An Efficient 2-D DOA Estimation Method for Unfolded Coprime L-Shaped Array

In this article, a novel two-dimensional direction of arrival (2-D DOA) estimation method using unfolded coprime L-shaped array is presented. First, the signal subspace is divided to establish the relationship between two subarrays. Thus, the 2-D DOA estimation problem is transformed into one-dimensional (1-D) one. Moreover, by introducing the extraction matrix, the nonuniform array can also fit polynomial root finding, from which the initial elevation and azimuth estimates can be obtained. Finally, to further improve the estimation accuracy, we compensate the estimation offsets via least square constructed from the first-order Taylor expansion of the direction matrix. The proposed algorithm outperforms the conventional algorithms in the aspect of computational complexity while achieves preferable estimation performance. Specifically, the complexity of the proposed method is reduced by several orders of magnitude, with RMSE reduced by up to 6 dB.