Computationally Efficient Algorithms for Estimating the Angle of Arrival of Helicopters Using Acoustic Arrays

Report No. ARL-TR-4998
Authors: Geoffrey Goldman
Date/Pages: September 2009; 38 pages
Abstract: Computationally efficient algorithms were developed to estimate the angle of arrival (AOA) of acoustic signals generated by helicopters using acoustic arrays. The data was transformed into the frequency domain, then AOA algorithms based upon both least squares and digital beamforming were evaluated. The algorithms were tested using data collected on a helicopter at Yuma, AZ, in summer 2007. The AOA ground truth data was calculated using global positioning system (GPS) data collected on the helicopter. The algorithms performed well at estimating the azimuth angle of the helicopter, but they could only obtain good elevation angle estimates over limited time intervals. To try to improve the elevation angle estimate, a multipath model was incorporated into the beamforming algorithm.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2009