On the use of an autonomous underwater vehicle for seabed characterization.

In 2009 NURC conducted the CLUTTER’09 experiment on the Malta Plateau, south of Sicily, in collaboration with the CLUTTER JRP partners from USA and Canada. One of the main objectives of this experiment was to characterize the seabed for geoacoustic and scattering properties related to clutter, i.e., around regions on the bottom which generate target‐like returns on active sonar displays. The equipment used was a newly developed sound source and 32‐m horizontal line array at NURC towed behind the Ocean Explorer Autonomous Underwater Vehicle (OEX‐AUV). The source transmitted signals in the frequency band 800–3500 Hz and were received on the line array. The array has a four‐level aperture which allows both for utilizing individual hydrophone data and beamformed data for the seabed characterization. The advantage of using the OEX‐AUV is that measurements can be performed close to the seabed which are difficult to obtain from conventional sonar systems towed from a surface vessel. Results of environmental char...