A Partial Relaxation Doa Estimator Based On Orthogonal Matching Pursuit

A family of computationally efficient DOA estimators under the partial relaxation framework has recently been proposed. In this framework, the manifold structure of the ``interfering" signals is relaxed, and only the manifold structure of one desired signal is retained. This particular type of relaxation results in closed-form estimates for the interference parameters and enhances the estimation performance compared to the conventional spectral-search methods. By adopting the principle of the partial relaxation approach, in this paper, a modification of the Orthogonal Matching Pursuit algorithm is proposed and applied to the Direction-of-Arrival estimation problem. In each iteration of the proposed partial relaxation-based orthogonal matching pursuit (PR-OMP) algorithm, the impact on the receive signal from the previously-estimated directions and the remaining direction with the relaxed steering structure are considered. Simulations show that the proposed PR-OMP algorithm outperforms conventional estimators in the case of low Signal-to-Noise-Ratio or small number of snapshots.