Gap-less Bilateral Swath Bathymetry

Side scan sonars commonly encounter large gaps in the nadir region, without a convenient way to compensate for the lost area. Likewise, swath bathymetric sonars collect 3D images to both sides of the sonar but cannot connect the two sides of the image without missing data, therefore effectively reducing bilateral swath to unilateral. Described is a novel bilateral swath bathymetry system and method with angled fan-shaped beams for a gapless 3-D reconstruction of the sea bottom scene on port, starboard and in front of the underwater vehicle without incurring data losses in the nadir area. The sonar system contains two angled forward port and starboard interferometric acoustic arrays, each transmitting a fan-shaped beam and measuring the angles of arrival of the returned echoes with spaced acoustic elements.