Abstract:

A modified covariance differencing method is proposed to the direction of arrival (DOA) estimation of narrowband signals under a colored noise environment. The covariance matrix of received data is transformed in a linear way. The noise component is eliminated finally by assuming a symmetric Toeplitz matrix for the unknown array noise. The covariance differencing algorithm works well when impinging signals are uncorrelated or just two signals are coherent. The proposed approach combined with spatial smoothing technique is further investigated in the case that coherent signals are more than two. Analysis shows that new approach can avoid generating “phantom” angles while providing accurate DOA estimation. Therefore the proposed method operates at a lower computational complexity compared with conventional methods. Simulation results demonstrate the effectiveness of presented algorithm.

Key words: direction of arrival estimation, covariance differencing, colored noise, coherent signals