Optimum localization of coherent signals having diverse polarizations

The problem of estimating the angles of arrival (AOA) of narrowband sources, having the same frequency, is considered. The authors previously derived (1986) a computationally attractive method for computing the maximum-likelihood (ML) estimator for the case of an identically polarized array. The method is based on an iterative technique referred to as alternating projection maximization (APM), which transforms the multivariate nonlinear maximization problem into a sequence of much simpler one-dimensional maximizations. Here, the ML estimator and the APM algorithm are derived for an array of antennas having diverse polarizations. Since the algorithm realizes the ML estimator, it is applicable equally well for signals that are either uncorrelated or fully correlated. The results from two simulations are reviewed to demonstrate the performance of the ML estimator for the diverse polarization array case.<>