Precise measurement of sonar bearing angle - obtained by determining error in difference signal from two hydrophones

摘要

A sonar source bearing is detected by hydrophones whose distance apart is known. Knowing the speed of the sonar wave in the transmission medium enables determination of the bearing from the difference in arrival of the sonar wave. Measurement of error in this difference enables a precise bearing to be obtained. Two hydrophone detectors arelocated a known distance apart. Their outputs feed into matching circuits containing sampling circuits driven in phase by a clock circuit. The matching circuit outputs pass into delay circuits one of which is adjustable. These are multiplied with additional delay circuit outputs and integrated. The integrator outputs are subtracted and divided to obtain the signal ratio which is then multiplied by a delay circuit output to produce input signal delay error and thus tolerance on the bearing angle.