An Experimental Test of End-Fire Synthetic Aperture Sonar for Sediment Acoustics Studies

TitleAn Experimental Test of End-Fire Synthetic Aperture Sonar for Sediment Acoustics Studies
Publication TypeConference Abstract
Year2018
AuthorsSteele, SM, Lyons, AP
Conference Name176th Meeting Acoustical Society of America
Conference LocationVictoria, BC, Canada
Conference DatesNovember 5-9
KeywordsSeafloor Characterization, seafloor scattering, synthetic aperture sonar

Seafloor sediment acoustic returns are comprised of scattering from both the interface and sediment volume. At low-frequencies, volume scattering is often the dominant mechanism; however, direct measurements of this component have rarely been made, due to interface roughness biasing caused by large beamwidths. End-fire synthetic aperture sonar (SAS) can achieve narrower beamwidths by coherently combining multiple acoustic returns as a vertically oriented transmitter and/or receiver is moved towards the seafloor. Beam pattern simulations suggest end-fire SAS can reduce the beamwidth of a sonar by a factor of 6 with an array length of 100 wavelengths. Achieving these gains is dependent on the ability to resolve relative sonar motion to at least an eighth of a wavelength. This talk will present results from an end-fire SAS field trial. Results will include an analysis of beamwidth gains achieved during the end-fire SAS field test and methods to improve these gains by using the scattered field to refine sonar positions.

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