Target tracking system for determining bearing of a target

Abstract

A passive acoustic target tracking system includes three microphones arrayed respectively at corners of an equilateral triangle for sensing acoustic energy emitted by a target, such as a heavy vehicle, and generating separate streams of analog signals representative of the acoustic energy sensed at the triangle corners. Hardware of the tracking system receives the separate streams of analog signals from the microphones and conditions and converts the separate streams of analog signals from analog to digital form and outputs the separate streams as digital signals. Software of the tracking system receives the separate streams of digital signals and provides the bearing to the target emitting the sensed acoustic energy. The software includes a minimum residual correlation algorithm and a two-state kalman filter algorithm. The minimum residual correlation algorithm receives the separate streams of digital signals, performs correlations on the separate streams from pairs of the microphones, and produces a raw azimuth signal as a result of the correlation. The two-state kalman filter algorithm receives the raw azimuth signal, performs a two-state kalman filtering of the raw azimuth signal, and produces a smooth azimuth signal constituting the bearing to the target emitting the sensed acoustic energy.