True angle estimation from a line array using time-delay estimates over a known rotation

The passive determination of conical-bearing angle from a line array is routinely accomplished by estimating the differences in the arrival times of an acoustic wavefront along the aperture. The conversion from a conical bearing angle to a true bearing (azimuth) angle requires an estimate of the depression/elevation angle of the source. This paper shows that the observation of time-delay estimates over a known rotation of the line array is an effective procedure for true angle estimation. Theoretical performance analysis and Monte Carlo simulation results are presented for a broad class of true angle estimation algorithms. This includes the optimal algorithm which utilizes all of the available time-delay information over the array rotation. This work has significant implications regarding source localization from line arrays.