International Dredging Review

International Dredging Review

EdgeTech delivered a new sonar system for the high-speed MMT Surveyor Interceptor ROV (SROV).

The EdgeTech system is a dual frequency side scan sonar operating at 600/1600 kHz combined with a sub-bottom profiler operating at 1-10 kHz with custom multi-pulse (MP) and dynamically focused (DF) capabilities on the side scan sonar.

For the SROV the sonar needed to produce high quality images while operating at higher speeds than typically seen with work class or inspection class ROVs. Conventional side scan sonar systems are limited in transmit-receive cycle times by the sound propagation velocity of 1500m/s. Following the transmit pulse the sonar system has to wait for reception of the echo data from the farthest range before the cycle can repe at. This restriction results in ping rates that are adversely affected by range and can severely limit the speed of the side scan sonar.

With the ability to place more than one sonar ping in the water simultaneously EdgeTech side scan sonars break this sound speed barrier. EdgeTech’s multi-ping side scan sonar can transmit pulses during normal reception without any cross pulse interference. This technique allows sonar ping repetition rates greater than those achieved with standard sonar.

DF technology can achieve higher resolution imagery at longer ranges through a virtual curvature and focusing of the arrays using software algorithms and a multi-segmented array with a number of short linear elements.

EdgeTech’s MP and DF technology on-board the high-speed MMT Surveyor Interceptor ROV was delivered in a compact 2205 AUV/ROV-based sonar package. The technology is also available in towed configurations.