SENSORS 



The vehicles already described are primarily outfitted with commercially available 

 sensor systems, e.g., high resolution sonars, television and film cameras, compasses, and 

 depth-and height-sensing devices. Special sensor development in the fields of high resolu- 

 tion acoustic imaging, real-time optical mapping, and minimal-sized sonar and the applica- 

 tion of pressure-tolerant-electronic (PTE) components to all possible systems are the sub- 

 jects of current research and development programs. In addition, the output from material's 

 research and development directly applies to the structural components, windows, and 

 cabling systems of undersea work systems. 



ACOUSTIC IMAGING SYSTEM (AIS) 



The acoustic imaging program was initiated as part of the Navy's DOT program to 

 improve the range of underwater visibility, particularly in turbid water. The general object- 

 ive is to develop and demonstrate acoustic imaging technology for underwater search, re- 

 covery, classification, manipulation, and inspection aboard manned and unmanned submer- 

 sibles to depths of 12,000 feet (3660 meters). The program has focused on the develop- 

 ment of a holographic (lensless) system. The AIS was designed to achieve a recognizable 

 image of a beer can in turbid water at ranges to 25 feet (8 meters) anywhere within the 

 1 1- by 1 1-degree (0.2 radian) field of view. Larger objects can be seen at ranges up to 

 150 feet (46 meters). Photographs are taken at the rate of one every 2 seconds with a 

 future capability of 15 per second. The system consists of two assemblies: (1 ) an under- 

 water unit (figure 8) which has an acoustic projector, receiving hydrophone array, and 

 processing electronics, and (2) a rack of control electronics that holds the control panels, 

 minicomputer image reconstructor, and displays. 



Figure 8. Transmitter/receiver unit for acoustic imaging system. 



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