Low-Complexity Matrix Reconstruction-Based Method for Direction Estimation of Coherent Signals

A novel direction finding method called Toeplitz matrix reconstruction-based orthonormal propagator method (TMR-OPM) is proposed for narrowband coherent signals impinging on a uniform linear array (ULA). In the proposed method, the coherency of incident signals is firstly decor related through reconstructing a Hermitian Toeplitz matrix formed from fourth-order cumulants (FOC). And in Gaussian noise case, it is proved theoretically that the rank of this Toeplitz matrix is determined merely by the number of incident sources and has no relations with the coherency of the signals. Finally, the coherent signals can be resolved by performing the orthonormal propagator method (OPM). Without spectrum-peak searching and eigenvalue decomposition (EVD) of the Toeplitz matrix, the presented method can provide significantly lower computational complexity and yield good estimation performance. The theoretical analysis and simulation results confirm the effectiveness and efficiency of the proposed method.