Auto-alignment of acoustic transducers in a multipath environment

A system incorporating a priori information and various estimation algorithms to continuously point an ultrashort baseline (USBL) array toward the first arrival of a sound pulse in a multipath environment has been developed. The system was designed for use underwater to establish and maintain a narrow-beam acoustic telemetry channel between two communicating stations that may or may not be stationary. The object is to determine the direction of arrival (DOA) of the leading portion of an omnidirectional signal transmitted from one station and point a narrow-beam transducer in the return direction. With each pulse received, a new DOA is calculated and the transducer orientation is revised. The USBL array points in that DOA; hence, an appropriate narrow-beam transducer physically coupled to the USBL array would realize the prescribed communications link. Test results are presented