Abstract:

To solve the problem of poor identification performance of coherent signals in the presences of non-uniform noise and mutual coupling, a Direction of Arrival (DOA) estimation method based on non-uniform noise covariance matrix and mutual coupling coefficient reconstruction is proposed in this paper. Using the Least Squares (LS) theory, the noise-free covariance matrix in the sense of mutual coupling can be recovered by iterative optimization approach. Then, the uncorrelated signals angle determined by applying the principle of signal subspace can be used to reconstruct the mutual coupling matrix, so that the noise-free signal covariance matrix after compensating the mutual coupling can be obtained. Finally, the spatial smoothing techniques can be employed to decorrelate the coherent signals, which enable us to apply the MUSIC algorithm to achieve DOA estimation. Simulation results demonstrate that, compared to the traditional MUSIC and DOA estimation algorithms, which only considers coherent signals, non-uniform noise or mutual coupling, the proposed method can suppress non-uniform noise significantly, overcome the decorrelation failure of the conventional spatial smoothing techniques in the case of mutual coupling, and improve the DOA estimation performance of coherent signals under the coexistence of both non-uniform noise and mutual coupling considerably.

Key words: communication technology, direction of arrival, non-uniform noise, mutual coupling, coherent signals, spatial smoothing, least-squares