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Seabed geoacoustic characterization with a Vector Sensor Array

Published in Journal of the Acoustical Society of America

P.J. Santos,
O. C. Rodrígues,
P. Felisberto,
S. M. Jesus,
Institute for Systems and Robotics, University of Algarve
Campus de Gambelas, PT-8005-139 Faro, Portugal
Ref.: Journal of the Acoustical Society of America,

Abstract:This paper proposes a vector sensor measurement model and the related Bartlett estimator based on particle velocity measurements for generic parameter estimation, illustrating the advantages of the vector sensor array (VSA). A reliable estimate of the ocean bottom properties such as sediment compressional speed, density and compressional attenuation based in matched-field inversion (MFI) techniques can be achieved using a small aperture VSA. It is shown that VSAs improve the resolution of seabed parameter estimation when compared with pressure sensor arrays with the same number of sensors. The data considered herein was acquired by a four-element VSA in the 8-14kHz band, during the Makai Experiment in 2005. The results obtained with MFI techniques are compared with those obtained with a method proposed by C. Harrison, whichi determines the bottom reflection loss as the ratio between the upward and downward beam responses. The results show a good agreement and are in line with the historical information for the area. The particle velocity information provided by the VSA increases significantly the resolution of seabed parameter estimation and in some cases reliable results are obtained using only the vertical component of the particle velocity.