Sidescan sonar is somewhat similar to the mechanically scanned system except that scanning is achieved by moving the sonar bodily through the water, usually by towing the system behind the ship, while the beam points broadside to the direction of motion. In this way a swarf is swept out on one side of the ship. By using what is in effect two systems it is possible to view on both sides of the ship at the same time. An example of a very large sidescan sonar developed by the Institute of Oceanographic Science is called Project Gloria. This operates at a frequency of about 6.5 kHz, has a beamwidth of 2 degrees, a maximum range of about 20 km and a range resolution of 10 metres.
Scan converters in sonar, Page 1 of 2
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