Chemical Warfare Directional Detector (CWDD) AN/KAS-l

The Chemical Warfare Directional Detector (AN/KAS-1) system (fig. 9-10) is a passive, infrared imaging sensor. Its primary function is to provide U.S. Navy ships with the capability to detect and identify a chemical warfare (CW) agent attack. The AN/KAS-1 can be used to detect and identify nerve agent attacks against sister ships in a task force, against waves of amphibious assault ships and boats proceeding ashore, or against assault forces in the vicinity of the landing area. Chemical warfare agent cloud detection and identification can be accomplished against a sky background for all conditions under which CW attacks may be expected to occur. Detection of CW activity against a land background can be accomplished also, but less effectively.

The AN/KAS-1 infrared sensor gives the equipment a secondary function of low-visibility/ night pilotage and area surveillance. The operator of the AN/KAS-1 can detect and provide relative bearing to prominent land features, such as lighthouses and water towers. In the future, the AN/KAS-1 may be approved for the detection of buoys and personnel on the water's surface.

The AN/KAS-1 is a shipboard mounted, portable unit. It consists of a sensor unit, a pivot mount, a power conversion unit (PCU), a carrying and stowage case, a maintenance kit, an overboard lanyard, and a foul weather cover.

The sensor unit (fig. 9-11) is equipped with the following controls.

. A field of view switch. This switch enables you to use a wide field of view (WFOV) and a narrow field of view (NFOV). . A range/focus knob. . A brightness knob. . A contrast knob.

. A filter wheel switch. This switch allows you to rotate a wheel positioned in the optical chain of the unit through the following

Figure 9-11.-Three views of the chemical warfare directional detector.

positions: filter 1, filter 2, filter 3, and filter out. This is referred to as interrogating. These filters are used to identify CW nerve agent clouds.

The pivot mount provides the mechanical interface between the sensor unit and the standard bracket and lock assembly. The pivot mount provides a minimum elevation of -350 to +450 and 3600 of azimuth. Handlebars are provided to assist you in positioning the sensor unit. The interconnecting cable provides electrical connection and power transfer from the PCU to the sensor unit through a coiled, double-shielded cable.

The power conversion unit (fig 9-12) provides operating power to the sensor unit from the ships 115 vac 60 Hz supply. Press-to-test switches and lights are included to verify input and output voltages. The unit consists of an electronics tray contained in a watertight, protective housing. The carrying and stowage case is provided for

_{Figure 9-12.-Power conversion unit (PCU).}

transportation and stowage of the AN/KAS-1 system. Space is also provided in this case for the stowage of the sensor unit, pivot mount, interconnecting cable, overboard lanyard, maintenance kit, and foul weather cover. The maintenance kit (stowed inside the carrying and stowage case) is provided with each system. The maintenance kit contains the following:

Expendable nitrogen gas cartridges (six) to purge the sensor unit of moisture (30-day requirement)

A purge kit regulator and connector assembly

Lens wipers (cleaning pads)

A lens cleaning solution

Spare bulbs and lenses

The overboard lanyard is a vinyl-covered, stainless steel cable. It is used to secure the sensor and pivot mount unit to an eyelet on the PCU unit mounting plate prior to installation and/or removal. The overboard lanyard and associated safety procedures prevent accidental over-the-side loss or severe damage to the equipment, due to a fall to a lower deck, during installation or removal of the sensor unit.

The foul weather cover, or waterproof canvas, is used to protect the sensor and pivot mount when they are not in use. (Do not cover the sensor unit with the foul weather cover while the unit is in operation. The confined heat that is generated by the sensor unit cooler will harm the sensor unit.)

Six AN/KAS-1 locations are to be established on each ship. Each location should be carefully chosen so that it has a wide field of view. The view should not be blocked by other hardware. Also, take care to avoid interference with other ship's equipment. The locations already selected for the Mk-37 night observation device (NOD) are usually excellent. When possible, the mounting locations should be high on the ship, such as on the signal bridge and pilothouse bridge wings. Finally, the locations must be accessible to sound-powered headphones.

Use the following procedures to put the AN/KAS-1 in position for use.

1. Have two people carry the AN/KAS-1 stowage case to the mount site to be used.

2. Remove the free end of the overboard lanyard from the case and secure it to the eyelet in the PCU mount.

3. Have the people carefully remove the sensor unit from the case by grasping it by the yoke, and then lift and turn the pivot mount to line up with the locater pins in the bracket and lock assembly mount. Move the unit into place on the mount.

4. Secure the sensor unit to the mount by securing the lock mechanism on the bracket and lock assembly. Try to lift the sensor from the mount to ensure that it is locked in place.

5. Position the left and right handles by placing one hand on the sensor assembly for support. Pull out each handle, one at a time, and rotate each one into a horizontal position.

6. Notify the support maintenance signalman to purge the sensor unit according to the applicable MRC from the PMS.

7. Free the lens cover by releasing the two side latches. Remove the lens cover and secure it to the lens cover stowage mount on top of the sensor unit with the two side latches.

8. Verify that the PCU CB1 switch is off, and then connect the sensor unit power cable to the PCU connector (J2).

After the AN/KAS-1 is set up, perform the AN/KAS-1 operator check procedure. Now the AN/KAS-1 system is ready to be aligned.

To set up the AN/KAS-1 for operation, use the following procedures:

1. Remove the canvas foul weather cover.

2. Push the button flap on the cover into the cover. Roll the cover up and secure it with the drawstring. Ensure that the cover is secured by its strap to the mount eyebolt. This will prevent the equipment cover from being blown overboard.

3. Remove the lens guard cushion by releasing the two latches, one on each side. Secure the lens guard cushion to the top of the sensor unit using the same two latches.

4. Rotate the mount control handles 1800 into the operational position.

5. Release the elevation stow pin and azimuth locks. Adjust the azimuth friction lock to the desired level of control.

6. Perform the AN/KAS-1 operator check procedure.

7. Check the sensor unit alignment with the alignment bench mark data engraved on the data plate. If necessary, perform the alignment procedure.