Towards multi-frequency imaging and analysis of sub-surface targets using SAS

The problem of detecting and imaging buried targets with side-scan sonars is of considerable practical interest to the defense as well as the remote sensing and archeological communities. Side-scan sonars usually insonify the seafloor at close to glancing angles, i.e., well beyond the critical angles specified by Snells law of refraction. Consequently there is often little penetration into the seafloor sediments by the incident sound and targets covered by only a few centimeters of sand or mud are often invisible. We report here some results from a recent sea trial and then some extensive simulations of our dual frequency band, Interferometric Synthetic Aperture Sonar (InSAS) in an attempt to understand if sediment properties affect the image