Spatially coincident measurements of acoustic backscatter and forward scatter at shallow grazing angles

Abstract

Direct measurement of acoustic scattering from the seabed at shallow grazing angles presents a considerable challenge in littoral waters. Specifically, returns from the air–water interface typically contaminate the signal of interest. To address this issue DREA has developed a pair of sea going research systems for measuring acoustic scatter from the seabed in shallow water environs. The first system is a bottom mounted parametric transmitter with a 6-channel superdirective line array receiver. The second system is a vertical line array of 8 hydrophones and 2 transmitters. Operating the systems in tandem allows measurements of backscatter and forward scatter from the same scattering patch at the same time. In this paper the acoustic attributes of both systems will be outlined, the experimental geometry will be described, and measurements of acoustic backscatter and forward scatter collected during one such experiment will be presented.