Ultra-deep low-frequency sub-bottom profilerfor AUV and ROV
|Author(s)||Le Gall Yves1, Pacault Anne1, Saint-Laurent Xavier2, 3, Viaene Jean-Michel3, Mosca Frédéric4, Greninguey Gilles4, Vial Marcel4, Aissa Jean Claude4|
|Affiliation(s)||1 : IFREMER, Unité Navires et Systèmes embarqués, Service Acoustique Sous-Marine, BP 70, 29280 Plouzané, France
2 : GENAVIR, DSM-SOE, Zone Portuaire de Brégaillon - CS20 330 - 83507 La Seyne-sur-Mer Cedex
3 : IFREMER, Unité Systèmes Sous-marins, Service Ingénierie d’Intervention et Développements Mécaniques, Zone Portuaire de Brégaillon - CS20 330 - 83507 La Seyne-sur-Mer Cedex
4 : IXBLUE, 46, quai François Mitterrand, 13600 LA CIOTAT
|Meeting||Acoustics’08, Palais des Congrès, Paris, 4 juillet 2008|
|Abstract||Acoustical techniques for ultra-deep sub-bottom exploration are still little investigated. IXSEA and IFREMER have launched in 2006 the development of a new deep-sea low-frequency sub-bottom profiler, working up to 6000 meters depth. Based on the Janus-Helmholtz broadband technology, two acoustic sources have been modelled, achieved and in-tank and at-sea measured : a single transducer working in the [1.8, 6.2 kHz] frequency band, and a three-transducer array operating in the [2, 8 kHz] frequency band. In both cases, vertical resolution is better that 20 cm. Comparison between finite element modelling and in-tank measurements is presented, together with the specific constraints linked to very-deep water and AUV mounting.
Power electronics and impedance matching unit have been specifically optimised to deliver a sound level of 190 dB (ref. 1 µPa @ 1 m), with 48 VDC supply voltage and 250 W available electric power.
The receiving part is made up of a three-hydrophone array with a loss of sensitivity lower than 1 dB between 0 and 600 bar.
This ultra-deep light system has been mounted on an IFREMER's AUV and the first results at sea are presented and discussed.