DOA Estimation for Coherent Signals With Improved Sparse Representation in the Presence of Unknown Spatially Correlated Gaussian Noise

In this paper, a new method is proposed for direction-of-arrival (DOA) estimation of coherent signals with improved sparse representation in unknown spatially correlated Gaussian noise. To be specific, leveraging a symmetric uniform linear array, the entries of the signal covariance matrix is firstly recasted to eliminate the spatially correlated noise. Subsequently, it is shown that an equivalent source vector can be obtained by squaring any row of the noise-free signal covariance matrix, irrespective of the coherency between the signals. Finally, an improved sparse representation, which enhances signal sparsity via utilizing a designed weight vector, is derived to determine the DOAs of the signals. Numerical examples are provided to demonstrate its superiority of DOA estimation performance in low signal-to-noise ratio (SNR) environments. Besides, it is computationally efficient, which is critical for large array and/or real-time data processing systems.