Effect of Suspended Sediment on Acoustic Detection Using the Navy's CASS-GRAB Model

Sidescan sonar detects objects buried in the seafloor through generating images of ordnance such as sea-mine buried in sediments. The sonar operates by illuminating a broad swath of the seabed using a line array of acoustic projectors while acoustic backscattering from the illuminated sediment volume is measured. The effect of suspended sediment on the sonar imagery depends on the volume scattering strength of the suspended sediment layer. Understanding the acoustic characteristics of suspended sediment layer can aid the Navy in the detection of mines using the sonar imagery. This study describes a combined experimental and modeling effort on the volume scattering strength on the burial object detection. A range of critical values of volume scattering strength for the buried object detection were discovered through repeated model simulations.