Two-dimensional direction of arrival estimation by exploiting the symmetric configuration of uniform rectangular array

In this study, a new two-dimensional direction of arrival (2D DOA) estimation method is proposed for a uniform rectangular array (URA). The impinging signals are a mixture of uncorrelated and coherent signals. The method consists of two steps. The DOAs of uncorrelated signals are first estimated by a modified 2D estimation of signal parameters via rotational invariance techniques (ESPRIT). Then the contributions of uncorrelated signals and noises are eliminated after performing a subtraction operation on the elements of the covariance matrix and only those of coherent signals remain. Based on these subtracted elements, a decorrelating matrix with a larger size is constructed to estimate the DOAs of coherent signals. These two-step processes can be carried out in parallel because there is no inherent relationship between them. The proposed method has high estimation precision, needs no 2D angle searching and is suitable for the array no matter whether the number of sensors is odd or even. Simulation results demonstrate the effectiveness and performance of the proposed method.