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TOBI is a deep-towed multi-sensor sonar system developed at SOC ( Southampton Oceanographic Centre). The system comprises a two-sided 30kHz sidescan sonar, a 7.5kHz sub-bottom profiling sonar, a set of scientific instruments (magnetometer and CTD), and a range of vehicle attitude sensors (pitch, roll, and heading from a gyro-compass). The underwater vehicle is towed with a 200 m umbilical behind a depressor weight. The depressor is attached to the surface ship via the main 0.68" armoured coax cable. This towing method prevents ship induced heave influencing the vehicle. The vehicle is usually 'flown' at heights of between 200 to 500 m above the seabed. All signals to and from the vehicle are sent via the single coax conductor. Signals are processed on the ship and logged onto magneto-optical disks. The sidescan sonar has a total range of 6km and a has a seabed footprint ranging from about 4 x 7m close to the vehicle track to 42 x 2 at far range. The profiler sonar can penetrate up to 70m into soft sediments and has a vertical resolution of better than 1m. |
