EFFECTS OF MODELING ERRORS ON THE RESOLUTION THRESHOLD OF THE MUSIC ALGORITHM

Subspace-based algorithms for narrowband direction-of-arrival (DOA) es timation require detailed knowledge of the array response (the array m anifold) and assume that the noise covariance matrix is known up to a scaling factor. In practice, these quantities are not known precisely. Estimation accuracy can degrade significantly when the array response or the noise covariance deviate from their nominal values. In this wo rk, we examine the resolution threshold of the MUSIC algorithm when th e array response is perturbed from its assumed value and when the nois e covariance does not match the assumed model. Analytical expressions for the resolution threshold are derived and verified by computer simu lation. We also demonstrate the fact that preprocessing of the array d ata can improve somewhat the resolution in the presence of model error s. This work makes extensive use of the contributions of various autho rs.