Direction of arrival estimation by eigenstructure methods with imperfect spatial coherence of wave fronts
Arogyaswami J. Paulraj, T. Kailath · The Journal of the Acoustical Society of America · 1988
Eigenstructure/subspace methods for direction of arrival estimation are only applicable when each wave front contributes a rank one component to the array covariance. This implies that the wave fronts need to have perfect spatial coherence. In several practical situations where the wave fronts may only have partial spatial coherence, eigenstructure algorithms show poor performance such as overestimation of the number of sources, bias, and reduced accuracy and resolution in estimating the directions of arrival. In this article, the performance degradation due to partial spatial coherence is studied and a new approach is proposed that exploits the underlying coherence model to yield asymptotically exact estimates. For finite data, this method provides improved results only when the number of snapshots exceeds a certain threshold. Results of computer simulations are also presented.