DOA Estimation for Coherent and Non-Coherent Mixed Signals Using Toeplitz Diagonal Diffusion

Abstract

This letter introduces a new direction-of-arrival (DOA) estimation approach for mixed coherent and uncorrelated signals. The technique extracts cross-diagonal elements from the covariance matrix to form Toeplitz matrices, then averages them using a counting matrix to effectively decorrelate signals. This provides more accurate covariance estimates for subsequent subspace-based DOA estimation methods. Compared to existing approaches, the proposed method offers more degrees of freedom (DOFs) and lower computational complexity, while robustly detecting the directions of mixed coherent and uncorrelated signals under low signal-to-noise ratio (SNR) and limited snapshot conditions.