A low-cost, lightweight, stealthy broadband acoustic sensor is proposed to achieve surface and subsurface obstacle avoidance (no-compromise) for Advanced Amphibious Assault Vehicles (AAAV). The Marine Collision Avoidance Sonar (MARCAS) is based on a small size, retractable sparse planar array using a minimal number of commercial off-the-shelf transducers. The MARCAS provides both high vertical and high horizontal resolution over a wide aperture to provide AAAVs' drivers with WideViewTM detection without any moving parts. WideViewTM is important because drivers must make navigation decisions not only based on forward obstacles but also on potential obstacles on either side (similar to changing lanes on a highway). Thanks to the high vertical angular resolution and because of shallow water operation, the MARCAS will discern direct-paths from multipaths (reverberation) and differentiate obstacles above and below the 20-foot "safety-depth". Finally, the MARCAS is stealthy because it uses GORCA Technologies' proprietary concept, BiopulseTM, which is coded copies of naturally occurring biological transient pulses such as shrimp sounds. The broadband frequency content of these coded pulses drastically limits shallow water propagation interference and allows detection over a range of 400m. This distance represents the "safety cushion" that gives the AAAV driver approximately 30 seconds to avoid obstacles.
