Flight Path Estimation Using Multipath Delay Measurements from a Wide Aperture Acoustic Array

The flight path of an aircraft travelling at constant velocity and constant altitude is described by a set of five motion parameters which can be estimated using a ground-based wide aperture acoustic array. The narrowband motion parameter estimation method, based on the Doppler effect, requires the aircraft to emit an acoustic tone that is often absent in the case of a jet aircraft. The motion parameter estimation for jet aircraft or other airborne broadband acoustic sources requires the implementation of broadband techniques. However, existing broadband techniques are based on crosscorrelation methods whose performances are seriously degraded when the inter-sensor spacings are too large (as for the wide aperture array) due to the loss of spatial coherence between the received signals. In this paper, a new broadband motion parameter estimation method is described, which does not require spatial coherence between the received signals. The method is based on the multipath delay measurements from each sensor of the array. The effectiveness of the method is demonstrated using real data recorded from a wide aperture microphone array during various transits of a jet aircraft.