Robust beamforming algorithms for acoustic tracking of ground vehicles

The problem of detection and localization of multiple acoustic sources using unattended passive sensors is considered. Existing wideband Capon direction of arrival (DOA) estimation methods typically fail to accurately detect and resolve multiple closely spaced sources in presence of model mismatches and wavefront perturbations caused by senor location errors and near-field effects. This paper applies a set of adaptive beamforming methods in reduced dimension subspace for non-ideal acoustic array sensing scenarios. A robust wideband Capon method is studied to account for the inherent uncertainties in the array steering vector. To improve the resolution within a sector of interest the beampace method is extended and applied to this problem. These methods are then implemented and benchmarked on real acoustic signatures of multiple ground vehicles moving in tight formations.