Using co-located sidescan imagery to verify patch test results of a Multibeam sonar

While using a fixed mount multibeam sonar, one has the ability to collect bathymetry and co-located backscatter. During the course of running the Patch Test Calibration, finding a feature on the seafloor with the backscatter presents you an opportunity to verify three of four biases observed with the Multibeam patch test results. The backscatter will inherit the motion of the vessel and also all installation biases (of the Patch test) values can be seen in the imagery. The results of the backscatter processing have shown that the latency and pitch can very easily be correlated with the Multibeam data results. Yaw, although more difficult to analyze, can also be correlated to the values found from the Multibeam data. Certain conditions need to exist, and finding submerged features on the specific lines, while lying perpendicular to the trackline can prove elusive. However, when an object is found, the test process will allow for a correlation and a check for the results determined by the Multibeam Patch test.