAY potentiometer are shown in figure 4-40.
PANEL
DIMMING CONTROL (1A2R2) WIPER
DIMMING CONTROL CIRUIT CARD (1A2A1) PANEL ILLUMINATION LEVEL CONTROL
PANEL ILLUMINATION AMPLIFIER CONTROL LOGIC (1A2Q1, 1A2Q2, 1A2R1, 1A2R2) ILLUMINATION LEVEL CONTROL ILLUMINATION LEVEL CONTROL
THUMBWHEEL SWITCH (1A2S7)
EDGE-LIT PANEL (1A2A3)
ENTER LAT
SWITCH-IND (1A2S8) ILLUMINATION LEVEL CONTROL +15V -15V CCW CW
Figure 4-39.—Panel lighting dimming block diagram.
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INDICATOR ENABLING CMD INDICATOR ENABLING CMD INDICATOR ENABLING CMD MODE ALIGN
INDICATOR REF SP OFF
INDICATOR (1A2DS13) (1A2DS11) MODE NAV
INDICATOR (1A2DS12) REF SP OVRD LOG
INDICATOR (1A2DS14) INDICATOR ENABLING CMD DIGITAL DISPLAY
INDICATOR (1A2DS8) INDICATOR ENABLING CMD
DIMMING CONTROL CIRCUIT CARD (1A2A1) CW WIPER
DISPLAY
DIMMING CONTROL (1A2R1)
DIMMING CONTROL CIRCUIT CARD (1A2A1) +5V CCW P CONTROLLED WIDTH BLANKING PULSE INDICATOR ENABLING CMD INDICATOR ENABLING CMD INDICATOR ENABLING CMD ALARM
INDICATOR (1A2DS10) HDG FAIL
INDICATOR (1A2DS9) BATTERY OP
INDICATOR (1A2DS8)
Figure 4-40.—Indicator and displa y lighting dimming block diagram. 4-61 UNCLASSIFIED
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Power Supplies There are two power supplies to the AN/WSN-2 gyrocompass. These are the backup power supply and the normal power supply.
BACKUP POWER.— The backup power supply consists of the inverter and the inverter module, located in the synchro signal amplifier, for backup during loss of single-phase power, and the battery set and relays located on the transformer-rectifier assembly, for backup during loss of 3-phase power.
NORMAL POWER.— The normal power supply consists of the control monitor, battery charger, 5-volt regulator, 13-volt regulator, DC/DC module, and transformer rectifier. These are all located in the control power supply. Three-phase, 115-volt ac ship’s power is routed through an EMI filter and power circuit breaker to the transformer rectifier for normal power. The transformer rectifier converts the 115 volts ac to 35 volts dc and unregulated 28 volts dc. The 35 volts dc goes to the battery charger and the unregulated 28 volts dc is sent to the 5-volt and 13-volt regulators.
The battery charger receives high- and low-voltage sensing signals and a temperature- sensing signal from the battery set. The battery charger uses the temperature-sensing signal to regulate the 35 volts dc to provide a charging voltage to the battery set. The charging voltage is present as long as the 3-phase, 115-volt ac ship’s power is available and turned on.
The unregulated 28 volts dc is applied to the 5-volt and 13-volt regulators. The 5-volt regulator reduces the unregulated 28 volts dc to a regulated 5 volts dc, which is distributed to all using circuit cards and assemblies. The 13-volt regulator reduces the unregulated 28 volts dc to a regulated 13-volt dc level, which powers the DC/DC module. The 13-volt regulator is turned on before the 5-volt regulator to allow the DC/DC module and equipment to stabilize before the distribution of the 5 volts dc. The DC/DC module provides output voltages of +28 volts, -28 volts, +15 volts, -15 volts, +20 volts floating, +50 volts, and +50 volts floating. Floating indicates those voltages are isolated from power ground.
Single-phase, 115-volt ac ship’s power is applied to the gyro by an EMI filter, a relay, and the SYN REF (synchro reference) circuit breaker. The single-phase, 115 volts ac provides power for the inverter magnetic module, internal resolver reference, and a vital heading reference output.
The gyrocompass will automatically switch to battery operation when the 3-phase or single-phase ship’s power input is lost, loses a phase, or exceeds prescribed voltage or frequency tolerances. If the single-phase input is lost or exceeds tolerances, the system will shift to inverter backup.
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The gyro is turned on and off by logic circuits in the control monitor, which is located in the control power supply.
Certain conditions will cause the control monitor to automatically turn the gyro off. These conditions are over-temperature, power supply fault, IMU fault, and battery under voltage when operating on the battery. When automatic shutdown occurs, the control monitor turns the gyro off as if the MODE switch were turned to the POWER OFF position, with one exception. Built-in test signals are applied to the control power supply to energize the proper fault indicators and alarms.
BITE circuits in the control monitor continuously check the 5-volt regulator, 13-volt regulator, DC/DC module, transformer rectifier, and inverter assembly outputs for over- and under-voltage conditions. They also monitor the frequency and voltage of the 3- phase and single-phase, 115 volts ac and the power supply temperature.
Built-in Test Equipment The BITE provides four types of built-in tests. These are hard-wired, software, software- initiated, and software-monitored built-in tests. The hard-wired BITE consists of test logic that is wired directly to the fault circuits. Fault signals that start the automatic shutdown sequence are hard wired. The software built-in tests are tests that are controlled by the processor, rather than by hard-wired logic circuits. The software-initiated BITE consists of hard-wired logic circuits that are activated by the processor. The software- monitored BITE circuits are not wired directly to fault circuits. Instead, the monitored parameters are compared to predetermined parameters known to the software. If the monitored parameters are determined to be wrong, the appropriate fault indicator is energized; and if the fault warrants, the gyro is shut down. When any fault is detected by the BITE, the ALARM indicator on the control indicator and the appropriate fault indicator are energized.
The fault indicators are located on the control indicator. They are labeled FAULT AIR, FAULT DI, FAULT CTR, FAULTPS, BATIERY STAT, BATTERY OPR, FAULT BFR, HDG FAIL, FAULT IMU, and ALARM. These indicators serve to lead the operator to the failed area of the system.
FAULT INDICATORS.— The FAULT AIR indicator is energized when an over- temperature condition occurs in the power supply section of the control power supply, synchro signal amplifier, or the IMU. When this condition exists, an over-temperature no-go signal is sent to the control monitor, which starts the automatic power shutdown sequence.
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The processor monitors the control signals from the control indicator. When erroneous control output signals are detected, the processor sends out signals that energize the FAULT DI indicator and the ALARM indicator.
The circuit cards, in the control section of the control power supply, are monitored and tested by the processor. When a circuit card fails, the FAULT CTR and ALARM indicators on the control indicator are energized. A combination of the six indicators, located inside the control power supply, will be energized, indicating which circuit card is faulty.
BITE logic circuits in the control monitor continuously monitor the 5-volt regulator, 13- volt regulator, DC/DC module, battery charger, and battery set for overvoltage and under-voltage conditions. If an under-voltage condition in the battery charger occurs, the control monitor sends a battery status signal to the control indicator, setting the BATTERY STAT indicator. If an overvoltage condition occurs in the battery charger, 5-volt regulator, 13-volt regulator, or DC/DC module, the fault indicator on the faulty card will set, and the control monitor will send a signal to the control indicator, energizing the FAULT PS indicator. The control monitor will also turn off the 5-volt regulator, 13-volt regulator, and DC/DC module when an overvoltage condition occurs. The fault indicators will remain set after the power supply is turned off. A gyro over- temperature condition, failure of the servoamplifier or gyro spin supply will also initiate no-go commands to the control monitor, which will shut down the power supply.
The control monitor also senses the voltage and frequency of the 3-phase, 115-volt ac power and synchro reference inputs at the transformer rectifier. If the 3-phase input is lost or exceeds tolerances, the control monitor will switch the gyro to battery operation and send a signal to the control indicator, causing the BATTERY OPR indicator to come on. If the single-phase input is lost or exceeds tolerances, the control monitor will disconnect the ship’s faulty input switch on the inverter, sending a signal to the control indicator, causing the ALARM indicator to set.
Circuit cards and assemblies in the synchro signal amplifier we monitored by hard-wired BITE. The 1X heading amplifier, 36X heading amplifier, roll amplifier, pitch amplifier, and inverter in the synchro signal amplifier have fault indicators located on the individual circuit cards. The fault indicator on the inverter sets when the inverter or inverter magnetics module fails. A fault in any of these circuit cards or module will cause the fault indicator on the respective faulty circuit card to set and a BITE fail signal to be sent to the fault summary logic located in the inverter. The inverter then sends out a signal causing the FAULT BFR indicator on the control-indicator to set.
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If either of the heading amplifiers fail, the inverter will send a heading fail signal to light the HDG FAIL indicator on the control-indicator. If the inverter or inverter magnetics module fail during inverter operation, the inverter sends a signal to the control monitor to command a power shutdown. A failure of either the servoamplifier or gyro spin supply, located in the IMU, causes a no-go signal to be sent to the control monitor. The control monitor initiates a power shutdown and the IMU fault indicator on the control indicator to set.
Circuit cards and assemblies in the IMU are tested by a combination of hard-wired and software-monitored BITE. When either the servoamplifier or gyro spin supply circuit card fails, a hard-wired BITE fail signal is sent to the control monitor, which was discussed in the preceding paragraph. The gyro spin supply circuit card is also tested under control of the processor. The remaining circuit cards and assemblies are tested by the processor. If the processor detects a fault, a signal is sent, causing the four indicators located on the front of the IMU to set in the proper combination to indicate the faulty card. The control indicator also receives a signal, setting the FAULT IMU indicator.
ALARM RELAYS.— A circuit card in the control power supply contains alarm summary logic for the BITE circuits. The alarm summary logic receives hard-wired BITE fault signals, alarm signals from faults detected by the processor, and alarm signals from the transformer rectifier via the control monitor. Any one or all of these signals will cause the alarm summary logic to send a signal to the control indicator, lighting the ALARM indicator, and an alarm relay on signal to the normally energized alarm relay. The alarm relay on signal causes the alarm relay to reenergize, completing the circuit for the malfunction summary alarm.
When the 3-phase power input is lost or exceeds tolerances, the control monitor switches the operation to battery power and sends out an alarm signal to the circuit card containing the alarm summary logic. The alarm summary logic sends a signal to the on-battery relay, which is normally de-energized. When this relay energizes, it completes the circuit for the on-battery alarm.
4.9.6.7 SECURING PROCEDURES To secure the AN/WSN-2 compass under normal conditions, refer to figure 4-35 and perform the following steps:
1. Set the MODE control to the POWER OFF position.
2. Place the SYN REF switch to the OFF position.
3. Place the PWR switch to the OFF position.
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To secure the compass under emergency conditions, refer to figure 4-35 and perform the following steps:
1. Place the PWR switch to the OFF position.
2. Place the SYN REF switch to the OFF position.
3. Set the MODE control to the POWER OFF position.
4.9.6.8 WATCH STANDING The AN/WSN-2 operates unattended after a mode of operation has been selected and the automatic alignment sequence is completed. Audible and visual extension alarms will alert watch standers at various locations upon loss of normal power to the compass or if a malfunction exists within the compass.
4.10.0 AN/WSN-7B(V) RING LASER GYROCOMPASS (RLG) INERTIAL NAVIGATION SYSTEM The AN/WSN-7B(V) (Figure 4-41) is a self-contained system whose Inertial Measuring Unit (IMU) employs three RLGs and three accelerometers, in strapdown configuration. Unlike a stabilized gimballed system, high speed digital processing is employed to determine the ship’s attitude (pitch, roll, and heading). The AN/WSN-7B(V) requires external ship’s speed input and periodic input of position data. It uses ship’s log speed to provide damping of vertical gyro loops. Position data from the Global Positioning System (GPS) is used to calibrate gyro drifts and to provide position resets to the inertial navigation function. The inertial sensor, speed, and position reset data are processed to generate continuous, accurate position and velocity data, in addition to heading, roll, and pitch reference.
4.10.1 Normal Operation The AN/WSN-7B(V) is designed to operate automatically after application of power and requires minimum operator intervention during normal operation. A six-line, 40-character display and 28-key keypad provide display and operating controls for selection of a wide range of functions. These functions can be accessed for monitoring and modifying operating parameters, for evaluating system performance, and for selecting test and calibration modes.
4.10.2 Test Features A Built-In Test (BIT) function, incorporating both hardware and software tests, continuously monitors operation and periodically performs self-tests to determine the integrity of the AN/WSN-7B(V) and its inputs/outputs. Faults are automatically announced and fault codes which indicate the type of fault detected are displayed on the local control panel. 4-66 UNCLASSIFIED
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Figure 4-41.— AN/WSN-7B(V) Ring Laser Gyro.
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4.10.3 Power In the configuration described in this technical manual, the AN/WSN-7B(V) requires 115 VAC, 60 Hz or 400 Hz, 3-phase power; and 115 VAC, 400 Hz, single-phase synchro reference. An internal battery and inverter provide emergency power for operation with digital output and synchro heading and attitude output for a limited period of time in the event of failure of the ship’s power input. Table 4-3 lists the major design and physical characteristics of the AN/WSN-7B(V).
ENVIRONMENTAL CHARACTERISTICS Temperature
Humidity
Shock
Vibration
Linear Acceleration
Magnetic Fields Operating Full accuracy: 0 to 50 C ( 32 to 122 F)
Operating without damage: 0 to 65 C ( 32 to 149 F) Storage: -40 to 75 C (-40 to 167 F)
0 to 95% (non-condensing)
Meets the requirements of MIL-STD-901D. System functions may be interrupted during application of shock.
Meets the requirements of MIL-STD 167-1 for Type 1 equipment.
1 G PEAK (PLUS GRAVITY)
Operating: 20 Gauss Non-operating: 30 Gauss PHYSICAL/ELECTRICAL CHARACTERISTICS Size Height: 1215 mm (47.84 in) Width: 435 mm (17.13 in) Depth: 486 mm (19.12 in) Weight With IMU198 kg (435 lbs) Primary Power 115 VAC, 3 phase, 60 or 400 Hz Power requirements 500 VA Heat dissipation to air 300 Watts (max) Table 4-3.— Design and Physical Characteristics.
Heading, roll, and pitch output is provided as analog (synchro) data. Synchro Buffer Amplifier (SBA) is installed to provide additional load capability for the 1X and 36X heading outputs. Table 4-4 lists the synchro output characteristics and defines the synchro reference requirements.
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ANALOG INPUT (SHIP’S LOG) Reference 115 VAC, 60 or 400 Hz Format 90 V Low-Level (L-L) Synchro Scaling(1) 20 - 125 Knots/Revolution Fore/Aft Gradient(1) 90/10 or 50/50 percent REFERENCE VOLTAGE (NON-VITAL): Synchro reference voltage is applied to the system from the ship’s 400 Hz main power. Non-vital reference voltage and the synchro signals are affected in amplitude and frequency by variations in the reference voltage. Voltage/Frequency 115 VAC, 400 Hz Power capacity 100 VA Grounding Must not be grounded ANALOG OUTPUT: (HEADING, ROLL, PITCH) Reference 115 VAC, 400 Hz Format 90 V L-L Synchro Synchro Load Vital Heading: 100 ma Roll and Pitch 25 ma Two Speed (Heading) Fine 36:1 (10 degree/revolution) Coarse 1:1 (360 degree/revolution) Two Speed (Roll and Pitch) Fine 36:1 (10 degree/revolution) Coarse 2:1 (180 degree/revolution) or 1:1 (360 /revolution) (2) NOTE: (1) Selectable at installation based on Speed Log. (2) Selectable at installation based on attitude user requirements. Table 4-4.— Analog Synchro Input/Output and Reference Characteristics.
4.10.4 External Data Interfaces The basic digital data interface to the AN/WSN-7B(V) includes an RS-422 Input/Output (I/O) channel which provides interface for Doppler Sonar Velocity Log (DSVL) digital speed input, an RS-422 interface for an external (optional) Remote Control Display Unit (RCDU), and one spare RS-422 interface which can be configured for specific serial data requirements. Table 4-5 lists the functions and characteristics of the three standard serial digital data interfaces.
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I/O PORT DATA CHARACTERISTICS RCDU Interface (1J16) Data Rate - 9,600 bits/second Transmitted Character Format: 1 start bit 8 data bits 1 stop bit Bits total: 10 Least significant bit is transmitted first
DSVL Interface (1J7) Data Rate - 9,600 bits/second Transmitted Character Format: 1 start bit 8 data bits 1 stop bit Bits total: 10 Least significant bit is transmitted first
Signal Polarity (Output signals are referenced to AN/WSN-7B(V) ground): MARK: RS422 + High, RS422 - Low SPACE: RS422 + Low, RS422 - High
NMEA GPS Serial Digital Input and User Configurable Output (1J17) Input: NMEA Serial Data Input from GPS Output: Configured Serial Data Output Message (See Note) NOTE: The message content and data characteristics of this interface output are configurable. If this interface is used, the details of the message configurations and their specified data characteristics are given in the Interface Design Document (Litton Marine Systems document number 280-28901). Message type and content are selected at installation to match user requirements associated with the specific installation. Refer to Chapter 8 of S9427-AT-MMO-010/WSN-7, Table 8-5, for interface configuration possibilities.
Table 4-5.— Standard Digital (RS-422A) Data Interface.
4.10.5 Maintenance Concept The AN/WSN-7B(V) is designed for ease of maintenance through a modular design. Lowest Replaceable Units (LRUs) include the IMU, circuit cards, power supply, fuses, relays, and switches. All circuit cards and the power supply are connectorized for easy replacement. Replacement of relays and switches can be accomplished using standard screwdrivers and wrenches; no soldering or de-soldering is required. The IMU is positioned by precision alignment surfaces. IMU alignment offset parameters are maintained in a Programmable Read-Only Memory (PROM) on the Inertial Electronics (IE) card in the IMU. 4-70 UNCLASSIFIED
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This feature, along with optical calibration data which is stored in Non-Volatile Random Access Memory (NVRAM) and Indexer Assembly alignment calibration data stored in a PROM (U20) on the Sensor Interface Circuit Card Assembly (CCA) (A13) in the card rack, allows the IMU to be replaced without the requirement to optically realign the system. In addition, the system uses a passive cooling design, eliminating the need for periodic shipboard maintenance for air-filter replacement.
4.10.6 Units and Assemblies The AN/WSN-7B(V) cabinet is a single unit which is bolted directly to the ship’s deck in a sheltered naval environment (i.e., not on the weather deck). The cabinet can be oriented in azimuth to any multiple of 90 degrees relative to the ship’s keel. The AN/WSN-7B(V) must be optically aligned at installation using an alignment fixture which is temporarily mounted to Indexer Assembly mounting surfaces inside the unit. Alignment is then obtained by measuring offsets between the Alignment Fixture and the ship’s reference lines. The AN/WSN-7B(V) includes the following functional elements:
• Display/Control Panel • IMU • Mechanical Indexer Assembly • IMU/Shock Isolation System (SIS) Assembly • Card Rack Backplane Assembly containing the following CCAs:
o Digital Processing and Sensor I/O Function Circuit Cards (3) o Indexer Control Electronics Circuit Card (1) o 4-Channel RS-422 Serial Data Interface Card (1) o Digital-to-Synchro/Synchro-to-Digital (D-S/S-D) Converter Circuit Cards (2) o Optional Interface Cards (up to 4)
• Battery-Backed Power and Power Fault Detection System consisting of the following assemblies:
o Electro-Magnetic Interference (EMI)/Radio Frequency Interference (RFI) Filter (1) o 25 VAC/DC, DC/DC Power Supply (Transformer Rectifier) (1) o Battery (1) o DC/AC Inverter Power Supply (1) o Vital Bus(fault detector) Printed Wiring Assembly(1) o Low Voltage Power Supply (1)
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• Status and Alarm Relays (3) and Status Fault Indicator lamp (1)
Table 4-6, lists the AN/WSN-7B(V) subassemblies. Some of the subassemblies contain programmed devices. Other subassemblies are calibrated by installing an associated PROM, which contains factory established calibration parameters.
A calibration PROM, which is installed in socket XU20 on the Sensor Interface CCA (A13) in the card rack, contains calibration parameters for the Indexer Assembly in the AN/WSN-7B(V) cabinet. This PROM is serialized to the Indexer Assembly and must always remain with the system if Sensor Interface CCA (A13) is replaced with a new card. Programmed subassemblies are identified by a part number which includes the hardware with the programmed devices installed. The subassembly part number without the programmed device is also provided; however, only the part number for the subassembly with the programmed configuration is applicable for replaceable assemblies.
ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION (Unit 1) 1982852-var AN/WSN-7B(V) RING LASER GYRO 1A1 1900123 EMI/RFI Filter Assembly 1A2 1982618 Inverter Assembly (400 Hz) 1A3 1978322 Vital Bus CCA 1A4 1982863 Backplane Assembly 1A5 1982847 Battery Assembly 1A6 1900556 Power Supply (Transformer/Rectifier) Assembly 1A7 1983228-1 Battery Charger Assembly 1A8 1983179-1 Low Voltage Power Supply 1A9 1859873 Membrane Keypad 1A10 1977647 Panel Interface Assembly 1A11 1813734 Central Processor CCA (Nav Processor) CCA 1A12 1980513 Status and Command CCA 1A13 (Note 1) 1982430 Sensor (IMU) Interface CCA 1A14 1979087-3 Synchro Converter Assembly CCA 1A15 1979087-3 Synchro Converter Assembly CCA Table 4-6.— List of Electrical Units and Assemblies.
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION 1A16 1981171 Quad Serial Interface CCA 1A17 1983222 Indexer Electronics CCA 1A18 1982915 IMU Assembly (MX- 11906/WSN-7B) 1A19 (Note 2) 1900157 Indexer Assembly (Calibrated) (1A13U20) (Note 2) 1900158 Indexer Assembly Calibration PROM 1A20 1900228 Plasma Display 1A21 1976545-3 Synchro Buffer Amplifier (8 VA) CABLE AND HARNESS ASSEMBLIES 1W1 1983494 Main Harness Assembly 1W2 (Note 3) 1900013-2 Fiber Optic Cable 1W3 T967883 Ribbon Cable (Keypad) 1W5 1982880 Cable Assembly 1W6 - 1W11 (Note 4) P/O 1983494 (1W1) Triaxial Cable Assembly NOTE: 1. The Sensor (IMU) Interface CCA contains sockets for two calibration PROMs. One PROM is not needed for the AN/WSN-7B(V) equipment configuration. The second PROM is serialized to the Indexer Assembly (1A19). This PROM is programmed during factory calibration with correction parameters which are used by the system to compensate for mechanical offsets. The indexer calibration PROM must be replaced with the correct serialized PROM if the Indexer Assembly is replaced.
2. Indexer Assembly 1900157 is a calibrated assembly which includes a PROM (1900158) (serialized to the assembly), which is programmed during factory calibration and Indexer 1983233. The PROM is installed in location XU20 on Sensor Interface CCA (1A13).
3. Cable 1W2 is installed only if optional ATM/SONET optical interface CCA is installed in the system.
4. Triaxial Cable Assemblies are included in Main Harness Assembly 1W1, but are only connected and used in conjunction with NTDS Type E interface CCAs installed in locations 1A50, 1A51, or 1A52.
Table 4-6 (Cont’d).— List of Electrical Units and Assemblies.
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4.10.7 Optional Data Interface Configuration In addition to the basic system configuration, four circuit card locations are provided for optional data interface configurations. These interfaces include:
• Standard NATO Agreement (STANAG) 4156 parallel data; • Navy Tactical Data System (NTDS) Type A and Type B parallel data; • NTDS Type E serial data; and • Asynchronous Transfer Mode/Synchronous Optical Network (ATM/SONET) optical serial data interface.
The message protocol and data content for the messages associated with each interface type are programmed in the I/O Processor control software. The selection and configuration of these optional interfaces is dependent on the individual system installation requirements. Table 4-7, lists the possible optional serial data interface board configurations.
ASSEMBLY APPLICABLE I/O CCA TYPE NAME/FUNCTION NTDS A NTDS B NTDS E STANAG ATM CCA locations designated 1A50 through 1A53 are used for optional interface boards. Options include NTDS Standard interface, STANAG 4156 interface, and ATM/SONET optical interface. The quantity of each type interface board used is determined by the system part number. The part numbers for cables which interface between each interface board and the external connectors on the cabinet are determined by type of the associated interface boards installed (Refer to Figure 5-18 of S9427-AT-MMO-010/WSN-7). The Interface Assembly CCA part numbers currently supported are:
NTDS Interface CCA Type A (P/N 1981087) NTDS Interface CCA Type B (P/N 1981562) NTDS Interface CCA Type E (P/N 1981559) STANAG 4156 Interface CCA (P/N 1983410) ATM/SONET Interface CCA (P/N 1900040) (See Note 1) 1A50 CCA, Type X X 1A51 CCA Type X X X 1A52 CCA Type X 1A53 CCA Type (Note 1)
NOTE: 1. Board location 1A53 is reserved for future installation of hardware to support an ATM/SONET interface application. This interface type is not currently supported in system software and cannot be configured in the current version of the AN/WSN-7B(V) RLG.
Table 4-7.— AN/WSN-7B(V) Optional I/O Configurations.
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4.10.8 List of Applicable Documents Table 4-8 lists the specifications that are associated with the AN/WSN-7B(V). These documents list Interface Design Specifications (IDS) which describe the various message types which can be selected for data transfer between the AN/WSN-7B(V) and external equipment; and the NTDS digital interface specifications which describe timing, communication protocol, and transmission characteristics of the NTDS I/O.
DOCUMENT NUMBER DESCRIPTION MIL-STD-1397B (NAVY) Military Standard Input/Output Interfaces, Standard Digital Data, Navy Systems NAVSEA S9427-AN-IDS-010/WSN-7 Interface Design Specification, Super Channel to User for the AN/WSN-7 Ring Laser Gyro Navigator (RLGN) NAVSEA SE174-AB-IDS-010/GPS Interface Design Specification for Shipboard External Computer and NAVSTAR Global Positioning System NAVSEA S9427-AN-IDS-040/WSN-7 Interface Design Specification, Inertial Navigation Set AN/WSN-7 to External Computer in an Output Only Configuration - For Parallel Channels NAVSEA S9427-AN-IDS-020/WSN-7 Interface Design Specification, Inertial Navigation Set AN/WSN-7 to External Computer - For Low Level Serial (MIL-STD-1397B Type E) Digital Communication NAVSEA T9427-AP-IDS-010/RLGN Navigation Operational Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) AN/WSN-7 NAVSEA T9427-AP-IDS-020/RLGN Navigation Operational Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) AN/WSN-7 NAVSEA S9427-AP-IDS-030/RLGN Navigation Operational Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) AN/WSN-7 NAVSEA S9427-AP-IDS-040/RLGN Navigation Operational Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) AN/WSN-7 NAVSEA SN340-BO-SPN-101/AN/WSN-2A STANAG 4156 Sp eed Log Interface Design Specification
Table 4-8.— Associated Documents.
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4.10.9 Operation This section identifies all operation control functions and describes their use, provides instructions for turning on and operating the AN/WSN-7B(V) Ring Laser Gyro (RLG), and presents information for identifying system fault conditions. The top panel controls and indicators are shown in Figure 4-42. Operation procedures associated with testing, troubleshooting, optical alignment, and installation configuration are included in the appropriate chapters in S9427-AT-MMO-010/WSN-7.
Figure 4-42.— Top Panel Controls and Indicators.
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4.10.9.1 System Operating Controls System operating controls (Figure 4-42) consist of the power controls and indicator; a system fault indicator; a keypad, which provides all operator control interface; a menu display, which provides all mode and status information; and displayed menus, which allow selection of various control functions and display of specific data.
Power Controls and Indicators. The AN/WSN-7B(V) top panel contains the primary power controls and indicators for the system. The power control functions on the AN/WSN-7B(V) are:
• MAIN POWER Circuit Breaker (CB1) protects ship’s 115 VAC main power input to the system and breaks power to SYSTEM POWER switch (S1).
• SHIP’S REF Circuit Breaker (CB2) protects ship’s 400 Hz synchro reference input to the system.
• VITAL REF Circuit Breaker (CB3) protects AN/WSN-7B(V) generated 400 Hz synchro vital reference output.
• SYSTEM POWER switch (S1) operates to turn on the AN/WSN-7B(V). ON position - Applies ship’s 115 VAC input to the 24-volt power supply in the AN/WSN-7B(V) and selects the system power control function, to turn on the AN/WSN-7B(V).
• SYSTEM POWER indicator (DS1) illuminates whenever ship’s 115 VAC power is applied to the AN/WSN-7B(V) power supply (SYSTEM POWER switch set ON).
Keypad Functions and Menu Selection. The keypad on the AN/WSN-7B(V) (Figure 4- 43) is used in conjunction with the displayed menus to perform all control and data entry functions. The keys are grouped into three categories; these are Menu Selection, Data Entry, and Display Control.
Some keys perform dual functions. The operation of these keys is automatically determined by the selected menu, mode, or operation being performed. Each key and its general function is listed below:
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Figure 4-43.— Keypad.
Menu Selection keys consist of:
MODE Selects Page 1 of Mode Functions Menu.
AUX FUNC Selects Page 1 of Auxiliary Functions Menu.
SENSOR Selects Page 1 of Sensor Functions Menu.
DISPLAY Selects Page 1 of Display Functions Menu.
TEST Enables Self-Test Functions Menu (operates only during power-up).
NEXT PAGE Sequentially selects display of menu pages.
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Data Entry keys consist of:
0 through 9 Selects numbered function on displayed menu; and used to enter numeric data.
A through F Alternate functions reserved for entry of hexadecimal values.
CLEAR Clears displayed or manually entered data without accepting the value.
ENTER Accepts displayed or manually entered data for entry into selected function.
BACKSPACE Erases last entered numeric character for re-entry.
N/E/+ Enter North (N) or East (E) for position or positive (+) for numeric values requiring sign.
S/W/- Enter South (S) or West (W) for position or minus (-) for numeric values requiring sign.
Display Control keys consist of:
TRACK HOLD “Freezes” display of any continuously changing data which is selected for viewing.
BRIGHT Increases display illumination.
DIM Decreases display illumination.
ALARM ACK Removes the fault code from the display when a fault condition is detected.
Operation Menus and Display Functions. Table 4-9 lists the functions included in the four menus associated with operation and presents a brief description of the control and data functions associated with each. Figure 4-44 identifies the general menu layout and data presentation for the operations-related menus and it provides a listing of all mode and status indications that may be displayed on the top line of the Menu Display Panel. The top line indicates the system operating state, selected navigation aid, selected velocity reference, selected damping mode, selected coordinates (normal or transverse), and code for any detected fault. The next two lines display position, velocity, heading, day, and time. The last three lines present variable information and control functions, as determined by the selected menu and page. Figure 4-45 presents the full menu tree listing all functions available for display during normal operation. 4-79 UNCLASSIFIED
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A complete listing of the fault codes which may be displayed in the “FAULT” field is provided in Appendix B of S9427-AT-MMO-010/WSN-7, along with a description and analysis of the fault condition which most probably caused the code to be displayed.
Keypad/Menu Operation Procedure. The general procedure for key/ menu operation is:
a. Press a Menu Selection (MODE, AUX FUNC, SENSOR or DISPLAY) key to select the menu with desired function.
b. If selected menu has more than one page, press NEXT PAGE key to step through pages (page display sequence cycles back to Page 1 after last page is displayed). The page number is displayed in the lower right-hand corner of the display.
c. When function is located, press the Number key corresponding to the number beside the function to select the function.
d. If data entry is required, enter value using Data Entry keys. Correct error during data entry using CLEAR or BACKSPACE key. Pressing a Menu selection (MODE, AUX FUNC, SENSOR, or DISPLAY) key will abort operation completely.
e. After data has been entered, either press ENTER key to accept the displayed value or press the CLEAR key to clear the displayed value allowing for entry of new value.
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POSSIBLE DISPLAY VALUES ON TOP PANEL DISPLAY (MODE) (POS REF) (2) (VEL REF) (3) (DAMPING) (COORD) (FAULT) STANDBY GPS VMAN AUTOD ANORM See Appendix B TEST (1) DOCK ROD 1 AUTOU ATXVS ALIGN GNMEA ROD 2 MANU MNORM ALIGN-C EC DUMMY MAND MTXVS ALIGN-F DSVL GYRO VGPS NAV-C VNVE NAV SHUTDOWN NOTES: (1) TEST is displayed only when the AN/WSN-7B(V) is turned on in Test Mode. Refer to Chapter 5, Section 5.2.1. of S9427-AT-MMO-010/WSN-7 (2) This display region is blank if position reference is de-selected. (3) This display region is blank if velocity reference is de-selected.
Figure 4-44.—Menu Display.
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Figure 4-45.—Identifying Operation Menus and Data Entry. NOTE: This is a representative graphic. Consult S9427-AT-MMO-010/WSN-7, Chapter 2 for Operation Menus. 4-82 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION SENSOR Functions (Select by pressing SENSOR key.)
The SENSOR menu provides three pages of control functions associated with selecting the velocity reference source (page 1), position reference source (page 2), and depth reference (page 3).
Select the menu page by pressing the NEXT PAGE key. Select each function by pressing the Number key corresponding to the number of the function and then follow the instruction prompts. 1 1. VMAN OFF/ON When selected, displays current value set for manually entered fore/aft speed. Setting VMAN ON allows manual entry or change of fore/aft speed value. Setting VMAN OFF disables manual speed input as the velocity reference. 2. VSYN OFF/ON Enables or disables the synchro speed input as the velocity reference. Displays synchro speed to allow verification of selection. ROD 1, ROD 2 or DUMMY must be configured as a velocity reference to be selectable. 3. VDIG OFF/ON Enables or disables the digital speed input’s use as the velocity reference. Displays digital speed to allow verification of selection. ROD 1, ROD 2, DUMMY, DSVL, or VGPS must be configured as a velocity reference to be selectable. 2 1. GPS OFF/ON Enables or disables the use of GPS via the NTDS interface as the position reference. GPS must be configured as a position reference to be selectable. GPS is the default position reference if configured. 2. DOCK OFF/ON Enables or disables the use of dockside conditions as the position and velocity references. The ship’s position is input manually by the operator. The system sets the velocity reference to zero. To disable (exit) DOCK-side mode, a velocity reference must be selected or the operator must enter a reference velocity using VMAN. 3. GNMEA OFF/ON Enables or disables the use of NMEA GPS via the RS-422 interface port 3 (connector J17) as the position reference. NMEA format GPS input must be configured as a position reference input to be selectable. 4. EC OFF/ON Enables or disables the use of External Computer (EC) position data via the NTDS Type E Super-channel interface as the position reference. EC input must be configured as a position reference to be selectable.
Table 4-9.— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION Functions on page 3 of SENSOR menu are used for selecting the depth sensor source to be used.
Note: These functions are normally configured only for subsurface installations. 3 1. DMAN OFF/ON When selected, displays current value set for manually entered depth. Setting DMAN ON allows manual entry or change of depth value. Setting DMANOFF disables manual depth data input to the navigation processor. Depth is ship’s keel depth below the surface. 2. DDIG OFF/ON On RLG configured for depth input from digital depth sensor, enables or disables the digital depth input. 3. VERT VEL OFF/ON On RLG configured for DSVL or VNVE (Vertical Velocity capable velocity reference), enables or disables use of that vertical velocity input. MODE Functions (Select by pressing MODE key) The MODE menu provides control functions associated with the position filter and navigation calculation modes.
Select each function by pressing the Number key corresponding to the number of the function and then follow the instruction prompts. 1 1. Damping Allows selection of the damping mode for the horizontal velocities. Refer to Section 2.5.1 of S9427-AT-MMO-010/WSN-7 for an explanation of damping operation. Three damping modes are available. These are:
Auto When selected, switching between damped and un-damped operation is automatic based on system determination of validity of reference velocity data.
Man Damp When selected, system is forced to remain damped regardless of velocity input or ship dynamics. Change to undamped operation must be selected Manually.
Man Undamp When selected, system is forced to remain undamped. Change to damped operation must be selected Manually. 2. Slew Displays current GMT and position data, and allows manual entry of a position slew from the keypad. Position slew data is used to correct the system estimate of position only. NOTE: Navigation filter is not reset when position data is entered with this function. 3. Fix Displays current GMT and position, and allows manual entry of a position fix and error estimates from the keypad. Position data is used to correct the system estimate of position and to update the navigation filter (self-calibrate).
To enter new values, press CLEAR key to reject displayed value, enter correct value from keypad, and then press ENTER key to accept data. 4. Nav Enable Allows the operator to select the AN/WSN-7B(V) to operate either as an Inertial Navigator providing inertial position and velocity data output in addition to attitude data (YES) or as a gyrocompass providing only heading, roll and pitch data output (NO).
Table 4-9(Cont’d).— Operating Menus/Functions Description. 4-84 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION 1 5. Coord Mode Allows manual or automatic selection of Earth coordinates reference used for calculating position and heading, and allows selection of synchro heading output format independent of system coordinates mode selected. Refer to Section 2.6.1 of S9427-AT-MMO-010/WSN-7 for an explanation of normal and transverse mode operations and display. Three system modes are available, these are: (cont)
AUTO – When selected, INS automatically switches between normal and transverse coordinates reference when normal coordinates latitude is approximately +85 degrees. (Transverse mode should be used above 85 degrees.) MNORM – When selected, INS remains in normal coordinates mode regardless of latitude. MTXVS – When selected, INS remains in transverse coordinates mode regardless of latitude.
Three synchro heading output modes are available, these are:
FOLLOW SYSTEM MODE – When selected, synchro heading output automatically provides transverse heading when the system is operating in transverse coordinates and provides normal heading when the system is operating in normal coordinates mode. NORMAL COORDINATES – When selected, the synchro heading output is always normal coordinates regardless of whether the system is operating in transverse or in normal coordinates mode. TXVS COORDINATES – When selected, the synchro heading output is always transverse coordinates regardless of whether the system is operating in transverse or in normal coordinates mode. 6. Reset Mode Allows selection of the acceptance mode for position fixes from the navigation aid. Refer to Section 2.7 of S9427-AT-MMO-010/WSN-7 for explanation of fix acceptance criteria. Three modes are available, these are:
Review – Requires that the operator review fix data and either accept or reject each position fix. With this mode selected, when a position fix is received from the navigation aid, the operator is prompted by display of Fault Code 221. The operator must then select the Reset Data function (DISPLAY, Page 1, Last Reset) to review the fix values and to accept or reject each position fix. Auto Review – Similar to Review mode, except the system automatically accepts valid fixes and allows the operator to review fixes which do not meet valid criteria. If the operator does not accept or reject the fix within 10 minutes, the fix is rejected by the system. Auto – System automatically accepts or rejects each position fix from the navigation aid without prompting the operator to review the fix. Display of last accepted fix is available in the Last Reset data display. Table 4-9(Cont’d).— Operating Menus/Functions Description. 4-85 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION AUXiliary FUNCtion (Select by pressing AUX FUNC key.) The AUXILIARY FUNCTION menu provides control functions associated with changing system configuration settings, displaying stored fault codes, performing display self-test, and setting display update rate. Select each function by pressing the Number key corresponding to the number of the function and then follow instruction prompts. 1 1. I/O Configuration Allows the operator to enable or disable digital interfaces for communications with external devices. 2. Faults Displays list of active faults. Active faults are faults which remain active after the alarm condition has been acknowledged by pressing the ALARM ACK key. 3. Display Test Initiates a dynamic self-test of the display. Test continues until one of the Menu Selection keys is pressed. 4. Display Rate Selects display update rate. Selectable rates are every second (1 Hz) or twice per second (2 Hz). 2 Hz is the default rate. 5. Display Coordinates Selects format for position and heading display as either Normal coordinates or Transverse coordinates. This function affects the display format only and does not affect calculation mode. 6. Indexer (Enable) Allows the operator to enable or disable the Indexer Assembly turntable torquer motor. Indexing of the IMU is normally enabled and this function is not used during normal operation. The indexing function can be enabled without cycling system power off/on in the event that it is automatically disabled as a result of detection of a fault in the torquer operation. 2 1. Simulated Output Allows the operator to select a simulation mode for system data output and to enter simulated values for heading, roll, pitch, position, and velocity on all outputs. Selection of this function and output of simulated values do not affect system operation. Some data messages contain status bits which are set to indicate that output data is simulated. When this mode is exited, the system remains in the Simulate mode for a short period of time while system output parameters are being slewed back to correct values. When all values are reset, the system reverts automatically to normal output. 2. I/O Restart Allows the operator to restart (enable) I/O Processing operation without recycling power. Function is used in the event that the I/O is shut down by Built-In Test Equipment (BITE) as a result of detection of a fault condition. Some fault conditions prevent I/O restart. Refer to Appendix B to identify Faults associated with I/O Processing shutdown. 3. KF Reinit Allows the operator to re-initialize the Kalman Filter and reset all sensor calibrations to stored PROM values. This function is not used for normal operation and should be used only if the operator is certain that performance is outside of specification. Selection of Kalman Filter re- initialization will realign the system and restore attitude and position accuracy. Position and velocity reference data must be available for realign.
Table 4-9(Cont’d).— Operating Menus/Functions Description. 4-86 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION 1 (cont)
4. Memory Inspect Allows the operator to observe the data values currently stored in memory. Function allows each memory address location to be selected and to be sequentially stepped up or down. This function is intended primarily as a software development tool. DISPLAY Functions (Select by pressing DISPLAY key.) The DISPLAY menu provides three pages of parameters and data which can be selected for display. After selection of a parameter, the menu listing is replaced by display of the selected parameter data. This condition remains current until a Menu Selection key is pressed. To change the displayed parameter, press the DISPLAY key to re-select the menu listing and then select another parameter. Select the menu page by pressing the NEXT PAGE key. Select the parameter to be displayed by pressing the Number key corresponding to the number of the parameter. 1 1. Roll/Rate Displays ship’s roll angle and roll rate.
For US Navy sign convention configurations:
(+) indicates roll to port.
(-) indicates roll to starboard. 2. Pitch/Rate Displays ship’s pitch angle and pitch rate.
For US Navy sign convention configurations:
(+) indicates pitch to bow.
(-) indicates pitch to stern. 3. Hdg/Rate Displays ship’s heading and turn rate.
(0 degrees to 359.99 degrees) 4. Vn/Ve Displays system velocity north and east.
Range is ±99.99 kts. 5. Grid N/E Displays system position in grid coordinate format. This display mode is associated with polar operation; however, this function can be selected at any latitude. This function affects the display format only and does not affect calculation mode. 6. Last Reset Displays last position fix data and resulting reset of system position or pending fix reset. The time of the position fix data, the time since last reset, and the position fix source are also displayed. 2 1. Day/Time Displays day and GMT and allows values to be changed. Normally, day is set relative to first day in calendar year. Time is in military (24 hour) format (HH:MM:SS). For operation with GPS, system will synchronize to GPS UTC. 2. Part Nos Multiple pages display listing of system level part numbers. These include system serial number, program part number and revision letter, IMU serial number, and recalibration letter. 3. Depth Displays depth if depth reference configured and selected.
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PAGE FUNCTION BRIEF DESCRIPTION 3 1. Vfa/Vps Displays velocity fore/aft and port/starboard. Range is ±99.99 kts. 2. Ocn/Oce Displays estimated ocean currents north and east. Range is ±99.99 kts. 3. Course Displays direction of ship’s velocity. Range is 0.00 degrees to 359.99 degrees. (Default for ship’s velocity less than 0.5 knots is 0 degrees.) 4. VT Displays total velocity (vector sum of Vn/Ve). Range is ±99.99 kts. 5. Set/Drift Displays Set (the direction of ocean currents) and drift (the vector sum of Ocn/Oce). 6. DVn/DVe Displays the difference between RLG inertial velocity and selected reference for north and east velocity.
Table 4-9(Cont’d).— Operating Menus/Functions Description.
4.10.10 Operation Procedures (Normal Conditions) NOTE: The following procedure assumes that the AN/WSN-7B(V) has been installed correctly and configured for available external reference (GPS, Speed log). Data from all configured external references should be available.
To turn on the AN/WSN-7B(V), first turn on and check operation of speed sensor source, external GPS receiver, and any other devices which accept data from the AN/WSN- 7B(V). Follow the procedure outlined below for turning on and operating the AN/WSN- 7B(V) in a normal situation.
An off-line Test Mode is also available. This mode is selected by turning off the AN/WSN-7B(V) and then setting the SYSTEM POWER switch to ON while the TEST key on the keypad is held depressed. When Test Mode is selected, the unit does not provide valid attitude or heading output data. Selection of the Test Mode and test functions is covered in Section 5.2.1. of S9427-AT-MMO-010/WSN-7.
Turning On the AN/WSN-7B(V). The following procedures are required when turning on the AN/WSN-7B(V).
a. Set the POWER, SHIP’S REF, and VITAL REF circuit breakers to ON.
b. Set SYSTEM POWER switch to ON. Observe that SYSTEM POWER indicator illuminates, and that the SYSTEM FAULT alarm indicator remains OFF.
c. Observe that a configuration mode message appears briefly and no fault codes are indicated in the upper right corner of the Display.
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d. Press AUX FUNC key to select AUXiliary Functions menu and then select Display Test function by pressing <3> key and verify that display is functioning properly.
e. Exit Display Test by pressing any Menu Selection.
Turning Off the AN/WSN-7B(V). The following procedures are required when turning off the AN/WSN-7B(V).
a. Set the SYSTEM POWER switch to OFF. The system will save all valid data to be used when the system is turned on again.
b. Set the POWER circuit breaker to OFF.
SELECTING THE ALIGN MODE. The AN/WSN-7B(V) will settle and operate as a gyrocompass (with degraded heading accuracy) without a source for either position or speed input and will operate as a full accuracy gyrocompass with only ship’s speed applied. Position and velocity reference must both be provided for precise attitude alignment and navigation performance. At start-up, the system will automatically select a configured position and velocity reference based on priority. The operator can select from any configured position or velocity reference following power-up.
Available references are determined by the installed configuration of the position and velocity references. Ship’s speed reference is configured through a single-axis synchro interface, through a single-axis STANAG 4156 interface, through a serial interface by DSVL, or through an NTDS interface by GPS. Automatic position input is configured through a GPS or EC interface. The GPS interface is a configurable NTDS interface or an RS-422A NMEA 0183 Guidance Gimbal Assembly (GGA) message interface.
Position fixes can also be entered manually by the operator. Four position references sources may be used for aligning the system. These are GPS, EC, manual entry of a position FIX entry through the operator panel, and DOCKside. The Sensor menus provide operator selection of velocity reference and position reference.
NOTE: The AN/WSN-7B(V) will use last Lat and Lon from NVRAM when the system is turned on again if the system has run (with no faults which prevent NVRAM update) for at least one hour at last power-up.
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DOCKside is a special reference function which provides fixed position and speed input. When DOCKside is selected, the AN/WSN-7B(V) sets the reference ground speed input to zero. Reference ship’s position is initialized by Manual entry. This position and zero velocity data continues to be used as the reference while DOCKside remains selected. DOCKside can only be used while the ship remains stationary (at dockside). If the ship is moving, position and speed reference other than DOCKside must be selected.
Procedure for Align Using Dockside Position Reference. NOTE: For DOCKside to be available for selection as the alignment reference source, the system must be configured as a Navigator. If the system is currently configured to operate as a gyrocompass (GYRO), press the MODE key and set NAV ENABLE = YES.
a. Press SENSOR key, Page 2, and then select DOCK ON to enter DOCKSIDE ALIGN.
b. When DOCKSIDE ALIGN is selected, the navigation system automatically selects zero ground speed input and displays the current stored position data along with prompts which allow the operator to either accept (ENTER) the displayed position data or to reject (CLEAR) the display and enter new position fix data. If displayed values are not current ship dockside position, manually enter ship’s position within 0.05 nm accuracy.
c. When the position fix is entered, the navigation system checks the values for reasonableness, applies a reset of position, and then enters the Dockside Align mode. ALIGN is displayed in the upper left field, DOCK is the displayed Position reference.
d. When ALIGN-F is displayed in the upper left field, the AN/WSN-7B(V) has achieved a fine aligned state and will transition to NAV mode when the DOCKside reference is removed. To remove the DOCKside reference, Press SENSOR key, Page 2, and then select DOCK OFF to exit Dockside Align. The AN/WSN-7B(V) will prompt the operator for selection of a velocity reference prior to leaving Dockside Align.
CAUTION: Leaving the navigation system in Dockside Align while getting underway will result in the display of Fault Code 52 and the navigation system cannot transition to the NAV mode.
e. The operator should exit Dockside Align mode before ship leaves the dock (15 minutes prior to sailing is recommended). Press SENSOR key, Page 2, and then select DOCK OFF to exit Dockside Align. The AN/WSN-7B(V) will prompt the operator for selection of a velocity reference prior to leaving Dockside Align.
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If ALIGN-F is displayed in the upper left field, the AN/WSN-7B(V) will transition to NAV mode on entry of a velocity reference.
If ALIGN or ALIGN-C is displayed in the upper left field, the AN/WSN-7B(V) will continue the Align process with selected velocity reference and position data.
NOTE: If inertial velocity is greater than 2 knots or 1 knot (filtered), then the AN/WSN-7B(V) will suspend the DOCKside align. The operator will be alerted with Fault Code 52. Operator must select DOCKside OFF to clear fault 52. Operator can then re-select DOCKside ON to continue align/calibrate.
Procedure for Align Using GPS Position Reference.
a. Press SENSOR key, select Page 1 of the Sensor Menu and select the applicable velocity reference ON, or review the default selection (refer to Section 2.5.1.2 of S9427- AT-MMO-010/WSN-7).
b. Select Page 2 of Sensor Menu and select GPS ON (or GNMEA ON) to select GPS position reference.
NOTE: Automatic acceptance or operator review of position fix data prior to acceptance of position fixes by the navigation system is selectively controlled by setting of the Reset function on the Mode menu. Selection of the Reset function is a matter of operation preference. A suggested method is to set the Reset function to Review and manually review the first fix from the navigation aid; then set the Reset function to Auto to allow all subsequent fixes to be automatically accepted/rejected without operator intervention. Operator advisory faults will alert the operator of bad fix data.
With GPS selected as the position reference for align, a velocity reference must also be available. The velocity reference may be manual entry or may be from the configured velocity reference source.
c. Press MODE key. On the Mode Menu, set Reset Mode function <6> key to operation preference for operator review or automatic acceptance of position fixes from the navigation aid. (REVIEW, AUTO REVIEW, or AUTO). Selection of REVIEW will require operator accept/reject of all position fix data prior to application of a position fix reset.
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d. If NAV ENABLE = NO, the AN/WSN-7B(V) will transition through ALIGN-C and reach GYRO state indicating full attitude accuracy. If NAV ENABLE = YES, the AN/WSN-7B(V) will transition through NAV-C and reach NAV state indicating that the AN/WSN-7B(V) has achieved full attitude, velocity, and position accuracy.
e. The selection of GPS as an external position reference can remain ON for normal steady state operation of the AN/WSN-7B(V). When GPS position is available and valid, the AN/WSN-7B(V) will remain slaved to the GPS position. During periods of time when GPS is not available or is invalid, the AN/WSN-7B(V) will provide position based on inertial measurements from the last reference position reset. Normal steady state operation requires a reference velocity for damping of inertial velocities.
Procedure for Align Using Operator Entered Position.
a. Verify that GMT and day are correct. If correct, proceed to step i.
b. If incorrect, press the DISPLAY key, select Page 2 of the Display Menu.
c. Press the <1> key for Day/Time. Press the CLEAR key and enter correct Julian date.
d. Use the BACKSPACE key to eliminate keypunch errors.
e. Press the ENTER key to accept the entry.
f. Press the CLEAR key and enter correct GMT.
g. Use the BACKSPACE key to eliminate keypunch errors.
h. Press the ENTER key to accept the entry.
i. Press SENSOR key, select Page 1 of the Sensor Menu and select the applicable velocity reference ON, or review the default selection (refer to Section 2.5.1.2 of S9427- AT-MMO-010/WSN-7).
j. Select Mode Menu and select FIX (<3> key) to enter a position fix.
k. Position fixes must be entered and applied periodically for 20 hours to achieve full NAV state. If available, position fixes should be applied every 15 minutes for at least the first 2 hours, and then every 1 hour.
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l. If NAV ENABLE = NO, the AN/WSN-7B(V) will transition through ALIGN-C and reach GYRO state indicating full attitude accuracy. If NAV ENABLE = YES, the AN/WSN-7B(V) will transition through NAV-C and reach NAV state indicating that the AN/WSN-7B(V) has achieved full attitude, velocity, and position accuracy.
m. Position fixes can be applied as available to maintain AN/WSN-7B(V) accuracy for subsequent NAV state operation.
Procedure for Align Without Operator Entered Position:
a. Press SENSOR key, select Page 1 of the Sensor Menu and select the applicable velocity reference ON, or review the default selection (refer to Section 2.5.1.2 S9427- AT-MMO-010/WSN-7).
b. AN/WSN-7B(V) will use previous position data stored in NVRAM as an initial position.
c. The AN/WSN-7B(V) will transition through ALIGN-C and reach GYRO state indicating full attitude accuracy.
d. If NAVENABLE =YES and sufficient position fix data is applied, the AN/WSN- 7B(V) will then transition through NAV-C and reach NAV state indicating that the AN/WSN-7B(V) has achieved full attitude, velocity, and position accuracy.
Procedure for Align Using EC Position Reference:
a. Press SENSOR key, select Page 1 of the Sensor Menu and select the applicable velocity reference ON, or review the default selection (refer to Section 2.5.1.2 S9427- AT-MMO-010/WSN-7).
b. Select Page 2 of Sensor Menu and select EC ON to select EC position reference.
NOTE: Automatic acceptance or operator review of position fix data prior to acceptance of position fixes by the navigation system is selectively controlled by setting of the Reset function on the Mode menu. Selection of the Reset function is a matter of operation preference. A suggested method is to set the Reset function to Review and manually review the first fix from the navigation aid; then set the Reset function to Auto to allow all subsequent fixes to be automatically accepted/rejected without operator intervention. Operator advisory faults will alert the operator of bad fix data. 4-93 UNCLASSIFIED
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With EC selected as the position reference for align, a velocity reference must also be available. The velocity reference may be manual entry or may be from the configured velocity reference source.
c. Press MODE key. On the Mode Menu, set Reset Mode function <6> key to operation preferences for operator review or automatic acceptance of position fixes from the navigation aid. (REVIEW, AUTO REVIEW, or AUTO). Selection of REVIEW will require operator accept/reject of all position fix data prior to application of a position fix reset.
d. If NAV ENABLE = NO, the AN/WSN-7B(V) will transition through ALIGN-C and reach GYRO state indicating full attitude accuracy. If NAV ENABLE = YES, the AN/WSN-7B(V) will transition through NAV-C and reach NAV state indicating that the AN/WSN-7B(V) has achieved full attitude, velocity, and position accuracy.
e. The selection of EC as an external position reference can remain ON for normal steady state operation of the AN/WSN-7B(V). When EC position is available and valid, the AN/WSN-7B(V) will remain slaved to the EC position. During periods of time when EC is not available or is invalid, the AN/WSN-7B(V) will provide position based on inertial measurements from the last reference position reset. Normal steady state operation requires a reference velocity for damping of inertial velocities.
Alignment Sequence. After power is turned on, the AN/WSN-7B(V) self-aligns system roll, pitch, and heading using the reference velocity and internal sensors. The self-align process outlined in Table 4-10 and Figure 4-46, takes place automatically following power-up self-test and consists of three stages:
• Leveling and Coarse Align.
• Latitude Coarse Align.
• Fine Align.
The latitude coarse align period is not used if any of the following operation conditions are valid:
• A position fix is accepted from the selected GPS or is entered manually by the operator at power-up.
• The NVRAM stored value of latitude and longitude are valid.
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The AN/WSN-7B(V) will automatically transition through this self-align process and achieve a steady state operation as an Attitude and Heading Reference (GYRO) using default velocity reference.
Reference velocity should be provided during the self-align process using either a synchro speed input (VSYN ON) or digital speed input (VDIG ON) or manual velocity (VMAN ON). If no reference velocity input is provided, a value of zero reference velocity is used during the align period. If the ship is underway during this time, heading align error will be proportional to the ship velocity north.
System advisory 222 will alert the operator that no velocity reference data is available. For improved heading accuracy, the operator should provide correct manual velocity if an automatic source is not available.
Operating in Align Modes. After power-on, the AN/WSN-7B(V) leaves the STANDBY mode and starts to align the inertial platform. The following conditions apply:
a. If GPS is configured, the system will default to use GPS data at power-up as available.
b. The configured velocity reference (synchro or digital speed log) will be the default speed reference if available.
Within the first few minutes, roll and pitch attitude is determined and the mode word “ALIGN” is displayed.
During ALIGN, the AN/WSN-7B(V) aligns heading by aligning the inertial platform with respect to earth’s rotation (in a fashion similar to a gyrocompass). When heading is coarse aligned, the mode word changes from “ALIGN” to “ALIGN-C”. At ALIGN-C, the navigation system attitude outputs are of sufficient accuracy to be used for stabilization or steering purposes. The navigation system continues to align to the accuracy (fine align) required for an inertial navigator.
When heading is fine aligned, the mode word transitions from “ALIGN-C” to “ALIGN- F” or “NAV-C”. During a DOCKside align, once ALIGN-F has been reached, the navigation system can be put into NAVIGATE mode by de-selecting DOCKSIDE as a reference. If DOCKside is de-selected while coarse aligned (ALIGN-C is displayed), the navigation system will continue to align with available position and velocity data.
While underway (At-sea Align) and with GPS selected, the navigation system will automatically transition from ALIGN to NAV-C and then into NAVIGATE mode.
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TIME SINCE DISPLAY MODE POWER-UP PROCESS (Minutes) DOCKSIDE (DOCK ON) SELECTED STANDBY 0 Power-up self-test. ALIGN Coarse Align mode in progress 0 to 3
Level in Roll and Pitch. Leveling adjusts system roll and pitch values toward actual roll and pitch. Heading is initialized with a value of zero at start-up position of ship fore/aft axis.
Operator should select DOCK ON and enter ship position accurate to 0.05 nm. 3 to 8.5 Calculate heading coarse align reset.
Heading coarse align is applied to AN/WSN-7B(V) heading.
DOCKSIDE position is used for align. ALIGN-C (DOCK ON reference selected and initial position reset entered) Fine Align mode in progress 8.5 to 1200
With valid DOCKSIDE position, system will complete attitude Fine Align in 10 minutes at dockside (static). When NAVIGATE is enabled, DOCK OFF, and a valid velocity reference is selected by the operator prior to the ship leaving dockside, system will switch to NAV-C mode. ALIGN-F (DOCK ON reference selected) Fine Align mode completed 1200 with DOCKSIDE position reference Steady state operation after attitude align if DOCK ON remains selected. When NAVIGATE is enabled, DOCK OFF, and a valid velocity reference is selected by the operator prior to the ship leaving dockside, system will switch to NAV mode. NAV (DOCKSIDE position reference removed) Full specification accuracy Navigation mode. 1200 with DOCKSIDE position reference removed System will continue self-calibrate with available position data.
Table 4-10.— Alignment Sequence and Settling Times for Inertial Navigator.
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DISPLAY MODE TIME SINCE POWER-UP (Minutes) PROCESS AT SEA (GPS OR EC ON) SELECTED STANDBY 0 Power-up self-test. ALIGN 0 to 3 Coarse Align mode in progress
Level in Roll and Pitch. Leveling adjusts system roll and pitch values toward actual roll and pitch. Heading is initialized with a value of zero at start-up position of ship fore/aft axis. 3 to 8.5 Calculate heading coarse align reset.
Insert heading coarse align.
Determine latitude value to be used for align or if the process should continue with latitude coarse align.
NOTE:
If latitude is entered from the GPS or is entered manually at the AN/WSN-7B(V), use input latitude for Fine Align. or If NVRAM stored latitude is valid, use stored latitude for Fine Align. ALIGN-C (At Sea with GPS ON selected) 8.5 to 30 Fine Align mode in progress
With valid initial position, system will complete Coarse Align in 30 minutes at sea (under motion) and will switch to NAV-C mode. NAV-C Fine Align mode completed 10 (not moving)
30 (moving) Navigate transition state if Nav Enable function is set YES and at least one position reset has been applied.
System enters this mode from Fine Align if internal performance measure indicates that navigation performance does not yet meet specification.
Reduced accuracy inertial position and velocity, and valid roll, pitch, and heading data is available. NAV 1200 with sufficient reference data Full specification accuracy Navigation mode.
NAV is displayed if at least one position reset has been applied and navigation data is within specification. System will continue self-calibrate with available position data.
Table 4-10(Cont’d).— Alignment Sequence and Settling Times for Inertial Navigator.
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DISPLAY MODE TIME SINCE POWER-UP (Minutes) PROCESS AT SEA (NO INITIAL POSITION) OR NAVIGATE NOT SELECTED STANDBY 0 Power-up self-test. ALIGN 0 to 3 Coarse Align mode in progress
Level in Roll and Pitch. Leveling adjusts system roll and pitch values toward actual roll and pitch. Heading is initialized with a value of zero at start-up position of ship fore/aft axis. 3 to 8.5 Calculate heading coarse align reset and cos (latitude) reset.
Insert heading coarse align.
Determine latitude value to be used for align or if the process should continue with latitude coarse align.
NOTE: If latitude is entered from the GPS or is entered manually at the AN/WSN-7B(V), use input latitude for Fine Align. or If NVRAM stored latitude is valid, use stored latitude for Fine Align. ALIGN-C (Without initial position) 8.5 to 240 Fine Align mode in progress
If valid initial latitude is not provided, system will complete Coarse Align in 240 minutes either while static or at sea (under motion). System will go to GYRO but will not progress to NAV-C or NAV mode unless a position fix or position slew is entered. GYRO 15 (not moving) 45 (moving) 240 (no initial position) Fine Align mode completed. (NOTE 1) Steady state operation if Nav Enable function not set YES or no position reset has been applied.
Valid roll, pitch, and heading data is available. NOTE:
1. GYRO mode is a valid system operating state when:
a. The system is selected to operate as a gyrocompass [Navigate Enabled (NO) selected in the off-line configuration or in the on-line MODE menu]
b. No valid position reset has been applied to the system. Table 4-10(Cont’d).— Alignment Sequence and Settling Times for Inertial Navigator.
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NOTE: This is a representative graphic. Consult S9427-AT-MMO-010/WSN-7, Chapter 2 for Alignment Sequence Timing. Figure 4-46.— Alignment Sequence Timing Diagram. 4-99 UNCLASSIFIED
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4.10.11 Monitoring and Changing System Parameters
Selecting the Velocity Damping Mode and Source:
Selecting Damped or Undamped Operation. Based on the selection of the damping mode (MODE menu, Damping function) damping of the horizontal velocity loops will either be automatically selected based on the filtered velocity or will be manually selected to fully damped or fully undamped operation.
• When Auto damping is selected, the system automatically selects damped (AUTOD displayed) or undamped (AUTOU displayed) mode based on comparison of the reference velocity with the systems inertial velocity. As long as this corrected difference does not exceed the internal limit, the system uses reference velocity to damp inertial velocities. If the corrected difference between the reference velocity and inertial velocity exceeds an internal limit, the system will automatically switch to undamped mode. Automatic damping (Auto selected) is the preferred mode since it provides velocity damping and minimizes the effects of ship’s speed reference errors due to ship’s maneuvers or other sources.
• When Man Damp is selected, the system is forced into the damped mode (MAND displayed) regardless of the reference comparison. The operator can use this function to force the system to accept data from the velocity source and keep the system damped. Selection of Man Damp is used to force manual damping if advisory Fault Code 223 is displayed. This indicates that the system has remained undamped for an excessive period of time with Auto damping selected.
• When Man Undamp is selected, the system is forced into the undamped mode (MANU displayed) regardless of the reference comparison. This function is useful if the system is in NAVIGATE Mode and reference velocity is incorrect or is not available from the selected device. An example of this condition would be the case where an EM log with a retractable sword is the selected damping source but cannot be used until operating depth permits or the doppler speed log velocity is incorrect due to water depth.
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Selecting the Horizontal Velocity Damping Reference:
When automatic damping is selected, damping and un-damping of the velocity loop is determined by the filtered velocity differences. The criterion for determining the damping mode is periodically tested, and the system switches from damped to undamped operation whenever the filtered velocity difference exceeds the internal limit. The transition from undamped operation to damped operation will occur whenever the filtered velocity’s differences have settled to within the internal limit.
The available speed reference interface for velocity damping is determined by the system configuration. The speed reference interface is selected on SENSOR Menu, Page 1. If either VDIG or VSYN is selected and is not available or is invalid, the AN/WSN- B(V) will default to using a zero water speed for damping. This mode of operation will be announced with display Fault code 222. AN/WSN-7B(V) errors will be proportional to ship velocity north. Correct manual speed should be entered in the event of loss of valid speed reference.
4.10.12 Selecting for Display During operation, the operator can select any display of system parameters and data in addition to the normal position, heading, velocity reference speed, day and time display. Display of additional parameters is not necessary for normal system operation; however, selection of these display functions is useful for manually verifying data transmitted to external systems. Data is selected for display by pressing the DISPLAY key and selecting the PAGE with the parameters to be displayed (see Table 4-9).
Selecting Transverse Coordinate Mode and Display
In a gyro stabilized platform, torque values based on the Tangent (Tan) and Secant (Sec) of latitude are used in system control loops. While the AN/WSN-7B(V) is a strapdown system based on ring lasers, calculations involving these functions are also utilized. As the AN/WSN-7B(V) approaches 90-degrees latitude, these values become indeterminate (approach infinity) and are no longer valid for calculations. In addition, at high latitudes, the magnitude of east/west vectors has less meaning. For this reason, an alternate (Transverse) Earth coordinates reference system is utilized when the AN/WSN-7B(V) is operating at latitudes greater than approximately 85 degrees.
The Transverse North Pole is located at the intersection of the geographic 180-degree meridian and the equator. The geographic 90-degree and 270-degree meridians become the Transverse equator, and the geographic equator becomes the Transverse 90-degree and 270-degree meridians. Refer to Figure 4-47.
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Figure 4-47.— Earth Coordinates References.
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Three modes of selection are available for selecting operation using Transverse coordinates reference. These are selected from MODE menu, Page 1 and are: AUTO, MNORM, and MTXVS. Normally, AUTO should be selected. When AUTO is selected, the AN/WSN-7B(V) automatically switches from normal to Transverse coordinates when the AN/WSN-7B(V) crosses 86 degrees north/south latitude and switches back to normal coordinates when the AN/WSN-7B(V) crosses back through 84 degrees. Selecting MNORM forces the AN/WSN-7B(V) to continue using the normal (geographic) reference regardless of operating latitude. Selecting MTXVS forces the AN/WSN-7B(V) to use Transverse coordinates reference regardless of operating latitude and longitude. The selected mode and the operating mode presently being used by the AN/WSN-7B(V) is displayed in the COORDinates field of the display (see Figure 4-44). Displayed indications are:
• ANORM - AUTO selected, normal coordinates being used.
• ATXVS - AUTO selected, Transverse coordinates being used.
• MNORM- Normal coordinates manually selected.
• MTXVS - Transverse coordinates manually selected.
In addition to the operation mode, the position and heading can be displayed in either normal or transverse coordinates regardless of the selected AN/WSN-7B(V) operation reference. Display of position and heading is selected from AUX FUNC menu, Page 1, Display Coord function. This function is a toggle selection. When Transverse position and heading are being displayed, the LAT, LON, and HDG indications are replaced by Transverse Latitude (TLT), Transverse Longitude (TLN), and Transverse Heading (THD) respectively.
4.10.13 Accepting and Entering Position Fixes Position resets are based on inertial position, an uncertainty area (system accuracy) defined by system calculated sigma latitude (SN) and sigma longitude (SE), and position fix data. The estimated values of SN and SE increase with time, but are decreased by the application of a position fix. Entry of valid fix data with suitable fix variances should always improve system accuracy.
Several available functions allow the operator flexibility in selecting the manner in which automatic fixes are accepted or rejected, and allow review of last accepted fix data. They also allow review of and overriding acceptance of pending fixes which have been rejected by the system as being unreasonable.
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The fix review mode can be selected from the Mode menu, Reset Mode function. The mode selected on this menu determines how the system involves the operator in the process of review and acceptance of fixes from external position sensors.
Manual fixes can be entered into the system at any time using the Mode menu, Fix function. When fixes are entered manually, the system checks the fix data for reasonableness in the same manner as for fixes received from external position sensors. If the manually entered fix data is determined to be invalid, an appropriate fault code is displayed and a Reset Data menu is displayed. This allows the operator to review the entered fix data and either force acceptance or discard the data.
At any time, the operator can review the data for the last position fix accepted by the system. This function is selected from the Display menu, Page 1, Last Reset function. Figure 4-48, presents an outline of the various states associated with the position fix functions.
Figure 4-48.— Position Fix, Data Entry and Review Functions. 4-104 UNCLASSIFIED
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Processing of a Position Fix
When a fix is entered, either manually or automatically from a navigation aid, such as a GPS, the Kalman Filter compares the inertially derived position with the available position reference (fix) data and operates on these measurements to generate corrections to the modeled system states. The process attributes navigational errors to sensor or system drifts and then modifies the Kalman parameters to neutralize the error pattern. Corrections are made to latitude, longitude, velocities, tilts, heading, gyro biases, and horizontal accelerometer biases. The Kalman Filter operates on the fix as entered. Fix processing within the Kalman Filter calculates the latitude and longitude resets using the difference between system position and fix position. The Kalman Filter calculates a weighting based on the estimate of system accuracy (SN and SE) as compared to the fix accuracy as defined by fix sigma latitude (FSN) and fix sigma longitude (FSE). This weighting is used to determine the proportion of the difference in position to be applied as the position reset. If a fix is entered with a small sigma value (high accuracy), then a large percentage of the difference in position will be applied as a reset.
The difference between the system position and the fix position does not determine the weighting. The weighting is determined by the estimated system accuracy and fix accuracy. The estimated value of system error increases with time, but is decreased by the application of fix data as a reset. This results in a higher weighting being given to fix data following a long navigate period as compared to fix data entered closely spaced in time. The latitude and longitude weighting or gain (K) is calculated using the system sigma values at the time of fix and the fix sigma values (or the sigma values calculated from Radial Position Error (RPE) data) which are used as entered:
K = (system sigma) 2/((system sigma)2 + (fix sigma)2) FSN and FSE = 0.707 × RPE
The north and east distances that the reset will move the system position (DN and DE) are given by:
Reset = K × (fix position - system position)
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Criteria for Acceptance of a Position Fix
When a position fix is entered, the Kalman Filter checks the fix using the following limits:
(Position error)2 = (system lat - fix lat)2 + [(system lon - fix lon) x cos(fix lat)]2 Error limit = 9 x (SN2 + FSN2 + SE2 + FSE2)
If (Position Error) 2 is greater than the Error Limit, then an operator advisory (Fault Code 209) is announced, the fix is rejected, and may be held for review. The system resets for latitude, longitude, velocity, and various system feedback parameters are also checked using appropriate limits similar to the above limit on fix position error. If a reset exceeds an error limit, then an operator advisory (Fault Codes 212 through 217) will be declared.
If the fix data is unreasonable, the operator should then review the reset DN and DE (the north and east distances the reset will move the system solution) and either correct the fix data or, if the fix data is known to be accurate, accept it and “force” the reset.
If operation of the AN/WSN-7B(V) during the prior navigation period has excessive error due to any cause (loss of reference velocity, operation in an area of changing vertical deflection, excessive time since last reset, etc.), then the operator should apply the position fix data as a position slew.
The operator is alerted (using Fault Codes 209 - 217) to fix data or a reset outside acceptable bounds.
Reset Modes and Operator Acceptance of a Position Fix
The reset mode (MODE Menu, Reset Mode function) defines the conditions for fix entry and is set by the operator. The effect of the fix is calculated and can be displayed for review before acceptance; but once the reset is applied, its effects cannot be undone. The operator may select from the following reset modes:
a. REVIEW Reset mode - An operator accept/reject is required after review of the reset data. When a position fix is received, the system will prompt the operator by announcing a fault and by displaying Fault Code 221. To review and either accept or reject the fix data, select DISPLAY menu, Page 1, Last Reset function.
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NOTE: Fix must be either accepted or rejected by the operator or the system will not process new fix data for ten (10) minutes.
b. AUTO REVIEW Reset mode - Position fixes or resets which meet the error limit criteria are applied without operator review. Position fixes or resets which do not meet the error limit criteria are held for operator review. When a position fix or reset is rejected, the system will prompt the operator by announcing a fault and by displaying a Fault Code. To review the out of limit fix data, select DISPLAY menu, Page 1, Last Reset function. If the fix is not reviewed within 10 minutes, the fix data is discarded. Additional fixes received during this time are not processed and may be overwritten by later fix data.
c. AUTO Reset mode - No advisory Fault Codes are provided. Position fixes or resets which do not meet the error limit criteria are not applied. Position fixes which do meet the error limit criteria are applied to the system without operator review. Automatic acceptance/rejection of position fixes is the mode normally selected for system operation.
CAUTION: Depending on the review mode selected, a rejected fix may be entered by the operator. These functions allow the operator to force the acceptance of a good fix to correct system errors. This is useful if a fix is rejected as a result of errors in the system’s estimate of position. Care should be taken when manually entering or accepting a fix which has been rejected. Acceptance of an unreasonable fix introduces position errors and will cause calculations of position and velocity to diverge. Changing system position with a position slew will avoid introducing errors and will reset system Lat, Lon to reference position.
NOTE: Any position fix for which the resulting radial position reset exceeds 2 nm should be reviewed closely before accepting. Any fix which exceeds the range of the latitude and longitude reset (DN and DE) display (+/- 100 nm) is immediately suspect.
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Automatic Entry of a Position Fix or Position Slew
Fixes may be entered automatically via the data interface from a configured navigation aid (SENSOR menu, page 2, GPS (or GNMEA) set to ON). These fixes will either be automatically accepted or rejected by the system, or the operator will be prompted to review the fix data and manually accept or reject the fix depending on the reset mode selected at the MODE menu, Reset Mode function (see above).
If continuous position data is available from GPS (NTDS or NMEA interface), then the AN/WSN-7B(V) position output is slaved to the GPS input and will provide performance similar to GPS. If AUTO Reset mode is selected, then erroneous GPS data will be rejected. If GPS data has not been continuously available, then the operator can select AUTO/REVIEW mode to review any unreasonable fixes prior to application of reset.
4.10.14 Manual Entry of a Position Fix or Position Slew
Position Fix vs Position Slew
Position data is entered into the system either as a fix or as a slew. The way that the data is entered determines how it affects system operation. Refer to Section 2.7.1 of S9427- AT-MMO-010/WSN-7.
• A position slew directly updates the system’s position estimate to agree with the current position data entry but does not change the system’s navigation filter values. The first position data applied to the system (either automatic or manual) after start-up is always applied as a slew.
CAUTION: Ensure that position slew data is accurate. Entry of inaccurate position slew data will cause the system’s navigation performance to be adversely affected.
• A position fix is used to correct the system estimate of position and to update the navigation filter (self-calibrate). The amount (or weighting) of the fix is determined by the system’s estimate of fix accuracy and by the elapsed time since the last fix was applied.
CAUTION: Ensure that position fix data is accurate. Entry of inaccurate position fix data will cause the system’s navigation performance to be adversely affected.
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General Information
A manual position fix may be entered at any time when the system is in navigate or align modes, even when navigation aids are selected for automatic entry of position fixes.
To perform a manual position reset (i.e., to enter a fix), the operator must enter fix time; latitude, longitude, and estimate of fix accuracy (Sigma value of the fix) in nautical miles.
After the fix data is entered through the display, the system will not immediately use the data for reset, but will first calculate the system parameters based on the fix data. The operator must review the calculated effect of accepting the fix by examining the delta (DN and DE) and sigma (FSN and FSE) latitude and longitude values. If it is determined that the reset data is acceptable, the manual fix is accepted for reset by pressing the ENTER key. If the operator decides not to accept the fix, he may clear the fix data by pressing the CLEAR key. If the ENTER or CLEAR key is not pressed, the system will retain only the last accepted fix.
NOTE: The system will find the manual fix unreasonable if the reset exceeds the error limits described in Section 2.7.2 of S9427-AT-MMO-010/WSN-7. Care must be taken when manually forcing acceptance of a fix which has been rejected by the system. Forcing acceptance of an unreasonable fix introduces position errors and will cause the system calculations of position and velocity to diverge. Changing system position with a position slew will avoid introducing errors into the navigational filter and will reset system LAT, LON to reference position.
Manual Fix Entry Procedure
Proceed as follows:
a. Press MODE key and select Fix. The display will prompt the operator for entry of fix time. Current time is displayed and may be accepted by pressing ENTER. To enter any other time (up to a maximum of 1 hour in the past) press CLEAR and enter the fix time in HH:MM:SS format. The BACKSPACE key may be used to eliminate data entry errors. Press ENTER to accept the entry.
b. The display will now prompt for entry of fix latitude. Current system latitude is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter fix latitude in DD 0MM.mm’ format, and North or South Hemisphere. Press ENTER to accept the entry.
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c. The display will now prompt for entry of fix longitude. Current system longitude is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter fix longitude in DDD0MM.mm’ format, and East or West Hemisphere. Press ENTER to accept the entry.
d. The display will now present two options for entry of fix error estimate, 1/North and East Error or 2/Radial Position Error. Only one option may be selected. North and East Error: Press <1> key to select North and East Error format. The display will now prompt for entry of fix Sigma North. Current Sigma North (SN) is displayed, and may be accepted by pressing ENTER.
To enter a different value, press CLEAR and enter fix Sigma North in xx.x NM format. Press ENTER to accept the entry. The display will now prompt for entry of fix Sigma East. Current Sigma East is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter fix Sigma East (SE) in xx.x NM format. Press ENTER to accept entry.
Radial Position Error: Press <2> key to select RPE format. RPE is equal to 1 sigma CEP (Circular Error Probable). The CEP defines that circular area within which the actual ship position exists with a certain defined probability. The RPE defines that probability as 68.3% (i.e., the size of the CEP is defined by RPE such that there is a 68.3% probability that the ship’s position exists within the CEP). The display will now prompt for entry of RPE. Current system RPE is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter fix RPE in xx.x NM format. Press ENTER to accept the entry. The system now uses the RPE to calculate FSN and FSE.
NOTE: In either of these fix error estimate options, the Sigma values must reflect the true position fix accuracy. Assigning a large Sigma to an accurate fix will not disturb the system, but the reset will have a reduced correction to the system. On the other hand, assigning a small Sigma to an inaccurate fix will disturb the system and result in position and velocity divergence.
e. The display will now show the complete fix data, and prompt the operator to enter the fix by pressing ENTER or reject by pressing CLEAR. When the fix data is correct, press ENTER and the system will calculate and display the reset parameters.
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f. If the fix parameters are within the error limits, the system will prompt the user with “REASONABLE.” If outside the error limits, the system will prompt the user with “UNREASONABLE.” In either case, the operator has the following choices:
(1) Reject the fix by pressing CLEAR.
(2) Accept the fix by pressing ENTER.
(3) Do nothing and allow the fix to be discarded after 10 minutes.
NOTE: The system maintains a history of position data to allow fix computations using the data obtained up to 60 minutes prior to the current time. Fault Code 218 will be declared if the fix data is more than 60 minutes old or has an invalid time.
Manual Position Slew Procedure
Proceed as follows:
a. Press MODE key and select Slew. The display will prompt the operator for entry of fix time. Current time is displayed and may be accepted by pressing ENTER. To enter any other time (up to a maximum of 1 hour in the past) press CLEAR and enter the fix time in HH:MM:SS format. The BACKSPACE key may be used to eliminate data entry errors. Press ENTER to accept the entry.
b. The display will now prompt for entry of latitude. Current system latitude is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter new latitude in DD MM.mm’ format, and North or South Hemisphere. Press ENTER to accept the entry.
c. The display will now prompt for entry of fix longitude. Current system longitude is displayed, and may be accepted by pressing ENTER. To enter a different value, press CLEAR and enter new longitude in DDD MM.mm’ format, and East or West Hemisphere. Press ENTER to accept the entry.
d. The display will now show the slew data, and prompt the operator to enter the position slew by pressing ENTER or reject by pressing CLEAR. When the data is correct, press ENTER and the system will calculate and apply the position slew.
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4.10.15 Acknowledging and Identifying Fault Conditions The AN/WSN-7B(V) contains a complete and versatile fault indication system. The system provides five on-line sources for fault announcements.
• Three sets of relay contact closures for operator use to actuate audible or visual alarms.
• Two lamp drivers for operator use to actuate visible alarms.
• SYSTEM FAULT indicator lamp on front panel.
• Display of faults for operator.
• Display list of active faults.
At start-up and during operation, the AN/WSN-7B(V) BIT function continually monitors hardware and software functions and checks calculation results for reasonableness. Any fault condition detected by BIT is announced by setting appropriate relays, turning the SYSTEM FAULT indicator (DS2) ON, and displaying the Fault Code in the upper right corner of the display. Each detected condition results in the generation of a system Fault Code which is stored for display and review as long as the fault remains active.
Appendix B, Table B-1 of S9427-AT-MMO-010/WSN-7, provides a complete listing of all BIT Fault Codes, indicates the source of the fault, and indicates the classification(s) of the fault(s) with an asterisk in the adjacent classification column(s).
Appendix B, Table B-2 of S9427-AT-MMO-010/WSN-7, provides diagnostic information and references off-line BIT to be performed to verify and troubleshoot the fault condition.
Based on the type of Fault Code displayed, the operator may acknowledge the fault by pressing the ALARM ACK key and choose to continue operation of the AN/WSN-7B(V) or may take the unit out of service. Certain faults automatically shut down the AN/WSN- 7B(V) and cannot be overridden by the operator. The following list outlines the major fault classifications of interest to the operator:
a. Fault Codes classified as “operator advisory” inform the operator that manual intervention is required to review data or to select functions related to system operation. An example of an operator advisory code is Fault Code 221.
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b. Fault Codes classified as “non-critical” indicate that a fault condition exists which may be bypassed by changing operation modes or selecting other sensors, or by manual entry of data. Non-critical codes generally result from conditions which allow continued operation at reduced capability or at degraded performance levels. Non-critical faults may also result from a fault condition in the I/O, data messages, or in equipment external to the AN/WSN- 7B(V). An example of a non-critical code is Fault Code 222.
c. Fault Codes classified as “critical” indicate that a fault condition exists which makes the system unusable as a reference source. Critical faults may or may not result in automatic shutdown of the AN/WSN-7B(V).
NOTE: In addition to the defined Fault Codes, several “spare” code numbers are reserved for future expansion of the system. These codes will not be announced by the system during normal operation.
4.10.16 Operating with System Faults
NOTE: Before acknowledging each fault, first record the displayed Fault Code number.
If a fault is detected during operation, the appropriate relays are set and the Fault Code generated by the BIT function is displayed in the upper right corner of the display. To acknowledge the fault, press the ALARM ACK key. For each fault condition, proceed as follows: Determine the Fault type:
a. Operator advisory - Acknowledge advisory and perform required action.
b. Non-Critical fault - Acknowledge the fault and observe system operation to determine if the fault is cleared or if the fault condition is again announced, or appears in persistent fault list (AUX FUNC, Faults). If the fault condition is repeated, acknowledge fault and determine operating status or alternate mode for continued system operation. Record the Fault Code(s) displayed for future troubleshooting reference.
c. Critical fault - Record Fault Code(s) displayed for future troubleshooting reference. Turn off system power and tag system OUT OF OPERATION. Perform fault testing (refer to Chapter 5 of S9427-AT-MMO-010/WSN-7).
d. System automatic shutdown - Turn off system power and tag system OUT OF OPERATION. Perform fault testing (refer to Chapter 5 of S9427-AT-MMO-010/WSN- 7).
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The following paragraphs outline the recommended operator action with selected non- critical faults.
Speed Data Source Faults
For Fault Codes 36, 56, 57, 222, and 223:
Loss of speed data or unreasonable speed input will cause the system to switch to undamped operation. Loss of log data can result from the selected velocity reference or speed sensor equipment being turned off or switched to a test mode at the source. In installations where more than one synchro speed reference can be externally selected to provide the synchro speed input to the system, (such as synchro input from Rod 1 and Rod 2) loss of log may result when changing the external selection. If any of the indicated Fault Codes are displayed, it may be necessary to select manual entry of ship’s speed. If the system is operating with Auto damping selected and if the system is excessively undamped, an operator advisory (Fault Code 223) will be displayed.
This code alerts the operator to take corrective action. If the operator does not change the damping selection, the system will automatically go into the forced damped mode (AUTOD displayed) for the next 128 minutes using the currently selected speed data source as the velocity reference.
If Fault Code 223 is displayed, the operator should review the status of the selected velocity reference source. If the selected velocity reference is found to be accurate, then the operator may elect to manually select forced damping of the system (select Man Damp) for approximately two hours and then return to Auto damping.
If the operator finds that the selected velocity reference is not sufficiently accurate to provide velocity damping, then the operator should select SENSOR Menu, Page 1, and select a different source as the velocity reference. Select Man Damp for approximately two hours, or select force undamping of the system (select Man Undamp).
Selection of either Man Damp or Man Undamp will reset the 128 minute forced damping timer.
If a valid speed reference is not available, select SENSOR Menu, Page 1, VMAN ON and manually input ship’s forward water speed from the keypad. Ship’s speed should be monitored by the operator and the manually entered value should then be changed whenever the ship’s speed changes by more than ±10 percent from the set value.
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Velocity Reference Error Faults
For Fault Codes 210, 211, and 212:
Fault Codes 210 and 211 indicate that the reference velocity data does not agree with the system calculated velocity within the system reasonableness bounds.
Fault Code 212 indicates that a reset resulting from the reference velocity data is outside the system reasonableness bounds.
The operator should review the provided velocity data during the time when faults are being reported (only multiple fault occurrences will degrade navigation performance). The system may undamp if Auto damping is selected (refer to Section 2.5.1 of S9427- AT-MMO-010/WSN-7). If reference velocity data is found to be invalid or noisy, then another velocity reference should be selected.
If reference velocity is found to be continuously valid, then the system should be manually damped for approximately two hours, then returned to Auto damping. If the faults recur, the system may need realignment using KF reinit to restore full navigation accuracy.
Position Reference Error Faults
For Fault Codes 209, 213 through 217:
Fault Code 209 indicates that the position fix data does not agree with the system calculated position within the system reasonableness bounds.
Fault Codes 213 through 217 indicates that a reset resulting from the position data is outside the reasonableness bounds.
CAUTION: Forced acceptance of correct position fix data over a period of time will restore a system to full navigation data accuracy; however, forced acceptance of incorrect position fix data will quickly degrade navigation performance. It may be necessary to realign the system following a Kalman Filter re-initialization to restore navigation accuracy if an invalid position fix has been force accepted.
If the position fix was processed in a Review or Auto/Review mode, then the operator should review the data for correct LAT, LON, fix time, and fix variance. If the data is found to be incorrect, then the operator can reject the fix. If the data is found to be correct, then the operator can force acceptance of the fix. The error codes will occur again on a forced acceptance of the position fix. 4-115 UNCLASSIFIED
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GPS or GPS I/O Faults
For Fault Codes 53 through 55:
Failure of the GPS position sensor input to the AN/WSN-7B(V) will result in slow degradation in the accuracy of the estimate of position. Position performance degrades approximately as a function of the square root of time as shown in Figure 4-49. The chart below is shown for illustration of proportion only, no units are implied. System performance can be maintained by periodically entering a position fix manually. To manually enter position fix data, select MODE menu, Fix function.
Figure 4-49.— Position Estimate Accuracy vs. Time without Position Update.
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External Serial Interface or I/O Processor Fault
For Fault Codes 256 through 282, 338, 347 through 351:
Detection of a fault which results in any of the listed Fault Codes will cause the I/O Processor to shut down. While the AN/WSN-7B(V) may continue to operate normally and to provide local display of data, as well as output of synchro format data, input of GPS data, and all other input and output data messages will be halted.
To restart the I/O Processor, clear the Fault Code(s) and then select the AUX FUNC menu Page 2, I/O Restart function, and set the I/O Processor to Enabled. If the fault condition is cleared by restarting the I/O Processor, normal operation can be resumed. If the operator was successful in restarting the I/O Processor, the “Enabled” message will change from flashing to non-flashing. If the operator was not successful in restarting the I/O Processor, the “Enabled” message will again read “Disabled”.
If the fault condition recurs, select the AUX FUNC menu I/O Config function, disable the associated interface port(s), and then select the I/O Restart function to enable the I/O Processor. If the fault condition is cleared, enable each interface port (one at a time) and check operation to determine if the fault is in the I/O communications interface port or in an external device. If the condition cannot be corrected by use of the above procedure, the AN/WSN-7B(V) must be shut down and then restarted in the off-line Test Mode so that troubleshooting can be performed to isolate and correct the fault condition. Refer to Section 5.2.2 of S9427-AT-MMO-010/WSN-7.
Laser Intensity Monitor Faults
For Fault Codes 105, 106, and 107:
The voltage sample associated with the laser intensity for each ring laser gyro in the Inertial Measuring Unit (IMU) is periodically compared with a pre-established lower limit (or “pull voltage”). If the sample voltage falls to the pull voltage, the system will announce a fault for the affected gyro. This fault is intended to warn the operator that the gyro may be reaching the acceptable limit for reliable operation and that the IMU should be replaced at the next scheduled maintenance opportunity. When the fault is acknowledged, a seven day timer is reset which prevents the fault from being announced again within the next seven days. This function allows the AN/WSN-7B(V) to continue operation without the annoyance of a repetitious fault being announced. Detection of these faults does not affect other system operation and does not indicate an immediate operational concern.
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4.10.17 Viewing Memory Contents The contents of each memory location in the Navigation Processor can be inspected while the system is operating on-line. This function, selected from AUX FUNC menu Page 2 is incorporated into the operating program primarily to assist software development and has no operation or maintenance significance for the level of information addressed by this technical manual.
To inspect Nav Processor memory, select Mem Inspect. Follow menu prompts to select the memory type (16 or 32 bit) and then enter the address (in hexadecimal) of the first memory location to be inspected. To step up or down sequentially through the memory address, press the NE+ or SW- keys. To change to a new starting address, press CLEAR, select the change address function and enter a new starting address. The contents of memory locations cannot be changed using this function.
4.10.18 On-line Simulated Attitude, Velocity, and Position Outputs The on-line Simulated Outputs function is similar to the off-line Simulated Outputs function described in Section 5.4 of S9427-AT-MMO-010/WSN-7 This function provides a means of generating static output data values from the AN/WSN-7B(V) while the unit is operating in a normal mode. This function is available for checking the operation of external systems which receive data from the AN/WSN-7B(V). The simulated values are applied on all applicable configured synchro and digital I/O functions.
To select and enable the simulated outputs functions, proceed as follows:
a. Press AUX FUNCtion key, select Page 2 and select 1. Simulated Outputs.
b. Observe that the Simulated Outputs Menu is displayed. This menu provides an enable/disable toggle function for the simulated outputs and provides three categories of menus which may be selected for setting the output data values. Displayed functions are:
1 Enable Simulated Outputs = ON (or OFF)
2 Modify Attitude Output
3 Modify Velocity Output
4 Modify Position Output
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c. At the Simulated Outputs Menu, if Enable Simulated Outputs is set to OFF, press the <1> key to toggle the selection to ON.
d. Select the applicable category of operation functions <2>, <3>, or <4> key.
e. When any category of operation functions is selected, a list of associated parameters will be displayed. To change the value of any parameter, press the number key corresponding to the number of the parameter. The display will indicate the currently set data value for the parameter and the bottom line will display “ENTER to accept, CLEAR to reject”. To change the data, press CLEAR. The data value will change to a data entry field to allow entry of a new value and the operator entry will be echoed directly into the field.
f. After the new value has been entered, press the ENTER key. Output value will then slew to the entered value.
Table 4-11 provides a brief outline of the simulated output settings associated with each of these functions.
SIMULATED FUNCTION DESCRIPTION ENTRY RANGE 2 Modify Attitude Output Functions (Select by pressing the <2> key) 1 Roll Sets a positive or negative roll angle which is output from Synchro Converter CCA (A15). -45 to +44.99 degrees 2 Pitch Sets a positive or negative pitch angle which is output from Synchro Converter CCA (A15). -45 to +44.99 degrees 3 Heading Sets a heading angle which is output from Synchro 0 to 359.99 degrees Converter CCA (A14). 3 Modify Velocity Output Functions (Select by pressing the <3> key) 1 Vel N Sets a north/south velocity value which is output in all applicable output data messages. -128 to +127.99 knots (North Velocity) 2 Vel E Sets a east/west velocity value which is output in all applicable output data messages. -128 to +127.99 knots (East Velocity) 4 Modify Position Output Functions (Select by pressing the <4> key) When entering Latitude and Longitude, the N/S field is set with the N/E/+ or S/W/- key 1 Latitude Sets a latitude value which is output in all applicable output data messages. 0 to 90 degrees 0 to 59.99 minutes 2 Longitude Sets a longitude value which is output in all applica- ble output data messages. 0 to 180 degrees 0 to 59.99 minutes
Table 4-11.— Simulated Outputs Description.
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4.11.0 RING LASER GYRO NAVIGATOR INERTIAL NAVIGATION SYSTEM, AN/WSN-7(V)1, -7(V)2, -7(V)3 The AN/WSN-7(V) Ring Laser Gyro Navigator (RLGN) (Figure 4-50) is part of the AN/WSN-7(V) INS. Each RLGN is a self-contained unit that employs an Inertial Measuring Unit (IMU) using three single-axis Ring Laser Gyros (RLGs) and three accelerometers as the inertial reference to determine ship’s position, velocity, heading, roll and pitch. The system continuously accepts ship’s speed information from a speed log and/or Global Positioning System (GPS), and periodically accepts ship’s position information from an external navigation reference (GPS), manually via a keypad and display on the RLGN control panels, or from the IP-1747/WSN Control Display Unit (CDU).
Figure 4-50.— PART NUMBERS CN-1695/WSN-7(V), CN-1696/WSN-7(V), and CN- 1697/WSN-7(V).
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As shown in Figure 4-51, sheet 1 and Figure 4-51, sheet 2, each RLGN is part of a dual system that provides ship’s heading, log speed and distance, ship’s velocities, pitch, roll, attitude rates, position and time data to other ship’s systems and indicators. The AN/WSN-7(V) INS comprises two single-enclosure AN/WSN-7(V) RLGNs and a single IP-1747/WSN CDU, supported by a GPS Navigator interface and a Speed Log data interface. Only the RLGN and the power and signal interface to the RLGN are covered in this technical manual. The IP-1747/WSN is Unit 4 of the RLGN, but it has a separate technical manual. Refer to appropriate technical manuals for details on installation, operation, and maintenance of the CDU, GPS, Doppler Sonar Velocity Log (DSVL), and other support equipment. (See Table 4-12.)
Figure 4-51.— Typical System Configuration (Sheet 1 of 2).
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Figure 4-51.— Typical System Configuration (Sheet 2 of 2).
DOCUMENT NO. DESCRIPTION NAVSEA Dwg. No. 7100680 Inertial Navigation System AN/WSN-7(V) Drawing List NAVSEA Dwg. No. 7100681 Inertial Navigation System AN/WSN-7(V) Block Diagram NAVSEA Dwg. No. 7100682 Inertial Navigation System AN/WSN-7(V) Summary List of Installation Materials NAVSEA Dwg. No. 7100683 Inertial Navigation System AN/WSN-7(V) Input/Output Sheets NAVSEA Dwg. No. 7100684 Inertial Navigation System AN/WSN-7(V) Cable Running Sheets NAVSEA Dwg. No. 7100685 AN/WSN-7(V) Ring Laser Gyro Navigator Outline and Installation Drawing MIL-STD-1397B(NAVY) Military Standard Input/Output Interfaces, Standard Digital Data, Navy Systems NAVSEA S9427-AN-IDS-010/WSN-7 Interface Desi gn Specification, Super Channel to User for the AN/WSN-7(V) Ring Laser Gyro Navigator (RLGN) Table 4-12.— Documents Required but Not Supplied.
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DOCUMENT NO. DESCRIPTION NAVSEA SE174-AB-IDS-010/GPS Interface Design Specification for Shipboard External Computer and Navigation Satellite Timing and Ranging (NAVSTAR) Global Positioning System NAVSEA T9427-AB-IDS-050/WSN-7 Interface Design Specification, Aircraft Carrier Navigation System (CVNS) to External Computer EE17A-AA-OMI-010 Operator and Maintenance Manual, Organizational Level (Windows software version) with for Control Display Unit, IP-1747/WSN-7 and Secondary Change A Control Display Unit, IP-1746/WSN-7A EE17A-AA-OMI-A10 (Linux software version) Operator and Maintenance Manual, Organizational Level for Control Display Unit, IP-1747/WSN-7 and Secondary Control Display Unit, IP-1746/WSN-7A EE17A-AC-IEM-010/ EE17A-AD-IEM-010 IP-1747/WSN Control Display Unit and IP-1746/WSN-7A Secondary Control Display Unit Interactive Electronic Technical Manual and Interactive Courseware NAVSEA S9427-AN-IDS-010/WSN-7 Interface Desi gn Specification, Superchannel to User for the AN/WSN-7 Ring Laser Gyro Navigator (RLGN) System NAVSEA S9427-AN-IDS-020/WSN-7 Interface Desi gn Specification, Inertial Navigation System AN/WSN-7(V) to External Computer - for Low Level Serial (MIL-STD-1397B Type E) Digital Communication NAVSEA S9427-AN-IDS-030/WSN-7 Interface Desi gn Specification, Inertial Navigation System AN/WSN-7(V) to Users - for MIL-STD-1397 Type D Serial Channels No. 1 and No. 2 NAVSEA S9427-AN-IDS-040/WSN-7 Interface Desi gn Specification, Inertial Navigation System AN/WSN-7(V) to External Computer in an Output Only Configuration - for Parallel Channels NAVSEA S9427-AN-IDS-050/WSN-7 Interface Desi gn Specification, Ring Laser Gyro Navigator (RLGN) System to External Computer NAVSEA S9427-AN-IDS-070/WSN-7 Inertial Navigation System AN/WSN-7 External Computer for Parallel (MIL-STD-1397B Type A) Input/Output Digital Communication, Interface Design Specification NAVSEA S9427-AP-IDS-010/RLGN Navigation Operati onal Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) NAVSEA S9427-AP-IDS-020/RLGN Navigation Operati onal Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) NAVSEA S9427-AP-IDS-030/RLGN Navigation Operati onal Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN) NAVSEA S9427-AP-IDS-040/RLGN Navigation Operati onal Program Interface Design Specification for Use with the Ring Laser Gyro Navigator (RLGN)
Table 4-12(Cont’d).— Documents Required but Not Supplied. 4-123 UNCLASSIFIED
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DOCUMENT NO. DESCRIPTION NAVSEA S9427-AN-IDS-080/WSN-7 Interface De sign Specification for the AN/WSN-7(V) Ring Laser Gyro Navigator (RLGN) to user via ATM Local Area Network (LAN) 03956 SCM-25417 Interface Design Specification for the AN/WQN-2 Doppler Sonar Velocity Log (DSVL) to AN/WSN-7(V) Ring Laser Gyro Navigator (RLGN) Interface Part Number 03956-JA17-6608 DSVL Data Interface Supplement for CN-1695(V)/WSN- 7(V) Ring Laser Gyro Navigator (RLGN) 03956-PL1813788-Var DSVL Interface Field Change Kit Parts List NAVSEA SE178-A2-MMM-010 Doppler Sonar Velocity Log (DSVL), AN/WQN-2(V)2 through 2(V)7, Electronic Equipment, Operation and Maintenance Instructions 03956-4300201-1 ATM Interface Field Change Kit S9427-AN-FCB-001/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 1 S9427-AN-FCB-002/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 2 S9427-AN-FCB-003/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 3 S9427-AN-FCB-004/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 4 S9427-AN-FCB-006/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 6 S9427-AN-FCB-009/WSN-7 AN/WSN-7/7A(V) Field Change Bulletin 9 Table 4-12(Cont’d).— Documents Required but Not Supplied.
General Equipment Function Table 4-13 lists the major design and physical characteristics of the AN/WSN-7(V) RLGN. The RLGN requires external ship’s speed input and periodic input of position data. The RLGN uses ship’s log speed or velocities obtained from a GPS or DSVL to provide damping of vertical gyro loops. Position data from a GPS is used to calibrate gyro drifts and to provide position resets to the inertial navigation function. The inertial reference, speed, and filtered position reset data are processed to generate continuous and accurate position and velocity data in addition to heading, roll, and pitch reference. The RLGN transfers data to and from Battle Force Tactical Trainer (BFTT) equipment via the Asynchronous Transfer Mode (ATM) interface.
ENVIRONMENTAL CHARACTERISTICS Temperature Storage: -40° to 75° C (-40° to 167° F)
Operating: 0° to 50° C (32° to 122° F)
Extreme Operating: 1 -6.7° to 65° C (20° to 149° F)
Humidity (relative): 0 to 95% Humidity
Barometric Pressure
Storage: 0.5 to 30 psi Operating: 10 to 30 psi
Table 4-13.— Design and Physical Characteristics.
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ENVIRONMENTAL CHARACTERISTICS Shock
Vibration
Linear Acceleration Meets the requirements of MIL-STD-901D. System functions may be interrupted during application of the shock.
Meets the requirements of MIL-STD-167-1 for Type 1.
Operating: Horizontal: ±0.5 g peak Vertical: 1.0 g ±0.5 g peak PHYSICAL/ELECTRICAL CHARACTERISTICS Size Height: 169.7 cm (66.8 in)
Weight
Power requirements 2
Heat dissipation Width: 59.7 cm (23.5 in) Depth: 73.3 cm (28.9 in)
381 kg (840 lbs)
105-125 VAC, 50, 60 or 400 Hz, 3-phase, 600 Volt Amps (VA) (max)
600 Watts (max)
1 The AN/WSN-7(V) RLGN is capable of withstanding environmental extremes with no interruption of system functions. The RLGN returns to operating condition at full accuracy following restoration of applicable environment and performance of a reset cycle.
2 The main power fault detector is configured to match input power frequency by switch S1 on Vital Bus CCA (1A1A3). The AN/WSN-7(V) is configured for 60 Hz main power input from the manufacturer.
Normal Operation
The RLGN is designed to operate automatically after application of power and acceptance of the first position reset and requires minimum operator intervention during normal operation. A 6-line, 40-character display and 28-key keypad provide display and operating controls for selection of a wide range of functions. These functions can be accessed for monitoring and modifying operating parameters, for evaluating system performance, and for selecting test and calibration modes. Table 4-13(Cont’d).— Design and Physical Characteristics.
Test Features A Built-In Test (BIT) function incorporating both hardware and software tests continuously monitors operation and periodically performs self-tests to determine the integrity of the AN/WSN-7(V) RLGN and its inputs/outputs. Faults are automatically announced, and fault codes that indicate the type of fault detected are displayed on the local/remote control panels.
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Power In the configuration described in this technical manual, the RLGN requires 115 Volts, Alternating Current (VAC), 60 Hertz (Hz), 3 phase power and 115 VAC, 400 Hz, single- phase synchro reference. An internal battery and inverter provide emergency power for operation with digital output and limited synchro outputs (vital heading and synchro velocities) for approximately 30 minutes in the event of failure of the system power.
4.11.1 AN/WSN-7 (V) Configurations and Interfaces
Configurations
The AN/WSN-7(V) INS is available in three configurations. CN-1695/WSN-7(V) is installed on selected surface combatants. CN-1696/WSN-7(V) is installed on selected cruisers and LHA-1 class ships. CN-1697/WSN-7(V) is installed on aircraft carriers and LHD-1 class ships.
External Data Interfaces
The basic external data interface to each RLGN consists of Naval Tactical Data System (NTDS) Standard Type A parallel slow, NTDS Standard Type D high level serial, and Type E low level serial interfaces. These interfaces are Circuit Card Assemblies (CCAs) located in the Input/Output (I/O) Card Rack Assembly. The combat systems suite or aircraft alignment aboard the ship on which the RLGN system is installed determines the specific configuration of NTDS interface circuit cards.
PLATFORM TYPE QUANTITY DDG CN-1695/WSN-7(V) NTDS Type A 3 ea NTDS Type D 1 ea NTDS Type E 4 ea
CG/LHA CN-1696/WSN-7(V) NTDS Type A 5 ea NTDS Type D 1 ea NTDS Type E 2 ea
CVN/LHD CN-1697/WSN-7(V) NTDS Type A 7 ea NTDS Type E 1 ea
Table 4-14.— RLGN/NTDS Configurations.
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The basic external data interface also consists of a 1-pulse per second timing interface, which provides time synchronization in a dual-system configuration; an RS-422 serial data interface, which exchanges position, velocity, and status information in a dual- system configuration; an RS-422 interface to an external CDU; and an ATM interface to External Local Area Network (LAN). Heading, roll, pitch, north-south velocity, east-west velocity and total velocity are output as analog (synchro) data. Synchro amplifiers are provided for the heading, roll and pitch outputs. Table 4-15 outlines the serial interface and data message characteristics. Table 4-16 lists the synchro output characteristics and defines the synchro reference requirements.
I/O PORT DATA CHARACTERISTICS RLGN to RLGN Interface (J6) Data Rate − 38,400 bits/second Transmitted Character Format: 1 start bit 8 data bits 1 stop bit Bits total: 10 Least significant bit is transmitted first Signal Polarity (Output signals are referenced to INS ground): MARK: RS-422 + High, RS-422 - Low SPACE: RS-422 + Low, RS-422 - High
Display-Control Unit Interface (J5) Data Rate − 9,600 bits/second Transmitted Character Format: 1 start bit 8 data bits 1 stop bit Bits total: 10 Least significant bit is transmitted first Signal Polarity (Output signals are referenced to INS ground): MARK: RS-422 + High, RS-422 - Low SPACE: RS-422 + Low, RS-422 - High
DSVL Interface (J23) Data Rate − 9,600 bits/second Transmitted Character Format: 1 start bit 8 data bits 1 stop bit Bits total: 10 Least significant bit is transmitted first Signal Polarity (Output signals are referenced to INS ground): MARK: RS-422 + High, RS-422 - Low SPACE: RS-422 + Low, RS-422 - High
Table 4-15.— Digital (RS-422A) Data Interface.
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SYNCHRO INPUT (SHIP’S LOG) Reference
Scaling1
Fore/Aft Gradient2 115 VAC, 400 Hz; 90 V L-L Synchro
20 - 125 Kt/Rev
90/10 or 50/50 percent TRANSMITTERS OUTPUT: (HEADING, ROLL, PITCH) Type/Signal Format
Output Power
Two Speed (Heading) Format
Two Speed (Roll and Pitch) Format Amplifier: Equivalent to synchro 115 VAC 11CX4
Heading: Total (Vital + Non-vital) = 32 VA max (400 ma/leg) Vital = 2.5 VA max (100 ma/leg) Roll/Pitch: 8 VA max (100 ma/leg)
Fine 36:1 (10°/revolution) Coarse 1:1 (360°/revolution)
Fine 36:1 (10°/revolution) Coarse 2:1 (180°/revolution)2 or 1:1 (360°/revolution) Synchro Velocity Output: (Vn, Ve, and Vt) Output Power
Two Speed (Vt) Format
Two Speed (Vn, Ve) Format 2 VA max (20 ma/leg)
Fine 10:1 (10 kt/revolution) Coarse 1:1 (100 kt/revolution)
Fine 10:1 (±10 kt/revolution) Coarse 1:1 (±100 kt/revolution) Reference Voltage (Non-Vital): Synchro reference voltage is applied to each RLGN. Reference is always derived from own ship’s 400 Hz main power. The reference voltage and the synchro signals are affected in amplitude and frequency by variations in the reference voltage. Voltage/Frequency
Power capacity
Power factor
Grounding 115 Volts, 400 Hz
3 VA
≥0.9
Must not be grounded 1 Selectable at installation based on Speed Log output. 2 Selectable at installation.
4.11.2 Units and Assemblies As shown in Figure 4-50, the RLGN Cabinet consists of an upper Cabinet Assembly and a lower Measurement Cabinet Assembly, which are separated by a heat shield. The upper cabinet houses power supplies, synchro amplifiers, and rack-mounted circuit cards that contain the interface, control, and data processing circuits. The lower cabinet contains the IMU components.
Table 4-16.— Analog Synchro Input/Output and Reference Characteristics. 4-128 UNCLASSIFIED
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Table 4-17 lists the units and assemblies that make up the AN/WSN-7(V) RLGN. Some assemblies contain programmed devices. Other assemblies are calibrated by installation of an associated Programmable Read-Only Memory (PROM), which contains calibration parameters that are determined at factory test and are specific to the assembly with which the PROM is supplied. These assemblies are identified with a programmed part number, which specifies the hardware with the programmed configuration, and with a hardware part number, which identifies only the hardware without the programmed device. Normally, only the programmed part number is applicable for identifying replaceable assemblies. The RLGN contains the following functional elements:
• IMU(1A2A1)
• IMU support electronics
• Navigation (Nav) Processor (1A1A13), I/O Processor (1A1A21), ATM Processor (1A1A4), and interface electronics
• Power Supplies (1A1A6), (1A1A8) and Battery (1A1A5) for emergency power generation
• Keypad (1A1A9) and Display Panel (1A1A10)
• IP-1747/WSN CDU
Consult the Allowance Parts List (APL) for the appropriate revision level of each assembly. 4-129 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION Unit 1
(1A1)
(1A1A1)
(1A1A2)
(1A1A3)
(1A1A4)
(1A1A5)
(1A1A6)
(1A1A7)
(1A1A8)
(1A1A9)
(1A1A10)
(1A1A11)
(1A1A12)
(1A1A13)
(1A1A14)
1, 11
11
11, 12, 13
11
2, 12, 13 1981101-6
1981101-2
1981101-3
1981539-var
1981532
1982618
1978322
1900040
1981554
1979342
1810853
1205050-3
1859873
1979344
1981660
1981534
1812590-XX
1977455
AN/WSN-7(V) Ring Laser Gyro Navigator (CN-1695/WSN-7)
AN/WSN-7(V) Ring Laser Gyro Navigator (CN-1696/WSN-7)
AN/WSN-7(V) Ring Laser Gyro Navigator (CN-1697/WSN-7)
Processor Cabinet Electrical Equipment Assembly
Filter, Power Line
Inverter Assembly, 400 Hz
Vital Bus CCA
AN/WSN-7(V) ATM Processor Computer Software Configuration Item (CSCI)
Battery Assembly
Power Supply
Battery Charger
Power Module
Membrane Keypad
Display Assembly
Backplane Assembly, Nav Processor
I/O Processor, Backplane Assembly
Nav Processor CCA (Programmed Navigation Processor)
Dual Panel Interface CCA (RLGN-to-RLGN)
Table 4-17.— Summary of AN/WSN-7(V) Units and Assemblies. 4-130 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION (1A1A15)
(1A1A16)
(1A1A17)
(1A1A18)
(1A1A19)
(1A1A20)
(1A1A21)
(1A1A23)
(1A1A30)
(1A1A31)
(1A1A32)
(1A1A33)
(1A1A34)
(1A1A35)
(1A1A36) (1A1A37)
(1A1A38)
(1A1A39)
(1A1A40)
3, 12, 13
11
11
4, 11 1980513
1977455
1977538-0
1977569
1977569
1980488-2
1812591-XX
1980486-2
1981572
1981570
1811791
1979023
1979047
1979046
1979348
1979057
1979087-3
1979087-3
1979087-3 Status and Command CCA
Dual Panel Interface CCA
IMU Interface CCA
Torquer CCA (Roll)
Torquer CCA (Azimuth)
Bus Interface CCA
I/O Processor CCA (Programmed I/O Processor)
Dual Port Memory CCA
Support Electronics, Backplane
I/O Control Built-in Test Equipment (BITE) and Filter CCA
IMU Processor CCA
Repositioning Interface CCA
Analog-to-Digital (A/D) Multiplexer CCA
Accelerometer and Sensor Electronics Assembly
Gyro Support Electronics CCA
Support Electronics Power Supply
Synchro Converter CCA
Synchro Converter CCA
Synchro Converter CCA
Table 4-17(Cont’d).— Summary of AN/WSN-7(V) Units and Assemblies. 4-131 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION (1A1A41)
(1A1A42)
(1A1A43)
(1A1A44)
(1A1A51) through (1A1A58)
(1A1DS1), (1A1DS2)
(1A1MP3)
(1A1MP4)
(1A1MP2)
(1A1MP6)
(1A2)
(1A2A1)
1A1A32U13
1A1A32U03
(1A2A1A1)
(1A2A1A1A1)
1A1A32U15
5, 10, 11
11
11
11
11
6
6
6
7
7 1976545-3
1976545-3
1976547-4
1976547-4
1981087
1981561
1981559
FF200CW600-28V-P or FF200-0CW-028B
1981510
1979347
1891448
1983105
4800307
1983108
1981548
1812593 or 4300859
1810807
1812809
1981549 or 4800592
1812594-3
1810563 Synchro Buffer Amplifier (8 VA)
Synchro Buffer Amplifier (8 VA)
Synchro Buffer Amplifier (32 VA)
Synchro Buffer Amplifier (32 VA)
NTDS Interface, Type A (See Table 4-18)
NTDS Interface, Type D
NTDS Interface, Type E
Lamp
Upper Card Rack Assembly, Navigation and I/O
Card Rack Assembly, Support Electronics
Heat Shield Assembly
Connector Plate (CN-1695/WSN-7)
Connector Plate (CN-1696/WSN-7)
Connector Plate (CN-1697/WSN-7)
Measurement Cabinet Electrical Equipment Assembly
IMU MX-11681/WSN-7 or MX-11681A/WSN-7A(V) Assembly (Matched Set, with all EPROMs)
IMU Assembly Calibration PROM
IMU Assembly Calibration PROM
IMU Assembly
RLG Assembly (Matched Set) (Gyro A)
RLG Calibration PROM Table 4-17(Cont’d).— Summary of AN/WSN-7(V) Units and Assemblies. 4-132 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION (1A2A1A1A2)
1A1A32U02
(1A2A1A1A3)
1A1A32U04
(1A2A1A1A4)
(1A2A1A1A4A1)
(1A2A1A1A5)
1A1A32U12
(1A2A1A1A6)
1A1A32U01
(1A2A1A1A7)
1A1A32U14
(1A2A1A1MP1)
(1A2A1A1MP2)
(1A2A1A1A9A1)
(1A2A1A1A9W1)
(1A2A1A1A10)
(1A2A1A1A11)
(1A2A1A1A12)
7
7
7
7 (1A2A1A1A13)
11
8
8
8
8
8
8 1812594-2
1810563
1812594-1
1810563
1979045
1980509
1810720
1810562
1810720
1810562
1810720
1810562
1979356
1979354
1980596
T968693
1810553-1
1810553-2
1810553-3
1810553-4 RLG Assembly (Matched Set) (Gyro B)
RLG Calibration PROM
RLG Assembly (Matched Set) (Gyro C)
RLG Calibration PROM
High Voltage Power Supply (HVPS)
HVPS “A” and “B” CCA
Calibrated Accelerometer (Matched Set) (Accel. A)
Accelerometer Calibration PROM
Calibrated Accelerometer (Matched Set) (Accel. C)
Accelerometer Calibration PROM
Calibrated Accelerometer (Matched Set) (Accel. B)
Accelerometer Calibration PROM
Frame Assembly, Inner
Frame Assembly, Outer
Accelerometer Stimulus CCA
Harness Assembly
Slip Ring Assembly (Electrical Contact Ring Capsule Assembly)
Slip Ring Assembly (Electrical Contact Ring Capsule Assembly)
Slip Ring Assembly (Electrical Contact Ring Capsule Assembly)
Slip Ring Assembly (Electrical Contact Ring Capsule Assembly) Table 4-17(Cont’d).— Summary of AN/WSN-7(V) Units and Assemblies. 4-133 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION CABLE ASSEMBLIES (1A2A1A1B1)
(1A2A1A1B2)
(1A2A1A1B3)
(1A2A1A1B4)
(1A2A1A1M1)
1W1
1W2
1W3
1W4
(1A1W1)
(1A1W2)
(1A1W3)
1A1W4
1A1W5
1A1W6
(1A1W7)
1A1W10 through 1A1W26
P/O 1A1W1
Unit 2
9, 11
11
5
11
Same as Unit 1 1979358
1979358
1243107-2
1243107-2
1975362-6
T968889
T968890
T968891
T968892
T969420
T968840
T967883
T968841
T968842
T968894
1900013-1
(See Table 4-18)
T969380 Motor, Direct Current, Torquer (Outer Gimbal)
Motor, Direct Current, Torquer (Inner Gimbal)
Synchro Transmitter, Multispeed (Outer Gimbal)
Synchro Transmitter, Multispeed (Inner Gimbal)
Meter, Time Totalizing
Harness Assembly
Cable Assembly
Cable Assembly
Cable Assembly
Main Cabinet Cable and Harness Assembly
Cable Assembly (Door Cable and Harness Assembly)
Ribbon Cable Assembly
Cable Assembly
Cable Assembly
Harness Assembly
Cable Assembly, Fiber Optic ATM/Synchronous Optical Network (SONET) Interface
(See Table 4-18)
Harness Assembly for DSVL Table 4-17(Cont’d).— Summary of AN/WSN-7(V) Units and Assemblies. 4-134 UNCLASSIFIED
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ASSEMBLY NOTES ASSEMBLY PART NO. NAME/FUNCTION NOTE: 1. Inverter Assembly P/N 1982618 is manufactured with high reliability screened parts. This assembly is directly interchangeable with P/N 1980379.
2. Nav Processor CCA, 1812590-XX, is the programmed part number of unprogrammed Central Processing Unit (CPU)/Memory assembly part number 1981127. After assembly part number 1981127 is programmed with the stored program assembly, it is reidentified as part number 1812590-XX.
3. I/O Processor CCA, 1812591-XX, is the programmed part number of unprogrammed CPU/Memory assembly part number 1983195. After assembly 1983195 is programmed with the stored program assembly, it is reidentified as part number 1812591-XX.
4. IMU Processor CCA, 1811791, is the programmed part number of unprogrammed Bus Control Electronics assembly part number 1979021. After assembly 1979021 is programmed with the stored program assembly, it is reidentified as part number 1811791.
5. CCAs (1A1A51) through (1A1A58) and associated cables are selected based on the NTDS interface requirements for each installation. The assemblies and cables installed are defined by the Unit 1 part number. Refer to Table 4-18 for applicability.
6. The IMU Assembly part number includes two PROMs (serialized to the IMU Assembly) programmed during factory calibration with correction parameters which are used by the system to compensate for mechanical offsets in the IMU normal and inverted positions.
7. Each RLG Assembly part number includes a PROM (serialized to the RLG) programmed during factory calibration with correction parameters which are used by the system to compensate for mechanical offsets in the RLG.
8. Each Accelerometer Matched Set part number includes a PROM (serialized to the accelerometer) programmed during factory calibration with correction parameters which are used by the system to compensate for mechanical offsets in the Accelerometer.
9. If the RLGN has Field Change 1 (DSVL Interface), then the Harness Assembly (1A1W1) part number is T969420.
10. Part Number 1981087 (Rev A) is unacceptable if Programmable Array Logic (PAL) chip U11 part number is 1812652 (Rev A). Acceptable PAL U11 part number is 1812652 (Rev B).
11. Part of Field Change 1.
12. Part of Field Change 2 or 3.
13. Part of Field Change 4
Table 4-17(Cont’d).— Summary of AN/WSN-7(V) Units and Assemblies. 4-135 UNCLASSIFIED
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DSVL Interface Modification The DSVL interface (part of RLGN Field Change 1) uses I/O Channel No. 2 on Dual Panel Interface Circuit Card Assembly (CCA) (1A1A14) (previously an unused spare). This data I/O channel is wired from I/O Backplane connector J9 to an added connector 1J23 on the back of the cabinet using an added harness assembly T969380. I/O Central Processor (1A1A21) and the Navigation Central Processor (1A1A13) are replaced with a later part revision containing software support for the DSVL data interface function.
ATM Interface Modification (Part of RLGN Field Change 1) The ATM interface assembly consists of the ATM Processor Assembly 1A1A4A1A1 and the Peripheral Component Interface (PCI) Mezzanine 1A1A4A1A2. This data I/O channel is cabled, using fiber optic cable, from the front of the PCI Mezzanine to an added connector 1J22 on the back of the cabinet using harness assembly (1A1W7).
4.11.3 INS Interface Systems The AN/WSN-7(V) INS interfaces with numerous ship systems using digital and analog communications.
Additional and hull-specific interface information is available in the Combat Systems Technical Operation Manual (CSTOM) and Combat Systems Operational Sequencing System (CSOSS) and in Navigation (System) Operating Procedures (NOPs) for each ship class. (See Table 4-12.)
AN/WSN-7(V) Master to AN/WSN-7(V) Slave
A synchronous interface occurs between RLGNs in an AN/WSN-7(V) navigation suite with two RLGNs. This interface exchanges position, velocity and status information between the RLGNs.
IP-1747/WSN Control Display Unit (CDU)
The CDU is the primary man-machine interface to/from the RLGN. The CDU is part of the AN/WSN-7 INS and is identified as Unit 4 of the system. It can monitor and control the RLGNs from a separate installation location from the RLGNs. This interface sends INS Super Channel data to the CDU.
Additionally, the Remote Control Display Unit (RCDU) function, which simulates the display and keypad for the RLGN, is displayed on the CDU and enables remote operation of the RLGN from the CDU. Although the CDU is part of the AN/WSN-7(V) INS, operation and maintenance instructions for the CDU are not contained in this technical manual. (See Table 4-12 for information on the CDU technical manual.) 4-136 UNCLASSIFIED
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4.11.4 Troubleshooting and Maintenance Concept The AN/WSN-7(V) RLGN is designed for ease of maintenance through replacement of failed Lowest (or Line) Replaceable Units (LRUs) with replacements drawn from On- Board Repair Part (OBRP) stock. All LRUs, including power supplies and circuit boards, use plug and jack connectors for ease of replacement. The organizational level of maintenance will use the self-contained capability of system BIT and the diagnostic software program to identify faults to the LRU. RLGN alignment and configuration data are stored in Non-Volatile Random Access Memory (NVRAM) and Electrically Erasable Programmable Read-Only Memory (EEPROM).
Calibration information associated with the attitude and acceleration sensors is stored in PROM chips, which allow maintenance to be performed on the RLGN without the need for mechanical or electrical realignment after repairs have been performed.
4.11.5 List of Applicable Documents Table 4-12 provides a list of technical manuals and specifications associated with the AN/WSN-7(V) INS, but not supplied. These documents provide operation, maintenance, and installation information; Interface Design Specifications (IDSs), which describe the various message types that can be selected for data transfer between the RLGNs and external equipment; and the NTDS digital interface specifications, which describe timing, communication protocol, and transmission characteristics of the NTDS I/Os listed in Table 4-18. Table 4-19 describes the document supplied with the equipment.
CCA NAME/FUNCTION AN/WSN-7(V) CN-1695 CN-1696 CN-1697 Locations (1A1A51) through (1A1A58) are used for NTDS Standard Interface. (1A1A51) NTDS Interface CCA, Type E E E (1A1A52) NTDS Interface CCA, Type E A A (1A1A53) NTDS Interface CCA, Type E E A (1A1A54) NTDS Interface CCA, Type E D A (1A1A55) NTDS Interface CCA, Type D A A (1A1A56) NTDS Interface CCA, Type A A A (1A1A57) NTDS Interface CCA, Type A A A (1A1A58) NTDS Interface CCA, Type A A A Cables used with the NTDS interface are determined by the part number of the system. 1A1W10 Coaxial Cable Assembly T968912 * * * 1A1W11 Coaxial Cable Assembly T968912 * * * 1A1W12 Coaxial Cable Assembly T968912 * * * 1A1W13 Coaxial Cable Assembly T968912 * * * 1A1W14 Coaxial Cable Assembly T968912 * * 1A1W15 Coaxial Cable Assembly T968912 * *
Table 4-18.— AN/WSN-7(V) NTDS I/O Configurations.
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CCA NAME/FUNCTION AN/WSN-7(V) CN-1695 CN-1696 CN-1697 1A1W16 Coaxial Cable Assembly T968912 * * 1A1W17 Coaxial Cable Assembly T968912 * * 1A1W30 Coaxial Cable Assembly T968914 * * 1A1W10 Coaxial Cable Assembly T968914 * * 1A1W20 Cable and Harness Assembly T9689131 * * * 1A1W21 Cable and Harness Assembly T9689131 * * * 1A1W22 Cable and Harness Assembly T9689131 * * * 1A1W23 Cable and Harness Assembly T9689131 * * * 1A1W24 Cable and Harness Assembly T9689131 * 1A1W25 Cable and Harness Assembly T9689131 * 1A1W26 Cable and Harness Assembly T9689131 * 1 Part of Field Change 1.
TMIN/VID NO./ IDENTIFICATION NO. NSN TITLE/DESCRIPTION QTY. Technical Manuals S9427-AN-OMP-010/WSN-7, 0910-LP-102-7705 Technical Manual, Organizational Level, Ring Laser Gyro Navigator Inertial Navigation System, AN/WSN-7(V)1, -7(V)2, -7(V)3, Rev 1 Part Numbers CN-1695/WSN-7(V), CN-1696/WSN-7(V), and CN-1697/WSN-7(V); Operation and Maintenance with Parts Lists 1 ea CD-ROMs S9427-AN-IEM-010/REV1 0913-LP-101-6143 Interactive Electronic Technical Manual and Interactive Courseware for Navigation Unit, Ring Laser Gyro Navigator, AN/WSN-7(V)1, (V)2, (V)3 Inertial Navigation System
Table 4-18(Cont’d).— AN/WSN-7(V) NTDS I/O Configurations. Table 4-19.— Documentation Supplied. 4-138 UNCLASSIFIED
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4.11.6 Equipment and Accessories Table 4-20 provides a list of equipment and accessories supplied with the equipment. Table 4-21 provides a list of equipment required, but not supplied. Table 4-22, provides the Field and Factory Changes applicable.
QTY ITEM NAME OR UNIT NUMBER OVERALL DIMENSIONS WEIGHT AND VOLUME NOMENCLATURE HEIGHT WIDTH DEPTH 1 Ring Laser Gyro Navigator (RLGN) CN-1695/WSN-7(V), CN-1696/WSN-7(V), CN-1697/WSN-7(V) 1, 2 66.8 in. 23.5 in. 28.9 in. 840 lb. 1 Processor Cabinet Electrical Equipment Assembly (1A1) 1 Inertial Measurement Cabinet Assembly (1A2)
SUBCATEGORY (SCAT) CODE TEST EQUIPMENT CATEGORY TEST EQUIPMENT MODEL NUMBER EQUIPMENT TEST PARAMETERS APPLICATION - Digital Multimeter 89536-77/AN - - Continuity testing and analog signal and voltage checks - Wild T2 Theodolite(2 each) - - ±0.5 arc seconds Equipment Installation
Table 4-20.— Equipment and Accessories Supplied. Table 4-21.— Equipment Required but Not Supplied. 4-139 UNCLASSIFIED
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CHANGE NUMBER PURPOSE DESCRIPTION Field Change 1 (ECP N84-1) (ECOs 525, 526, 531, 539, 541, 546, 547, 548, 563, 577, 583, 588, 698, 702, 1. Adds a new fiber-optic I/O interface [ATM/Network Time Protocol (NTP)]. 2. Adds BFTT interface. 3. Adds AN/WQN-2 DSVL interface. 4. Revises the AN/WSN-7(V)2 I/O configuration. 736, 802) 5. Adds a feature for improving the RLGN position accuracy during periods of valid GPS data. 6. Adds support for the NTDS Type A I/O Interface. 7. Improves selected LRUs due to parts obsolescence or improvement of reliability. 8. Makes improvements to Navigation and I/O Operational programs. 1. Upgrades the revision level of the Nav Processor and I/O Processor CCAs. 2. Modifies the IMU High Voltage Power Supply. 3. Modifies the IP-1747/WSN CDU. 4. Modifies the NTDS Type A interface CCA. 5. Modifies the Navigation rack and Support Electronics backplane assemblies. 6. Changes the part number for two indicator lamps to improve reliability. 7. Adds the DSVL interface. 8. Alters the NTDS I/O configuration of the CN- 1696/WSN-7 by removing one NTDS Type E interface and replacing it with an NTDS Type A interface. 9. Adds ATM hardware. 10. Updates the revision levels of the IMU, Vital Bus, 400 Hz Inverter Assembly, and Dual Port Memory CCAs. Field Change 2 (ECP N84-2) (ECOs N84-814, -815, -816) Upgrades firmware to enable AN/WSN-7(V) to interface with BFTT equipment, without the need for the external ATM switch. Upgrades the revision level of the ATM, Nav Processor, and I/O Processor CCAs. Field Change 3 (ECP N84-2) (ECOs N84-814, -815, -816) Upgrades firmware to enable AN/WSN-7(V) to interface with BFTT equipment, without the need for the external ATM switch if Field Change 2 has not been installed. Upgrades the revision level of the ATM, Nav Processor, and I/O Processor CCAs if Field Change 2 has not been installed. Field Change 4 (ECOs N84-869, 1. Installs Nav Processor CCA P/N 1812590Rev-AB. Upgrades the revision level of the ATM, Nav Processor, and I/O Processor CCAs. -870, -871) 2. Installs I/O Processor CCA P/N 1812591Rev-W. 3. Installs ATM Processor CCA P/N 1900040Rev-C. Field Change 6 Installs MX-11681A/WSN-7 Inertial Measuring Unit Sound isolates the Inertial Measuring Units to lessen structure-borne noise from the equipment to the ship’s hull. Field Change 9 1. Replaces NTDS Type D and NTDS Type E CCAs with NTDS Type A CCAs, P/N 1981087 2. Installs Connector Plate P/N 1983108 Converts AN/WSN-7(V)2 to AN/WSN-7(V)3
Table 4-22.— Field Changes and Factory Changes. 4-140 UNCLASSIFIED
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4.11.7 WSN-7 Operation All operations, including mode control, sensor selection, data entry, and parameter display, as well as initiation of calibration, self-test, and installation setup, are performed using displayed menus and the keypad on the front of the RLGN.
The keypad is used in conjunction with the displayed menus to perform all control and data entry functions. The Front Panel controls and indicators are shown in Figure 4-52 and the keypad is shown if Figure 4-53.
The keys are divided into four categories: Menu Selection, Data Entry, Display Control, and Alarm Acknowledge. Some keys perform dual functions. The operation of these keys is automatically determined by the selected menu, mode, or operation being performed. The function of each key is listed in Table 4-23.
Figure 4-52.— Front Panel Controls and Indicators. Figure 4-53.— Keypad Controls. 4-141 UNCLASSIFIED
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KEY FUNCTION Menu Selection keys consist of: MODE Selects Page 1 of Mode Menu. AUX FUNC Selects Page 1 of Auxiliary Functions Menu. SENSOR Selects Page 1 of Sensor Menu. DISPLAY Selects Page 1 of Display Menu. TEST Selects Page 1 of Self-Test Functions Menu. (Functions only during power-up) NEXT PAGE Sequentially selects display of additional menu pages for each function. Data Entry keys consist of: 0 through 9 Selects numbered function on displayed menu and used to enter numeric data. A through F Alternate function reserved for entry of hexadecimal values. (Hexadecimal entry is not active in normal operating modes.) CLEAR Clears displayed or manually entered data without entering the value. ENTER Accepts displayed or manually entered data for entry into selected function. BACK SPACE Erases last entered numeric character for re-entry. N/E+ Enter North (N) or East (E) for position or positive (+) for numeric values requiring sign. S/W– Enter South (S) or West (W) for position or minus (-) for numeric values requiring sign. Display Control keys consist of: TRACK/HOLD Toggle on/off function used to freeze display of any continuously changing data which is selected for viewing. BRIGHT Increases display illumination. DIM Decreases display illumination. ALARM ACK Removes the fault code from the display and clears the Advisory Relay and the Malfunction Relay when a fault condition is detected. The general procedure for key/menu operation is: 1. Press a Menu Selection key (MODE, AUX FUNC, SENSOR or DISPLAY) to select the menu with desired function. 2. If selected menu has more than one page, press the <NEXT PAGE> key to step through pages (page display sequence cycles back to Page 1 after last page is displayed). 3. When function is located, press the Number key corresponding to number beside function to select the function. 4. If data entry is required, either press the <ENTER> key to accept displayed value or press the <CLEAR> key to clear displayed value for entry of new value. 5. Enter value using Data Entry keys and press the <ENTER> key to accept value. Correct error during data entry using the <CLEAR> key or the <BACK SPACE> key.
Table 4-23.— Keypad Control Functions. 4-142 UNCLASSIFIED
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Table 4-24 lists the functions included in the four menus associated with operation and presents a brief description of the control and data functions associated with each.
Figure 4-54 identifies the general menu layout and data presentation for the operations- related menus and provides a listing of all mode and status indications that may be displayed on the top line of the Menu Display Panel.
Figure 4-54.— Menu Status/Mode Indicators.
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PAGE FUNCTION BRIEF DESCRIPTION NOTE: In the following table, functions indicated with an asterisk (*) are displayed on the menu when Field Change 3 has been accomplished, but are not available for use until Field Change 4 has been accomplished.
Items with a double asterisk (**) are displayed on the menu only if installation configuration settings indicate that the function is installed and is available for use. Refer to Chapter 8 of S9427- AN-OMP-010/WSN-7 for installation configuration setup.
Items with a triple asterisk (***) are displayed on the menu only if Field Change 4 has been accomplished. SENSOR Functions SENSOR control functions are associated with selecting the alignment reference source upon startup, selecting and/or manually entering the position reference, and selecting and/or entering the speed and depth references. SENSOR control functions are presented and accessed via three display menu pages. Page 1 of the SENSOR menu provides control functions associated with selecting the RLGN alignment source. 1 1. DOCK OFF: Disables Dockside data as the position. ON: Enables Dockside data as the position and inputs zero velocity reference.
2. PDIG OFF: Disables GPS input (PDIG) (via dedicated NTDS interface), and allows data from an External Computer (selected NTDS interface data from port other than GPS interface) as the digital position sensor source. ON: Enables GPS input (PDIG) (via dedicated NTDS interface) as the digital position sensor source. Table 4-24.— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION 3. SLAVE OFF: Disables the second RLGN as the position reference for the first RLGN. ON: (after alignment of second RLGN): Enables the second RLGN as the position reference for the first RLGN. ON: (prior to alignment of second RLGN): Initiates at-sea alignment within the second RLGN. 4. BFTT OFF/ON* OFF: Disables operator command to “quickly abort” transmission of BFTT Simulated data. ON: Enables operator command to “quickly abort” transmission of BFTT Simulated data. Page 2 of the SENSOR menu provides control functions associated with selecting the RLGN’s velocity reference used to damp the velocity loop. 2 1. VMAN Displays current value set for manually entered ship’s speed. OFF: Disables manual speed input to the navigation processor. ON: Enables manual entry or change of fore or aft speed value. 2. VSYN OFF: Disables a configured synchro velocity input to be selected as the speed data source. ON: Enables a configured synchro velocity input to be selected as the speed data source.
NOTE: If more than one synchro velocity source is available (e.g., Rod1 and Rod2 EM Log), it may be necessary to switch external equipment to provide the correct data to the RLGN synchro velocity input. 3. VDIG ** OFF: Disables a configured, digital velocity input as the speed data source. ON: (INS configured for digital speed input via NTDS or ATM interface): Enables a configured, digital velocity input as the speed data source. Page 3 of the SENSOR menu (normally configured only for submarine installations) provides control functions associated with selecting the depth sensor source and vertical velocity reference to be used. 3 1. DMAN ** Displays current value set for manually entered ship’s keel depth below the surface. MAN OFF: Disables the manual depth input to the navigation processor. MAN ON: Enables manual depth data input and change to the navigation processor. 2. DDIG ** OFF: Disables depth data input from digital depth sensor for RLGNs configured to accept digital depth input. ON: Enables depth, data input from digital, depth sensor for RLGNs configured to accept digital depth input. 3. Vertical Velocity OFF: Disables vertical velocity input on RLGNs configured for a three-axis, digital speed and depth input. Enables or disables the vertical velocity input. ON: Enables vertical velocity input on RLGNs configured for a three-axis, digital speed and depth input. Enables or disables the vertical velocity input. Horizontal velocity inputs are not affected. Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION Functions on Page 4 of the SENSOR menu are used for selecting a heading source and entering heading data during High Latitude ALIGN. 4 1. HMAN OFF/NORM/TXVS *** Operator may manually specify a normal or transverse coordinate heading. Used if no other heading source is available. Manual input of heading may be necessary during High Latitude ALIGN, if the backup compass is providing attitude data via synchro interface (no digital source of heading available) and the other RLGN is inoperative. Manual heading will be taken as a single heading measurement at the time of operator pressing ENTER key. 2. SINS2 OFF/ON *** Turn on if secondary RLGN is operative during High Latitude ALIGN. Status word in RLGN/RLGN interface indicates valid/invalid and normal/transverse. 3. HDIG OFF/ON *** Turn on during High Latitude ALIGN if external digital heading source is available. Status word in Super Channel interface indicates valid/invalid. MODE Functions MODE control functions are associated with the position filter and navigation calculation modes. MODE control functions are presented and accessed via one display menu page. The MODE menu provides control functions associated with the position filter and navigation calculation modes. 1 1. Damping Auto: INS is automatically switched between damped and undamped operation depending upon reference velocity data validity and ship’s dynamics, such as turn rate. Man Damp: When selected, system is forced to remain damped, regardless of velocity input or ship dynamics. Change to Man Undamp for undamped operation can only occur when manually selected. Man Undamp: When selected, system is forced to remain undamped. Change to Man Damp for manually damped operation can only occur when manually selected. 2. Fix Displays present Fix Entry and GMT. ENTER: Accepts present Fix values. CLEAR: Enables manual position fix data entry via the keypad. Position data is used to correct the INS estimate of position and to update the Kalman filter. Other Kalman filter parameters are not reset when fix is entered via this function. 3. Slew Displays present slew Position Reference and GMT. ENTER: Accepts Position Reference values. CLEAR: Enables manual position slew to be entered via the keypad. Position data is used to reset INS estimate of position only. 4. Norm/Txvs 1. System normal/transverse mode: Provides three control function options for selecting Earth coordinates reference used to calculate position and heading.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION AUTO: When selected, INS automatically switches between normal and transverse coordinates reference when normal coordinates latitude is approximately +85°. (Transverse mode should be used above 85°.) MNORM: When selected, INS remains in normal coordinates mode regardless of latitude. MTXVS: When selected, INS remains in transverse coordinates mode regardless of latitude. 2. Synchro heading: Provides three control function options for synchro heading output formats, which may be selected independently from System normal/transverse mode. Follow system mode: When selected, synchro heading output automatically provides transverse heading when the system is operating in transverse coordinates reference, and provides normal heading when the system is operating in normal reference mode.
Normal coordinates: When selected, the synchro heading output is always displayed in normal coordinates regardless of whether the system is operating in transverse or in normal reference mode. Txvs coordinates: When selected, the synchro heading output is always displayed in transverse coordinates regardless of whether the system is operating in transverse or in normal reference mode. 5. Reset Mode Provides three control function options for accepting navigation aid position fixes. Review: Requires that the operator review fix data and either accept or reject each position fix. With this mode selected, when a position fix is received from the navigation aid, the operator is prompted by display of Code 221. The operator must then select the Reset Data function (DISPLAY, Page 3, Reset Data) to review the fix values. Auto Review: Similar to Review mode except that the INS automatically accepts valid fixes and allows the operator to review fixes that do not meet valid criteria. If the operator does not accept or reject the fix within 10 minutes, the fix data is discarded and the fix is rejected by the INS. Auto: INS automatically accepts or rejects each position fix from the navigation aid without prompting the operator to review the fix. Display of accepted, last rejected, or pending fix is available in the Reset data display. 6. LogCal Mode Provides two control function options for disabling and enabling Electromagnetic Logs (EM Logs). Not Selected: Disables automatic EM Log (Rod 1 or Rod 2) calibration during normal vessel operation. Selected: Enables automatic EM Log (Rod 1 or Rod 2) calibration during normal vessel operation. Also, the selected EM Log’s calibration tables are automatically updated with Kalman filter bias calibration values.
Table 4-24(Cont’d).— Operating Menus/Functions Description. 4-147 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION AUXiliary FUNCtions AUXiliary FUNCtions control functions are associated with changing configuration settings, displaying stored fault codes, performing display self-test, setting display update rate, selecting output of simulated position, heading, and velocity, calibrating the speed log data, monitoring system performance, and transferring waypoints. Changes to settings made using the AUX FUNC menus override defaults set by Installation Configuration as long as the AN/WSN-7(V) remains turned on. Except for changes made to speed log calibration tables, all selections return to installation defaults upon completion of the Normal Shutdown procedure. AUX FUNC control functions are presented and accessed via three display menu pages. Page 1 of the AUX FUNC menu provides control functions associated with the Remote Control Display Unit (RCDU), System Configuration, Faults, Indexers, I/O Configuration, and I/O Restart. 1 1. RCDU Lockout The RCDU Lockout control function is associated with controlling AN/WSN-7(V) operation from a separate control unit. RCDU Locked = Yes: Locks out interface port to CD-125/WSN-7 RCDU or IP- 1747/WSN CDU so that the AN/WSN-7(V) can be controlled solely from its control/display. The CDU still works to collect data across the Super Channel. No: Enables interface port to CD-125/WSN-7 RCDU or IP-1747/WSN CDU so that the AN/WSN-7(V) can be controlled from the RCDU or CDU. 2. System Configuration System Configuration control functions are associated with velocity damping filters, mode functions menu configuration, attitude comparison, faults, Indexers, I/O configuration. These System Configuration control functions are presented and accessed via six display menu pages. (Page 1 of 6) Sys Config (Page 1) is associated with setting system “Master” status and velocity damping filter control functions. 1. This RLGN Master = No: Disables the AN/WSN-7(V) as the Master system. Yes: Enables the AN/WSN-7(V) as the Master system and affects only a status word output in the NTDS interface messages. Does not affect system master/slave timing protocol as it relates to clock and position reset functions. 2. Velocity damping = KALMAN: Enables Kalman filter velocity damping. THIRD ORDER: Enables Third Order velocity damping. System must be in Navigate mode for Third Order to be selected. (Page 2 of 6) Sys Config (Page 2) is associated with setting the control function options that the operator will be able to review and select via the Mode function menu’s Norm/Txvs control function. 1. Normal/Transverse =
Table 4-24(Cont’d).— Operating Menus/Functions Description. 4-148 UNCLASSIFIED
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PAGE FUNCTION BRIEF DESCRIPTION AUTO/MANUAL: Enables and presents to the operator both the AUTO and the MANUAL control function options. MANUAL ONLY: Disables and replaces AUTO/MANUAL, and enables and presents the MANUAL ONLY control function option. 2. Reset Mode = AUTO, AUTO/REVIEW, REVIEW: Enables and presents to the operator all three Reset Mode control function options. AUTO/REVIEW, REVIEW: Enables and presents to the operator the AUTO/REVIEW and the REVIEW control function options only. REVIEW: Enables and presents to the operator the REVIEW control function option only. (Page 3 of 6) Sys Config (Page 3) is associated with setting attitude comparison control function options. 1. Att Comp Threshold: On dual system installations, allows the alarm threshold setting for difference in attitude (heading, roll, and pitch) output to be set from the on-line menu to temporarily override the default value set at installation. 2. Att Comp Filter Constant: On dual system installations, allows the time constant setting, used by the system for determining the difference in attitude, to be set from the on-line menu to temporarily override the default value set at installation. (Page 4 of 6) Sys Config (Page 4) is associated with setting the system Subnet Mask and Internet Protocol (IP) addresses. 1. Subnet Mask = xxx.xxx.xxx.xxx 2. IP Address = xxx.xxx.xxx.xxx (Page 5 of 6) Sys Config (Page 5) is associated with setting the system ARP address. 1. ARP Address = xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (Page 6 of 6) Sys Config (Page 6) is associated with setting the system NTP address. 1. NTP Address = xxx.xxx.xxx.xxx 3. Faults The Faults control function menu displays a list of active faults, which persist after pressing the <ALARM ACK> key to acknowledge the fault. The Faults control function is presented and accessed via one display menu page. 4. Indexers The Indexers control function menu is associated with inner and outer gimbal torquer settings. The Indexers control function is presented and accessed via one display menu page. Torquers are normally enabled and this function is not used during normal operation. Torquers can be enabled without removing system power in the event that they are automatically disabled as a result of detection of a fault in the torquer loop. 1. Inner indexer: On: Enables the inner (azimuth) torquer (1A2A1A1B2). OFF: Disables the inner (azimuth) torquer (1A2A1A1B2). 2. Outer indexer: On: Enables the outer (roll) torquer (1A2A1A1B1). OFF: Disables the outer (roll) torquer (1A2A1A1B1).
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PAGE FUNCTION BRIEF DESCRIPTION 5. I/O Configuration The I/O Config control function menu is associated with NTDS/ATM, INS and DSVL digital I/O settings. These I/O Config control functions are presented and accessed via three display menu pages. (Page 1 of 3) I/O settings. NTDS ON/OFF – Allows the operator to select each NTDS, Super Channel, or ATM port, turn the port on or off, and selectively activate or deactivate message data fields. From I/O Config page 1, choose NTDS Super Channel, or ATM to edit I/O configuration settings. NOTE: IDS configuration may be changed in Off-Line Test mode only.
The NTDS Configuration Settings control function menu lists control function options on three display menu pages, which allow specific message protocol and data fields to be selected or enabled for each fitted port, even if the port is selected as disabled.
NOTE: The letter prefix on each port designation identifies the physical location of the NTDS I/O board that contains the port set. Refer to Table 4-25.
a. NTDS Port = (port designation). Step function selects port to be enabled/disabled or reconfigured (up to 16 maximum available). b. NTDS Port Configuration Settings, Page 1: (1) Port nn = DSBL: Disables the selected NTDS port. ENBL: Enables the selected NTDS port. (2) IDS = Applicable to IDS 00 through 31. (3) Retries = Applicable to IDS 08, 09, and 10. DSBL: Disables I/O processor output message retries. Message is transmitted only once, even when acknowledgement is not received. ENBL: Enables the I/O processor output message to repeat once, if acknowledgement is not received. (4) Secondary = Applicable to IDS 14 and 15. DSBL: Disables a message bit setting that identifies the selected port’s status and data to the receiving equipment as secondary when redundant I/O interface functionality is implemented. ENBL: Enables a message bit setting that identifies the selected port’s status and data to the receiving equipment as secondary when redundant I/O interface functionality is implemented.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION c. NTDS Port Configuration Settings, Page 2: (1) Day = ENBL/DSBL. (Applicable to IDS 11) If ENBL is selected, allows the RLGN to transmit Julian Day data to the OU-174/WSN-5 Data Converter Group. If DSBL is selected, the RLGN will not transmit Julian Day data over this connection. (2) P Sen Fmt = AR57A/AS130. (Applicable to IDS 11) This setting determines the format (AR57A or AS130) for transmitting position senescence data to the OU-174/WSN-5 Data Converter Group. (3) Forced EF = ENBL/DSBL. (Applicable to IDS 04, 08 and 11). If receiving equipment does not implement an EIE line to indicate that it is ready to receive data, selecting ENBL causes the parallel output data message to be transmitted regardless of EIE status. (4) Parity = ENBL/DSBL. (Applicable to IDS 07, 09 and 10). Enables or disables message parity bit checking protocol for serial output. d. NTDS Port Configuration Settings, Page 3: (1) Nav Msg = ENBL/DSBL. (Applicable to IDS 04, 08, 09, and 10). Enables or disables the Navigation Data Periodic message transmitted at 1 Hz in the output data. (2) Precision = HIGH (NORM). (Applicable to IDS 04, 07, 08, 09, 10). Sets position data in the Navigation Data Periodic message precision to high or normal precision. (3) Attd Msg = ENBL/DSBL. (Applicable to IDS 04, 08, 09, and 10). Enables or disables the Attitude Data Periodic message output data. (4) Msg Rate = 8 Hz (16 Hz). (Applicable to IDS 04, 08, 09, and 10). Changes transmit rate for Attitude Data message. The Super Channel configuration settings control function menu lists control function options on three display menu pages, which allow specific message protocol and data fields to be selected or enabled for each fitted port, even if the port is selected as disabled. a. Super Channel Port Configuration Settings, Page 1: (1) Port nn = ENBL/DSBL. Enables or disables selected port. The options listed on Pages 1, 2, and 3 of the menu function allow specific message protocol and data fields to be selected for each fitted port, even if the port is selected as disabled. (2) IDS = 13. The number displayed in this field is a code that indicates the Super Channel IDS assigned to the port during system installation configuration. Data in this field cannot be changed from this on-line I/O Configuration mode. Refer to Table 4-26 for the Port Specification and Type indicated by each IDS number. (3) Ext Fix = ENBL/DSBL. If ENBL is selected, allows RLGN to accept a fix from an external computer, other than GPS, over the Super Channel interface. If DSBL is selected, no external computer fixes will be accepted. (4) GPS Fix = ENBL/DSBL. If ENBL is selected, allows RLGN to accept GPS fixes over the Super Channel interface. If DSBL is selected, no GPS fixes will be accepted.
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PAGE FUNCTION BRIEF DESCRIPTION b. Super Channel Port Configuration Settings, Page 2: (1) Rmt Cntrl = ENBL/DSBL. If ENBL is selected, allows the RLGN to accept Remote Control input over the Super Channel interface. If DSBL is selected, no Remote Control input will be accepted. (2) Vref Input = ENBL/DSBL. If ENBL is selected, allows RLGN to accept reference velocities over the Super Channel interface. If DSBL is selected, velocity references will not be accepted over the Super Channel interface. (3) Attd Data = ENBL/DSBL. If ENBL is selected, allows the RLGN to accept backup attitude data over the Super Channel interface. If DSBL is selected, no backup attitude data will be accepted over the Super Channel interface. (4) Waypoint = ENBL/DSBL. This setting is currently not in use. Should be set to DSBL. c. Super Channel Port Configuration Settings, Page 3: (1) Depth = ENBL/DSBL. This setting is not used on surface vessels. Should be set to DSBL. (2) Fcn 8 = ENBL/DSBL. Reserved. Should be set to DSBL. (3) Fcn 9 = ENBL/DSBL. Reserved. Should be set to DSBL. (4) Fcn 10 = ENBL/DSBL. Reserved. Should be set to DSBL. The ATM Port, configuration settings, control function menu lists control function options on three display menu pages, which allow specific message protocol and data fields to be selected or enabled for each fitted port, even if the port is selected as disabled. a. ATM Port = I. Step function selects port to be enabled/disabled or reconfigured. b. ATM Port Configuration Settings, Page 1: (1) Port I = ENBL/DSBL. Enables or disables selected port. The options listed on Pages 1, 2, and 3 of the menu function allow specific message protocol and data fields to be selected or enabled for each fitted port, even if the port is selected as disabled. (2) IDS = 16. Number displayed in this field is a code which indicates the ATM Interface Design Specification (IDS) assigned to the port during system installation configuration. Data in this field cannot be changed from this on-line I/O Configuration mode. The number 00 in this field indicates that the selected port is not fitted. Refer to Table 4-25 and Table 4-26. (3) Ext Fix = ENBL/DSBL. If ENBL is selected, the RLGN will accept a fix from an external computer, other than GPS, over the ATM interface. If DSBL is selected, no external computer fixes will be accepted. (4) GPS Fix = ENBL/DSBL. If ENBL is selected, the RLGN will accept GPS fixes over the ATM interface. If DSBL is selected, no GPS fixes will be accepted.
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PAGE FUNCTION BRIEF DESCRIPTION c. ATM Port Configuration Settings, Page 2: (1) Fcn 3 = ENBL/DSBL. Reserved. Should be set to DSBL. (2) Vref Input = ENBL/DSBL. If ENBL is selected, the RLGN will accept reference velocities over the ATM interface. If DSBL is selected, velocity references will not be accepted over the ATM interfaces. (3) Attd Data = ENBL/DSBL. If ENBL is selected, the RLGN will accept backup attitude data over the ATM interface. If DSBL is selected, no backup attitude data will be accepted over the ATM interface. (4) Fen 6 = ENBL/DSBL. Reserved. Should be set to DSBL. d. ATM Port Configuration Settings, Page 3: (1) Depth = ENBL/DSBL. If ENBL is selected, the RLGN will accept depth inputs via the ATM interface. If DSBL is selected, depth will not be accepted over the ATM interface. (2) BFTT Input = ENBL/DSBL. If ENBL is selected, the RLGN will accept BFTT data over the ATM interface and will distribute simulated data to NTDS I/O, as instructed by BFTT port selection. If DSBL is selected, RLGN will not accept BFTT simulated data. Users will only receive real data. (3) Grav Grad = ENBL/DSBL. If ENBL is selected, the RLGN will accept Gravity Gradient data for vertical deflection compensation over the ATM interface. If DSBL is selected, gravity gradient data will not be accepted over the ATM interface. (4) SLCM Input = ENBL/DSBL. If ENBL is selected, the RLGN will accept the SLCM enable/disable message over the ATM interface. SLCM enable/disable is applicable to submarine systems only. (Page 2 of 3) I/O Config Page 2, INS = ON/OFF, is associated with INS to INS interfacing in dual AN/WSN-7(V) installations. On: Enables INS-INS interfacing. Off: Disables INS-INS interfacing. (Page 3 of 3) I/O Config Page 3, DSVL = ON/OFF, is associated with navigation systems that interface with a DSVL. On: Enables the data port for DSVL interfacing. Off: Disables the data port for DSVL interfacing. 6. I/O Restart The I/O Restart control function menu is associated with I/O and ATM processor settings. I/O Restart is used to enable an I/O or ATM Processor disabled by BITE when a fault condition is detected. This control function does not require INS power to be cycled for the processor to be enabled. This control function is enabled by default when the INS is turned on. Enable: Restarts (enables) I/O or ATM Processor operation without recycling power.
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PAGE FUNCTION BRIEF DESCRIPTION Page 2 of the AUXILIARY FUNC menu provides control functions associated with the Display Test, Display Rate, Display Normal/Txvs, KF Reinitialize, Log Calibration, and Memory Inspection. 2 1. Display Test The Display Test control function initiates a dynamic self-test of the display. Test continues until one of the display menu keys is pressed. 2. Display Rate The Display Rate control function selects display update rate. 1 Hz: Updates display data once every second. 2 Hz: Is the default rate, and updates display data once every two seconds. 3. Normal/Txvs The Display Normal/Txvs control function selects coordinates format for position and heading display. This function affects display format only and does not affect calculation mode. Normal: Renders coordinate format as LAT XXX.XX N and LON XXX.XX W. Txvs: Renders coordinate format as TLT XXX.XX S and TLN XXX.XX W. 4. KF Reinitialize The KF Reinitialize control function is not used for normal INS operation. This control function should be used ONLY when INS performance is verified as outside of specification and when it is certain that Kalman Filter reinitialization will realign and restore INS attitude and position accuracy. 5. Log Calibration The Log Calibration control function presents an operator interface that enables data entry during a controlled calibration run. 6. Mem Inspt The Memory Inspection (Mem Inspt) control function enables the operator to observe the data values currently stored in memory. This function allows each memory address location to be selected and to be sequentially stepped up or down. This function is intended primarily as a software development tool. Page 3 of the AUXILIARY FUNC menu provides control functions associated with Simulated Output, Monitor Performance, Auxiliary Panel, NAV/DR Out, Digital-to-Synchro (D/S) Test, and DR Reset. 3 1. Simulated Output The Simulated Output control function is associated with producing and transmitting simulated values. This menu lists control function options on four display menu pages, which allows the operator to select a simulation mode for system data output and to enter simulated values for heading, roll, pitch, position, and velocity on all outputs. Selection of this function and output of simulated values does not affect system operation. Digital data messages contain status bits which are set to indicate that output data is simulated. Relay K6 is set to provide indication that analog outputs are simulated when this mode is active. When this mode is exited, the system remains in the Simulate mode for a short period of time while system output parameters are being slewed back to correct values. When all values are reset, the system reverts automatically to normal output.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION a. Enable On/Off On: Enables simulated system data output, and enables the Modify Attitude, Modify Velocity, and Modify Position control functions to be selected and edited. OFF: Disables simulated system data output, and disables the Modify Attitude, Modify Velocity, and Modify Position control functions. b. Modify Attitude – Enable On/Off control function must be set to On to select and edit. (1) Roll: Displays and enables editing of current Roll data via the display keypad. (2) Pitch: Displays and enables editing of current Pitch data via the display keypad. c. Modify Velocity – Enable On/Off control function must be set to On to select and edit. (1) VN: Displays and enables editing of current Velocity North (VN) data via the display keypad. (2) VE: Displays and enables editing of current Velocity East (VE) data via the display keypad. d. Modify Position – Enable On/Off control function must be set to On to select and edit. (1) Lat: Displays and enables editing of current latitude (Lat) data via the display keypad. (2) Lon: Displays and enables editing of current longitude (Lon) data via the display keypad. 2. Monitor Performance The Monitor Performance control function is associated with dynamic system performance testing while the system is operating in the Navigate mode. This menu lists control function options on two display menu pages. (Page 1 of 2) 1. Monitor On/Off: Presents the option to control the monitoring of the dynamic system performance test. On: Enables monitoring of dynamic system performance test. Off: Disables monitoring of dynamic system performance test. (Page 2 of 2) 2. Monitor data: Presents data monitoring options on three menu pages. Page 1 – Monitor Start Time: Displays dynamic system performance test start time and enables start time editing. Page 1 – Monitor Elapsed Time: Displays elapsed time since the dynamic system performance test’s start time. Page 2 – Position Sensor: Displays position sensor source. Page 2 – TRMS Position Error: Displays TRMS position error data as a percentage of system performance specification. Page 3 – RMS Vel North: Displays Velocity North data as a percentage of system performance specification. Page 3 – RMS Vel East: Displays Velocity East data as a percentage of system performance specification.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION 3. Auxiliary Panel The Auxiliary Panel control function is associated with indicating when an IP-1747/WSN Control Display Unit (CDU) or Factory Interface Monitor (FIM) is installed and interfacing with the INS. Monitor: Indicates an IP-1747/WSN CDU is installed and is interfacing via the system’s I/O interface port. FIM: Indicates an FIM is installed and is interfacing with the INS. This value may be toggled to Monitor, thereby forcing the system’s I/O interface open and enabling CDU operation without requiring the INS power to be cycled. 4. NAV/DR Out The NAV/DR Output control function is associated with INS NAV and DR data output to users. NAV: (Default) Enables NAV inertial data to be output from the INS to users. DR: Disables NAV inertial data output, and enables DR data output from the INS to users. 5. D/S Test The D/S Test control function is associated with a short loop, on-line wraparound test of the digital synchro converters. a. Periodic: On: Enables the automatic testing of the D/S converters at periodic intervals. Off: Disables the automatic testing of the D/S converters at periodic intervals, and sets the test to be performed ONLY when the INS is started. b. On Demand Test: On: Enables manual testing of the D/S converters at any time. Off: Disables manual testing of the D/S converters. 6. DR Reset The DR Reset control function is associated with determining the validity of, and resetting, DR position values. If the DR data menu shows asterisks, the DR solution is invalid and the operator should enter this menu and reset the DR position. Reset DR to Inertial: Resets DR data to inertial position values. Reset DR to Manual: Enables DR latitude and longitude values to be manually entered. DISPLAY Functions The Display Functions control functions are associated with INS parameters and output data, and their presentation for review. Output data available for review includes position, velocity, heading, and day/time information. Display control functions are presented and reviewed via five display menu pages. Select Display Functions by pressing the <DISPLAY> key. Select the menu page by pressing the <NEXT PAGE> key. Select the parameter to be displayed by pressing the number key corresponding to the number of the parameter.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION Page 1 of the DISPLAY functions menu provides control functions associated with velocity, roll, pitch, heading and depth. 1 1. Vn/Ve Vn: Displays the ship’s North/South inertial velocity in Knots (KTS). Ve: Displays the ship’s East/West inertial velocity in Knots (KTS). 2. Vfa/Vps Vfa: Displays the ship’s fore/aft inertial velocity in Knots (KTS). Vps: Displays the ship’s port/starboard (stbd) inertial velocity in Knots (KTS). 3. Roll/Rate Roll: Displays the ship’s roll angle. Rate: Displays the ship’s roll rate in Degrees per Second (°/SEC). 4. Pitch/Rate Pitch: Displays the ship’s pitch angle. Rate: Displays the ship’s pitch rate in Degrees per Second (°/SEC). 5. Hdg/Rate Hdg: Displays the ship’s heading. Rate: Displays the ship’s turn rate in Degrees per Second (°/SEC). 6. Depth * On INS configured with a selected depth input source, displays depth in Feet (FT). Page 2 of the DISPLAY functions menu provides control functions associated with reference velocities, divergence values in heading, roll, and pitch, ship course, and log biases. 2 1. Ref Vn/Ve Ref Vn: Displays the ship’s North/South components of the selected reference velocity in Knots (KTS). Ref Ve: Displays the ship’s East/West components of the selected reference velocity in Knots (KTS). 2. Ref Vfa/Vps Ref Vfa: Displays the ship’s fore/aft components of the selected reference velocity in Knots (KTS). Ref Vps: Displays the ship’s port/starboard (stbd) components of the selected reference velocity in Knots (KTS). 3. Vk/Ref Vk Vk: Displays the vertical component of ship’s velocity (Vk) in Knots (KTS). Ref Vk: Displays the selected reference velocity (Ref Vk) in Knots (KTS). 4. Divergence (Page 1 of 2) With dual INS installations, displays the difference between the heading, roll, and pitch values as determined by each navigation system. Hdg: Displays heading (Hdg) for each INS in minutes. Roll: Displays roll for each INS in minutes. Pitch: Displays pitch for each INS in minutes. (Page 2 of 2) With dual INS installations, displays the difference between the position values as determined by each navigation system. Lat: Displays latitude (Lat) for each INS in minutes. Lon: Displays longitude (Lon) for each INS in minutes. 5. Course Displays ship’s present direction of motion without regard to ship’s heading. Display range 0.00° to 359.99°.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION 6. Log Biases Displays up to ten log biases at speed values for Rod 1 and Rod 2 speed sources. Clear Biases Rod 1: Enables the operator to erase Rod 1’s bias values as stored in memory. Show Biases Rod 1: Enables the operator to review Rod 1’s bias values as stored in memory. Clear Biases Rod 2: Enables the operator to erase Rod 2’s bias values as stored in memory. Show Biases Rod 2: Enables the operator to review Rod 2’s bias values as stored in memory. Page 3 of the DISPLAY functions menu provides control functions associated with position and velocity variance and divergence, ocean current velocities, reset data and RLGN designation. 3 1. Sigma N/E Displays position variance estimates. Sigma N: Displays 1-sigma estimate for North (N) velocity in Nautical Miles (NM). Sigma E: Displays 1-sigma estimate for East (E) velocity in Nautical Miles (NM). RPE: Displays 1-sigma estimate for Radial Position errors (RPE) in Nautical Miles (NM). 2. Sigma Vn/e Displays velocity variance estimates. Sigma Vn: Displays 1-sigma estimate for North (N) velocity in Knots (KTS). Sigma Ve: Displays 1-sigma estimate for East (E) velocity in Knots (KTS). 3. DVn/DVe Displays the difference between INS inertial velocity and selected reference velocity. DVn: Displays the difference between North (n) INS inertial velocity and selected reference velocity in Knots (KTS). DVe: Displays the difference between East (e) INS inertial velocity and selected reference velocity in Knots (KTS). 4. OCn/OCe Displays the estimated ocean currents velocities. Displayed values are only true if a water speed velocity reference is selected. OCn: Displays the estimated North (n) ocean currents velocities in Knots (KTS). OCe: Displays the estimated East (e) ocean currents velocities in Knots (KTS). 5. Reset Data Displays the last received fix values to allow the operator to review the fix data. This menu should be selected by the operator to review the fix data to be within acceptable limits prior to accepting or rejecting the fix, when either Review or Auto/Review is selected for entry of fix reset data. FixLAT: Displays the last received Latitude (LAT) fix value to allow the operator to review, and accept or reject the fix data. FixLON: Displays the last received Longitude (LON) fix value to allow the operator to review, and accept or reject the fix data.
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION FSN: Displays the last received FSN fix value to allow the operator to review, and accept or reject the fix data. FSE: Displays the last received FSE fix value to allow the operator to review, and accept or reject the fix data. GPS: Displays the last received Global Positioning System (GPS) fix value to allow the operator to review, and accept or reject the fix data. 6. RLGN Designation Displays the RLGN’s designation when part of a dual RLGN INS without requiring the RLGN to be shut down and restarted in Test mode. The RLGN designation is used by some IDS users. This RLGN 1: Identifies the RLGN as number 1 in a dual RLGN INS. This RLGN 2: Identifies the RLGN as number 2 in a dual RLGN INS. Page 4 of the DISPLAY functions menu provides control functions associated with date/time settings, system part identification numbers, accelerometer and gyro bias data, DR data, and BFTT data. 4 l. Day/Time Displays and allows the date and time to be edited. Day: Displays the Julian day and time and allows values to be changed. Time: Displays the time in military 24-hour format. 2. Part No. This control function displays six menu pages containing: serial numbers and information for the RLGN and its sensor block components and assemblies; part numbers and revision numbers for RLGN programs; vendor ID numbers; and network information. (Page 1 of 6) Presents Accelerometer identification information. A Accel SN: Displays the A Accelerometer’s serial number. B Accel SN: Displays the B Accelerometer’s serial number. C Accel SN: Displays the C Accelerometer’s serial number. (Page 2 of 6) Presents Gyro identification information. A Gyro SN: Displays the A Gyro’s serial number. B Gyro SN: Displays the B Gyro’s serial number. C Gyro SN: Displays the C Gyro’s serial number. (Page 3 of 6) Presents INS identification information. Platform SN: Displays the RLGN’s platform serial number. Sensor Block SN: Displays the RLGN’s IMU sensor block serial number. Serial Number AN/WSN-7(V): Displays the RLGN’s serial number. (Page 4 of 6) Presents processor and IMU program identification information. Nav Prog PN: Displays the Nav Processor’s program part number. IMU Prog PN: Displays the IMU program part number. IO Program PN: Displays the IO Processor’s program part number. (Page 5 of 6) Presents ATM program and Peripheral Component Interface (PCI) identification information. ATM Prog PN PCI Vendor ID PCI Device ID PCI Class Code
Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION (Page 6 of 6) Presents PCI subsystem and Media Access Control (MAC) address identification information. PCI Subsystem Vendor PCI Subsystem ID MAC Address 3. Accelerometer Bias Displays accelerometer bias estimates. A Accel °/Hr: Displays A accelerometer (Accel) bias estimates in micro gravities within a range of plus or minus (±) 9999 micro-g. B Accel °/Hr: Displays B accelerometer (Accel) bias estimates in micro gravities within a range of plus or minus (±) 9999 micro-g. C Accel °/Hr: Displays C accelerometer (Accel) bias estimates in micro gravities within a range of plus or minus (±) 9999 micro-g. 4. Gyro Bias Displays gyro bias estimates: A Gyro °/Hr: Displays A Gyro bias estimates in degrees within a range of plus or minus (±) 2.1333°/hour. B Gyro °/Hr: Displays B Gyro bias estimates in degrees within a range of plus or minus (±) 2.1333°/hour. C Gyro °/Hr: Displays C Gyro bias estimates in micro gravities within a range of plus or minus (±) 2.1333°/hour. 5. DR Data This on-line menu displays the DR data as calculated by the RLGN. This data includes latitude, longitude, total velocity and heading. The selection of output data (inertial or DR) has no effect on this display. If the DR data display shows asterisks, it indicates that the DR solution is invalid. The DR solution can become invalid, for example, if the DR position hasn’t been initialized or heading reference is temporarily lost. A DR position reset is required. Once a DR reset is commanded, the DR data values will no longer be asterisks (assuming heading reference is not lost). (See AUXiliary FUNctions, Page 3, DR Reset.) LAT: Displays the DR latitude (LAT) calculated by the RLGN. LON: Displays the DR longitude (LON) calculated by the RLGN. Vt: Displays the DR total velocity (VT) calculated by the RLGN. HDG°: Displays the DR heading (HDG) calculated by the RLGN. 6. BFTT Data* When the RLGN is in BFTT mode, displays the BFTT Simulated data being transmitted. Page 5 of the DISPLAY functions menu provides control functions associated with Grid coordinates and Laser Intensity Monitor (LIM) Voltage. 5 1. Grid N/E*** Grid = °/S Grid = °/W Table 4-24(Cont’d).— Operating Menus/Functions Description.
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PAGE FUNCTION BRIEF DESCRIPTION 2. LIM Volts*** The LIM volts control function menu displays the LIM voltage for the A, B, and C gyro in an RLGN. A = Displays the LIM value for A gyro in volts (V). A LIM value greater than +1.1 volts indicate that the A gyro is within acceptable operating specification. B = Displays the LIM value for the B gyro in volts (V). A LIM value greater than +1.1 volts indicate that the B gyro is within acceptable operating specification. C = Displays the LIM value for the C gyro in volts (V). A LIM value greater than +1.1 volts indicate that the C gyro is within acceptable operating specification.
Table 4-25 lists identification of port types and physical locations, table 4-26 lists NTDS Port Interfaces, and table 4-27 lists Simulated Outputs.
PORT SET CCA LOCATION RECORD BOARD TYPES AND IDS CODES INSTALLED (IN THIS SYSTEM) NTDS I/O BOARD TYPE IDS CODE Part Number 1981101-6 AN/WSN-7(V)1 A1/A2 (1A1A51) Type E (Serial) B1/B2 ( 1A1A52) Type E (Serial) C1/C2 ( 1A1A53) Type E (Serial) D1/D2 (1A1A54) Type E (Serial) E1/E2 ( 1A1A55) Type D (Serial) F1/F2 ( 1A1A56) Type A (Parallel) G1/G2 (1A1A57) Type A (Parallel) H1/H2 (1A1A58) Type A (Parallel) I1/I2 ( 1A1A4) ATM 16 Part Number 1981101-2 AN/WSN-7(V)2 A1/A2 (1A1A51) Type E (Serial) B1/B2 ( 1A1A52) Type A (Parallel) C1/C2 ( 1A1A53) Type E (Serial) D1/D2 (1A1A54) Type D (Serial) E1/E2 ( 1A1A55) Type A (Parallel) F1/F2 ( 1A1A56) Type A (Parallel) G1/G2 (1A1A57) Type A (Parallel) H1/H2 (1A1A58) Type A (Parallel) I1/I2 ( 1A1A4) ATM 16
Table 4-24(Cont’d).— Operating Menus/Functions Description. Table 4-25.— Identification of Port Type and Physical Location.
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PORT SET CCA LOCATION RECORD BOARD TYPES AND IDS CODES INSTALLED (IN THIS SYSTEM) NTDS I/O BOARD TYPE IDS CODE Part Number 1981101-3 AN/WSN-7(V)3 A1/A2 (1A1A51) Type E (Serial) B1/B2 ( 1A1A52) Type A (Parallel) C1/C2 ( 1A1A53) Type A (Parallel) D1/D2 (1A1A54) Type A (Parallel) E1/E2 ( 1A1A55) Type A (Parallel) F1/F2 ( 1A1A56) Type A (Parallel) G1/G2 (1A1A57) Type A (Parallel) H1/H2 (1A1A58) Type A (Parallel) I1/I2 ( 1A1A4) ATM 16
IDS CODE NTDS TYPE DIRECTION SPECIFICATION 00 - - Not fitted 01 A Input/Output NAVSEA SE174-AB-IDS-010/GPS 021 B Input/Output NAVSEA SE174-AB-IDS-010/GPS 03 A Input/Output S9427-AN-IDS-050/WSN-7 04 A Input/Output S9427-AN-IDS-070/WSN-7 051 B Input/Output S9427-AP-IDS-010/RLGN 061 B Output S9427-AP-IDS-020/RLGN 07 D Input/Output S9427-AN-IDS-030/WSN-7 08 A Output S9427-AN-IDS-040/WSN-7 09 E Output S9427-AN-IDS-020/WSN-7 10 E Input/Output S9427-AN-IDS-020/WSN-7 11 A Output S9427-AN-IDS-060/WSN-7 12 - - (Reserved) 13 E Input/Output S9427-AN-IDS-010/WSN-7 (Super Channel) 141 B Input/Output S9427-AP-IDS-030/RLGN 151 B Input/Output S9427-AP-IDS-040/RLGN 16 ATM Input/Output S9427-AN-IDS-080/WSN-7 17-31 - - (Reserved)
Table 4-25(Cont’d).— Identification of Port Type and Physical Location. Table 4-26.— Identification of NTDS Port Interface Design Specification.
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SIMULATED FUNCTION DESCRIPTION ENTRY RANGE 2 Modify Attitude Output Functions (Select by pressing the <2> key) 1 Roll Sets a positive or negative roll angle, which is output from Synchro Buffer Amplifier 8 VA (1A1A41). -45 to +44.99 degrees 2 Pitch Sets a positive or negative pitch angle, which is output from Synchro Buffer Amplifier 8 VA (1A1A42). -45 to +44.99 degrees 3 Heading Sets a heading angle, which is output from Synchro Buffer Amplifiers 32 VA (1A1A43) and 32 VA (1A1A44). 0 to 359.99 degrees 3 Modify Velocity Output Functions (Select by pressing the <3> key) 1 Vel N (North Velocity) Sets a north/south velocity value, which is output from Synchro Converter CCA (1A1A38) (in synchro data Format) and in all applicable NTDS output data messages. -128 to +127.99 knots 2 Vel E (East Velocity) Sets an east/west velocity value, which is output from Synchro Converter CCA (1A1A38) (in synchro data format) and in all applicable NTDS output data messages. -128 to +127.99 knots 4 Modify Position Output Functions (Select by pressing the <4> key)When entering latitude and longitude, the N/S field is set with the <NE+> key or <SW−> key. 1 Latitude Sets a latitude value, which is output in all applicable NTDS output data messages. 0 to 90 degrees 0 to 59.99 minutes 2 Longitude Sets a longitude value, which is output in all applicable NTDS output data messages. 0 to 180 degrees 0 to 59.99 minutes
Table 4-27.— Simulated Outputs Description.
Selecting the Navigate Mode
Once the RLGN has settled to Fine Align state in the At-Sea Align mode, the RLGN switches automatically from Fine Align to the Navigate mode when error estimate criteria are met. If the RLGN has settled to Fine Align state (ALIGN-F indication) using the Dockside reference (DOCK ON), the operator must remove the selected reference (DOCK OFF) and select a velocity reference. The RLGN will then switch from Fine Align to the Navigate mode. The RLGN will determine position by dead reckoning until a position reference source is selected. In the same manner, when SLAVE is selected as the reference, SLAVE must be deselected to enter the Navigate mode. See Figure 4-55. 4-163 UNCLASSIFIED
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Figure 4-55.— Mode Transition Diagram.
Use of Transverse Coordinates Reference System In a gyro-stabilized platform, torque values based on the tangent (tan) and secant (sec) of latitude are used in system control loops. While the INS is a strapdown system based on ring lasers, calculations involving these functions are also used. As the INS approaches 90 degrees latitude, these values become indeterminate (approach infinity) and are no longer valid for calculations. In addition, at high latitudes, the magnitude of east/west vectors has less validity. For this reason, an alternate (Transverse) Earth coordinate’s reference system is used when the INS is operating at latitudes greater than approximately 85 degrees. The Transverse north pole is located at the intersection of the geographic 180-degree meridian and the equator. 4-164 UNCLASSIFIED
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The geographic 90-degree and 270-degree meridians become the Transverse equator, and the geographic equator becomes the Transverse 90-degree and 270-degree meridians. (Refer to Figure 4-56.)
Figure 4-56.— Earth Coordinate References.
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Accepting or Rejecting Fixes The reset mode allows the operator to select how automatic fixes are accepted or rejected, enables review of last accepted fix data, and enables review and manual acceptance of pending fixes that the system has rejected as unreasonable. The Fix Review mode can be selected from the Mode menu, Reset Mode function. The mode selected on this menu determines how the system involves the operator in the review and acceptance of fixes from external position sensors. Manual fixes can be entered into the system at any time using the Mode menu, Fix function. When fixes are entered manually, the system checks the fix data for reasonableness in the same manner as for fixes received from external position sensors. If the manually entered fix data is determined to be invalid, an appropriate fault code and a Reset Data menu are displayed. This menu allows the operator to review the entered fix data and either force acceptance or discard the data. At any time, the operator can review the data for the last position fix accepted by the system. This function is selected from the Display menu, Page 3, Reset Data function. Figure 4- 57 presents an outline of the various states associated with the position fix functions.
Figure 4-57.— Position Fix, Data Entry and Review Functions.
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Enhanced Performance Position Accuracy (EP2A) (Refer to Figure 4-58) The EP2A feature of the INS addresses the residual errors that remain in the INS position solution. The INS errors are characteristically slowly varying; e.g., the 84.4-minute Schuler period and the 24-hour earth loop. In contrast, the errors in the GPS aiding source are short period, typically on the order of seconds to minutes, and are more random in nature; e.g., ionospheric and multipath errors. The INS uses EP2A to estimate the current value of the slowly varying INS error and to “average out” the short- period GPS errors to provide a Real-time estimate of the correction to the Kalman- derived INS position.
Figure 4-58.— Enhanced Performance Position Accuracy (EP2A) Block Diagram.
GPS or GPS I/O Faults
Failure of the GPS position sensor input to the INS will result in slow degradation in the accuracy of the estimate of position. Position performance degrades approximately as a function of the square root of time as shown in Figure 4-59. INS performance can be maintained by selecting a different position sensor (if configured for additional position sensor) or by periodically entering a position fix manually.
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Figure 4-59.— Position Estimate Accuracy vs. Time without Position Update.
TRMS position error
Indicates the Time Root Mean Square (RMS) value of the position error, as calculated from the start time of the Performance Monitor function, as a percentage of a normalized system specification value. For an explanation of TRMS calculation method, refer to Figure 4-60.
Figure 4-60.— Time RMS (TRMS) Position Error Calculation Method.
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Maintenance of Gyrocompasses Ships having the Planned Maintenance System (PMS) installed should perform gyrocompass maintenance requirements as indicated on the equipment maintenance requirement cards (MRCs).
Such routine maintenance should not be recorded in the service record book. Repairs or replacement of parts resulting from such maintenance, however, should be recorded to aid those involved with future repairs to the gyrocompass.
The technical manual sent with the WSN-2 is laid out in such a manner as to greatly assist the troubleshooter. You should carefully study these technical manuals before starting any maintenance action.
Maintenance should not be undertaken by inexperienced personnel without close supervision of a qualified maintenance technician.
Records
The PMS of the 3-M Systems has cut the records and inspections of the gyrocompass to a minimum. Naval Ships’ Technical Manual, chapter 252, no longer requires lengthy records to be kept on gyrocompass equipment; however, it specifically requires the record book that is sent with each compass to be scrupulously maintained.
The gyrocompass service record book is used to record important repair information (major part replacement, overhaul, and field change installation), providing a continuous repair history of each gyrocompass. Instructions for maintaining the record book are given in the front of the book.
The service record book remains with the master gyrocompass throughout its service life. Should the compass be removed from the ship, its service record book accompanies it.
4.12.0 AN/SSN-6(V)2 NAVIGATION SENSOR SYSTEM INTERFACE SYSTEM The AN/SSN-6 Navigation Sensor System Interface (NAVSSI) System is an integrated shipboard system that automatically accepts, processes, and disseminates navigation and time information from various shipboard navigation sources.
The AN/SSN-6 provides a means for users to obtain data verification, digital mapping, and the programming of selected way points. The AN/SSN-6 utilizes inputs from the Inertial Navigation System (INS), AN/UQN-4 Sonar Sounding Set, and EM Log to provide extremely accurate position (latitude and longitude), velocities (N-S, E-W, and vertical), ownship heading (OSH), roll, pitch, depth below keel, speed through the water (OSS), own ships distance (OSD), and extremely accurate time. The AN/SSN-6 also receives GPS satellite data via two embedded GPS VME Receiver Cards (GVRC). 4-169 UNCLASSIFIED
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The inputs to the AN/SSN-6 are processed, and in the AUTO mode, NAVSSI selects the best source selection for each output component. In the manual mode, the source selection is made by the operator to provide the appropriate output.
The AN/SSN-6 is composed of three units: the Display Control Subsystem (DCS), the Real Time Subsystem (RTS), and the Bridge Work Station (BWS). The DCS provides overall system control, data processing, data storage, and Man-Machine Interface (MMI) for both operation and maintenance. The DCS also houses the Sensor Interface Unit (SIU) for processing depth below the keel sonar signals from the AN/UQN-4. The DCS monitor can be utilized as a backup to the BWS. The RTS is the primary means for communicating between the various sensors to obtain inputs for the AN/SSN-6 and to provide usable output information to various ships systems. The BWS provides parallel operator control, query, and readout of the DCS.
The Block 3 system is configured as a dual RTS. The current Block 3, Build 2 systems are all dual RTS systems. Figure 4-61 shows a typical NAVSSI system with dual RTSs. A Local Area Network (LAN) links these hardware components via fiber-optic cabling.
The DCS enables the operator to display the ownship's navigation sensor information, control the RTS(s), and display from the Global Positioning System (GPS). GPS data is initially received at the GPS Antenna, then is sent to the Global Positioning System (Versa Module Europa) Receiver Card (GVRC) that is installed in the Versa Modular Europa (VME) chassis of the RTSs. The GPS receiver cards (GVRC) together with the Digital Nautical Charts (DNC) database (supplied via CD-ROM) provide the information that may be displayed on the DCS and BWS monitors. For dual RTS systems, the RTSs exchange data via a reflective memory link. This feature allows the RTSs to share all incoming and outgoing data, thereby improving overall system robustness. In dual RTS configurations, the DCS communicates with each RTS via a Local Area Network (LAN). The BWS provides remote workstation access to the DCS. 4-170 UNCLASSIFIED
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Figure 4-61.— Typical Dual-RTS NAVSSI Block 3 System.
4.12.1 System Capabilities and Interfaces The primary capabilities and purpose of NAVSSI AN/SSN-6 Block 3 system is to distribute common position, velocity, time, and almanac data to onboard Command & Control and Combat Systems. This is done in real time, with the Global Positioning System (GPS) as the primary source of navigation data.
To elaborate, the system gives users a Human-Machine Interface (HMI) to perform navigation planning, execution, and manipulation of Digital Nautical Charts (DNCs).
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The system provides consistent, accurate, timely Position, Velocity, and Time (PVT) data to all navigation dependent shipboard systems. It provides autonomous almanac data to the Tomahawk missile system. It also provides, voyage planning and voyage management functionality, using Digital Nautical Charts (DNCs) and other National Imagery and Mapping Agency (NIMA) products. Users include other navigation systems; Command, Control, Communications and Computer Intelligence, Surveillance, and Reconnaissance systems; weapon systems; and the shipboard navigation teams. This composite PVT enhances the ability of surface ships to perform navigation, ship control, and combat missions. The AN/SSN-6 composite PVT will normally be the most accurate information onboard.
The NAVSSI Block 3 hardware and software marks an improvement over previous versions in several areas:
• It expands the number of sensor and user systems supported.
• It incorporates a Global Positioning System (GPS) receiver capability directly into the NAVSSI system.
• It has refined algorithms that are used to calculate an integrated navigational solution.
• It further expands the navigation tools available to the ship's navigation team.
4.12.2 System Hardware A typical hardware configuration for the NAVSSI system is show in Figure 4-61. The DCS is normally located in the chart room, and the RTSs are located in the forward and aft Interior Communication (IC) rooms. Most NAVSSI installations include the NAVSSI Bridge Workstation (BWS). The BWS is a fully functional, remote operator, station for the DCS providing NAVSSI display and control capabilities to ship's force on the bridge.
Early versions of the Bridge Work Station do not have computer, with the monitor, trackball and keyboard being interfaced to the DCS. The later versions of the Bridge Work Station, have a computer that interfaces via a LAN to the DCS.
The Block 3, DCS computing platform is based on a TAC-4 computer with a trackball and keyboard. The TAC-4 workstation is a Hewlett Packard computer with a Series 9000-J210 processor providing open system architecture.
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The Block 3 RTS computing platform is based on a 20-slot Versa-Modular Europa (VME) chassis. The VME chassis hosts a variety of interface cards and a single board computer or CPU (in slot 0) that is either a Motorola 68000 series processor or a Power PC processor. Some of the significant features of the Block 3 system include the following:
NOTE: Some of the equipment listed below is not associated with NAVSSI but is simply using available rack space. This is noted, where applicable.
• AN/WSN-7 Ring Laser Gyro Navigator (RLGN) inertial interface
• IP-1747/WSN Control Display Unit (CDU) (none NAVSSI Equipment)
• Global Positioning System (GPS) Versa Module Europa (VME) Receiver, Card (GVRC)
• Doppler Sonar Velocity Log (DSVL) interface
• Integrated Communications and Advanced Network (ICAN) interface
• Ship's Self Defense System (SSDS) interface
• Cooperative Engagement Capability (CEC) interface
• Battle Force Tactical Trainer (BFTT) interface (none NAVSSI equipment)
• Data Multiplexing System (DMS)/Fiber Optic Data Multiplexing System (FODMS) interface
• Aegis Light Exo-atmospheric Projectile Intercept (ALI) Vertical Launch System (VLS) interface
• PTTI precise time and time interval
• AN/SQS-53D (sonar) interface
• AN/KSQ-1 (amphibious assault direction system) interface
• Ship's Data Multiplexing System (SDMS) interface. 4-173 UNCLASSIFIED
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4.12.3 System Software The NAVSSI AN/SSN-6 Block 3 system software uses two Computer Software Configuration Items (CSCls): the DCS CSCI and the RTS CSCI.
The DCS CSCI is the operator interface for the NAVSSI operator's console and the Bridge Workstation. The software resides on the hard drive of the TAC-4. It enables NAVSSI operators to do the following:
• Control and monitor RTS operations
• Display navigation sensor data
• Record and retrieve navigation information
• Display Digital Nautical Chart (DNC) data
• Provide the capability for route planning
• Route monitoring and voyage recording functions
The RTS CSCI is firmware that resides on EPROMs of the CPU module (in slot 0 of the VME chassis) and provides the following:
• Real-time interface, analysis, and selection of incoming navigation data as well as a real-time interface with the shipboard navigation sensors and users
• It can analyze sensor data to select the best source for navigation data users
• Provides Inertial Navigation System (INS) position fix data to the inertial GVRC
• Has the capability to distribute data to the user systems within the required timing constraints.
Each Computer Software Configuration Item (CSCI) is identified with unique names, acronyms and numbers (software Identification). CSCls are assigned a unique identifier composed of SUBSYSTEM DESIGNATOR, BLOCK #, BUILD # RELEASE #, and REVISION of a given release.
Table 4-28 provides an example of the identification system used.
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SUBSYSTEM DESIGNATOR DCS or RTS BLOCK# 0 to 9 BUILD # 1 to 9 RELEASE # 1 to 9 REVISION 1 to 9
Table 4-28.— System Software Identification.
The charting requirements for NAVSSI Block 3 are met using the Defense Information Infrastructure (DII) Common Operating Environment (COE), and several DII segments including the Coast Guard's Command, Display, and Control (COMDAC) Integrated Bridge Segment (IBS).
Evolutionary Acquisition (EA) enhancements in Block 3 software include the following:
• Compliance with the Defense Information Infrastructure (DII)
• Common Operating Environment (COE) integration standards and software
• Interfacing the DCS Sensor Data Segment (SDS) software with the U. S. Coast Guard DII Segment Command Display and Control (Replacement) (COMDAC-r) software
• Integrated Navigation Segment (INS) software
• U.S. Naval Observatory (USNO) Celestial Navigation program known as System To Estimate Latitude and Longitude Astronomically (STELLA)
• Converting the NAVSSI LAN to a Fiber Distributed Data Interface (FDDI) LAN
• System complies with the Global Command and Control System-Maritime (GCCS-M) integration standards and software
4.12.4 System and Network Interfaces The main interfaces for the NAVSSI navigational system are the shipboard sensors, weapons, and information systems and the primary source of navigation data used by NAVSSI AN/SSN-6 Block 3 is the GPS satellite system. NAVSSI is the host for the GVRC and provides GPS-unique source data along with the digital navigation charts for use by the navigator. Additionally, NAVSSI supplies a common time source and enables the navigator to monitor navigation data sources and the distribution of data to other shipboard users. 4-175 UNCLASSIFIED
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Table 4-29 summarizes typical input data and message rates and the interface criticality for maintaining communications in single and multiple point failures for the sensor/user systems that provide navigation data.
SYSTEM INPUT DATA RECEIVED Other RTS All Sensor, Control, Configuration, Lever Arm Data, etc. DCS All Sensor, Control, Configuration, Lever Arm Data, etc. GVRC Position, Velocity, Time, Status, Almanac FOAL Switch Switch Position AN/WRN-6 Position, Velocity, Time, Status, Almanac AN/WSN-1 INS Position, Velocity, Attitude, Attitude Rate, Speed through Water, System Performance AN/WSN-5 Channel A Position, Velocity, Attitude, Attitude Rate, Speed through Water, System Performance AN/WSN-5 Channel B Position, Velocity, Attitude, Attitude Rate, Speed through Water, System Performance AN/WSN-7 INS Position, Velocity, Attitude, Attitude Rate, Speed through Water, System Performance AN/WSN-7 Position, Velocity, Attitude, Attitude Rate, Speed through Water, System Superchannel Performance Gyrocompass Synchro Heading DSVL Speed through Water or Speed Over Ground EM Log Synchro Speed through Water Digital Speed Log Speed through Water Fathometer Depth beneath the keel IP-1747/WSN ANIWSN-7 Control Data DMS/FODMS INS, Fathometer , Wind, Propulsion data ICAN Wind Speed and Direction SWAN TBD
Table 4-29.— Block 3 Data Input Summary.
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Table 4-30 summarizes typical data output requirements by system for maintaining communications in single and multiple point failures. The NAVSSI RTS outputs navigation and time data meets the requirements of each user system.
SYSTEM POSITION ACCURACY (Meters) ATTITUDE LATENCY (msec) TIME ACCURACY (msec) DCS N/A N/A N/A AN/WRN-6 N/A 100 N/A AN/WSN-1 (CVNS) 100 N/A 1 AN/WSN-5 100 N/A 1 100 N/AAN/WSN-7 (RLGN) 1 IP-1747/WSN N/A N/A N/A DSVL N/A Note 1 100 N/A FODMS (RS-422) 100 N/A FODMS (STANAG 4156) 20 10 10 ICAN 20 10 10 SWAN 100 N/A 1000 JMCIS TDBM 100 N/A 1000 NTCS-A RS-232 Link 100 N/A N/A Outboard (synchro) 100 N/A N/A Outboard/ BGPHES/ 100 N/A N/A Combat DF (digital) ACDS Blk 0 1000 60 1000 ACDS Blk 1 Lvl 3 20 10 Note 2 10 AN/KSQ-1 100 N/A 1000 AN/SQS-53D 100 N/A 100 SQQ-89 SLR 100 N/A 100 ATWCS/TEPEE N/A N/A N/A BFTT N/A N/A 0.1 CEC N/A N/A 0.001 ECS-Havequick N/A N/A 1 Mk-86 GFCS 20 N/A 100 ERGM 20 N/A 0.001 SDMS 1000 60 1000 SSDS 20 10 Note 2 10 TAMPS N/A N/A N/A SLAM N/A N/A N/A ALI/VLS 20 N/A 0.001 ALI/IWCS 20 N/A N/A Expansion Ports: High rate 25 100 100 Expansion Ports: Low rate 25 N/A 100 IP Expansion Ports 100 N/A 1000 Notes: (1) NAVSSI shall transmit attitude data to DSVL within 30 milliseconds of its receipt from the INS. (2) This requirement is applicable only to NAVSSI interfaces with the AN/WSN-7. The attitude latency requirement is undefined on AN/WSN-1 and AN/WSN-5 platforms. Table 4-30.— Block 3 Data Output Summary. 4-177 UNCLASSIFIED
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4.12.5 System Hardware Versions The hardware configurations of individual Block 3 systems vary by ship class and by kits and upgrades that have been installed. The differences are largely in the type of point to point electronic connections.
Because different ships have different combinations of PVT interfacing systems, they need different sets of point to point connections based on these interfacing systems.
The DCS and RTS hardware configurations are build and ship class specific. However, configurations also can vary based on kits and upgrades that have been installed. The various ship classes (or platforms) have different interfaces available to them. NAVSSI system hardware reflects the interfaces that the system has to support. The hardware configuration information is provided in Volume 4 of EE170-AF-OMI-010/SSN-6, Maintenance, identifying the configuration for specific ship classes, in recognition of its impact on maintenance actions.
4.12.6 System Interface Versions External interfaces supported by the NAVSSI Block 3 system are dependent on the hardware that has been installed on the particular ship. This available hardware will dictate which software functions are available to the NAVSSI system. If the hardware interface is not available, the NAVSSI system software will gray out the applicable (non- functional) features in the operator displays.
4.12.7 System Software Versions The currently installed NAVSSI, DCS software versions can be determined by accessing the "Help" pull-down menu, as described in Volume 2 of EE170-AF-OMI-010/SSN-6, Program Operation. Since there are substantial platform dependent differences in NAVSSI interface requirements, NAVSSI Block 3 software was developed to run all the different suites of hardware that are available to the NAVSSI system. Each of these suites provides connectivity to the interfaces, particular to those ship classes that the suite supports. NAVSSI software stores the configuration information needed to customize the software to the particular hardware suite in non-volatile memory.
The software has all of the necessary suites to interface the available hardware. If the hardware is not available, that software suite will simply not be functional. All ship classes are provided with the same software. 4-178 UNCLASSIFIED
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4.12.8 System Firmware The NAVSSI, RTS uses firmware in the CPU in Slot 0 of the VME chassis located in the RTS racks. Normally, this is of no consequence to the NAVSSI operator or maintenance technician. However, if the CPU is replaced for any reason, EPROMs on the CPU must be subjected to maintenance action. This requires either replacement EPROMs or the reloading ("or burned-in") of the EPROMs, depending on the type of CPU that installed in the RTS. This is required to maintain the correct firmware for the system.
Refer to Volume 4, Maintenance, and to Volume 3, System Administration of EE170- AF-OMI-010/SSN-6, for the applicable procedural steps.
4.12.9 Equipment Descriptions The following describes the three major hardware subsystems, they are the Display, Control Subsystem (DCS), the Real Time Subsystem (RTS), and the Bridge Workstation (BWS).
Display Control Subsystem (DCS)
The DCS is the Human-Machine Interface (HMI) subsystem of the AN/SSN-6 system. The DCS is located in the chart room on most ships. The user controls the AN/SSN-6 system by using the DCS video screen, trackball, and keyboard.
The DCS takes the Position, Velocity, and Time (PVT) information from the RTS and then creates the electronic navigation chart to places the PVT in a context that helps the user to navigate the ship. The DCS also acts as an interface to aid in a variety of navigation tasks such as piloting, voyage-planning, voyage-management, and training.
The DCS is mounted in a ruggedized, 19-inch rack with shock isolation intended to minimize the effects of battle damage. It is powered by an Uninterruptible Power Supply (UPS) that provides backup power if primary power fluctuates or there are power interruptions. This feature provides the time needed to perform an orderly system shutdown if there was shipboard power failure.
A typical DCS is shown in Figure 4-62. The DCS provides the overall system control, data processing, storage and the operator interface for the NAVSSI system.
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Figure 4-62.— NAVSSI Block 3 Display Control Subsystem (DCS).
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Power Distribution Unit (PDU) Both the RTS and DCS subsystems contain Power Distribution Units (PDUs). The DCS and RTS PDUs are functionally equivalent, except they contain a different EPROM. The EPROMs used in the RTS PDUs are programmed with a power-shed feature. This power- shed feature drops the power on J5 to J8 (outputs) on the RTS PDU, after approximately 55 seconds of power interruption to the PDU. Each component of the RTS and DCS has its own circuit breaker. The circuit breakers provide over-current protection for installed components. In addition, the breakers allow individual components to be electrically isolated for troubleshooting, maintenance, and repair. The total system power can be removed from each subsystem using the UPS power switches.
For safety reasons, the PDU senses and reports abnormally high temperature conditions. The over-temperature LED will light at temperatures exceeding 45° C (113° F). The PDU shuts down in 55 seconds when temperatures exceed 50° C (122° F) after issuing an audible warning. In an emergency battle situation, the BATTLE SHORT switch can be turned on to override the thermal sensors and cause the PDU to continue to distribute power throughout the subsystem.
The PDU operates with an Uninterruptible Power Supply (UPS) by controlling all power supplied to, and taken from the UPS. Specific procedures to remove (or secure) all power in the equipment rack must be followed. All equipment in the racks is provided power through the toggle switches on the PDU which will remove or supply power to all equipment in the rack where the UPS is installed. However, the main power to the rack (ship's input power to the PDU) must be secured prior to performing maintenance. This can be done by securing and tagging ship's power to the equipment rack at the appropriate power panel or switchboard.
RAID
The Random Access, Integrated Drive (RAID) is a mass storage device that uses an array of up to eight half-height drives each having a capacity of up to 18.0 gigabytes. The RAID has a maximum storage capacity of up to 144 gigabytes. These integrated drives provide mass storage for navigational charts for NAVSSI system. Information can be read-from or stored-to the RAID drive like any other hard disk drive.
The RAID drive occupies a storage drawer compartment in the DCS. Some later versions of the NAVSSI system use the RAID drive.
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CD-ROM Library (Jukebox) The CD-ROM is a random access, read-only, mass storage device that uses removable CD-ROM disks.
The jukebox has a capacity of storing up to 240 CD-ROMs. Information can be read from the drive like any other disk drive, except that CD-ROMs cannot be written to. CD-ROM discs are 120mm (4.7 in.) in diameter, and use one data surface with a capacity of over 600 megabytes. Early versions of the systems require the loading of DNC CD-ROMs manually via the TAC-4 computer's CD-ROM drive, as the jukebox is not functional (as no software exists to operate the jukebox). Later versions of the systems may provide functionality of the CD-ROM library Jukebox), whereby, the CD-ROMs are no longer loaded by hand and access to all of the DNC CD-ROMs is provided by software control. But, more then likely, later versions of the systems may not use the jukebox at all and may use the RAID drives instead.
DAT Tape Drive
The Hewlett Packard OAT (Digital-Audio Tape) format tape drive is a 3.5" half-height sequential-access tape drive that can handle multiple capacity removable 4mm DDS data cassettes. The DDS-format tape drive is located on a shelf in the rack of the DCS and is used primarily for re-installation of the NAVSSI and GCCS-M system software. The OAT tape drive is a SCSI device.
Monitor The DCS monitor in the NAVSSI system provides a color graphical interface to the DCS. The monitor can be either a CRT or LCD depending on ship class. The monitor receives signals from the G-2 Graphics Board in the DCS TAC-4 workstation.
Keyboard and Trackball The keyboard is a TAC 4-specific keyboard and the trackball provides 4-buttons with the upper-left and lower left having redundant functions, based on operator preference. The Bridge Work Station (BWS) keyboard features back-lighting.
TAC-4 Computer (HP9000-J210) The NAVSSI AN/SSN-6 Block 3 DCS subsystem is hosted on a TAC-4 workstation (HP 9000 Series J210). The workstation handles all user and peripheral input/output (I/O) as well as system booting. The workstation executes the UNIX operating system that provides an environment for executing application software on the system. The DCS software is run within this environment as a group of UNIX applications. The TAC-4 computer is enclosed in the DCS rack and is equipped with a CD ROM drive, a 3.5" floppy drive and two 4.5-GB hard drives with RAM that is configured with 256 Megabyte.
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Uninterruptible Power Supply (UPS) The RTS and DCS subsystems both contain Uninterruptible Power Supply (UPS) units. The DCS and RTS UPSs are functionally equivalent. The UPS protects the digital circuitry from damage during a sudden power loss or surge. The UPS contains rechargeable batteries that are kept fully charged during normal operation. If power is lost, the batteries in the UPS supply power to operate the system for a short time during power interruptions. This allows for an orderly shutdown of the system.
During normal operation, AC input power from the PDU is brought into the UPS. The UPS provides circuit protection for the electronic equipment in the rack. The noise filter reduces EMI/RFI electrical noise and to provide protection against high voltage transients on the input to the electronics.
When AC input is within limits, the UPS constantly converts the incoming AC power to DC, and then the DC back to AC to power the electrical loads attached to the UPS. The UPS maintains the battery pack in a ready state. When the AC input is outside the limits or has failed. The UPS supplies power from its battery pack (without any interruption of power) to the load. Power status indicators are provided at the UPS.
Real Time Subsystem (RTS 2) – Aft
The forward and aft RTSs are similar subsystems; they however contain different equipment in the racks as noted below. Each RTS is mounted in a 19-inch ruggedized rack with shock isolation and that minimizes the effects of any ship sustained battle damage. It is powered by an uninterruptible power supply (UPS) that provides backup power if primary power fluctuates or there are power interruptions. This ensures continued power and provides the crucial data.
The aft RTS, shown in Figure 4-63, operates independently of the DCS TAC-4. The RTSs communicate directly with navigation data sources and navigation data users. This is done by running real-time software that provides the data processing functions.
The aft RTS communicates with the DCS over the FDDI LAN and in dual-RTS configurations, the RTSs also communicate with each other via the same FDDI LAN. Dual RTS configurations provide reflective memory to each other, whereby current data is always available to the DCS.
The NAVSSI RTS system software resides in the RTS on EPROMs. The currently installed RTS software version may be determined by accessing the DCS "Help" pull- down menu as described in Volume 2 of EE170-AF-OMI-010/SSN-6, Program Operation.
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The forward and aft RTSs are essentially the same, except that in most cases, the aft RTS contains the Battle Force Tactical Trainer (BFTT) and the Control Display Unit (CDU) Assembly. The CDU (part of WSN-7 systems) includes a CPU, display, printer and peripheral devices. This equipment is not part of the NAVSSI system, but is housed in the same rack as the NAVSSI equipment. Please refer to separate documentation for information on this equipment.
Figure 4-63.— NAVSSI Block 3 RTS 2 (Aft).
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Battle Force Tactical Trainer (BFTT) - NON NAVSSI EQUIPMENT This equipment is installed in the NAVSSI racks, but is not part of the navigational equipment.
Control Display Unit (CDU) Assembly - NON NAVSSI EQUIPMENT
This equipment is installed in the NAVSSI racks, but is not part of the navigational equipment.
Fiber Optic Antenna Link (FOAL) Receiver
The overall FOAL consists of an antenna conversion module mounted in the GPS antenna and a receiver conversion module mounted in the FOAL unit in the RTS rack. Each RTS is supplied GPS signals from its own GPS antenna, and therefore, each RTS includes a FOAL.
The Fiber Optic Antenna Link (FOAL) provides an optical data transmission link between the RF output of the GPS antenna and the RF input to the GVRC board in the RTS. The GPS signal received at the antenna is routed to the RTS via fiber optic cable to maintain data integrity over the long distances from the antenna at the top of its mast to the RTS rack.
The FOAL provides optical conversion and switching of the GPS signals from the two antennas. The antenna module consists of a RF-to-optical converter to convert the received RF signal to an optical signal. At the RTS end of the fiber optic cable, the FOAL receiver converts the optical signal back to a RF signal for input to the GVRC board.
The FOAL also provides cross-connect switching for the signals from each GPS antenna. If one of the antennas malfunctions, the signal from the single operating antenna is switched to both the forward RTS and the aft RTS.
Real Time Subsystem (RTS 1) – Forward
The forward and aft RTSs are similar in relation to NAVSSI equipment; they however contain different equipment in the racks as noted below. Each RTS is mounted in a 19- inch ruggedized rack with shock isolation designed to counter shock effects from battle, a heavy sea state, or any other source. Each RTS receives operating power from the UPSs to ensure it continues to provide crucial data if there is a problem with shipboard power.
The forward RTS, shown in Figure 4-64, operates independently of the DCS TAC-4. The RTSs communicate directly with navigation data sources and navigation data users. This is done by running real-time software that provides the data processing functions. 4-185 UNCLASSIFIED
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Figure 4-64.— NAVSSI Block 3 RTS 1 (Forward).
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Multiple I/O boards are installed in each RTS to format each position and navigation (POS/NAV) output data stream in the format required by the individual user systems. The aft RTS communicates with the DCS over the FDDI LAN, and in dual-RTS configurations, the RTSs also communicate with each other via the same FDDI LAN. Dual RTS configurations provide reflective memory to each other, ensuring that current data is always available to the DCS.
The NAVSSI RTS system software resides in the RTS in EPROM memory. The currently installed RTS software version may be determined by accessing the "Help" pull-down menu as described in Volume 2 of EE170-AF-OMI-010/SSN-6, Program Operation.
The forward and aft RTS are essentially the same, except that the aft RTS contains the Battle Force Tactical Trainer (BFTT) and the Display Control Unit (CDU) Assembly. The CDU (part of WSN-7 systems) includes a CPU, display, printer and peripheral devices. This equipment is not part of the NAVSSI system, but is housed in the same rack as the NAVSSI equipment.
Bridge Workstation
The interactive workstation, located on the bridge, is shown in Figure 4-61. It provides bridge personnel with parallel control, query capability, and a display of NAVSSI system data, as supplied by the DCS.
Monitor The bridge monitor in the NAVSSI system provides a color graphical interface to the DCS. The monitor can be either a CRT or LCD depending on ship class.
NWS Computer The upgrade version of the Bridge Workstation, sometimes referred to as the Network Workstation, has a separate computer in lieu of a signal interface to the DCS TAC-4 computer. The pre-upgrade version of the BWS monitor, receive signals from the G-2 Graphics Board in the DCS TAC-4 workstation. The upgrade version of the BWS monitor, interface to DCS TAC-4 workstation via a LAN. This NWS computer controls all video for the BWS. 4-187 UNCLASSIFIED
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RTS VME Chassis and Installed Components The RTS VME chassis, shown in Figure 4-65 contains a backplane with 20 slots, numbered 0 through 19. Slot 0 is at the left of the chassis, as viewed from the front. Each slot provides two, 96-pin connectors labeled J1 and J2. J1 is located in the upper portion of the chassis and J2 is located in the lower portion. The pins of the J2 connector feed through to the back of the VME backplane to connector P2. The outer pin rows of the user defined P2 connector may be used by the card in that slot as an external connection to the VME chassis I/O connectors. The location of each board in the VME Chassis is described below. Each board in the VME chassis requires a unique bus address, even if the boards are identical.
Not all ships have a fully populated VME chassis'. In the cases where one or more of the boards is not included in the ship's configuration, blank panels are inserted in their place. Refer to Volume 4, Maintenance, Chapter 5, System Configuration and Composition of EE170-AF-OM1-01 0/SSN-6, to identify the hardware configuration of your system.
Figure 4-65.— VME Chassis and Installed Components - Typical.
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VME Power Supply The 750-watt VME power supply is mounted behind and below the VME card cage. The unit is powered by 115 VAC and is protected by a fuse located next to the line input (TB1). A detachable AC power cord for the supply is connected to the rear of the VME Chassis. All DC outputs are protected against overload and short circuit and have automatic recovery capability upon removal of fault. There is over-voltage protection for the +5VDC, wherein the trip point is set such that the +5VDC cannot exceed +6.8VDC. Input power to the supply may range from 90 to 132-VAC at 47 to 63 Hz. Output power is +5VDC at 120A and +/- 12VDC at 10A. The -5.2VDC is not used.
Slot 0 - MVME 147 CPU The MVME 147-023 CPU Board has a MC68030 processor and is the system controller for the VME bus. The processor operates at 32 MHz and has configurable random access memory (RAM). It is responsible for controlling all the boards in the RTS. It directs the interface boards to send/receive data, checks and processes data received, and communicates navigation solutions to the DCS. The CPU communicates with the DCS over the FDDI LAN to transfer information between the RTS and the DCS. It is always installed in the far-left slot (slot 0) to correctly initiate the bus grant daisy chain. The MVME 147-023 CPU board includes an onboard Ethernet communications processor.
Slot 0 - MVME 2700 [Power PC] CPU
Late versions and certain ship classes of the NAVSSI system have an alternate CPU. This is the MVME 2700 CPU Board. It has a PowerPC 750 microprocessor operating at 233 MHz, 266 MHz or 366 MHz. It has either 32 KB or 1 MB cache, and 1 MB flash RAM (or with expansion connector, 4 MB or 8 MB flash RAM). The MVME 2700 CPU is the system controller for the VME bus. The MPC750 processor operates through a 33 MHz 32/64-bit PCI local bus. The CPU is responsible for controlling all the boards in the RTS. It directs the interface boards to send/receive data, checks and processes data received, and communicates navigation solutions to the DCS. The CPU communicates with the DCS over the FDDI LAN to transfer information between the RTS and the DCS. It is always installed in the far-left slot (slot 0) to correctly initiate the bus grant daisy chain.
Slot 1 - VMIVME 5576-210
The VMIVME 5576 reflective memory board serves as the communications link between the two RTSs in a dual RTS system and places data from sensors in both RTSs.
This board allows the user to write any data to any specified location in a specified RTS. The same data will also be written to the same memory location in the other RTS. To execute this operation, the reflective memory board writes the data to the same location in the other RTS.
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Slot 2 - Currently Not Used Current configurations do not use slot 2.
Slot 3 – GVRC The GPS VME receiver card (GVRC) is a Precise Positioning Service (PPS) receiver that collects and processes GPS satellite signals to derive accurate three-dimensional position, velocity and time. The receiver can also be aided by an auxiliary sensor for increased performance in integrated applications. The GVRC calculates position, velocity and time solutions at a rate of one solution per second.
Slot 4 – PTU The Pulse Time Unit (VME-Sync Clock 32) is a digital clock that automatically synchronizes to time reference signals. The VME-Sync Clock 32's digital clock provides a resolution of 100 nanoseconds over the host systems "real time" clock. This provides stability and synchronization to universal coordinated time by locking to time reference signals. The time reference signals are standardized to an IRIG-B time code signal, and PTTI signals.
Slot 5 - FDDI 5211 Fiber Distributed Data Interface (FDDI) is a high-performance node processor for 125 Mbps fiber optic networks. The FDDI board performs much of the communications protocol processing and network management function required by FDDI using a Motorola 68EC040 processor and chip set. The FDDI card in this slot is for interface to the LAN.
Slot 6 - FDDI 5211 This board is identical to the FDDI board in slot 5. Refer to slot 5 for a narrative description to the board, except that this FDDI card in this slot is for interface to the ICAN LAN.
Slot 7 - MVCP-16 - SYNC/ASYNC The Macrolink, VME Communications Processor (MVCP) is a high-speed microprocessor-based board with sixteen independent, synchronous/asynchronous communication ports. 12 ports are RS485 and 4 ports are RS232. Each board supports data transfer rates at up to 2 megabits synchronous and 230 Kbits asynchronous. The board simultaneously supports RS232, RS422 and RS485 interfaces in four (4) line increments. Status, data movement, port arbitration, selection, and protocols are processed on-board, minimizing driver calls and host intervention that maximizes overall system throughput.
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Slot 8 - NTDS 1397A1B The NTDS 1397AB board provides support for communication with military computers and peripherals that support the MIL-STD-1397NB, type A and type B protocol. The board interfaces are software programmable to function as an NTDS computer, peripheral, or inter-computer channel, with an NTDS word size of 8, 16, or 32 bits.
The data is transmitted and received via connector P2. The interface can be configured as either a NTDS Type A (slow) or NTDS Type B (fast). The NTDS card in this slot is for interface to the SDMS and ACDS.
The electrical characteristics for the NTDS MIL-STD-1397AB are a logical "1" = 0 VDC; and logical "0" = -15 VDC at 41,667 words/second. The transmission rate for either ANIWSN-5 or AN/ WRN-6 to the NAVSSI is 4 Hz. The transmission rate for the NAVSSI to either the ANIWSN-5 or ANIWRN-6 is 1 Hz.
Slot 9 - NTDS 1397AlB
This board is identical to the NTDS board in slot 8. Refer to slot 8 for a narrative description to the board, except that this NTDS card in this slot is for interface to the ANIWSN-1, 5, or 7.
Slot 10 - NTDS 1397AlB
This board is identical to the NTDS board in slot 8. Refer to slot 8 for a narrative description to the board, except that this NTDS card in this slot is for interface to the WRN-5 (B), WSN1, CVNS, or LEAP.
NTDS 1397A1B
This board is identical to the NTDS board in slot 8. Refer to slot 8 for a narrative description to the board, except that this NTDS card in this slot is for interface to the MK86 GFCS.
Slot 12 - Currently Not Used Current configurations do not use slot 12.
Slot 13 - STANAG 4156 This interface adapter allows the user to interface a serial interface system. The board can be configured to operate as a terminal access unit, a user interface device or a direct connection coupler. The board is controlled by an onboard MC6800 microprocessor and a four channel direct memory controller. The DMA controller is used to move data between designated memory buffers areas and the two S4156 ports. The input and output ports can operate in simplified (type A) or complete (type B) protocol modes. 4-191 UNCLASSIFIED
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The two ports operate independently and support full duplex transfers. The S4156 interface consists of a set of micro-programmed, sequence logic circuits that control the data transfers between the serial S4156 data ports and the rest of the S4156. The connector for the S4156 input and output ports is mounted on the front of the board. When operating as a user interface device the data rate will automatically operate at the clock speed supplied by the terminal access. When operating as a terminal access unit or a direct connection coupler, a 2.5 MHz data clock is used.
Battery Board All configurations use this slot to hold a battery pack for the GVRC board. No interface to VME bus.
Slot – 15 NTDS 1397E The NTDS 1397E board provides support for communication with military computers and peripherals that support the MIL-STD 1397 type E protocol. The data is transmitted and received via two connectors labeled (Receive) and. (Transmit) located on the front panel. The NTDS card in this slot is for interface to the ANIWSN-7 superchannel A.
Slot 16 - NTDS 1397E
This board is identical to the NTDS board in slot 15. Refer to slot 15 for a narrative description to the board, except that this NTDS card in this slot is for interface to the ACDS.
Slot 17 - NTDS 1397E
This board is identical to the NTDS board in slot 15. Refer to slot 15 for a narrative description to the board, except that this NTDS card in this slot is for expansion port 1.
Slot 18 - Currently Not Used Current configurations do not use slot 12.
Slot 19 – S/D Converter The Synchro-to-Digital (SID) board provides an interface for analog inputs from the gyrocompass and the EM-LOG (electromagnetic pitometer log). This single slot board incorporates four separate transformer isolated tracking converters that are programmable for either; four single speed or two, two-speed or other combinations adding up to 4 channels. Speed ratios are available from 1:1 to 127:1 with 24-bit resolution with up to 255:1 ratio. Each channel pair has individual transformer isolated reference inputs.
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Blank Fascia Spacer When a slot is not used, a blank fascia spacer is installed in the unused slot position of the VME chassis allowing for proper cooling airflow. The blank fascia spacer physically seals the front of the VME chassis. It provides no interface to the VME bus or addressing for the CPU (in slot one) for the unused position.
BWS J-Box An outline of the J-box for interconnecting the bridge workstation is shown in Figure 4- 66. The J-box contains a power supply and an interactive DB-25 connector that is used to interconnect the TAC-4 computer and the keyboard and trackball of the BWS.
The rose box does not have any physical operator interface. Interconnection is a function of installation and maintenance activities. Please refer to Volume 4 of EE170-AF-OMI- 010/SSN-6, Maintenance, for interconnection information.
Figure 4-66.— BWS J-Box.
GPS Antenna Signals received through the Global Positioning System (GPS) antenna module, transmitted by Navstar Global Positioning System (GPS) satellites, enables the computation of accurate position coordinates, elevation, speed, and time information. GPS navigation is based on satellite ranging that involves measuring the time it takes the satellite signal to travel to from the satellites to the navigation user. By ranging three satellites, a three-dimensional position can be determined that accurately pinpoints where the signals intersect on the earth surface.
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Antenna Module The GPS antenna is shown in Figure 4-67. This figure shows both types of antennas that could be used. The type of antenna used is base on the type of receiver module or FOAL (and its interconnection) used in the NAVSSI system.
Antenna Interface and Interconnection The GPS antenna does not have any physical operator interface. Interconnection is a function of installation and maintenance activities. Please refer to Volume 4 of EE170- AF-OMI-010/SSN-6, Maintenance, for interconnection information.
Fiber Optic Interconnect Box
An outline of fiber optic interconnect box is shown in Figure 4-68. The fiber optic interconnect box contains an isolation transformer and is used to interconnect the GPS antenna and Fiber Optic Antenna Link (FOAL) receiver in the RTS.
NOTE: Interconnect box is only installed on DDG-77 through DDG84 and CVN-68.
The fiber optic interconnect box does not have any physical operator interface. Interconnection is a function of installation and maintenance activities. Please refer to Volume 4 of EE170-AF- OMI-010/SSN-6, Maintenance, for interconnection information. Figure 4-67.— GPS Antenna Module. Figure 4-68.— Fiber Optic Interconnect Box.
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4.13.0 SHIP’S COURSE INDICATORS (REPEATERS) The trend to transistorized equipment has resulted in gyro installations being equipped with highly reliable transistorized ship’s course indicators, or repeaters as they are commonly called. Ship’s course indicators are used to visually display gyrocompass heading data for navigational purposes. They are installed at the helm, on the bridge wings, in the after steering room, and other remote locations aboard ship. Figure 4-69 is a breakdown of the various types of ship’s course indicators used with gyrocompass systems.
TYPE FREQUENCY SPEED DRIVE DIAL MOUNT A 400 1 Servo Single Bulkhead B 400 1X + 36X Servo Single Pelorus Bulkhead E 400 1X + 36X Servo Dual Bulkhead F 400 Dual 1X + 36X Servo Console Dual G* 60 1 Servo Bulkhead Dual H* 60 1 Servo Bulkhead L 400 1 Synchro Single Console Bulkhead
The several variations of mounting dials, data transmission systems, and power requirements for ship’s course indicators will be discussed in the following paragraphs.
Units may be designated as single-speed or 1 and 36 speed. Single-speed units contain one synchro control transformer in larger units and one synchro receiver in miniature units. The 1 and 36 speed units provide greater accuracy in reading and contain two control transformers. In the 1 and 36 speed, coarse control is 1 speed and fine control is 36 speed.
Figure 4-69.—Gyrocompass repea ters by letter designation. Units also may be divided by power requirements with some using 60 Hz and others using 400 Hz.
An additional feature is the low noise and normal (nonlow) noise characteristic of several repeaters. In the nonlow noise variety, the servo and dial assembly mount directly to the cast housing. In the low noise variety, the mounting is on vibration isolators similar to rubber shock mounts.
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Figure 4-70 shows a type E repeater minus terminal block and cord. The inner dial is single speed and the blocked out outer dial is 36 speed. These repeaters are generally located in enclosed spaces, such as the OOD’s repeater on the bridge.
The basic block diagrams of the various repeaters are shown in figure 4-71. View A shows the type L repeater synchro drive. View B displays the type A servo drive single speed. In view C, types B, E, and F are depicted, and view D shows the G and H course- to-steer repeaters.
Figure 4-70.— Type E ship’s course in dicator (designed for bulkhead mounting).
Figure 4-71.— Block diagram of ship’s course indicators. 4-196 UNCLASSIFIED
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The operation of the components is standard; however, and explanation of the mixer and anti-stick off voltage may be of assistance.
The 36X synchro control transformer determines the accuracy of the indicator, but because this synchro has 36 null positions for one revolution of the indicator dial, the 1X synchro sets the proper null. The two synchro rotors are connected in shunt through a mixing network consisting of pairs of diodes and two resistors. The mixing network performs three functions. First, it effectively opens the 1X synchro signal circuit whenever the indicator dial is within 2.5° of null. Second, it limits or attenuates the 36X synchro signal whenever the 36X synchro is more then ±2.5° from its null. Third, it keeps synchro loading to its minimum allowable level.
The use of the mixing network eliminates every false null except the one at the 180° point of the indicator dial. This null is eliminated by adding a 2.5- volt, 400-Hz, anti-stick off voltage in series with the 1X synchro rotor voltage, and shifting the phase of the 1X synchro voltage by 2.5° to bring the indicator null back to a true reading. This procedure converts the 180° point to an unstable (or re-centering) null. If the coarse (1X) and fine (36X) control transformers were installed (adjusted to the same electrical zero as the electrical zero position of the compass transmitters), there would be a position of the coarse control transformer shaft 180° out of correspondence with the compass transmitter, at which the rotor volt ages of both the coarse and fine control transformers would again both equal zero. Thus, the coarse synchro system provides two null points in a complete cycle. Regarding the coarse control transformer (1XCT), it’s null at the 180° point is an unstable null, because if the shaft were on either side of that point, by an infinitesimal angle, the servo would drive toward the correct null, 180° away. The fine synchro has 72 null positions or 36 times as many as the coarse synchro system. If only the fine control transformer (36XCT) were connected in the system, there would be 36 positions of the transmitter shaft that would produce a stable null error voltage. Only one of these 36 positions is desired, that position being the point where the 1XCT also provides a stable null.
The mixing network switches the fine error signal into the servoamplifier when the error is small (output of the coarse synchro is small) and introduces the coarse error signal to the amplifier when the error is large (output of the coarse synchro is large).
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The coarse error signal can be small enough at the 180° point to result in the tine error signal being fed into the servo, through the action of the mixing network. If only the 1X error voltage were applied at the 180° point, the servo would drive away from this false null; but, because the 36X voltage has control, it drives the servo toward this 180° point. The 36X error voltage (negative between 175° and 180°) tends to drive the servo to an increased angle (180°). The 36X voltage is positive between 180° and 185°, and tends to drive the servo to a decreased angle (180°), the same point. In other words, if this condition were tolerated, the servo would lock in at a false null.
To remove this condition (false null), an anti-stick off voltage of 2.5 volts is obtained from a transformer in the amplifier unit and applied to the coarse error voltage. This voltage is applied either in phase or 180° out of phase with the 1X error voltage and is sufficient to shift the IX error signal null points 2.5°. The resultant voltage does not pass through the zero reference position of the 36XCT voltage. To restore the resultant voltage to the zero reference position, the 1XCT stator is shifted 2.5° in its housing. Thus, the resultant 1X error voltage is shifted a total of 5°, which corresponds to 180° rotation (36 x 1X) of the 36X synchro.
With anti-stick off bias, the false null at the 180° point cannot be attained by virtue of the 36X or 1X error signal on either side of this point, both being of such polarity as to drive in the same direction to the real null at zero degrees. The 36X error signal drives 2.5° toward the correct null and then the mixing network switching to the 1X error signal, which drives to 2.5° of the zero degree null position.
As the 2.5° point is reached, the mixing circuit automatically shifts the amplifier input signal from the 1X synchro to the 36X synchro. This signal, with amplifier output and motor torque reacting accordingly, is reduced as the servo approaches null. The final null position is reached at the point of minimum 36X synchro rotor voltage. Because these synchro voltages are very low, the amplifier output and motor torque are reduced substantially to zero.
Mixing networks and anti-stick off voltages are unnecessary in 1-speed systems. Although synchro voltage and thus motor torque go to zero at the 180° point, this point is an unstable (de-centering) null. If the servo approaches this false null with slight overshoot, the servo will not come to rest at the null. Instead, the servo will continue to rotate toward the true null, where it will come to final rest.
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4.13.1 Features
• Ship's Course Indicators (SCI) function as remote repeaters to indicate the ship's heading or course-to-steer. These devices may be installed at any desired location on the ship and oriented at the location in any convenient direction.
• A number of types are available. Each is designated by a type number and by mark and modification numbers.
• Types A, B, E, F and M indicators are servo-driven. Types L and N are synchro- driven. A servo-driven version of Type L is available. Types G and H have a servo-driven course-to steer dial and a synchro-driven heading dial.
• All indicators receive synchro heading data from the ship' gyrocompass or other synchro transmitting equipment. The gyrocompass signals and the reference power from the ship's supply actuate the indicators to position graduated dials which show the ship's heading.
• There are two basic types: one-speed and two-speed (1X and 36X) units. Two- speed indicators provide greater accuracy because lX synchro only provides coarse control of the dial and the 36X synchro provides fine control.
• Types E and F may have two dials geared together 10 be read as a mechanical vernier. Types G and H have two independent concentric dials, one displaying ship's heading and the other dial displaying course-to-steer.
• Any SCI is available in either low or non-low noise variations. In the non-low noise variation, the servo and dial assembly mount directly to the cast housing. In the low-noise variation, the servo and dial mount on vibration isolators inside the cast housing.
Figure 4-72.— Type A 1-Speed Bulkhead Mount. 4-199 UNCLASSIFIED
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• All types, except F and H, have integral dimmer rheostats for dial illumination control. Types F and H require a remote dimmer rheostat. Type l can be used with either an integral dimmer control or remote rheostat.
• Each Ship's Course Indicator is complete unit with facilities or mounting and for external electrical connections. (Figure 4-73).
Figure 4-73.— Ship’s Course Indicator Types. 4-200 UNCLASSIFIED
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4.13.2 Indicator Types
TYPE A, Mark 3 Mod 6, is a400 Hz, one-speed single dial servo-driven Ship's Course Indicator. Available for bulkhead mounting.
TYPE B, Mark 2 Mod 6, is a 400 Hz, two-speed single dial SCI. Housing mounts in a gimbal which is supported by a bracket, mounted on a shelf or on a pelorus stand for bearing determination.
TYPE E , Mark 1 Mod 6, is a 400 Hz, two-speed vernier dial servo SCI for steering. Available for bulkhead mounting.
TYPE F , Mark 1 Mod 6A, is a 400 Hz, two-speed vernier dial servo SCI for steering. Housing mounts to the sub-plate of a console panel.
TYPE G , Mark 6 Mod 6, is a 60 Hz, one-speed dual dial unit. The outer dial contains only a solitary diamond-shaped mark which indicates course-to steer. It is driven through a servo. The inner dial indicates heading and is directly gear-driven by a receiver synchro. The drive mechanisms and dials mount as a single assembly inside the cast housing. The housing, in turn, mounts to a bulkhead.
TYPE H , Mark 6 Mod 6A, is identical to the Type G, except for the housing which mounts to the sub-plate of a control panel.
TYPE L , Mark 7 Mod 6, is a one-speed, single dial synchro motor-driven miniature SCI. Mod 6 is a400 Hz unit and Mod 6A is 60 Hz. The servo-driven Type L uses a special servo built into a standard BuOrd Size 23 configuration. It can be used on either60 or 400 Hz. Housing for all variations mounts either to a bulkhead or to a panel.
TYPE M , Mark 9 Mod 6, is a 400 Hz, one-speed, single dial servo SCI for bulkhead mounting. Its large dial makes it suitable for distant viewing.
4.13.3 Accessories
GIMBAL RING and BRACKET (SURFACE) PART 1878032 - provide mechanical mounting for Types Band N, usually on a Pelorus Stand.
PELORUS STAND PART 1675676 - is a deck mounting stand. It contains a terminal board which serves as a junction between ship's wiring and the SCI. A Gimbal Ring and Bracket can be bolted on top of the stand.
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GIMBAL RING and BRACKET (SUBMARINES) PART 1880789 - provide for mounting of Type N SCI for use on submarines. The indicator and ring are quickly removable from the bracket; and the bracket is, in turn, removable from the mounting plate.
SINUOUS CLOCK ADAPTER RING PART 1677075 - provides for the use of a clock with Types E and F SCI's by replacing the bezel with an adapter ring.
PART TYPE MK MOD VOLTS SERVO POWER LIGHTS (WATTS) FREQ OVERALL SIZE WIDTH HEIGHT DEPTH WEIGHT (POUNDS) 1878094·1 A 3 6 115VAC 7 7 400Hz 10 10 10.75 22 1878091-1 B 2 6 115VAC 7 7 400Hz 10 10 10.75 28 1878089-1 E 1 6 115VAC 7 7 400Hz 10 10 10.875 24 1878088·1 F 1 6A 115VAC 7 7 400Hz 8.875 8.875 10.875 20 1878086·1 G 6 6 115VAC 8 7 60Hz 10 10 10.875 32 1878085·1 H 6 6A 115VAC 8 7 60Hz 8.875 8.875 10.875 30 1878158·1 L 7 6 115VAC 4 6 400Hz 6 6 6 9 1878158-2a L 7 6A 115VAC 4 6 60Hz 6 6 6 9 1878158·2b L - - 115VAC 6 6 60/400Hz 6 6 6 9 1880160·1 M 9 6 115VAC 7 4 400Hz 15.5625 16.5625 10.4375 33 1880787 N 10 6 115VAC 4 7 400Hz 10 10 7.5 13
4.13.4 Mounting Information
sical Characteristics. Table 4-31.— Part Numbers , Power Requirements, and Phy
Figure 4-74.— Recommended Mountin g Information. 4-202 UNCLASSIFIED
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4.14.0 DIGITAL INDICATORS
Figure 4-75.— Inte grated Digital Indicator Panel. 4.14.1 Features
• Microprocessor-controlled unit.
• Operates on 115VAC, 60Hz input power via MS3406DJ14S-2S connector.
• 2 simultaneous interfaces and decoding data independently for each indicator). Interfaces with shipboard DMS syst em's RS-422 interface via MS3406DJ18-1S data connector (capable of supporting 2 simultaneous interfaces and decoding data independently for each indicator).
• Separate adjustable panel (dial and legends) and digital display dimmer controls (dimmable to a full off position).
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• "TEST" button to test digital display segments and zero-reading indication.
• Electro-mechanically driven analog dial.
• Available in Single, Dual, and Quad configurations (see Related Equipment List below). (Table 4-32).
AVAILABLE CONFIGURATIONS DESCRIPTION PART NUMBER Single Dual Rudder Angle Indicator 62416-000 Single Wind Speed and Wind Direction Indicator 62416-100 Single Ship's Course and Ship's Speed Indicator 62416-300 Dual Ship's Course/Speed & Wind Speed/Direction Panel 62416-400 Dual Ship's Course/Speed & Dual Rudder Angle Panel 62416-500 Dual Speed/RPM/Pitch & Dual Rudder Panel 62416-600 Quad Indicator Panel (includes the following:) 62416-700 • Ship's Course and Ship's Speed Indicator • Dual Rudder Angle Indicator • Wind Speed and Wind Direction Indicator • Ship's Speed, Dual RPM, and Dual Pitch Indicator ELECTRICAL CHARACTERISTICS CONTROL UNIT: INPUT POWER 115 VAC, 60Hz, Single Phase HEAT DISSIPATION 51 BTU/HR, max (15 Watts) ENVIRONMENTAL CHARACTERISTICS OPERATING TEMPERATURE -20 Degrees C TO 65 Degrees C HUMIDITY 95% RH, Maximum WATERTIGHT MIL-STD-810E, SECT 512, METHOD 512.3 SHOCK MIL-S-901C VIBRATION MIL-STD-167-1 EMI MIL-STD-461C
Table 4-32.— Di gital Indicator Configurations.
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Figure 4-76.— Quad Indicator.
4.15.0 SUMMARY In this chapter, we have discussed basic gyroscopic principles and the making of the gyroscope into a gyrocompass. We have identified and discussed the major components of some of the most common gyrocompass systems installed on board Navy ships today and described the procedures for starting, standing watch on, and securing these gyrocompasses. We have also described the purpose of the synchro signal amplifiers and ship’s course indicators used with the various gyrocompass systems.