Abstract:
Over the past 3 years, a multisensor digital Deep Tow vehicle has been developed at the Marine Physical Laboratory to carry out fine-scale measurements near the seafloor down to 6000 m depth. The suite of sensors include: a pair of 110-kHz side-looking sonars, a 4-kHz sub-bottom profiler, a 40-kHz obstacle avoidance sonar, a 12-kHz navigation sonar, a 23.5-kHz up-looking sonar, a CTD, a transmissometer, a magnetometer, a complement of still and TV cameras, and a 100-kHz multibeam echo-sounder. The latter provides fine-scale swath bathymetry and acoustic backscatter imagery of the bottom over a swath roughly 60 deg wide. All the sensor data are digitized in the vehicle and are telemetered to the ship over a standard 0.680-in. electromechanical tow cable at bit rates between 500 and 1000 kb/s depending on the length and condition of the cable. Examples of the data collected during sea trials and during deep-water search operations are presented.