Underdetermined Direction of Arrival Estimation for Coprime Array in the Presence of Nonuniform Noise

The underdetermined Direction Of Arrival (DOA) estimation method based on the coprime array will degrade in the presence of nonuniform noise. To address this problem, a robust DOA estimation method based on covariance matrix reconstruction and matrix completion is proposed in this paper. Firstly, the covariance matrix of the received data is decomposed to obtain a diagonal matrix containing non-uniform noise terms. Then, the minimum value of the diagonal matrix elements is selected to replace the remaining diagonal matrix elements to obtain the reconstructed data covariance matrix. Finally, based on the matrix completion theory, the reconstructed covariance matrix is extended and filled, and the subspace method is used for DOA estimation. Theoretical analysis and simulation results show that, compared with the existing methods, the proposed method suppresses effectively the influence of nonuniform noise and has better DOA estimation performance.