Azimuth & elevation estimation using acoustic array

Tracking of helicopters or any airborne targets requires estimation of both azimuth and elevation angles of the target. In this paper, an algorithm for estimation of azimuth and elevation using acoustic array (array of microphones) will be presented. There are several super resolution algorithms for estimation of direction of arrival (DoA) angles, such as minimum variance distortionless response (MVDR), multiple signal classification (MUSIC), ESPRIT, etc. While these algorithms are able to provide fairly good estimation of azimuth, they are unable to estimate the elevation angles with reasonable accuracy. In this paper, a new paradigm is developed to estimate the pointing vector (azimuth & elevation) to the target using the angle of arrivals (AoA) of a target's signal at each pair of microphones in the array. Mathematical formulation of the problem is presented. The algorithm for estimation of azimuth and elevation is used on actual helicopter data, and the results are presented.