UNDERSEA TECHNOLOGY 61 



based on a compass and stopwatch— assuming the vehicle's velocity 

 through the water was known. Control of the submersible's movement 

 and direction was by direct on/off control of motors. 



Improved equipment was available for second-generation submersibles, 

 such as the ALVIN and ALUMINAUT, but their sensors, navigation 

 equipment, and control systems were not integrated. An advanced and 

 integrated sensor-navigation-control system has been developed for the 

 DSRV because of the many complicated maneuvers required of this par- 

 ticular submersible. 



The DSRV will be equipped with a total of six different kinds of sonars, 

 all integrated with a timing coordinator, to avoid signal interference, and 

 a master display system. It will use horizontal and vertical obstacle- 

 avoidance sonars to detect objects in the path of the submersible. The 

 vertical sonar, in addition to determining the height of obstacles ahead of 

 the DSRV, will be used to interrogate a transponder carried by the mother 

 submarine or surface-support ship during recovery operations. 



An altitude-depth sonar in the DSRV will have two transducers, one to 

 determine distance from the submersible to the ocean floor and the other 

 to determine distance to the surface. The DSRV pilot can select altitude 

 or depth, or he can alternate the sonar pinging. These signals will be used 

 to compute depth for digital display to the pilot and to produce an analog 

 trace on a chart recorder. This sonar wUl be the prime sensor for main- 

 taining a constant altitude over the sea floor, and will serve as an alterna- 

 tive to the pressure-depth gages for depth measurement. 



Once near the sea floor the DSRV will use its doppler to measure 

 ground track. This four-beam system determines fore-aft and athwart- 

 ship velocities. It can also be used to find vertical velocity, which is 

 required during the final stages of mating with the disabled submarine's 

 hatch. Velocity information wUl be displayed to the pilot and used by 

 the central processor in dead reckoning navigation computations. 



Directional listening hydrophones, mounted on each side of the DSRV 

 control sphere, will permit the submersible to home on acoustic signals 

 from a disabled submarine. As the DSRV closes with the disabled sub- 

 marine, the submersible's short-range sonar can be used to determine the 

 attitude of the disabled submarine and locate its escape hatches when the 

 water is too turbid for effective use of optical systems. This sonar will be 

 equipped with two scales, one a 150 ft range and the other a 15 ft range. 

 Two transducers, located in the DSRV mating skirt, alternately scan the 

 area below the DSRV. The fore-aft scan will provide a cathode-ray tube 



