Exploiting sediment acoustics properties for subcritical buried target detection using a synthetic aperture sonar aboard the AUV Reliant

Abstract

The Coastal Systems Station High Frequency/ Low Frequency Synthetic Aperture Sonar (HF/LFSAS) was recently integrated into a Bluefin Robotics, Inc. Odyssey III Family autonomous underwater vehicle (AUV). This vehicle, designated Reliant, has been used in several at-sea experiments to determine the feasibility of using bottom roughness to enhance detection of buried targets at subcritical grazing angles. Previously, the HF/LFSAS was deployed on a towed 21-in. vehicle and made some remarkable buried target detections at subcritical angles. However, due to the complexities associated with using a towed platform, only a limited amount of data was obtained during these exercises. This sparse data set made it difficult to quantify the enhancing effects of bottom roughness on buried target detection. An extensive run matrix for buried target detection was completed this year using the Reliant AUV. The primary variables in the experiments were ripple orientation, standoff range, and grazing angle. Results from these sea tests are presented and compared to theoretical models.