A multibeam, diver-held sonar using a liquid-filled, spherical acoustic lens

Swath bathymetry, underwater searches, obstacle avoidance, and navigation are greatly enhanced by a high resolution, multibeam sonar. Acoustic lens technology provides a relatively compact and inexpensive sensor that can transmit and then receive multiple conical or rectangular beams using no beamforming electronics. The paper describes the basic components of a liquid-filled, spherical acoustic lens and provides both theoretical and empirical data which show lens beam patterns and how lens focus changes with temperature. The paper also describes a lens implementation in a compact, multibeam, diver-held sonar