Effects of nonzero bandwidth on direction of arrival estimators in array signal processing

The authors consider the impact of a small but nonzero bandwidth on narrowband direction-of-arrival (DOA) estimation using an array of sensors. They derive expressions for the DOA error for three commonly used array processing algorithms: MUSIC, ESPRIT and weighted subspace fitting (WSF). The error expressions are found by a perturbation analysis of these algorithms for small relative bandwidths of the sources. The perturbation-based error predictions are compared to the exact deviation for some special cases of interest