DOA Estimation Based on Subspace Compensation for Unfolded Coprime Array

Direction of arrival (DOA) estimation for unfolded coprime array (UFCA) is discussed, and a method based on subspace compensation is proposed. Conventional DOA estimation methods partition the UFCA into two subarrays for separate estimations, which are then combined for unique DOA determination. However, the DOA estimation performance loss is caused as only the partial array aperture is exploited. We use the estimations from one subarray as initial estimations, and then enhance the estimation results via a compensation based on the whole array, which is implemented via a simple least squares (LS) operation constructed from the initial estimation and first-order Taylor expansion. Compared to conventional methods, the DOA estimation performance is improved while the computational complexity is in the same level. Multiple simulations are conducted to verify the efficiency of the proposed approach.