PERFORMANCE ANALYSIS OF SPATIAL SMOOTHING WITH INTERPOLATED ARRAYS

The interpolated spatial smoothing algorithm is a computationally effi cient method for estimating the directions of arrival (DOA's) of signa ls, some of which may be perfectly correlated. It extends the spatial smoothing method to arbitrary array geometries. In an earlier paper we derived this algorithm and studied its properties. This paper provide s a statistical performance analysis for the algorithm. Closed form ex pressions for the covariance matrix of the DOA estimation errors are d erived using a perturbation analysis. Evaluating these expressions for specific cases and comparing them to the Cramer-Rao lower bound for t he DOA estimates, provides insight into the statistical efficiency of this algorithm. The formulas for the error covariance are quite genera l, and can be specialized to provide results for other DOA estimation algorithms as well.