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Inversion for bottom parameters using low frequency reverberation data

Attachments

Author: Muller, S.H.E. · Ainslie, M.A. · Boek, W. · Simons, D.G.
Type:article
Date:2002
Publisher: Gdansk Univ. of Technology
Place: Gdansk
Institution: TNO Fysisch en Elektronisch Laboratorium
Source:Proceedings of the 6th European conference on underwater acoustics, ECUA 2002, 24-27 June 2002, Gdansk, Poland, 147-152
Identifier: 95511
ISBN: 83-907-5918-7
Keywords: Sonar · Seabed classificartion · Reverberation · Inversion techniques · Shallow water · Sound propagation · Low frequency active sonar · Genetic algorithms

Abstract

Active sonar reverberation returns offer the possibility to invert for geo-acoustic bottom parameters to characterise the underwater environment. We present the results of synthetic inversions of reverberation returs generated with a ray-based reverberation model in which bottom scattering is modelled according to a modified Lambert's rule. The inverted parameters are sediment sound speed, attenuation and the scattering strength, parametrised by Lambert's constant and a low grazing angle threshold. The sediment density is calculated during the inversions through an empirical relationship to sediment sound speed. Results of inversions of synthetic data using a genetic algorithm are presented both for a soft muddy bottom and a harder and rougher bottom consisting of coarse sand. We also investigate the effect of an error in water depth.