A unitary transformation method for angle-of-arrival estimation

Eigenstructure methods for estimating angles of arrival of radiation sources generally require complex computations in computing eigencomponents of the covariance matrix and calculating the search function. A unitary transformation method that transforms the complex covariance matrix of an equally spaced linear array, which is Hermitian persymmetric, and the complex search vector into a real symmetric matrix and a real vector, respectively is presented. Both tasks can be accomplished by real computations. The sampled covariance matrix available is not persymmetric. To suit the unitary transformation method, a persymmetrized estimator of the sampled covariance matrix, which is optimal in the sense of Euclidean distance, is proposed