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Service + Software for Seafloor Mapping
Synthetic Aperture Sonar / Overview
Real sidescan systems are limited in along-track resolution by array length, survey speed and ping rate (effectively, survey range). To illustrate, a conventional sidescan with an array length of 25 centimeters at 100 KHz will have a beam pattern of about one degree. At 300 meters, 1 degree of arc covers about five meters along-track.
At 300 meter range, a traditional sonar can ping about 2.5 times per second.
At five knots, a sonar is traveling 2.5 meters per second, so it would travel approximately one meter between pings. This means that objects smaller than one meter are likely to be missed in the near range, and that items smaller than five meters cannot be distinguished at far range.
To overcome this, synthetic aperture sonar systems attempt to create a “synthetic” array, by summing returns from multiple pings, to produce output imagery with constant along-track resolution. To do this, they need precision micro-navigation data to properly align overlapping “phase centers”.
OIC supports the feeding of SAS processors the raw, high bandwidth data and precision time-stamped navigation/attitude data, and the control/display/ processing of SAS output.