Honeywell G.m.b.h.

Alliant Techsystems Inc.

David P Olson

Jonathan C Werder

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.

Target tracking system for determining bearing of a target

A target engagement system uses target motion analysis to determine a target engagement decision for ground targets, such as vehicles. The input to the engagement system is the target azimuth as a function of time. A detect algorithm issues and records a detect azimuth when confirmation is made that a valid target is being tracked and legitimate azimuth information is being provided. The engagement algorithm then begins and records the time intervals it takes for the target to cross two sectors, each covering 20.degree. and separate by 10.degree.. Thus, first time interval is measured from detect azimuth to 20.degree. after detect azimuth, and the second time interval is measured from 30.degree. after detect azimuth to 50.degree. after detect azimuth. When the first and second time intervals have been recorded, the ratio of the first time interval to the second time interval is calculated. If this ratio is greater than 2.0, then the target is estimated to be within range and is subsequently attacked. Otherwise, the target is greater than the range and no action is taken.

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Mound, MN, United States of America

David P Olson