Reduced-Rank Joint Estimation of DOA with Mutual Coupling

In this paper, an extended reduced-rank direction-of-arrival (DOA) estimation with unknown mutual coupling in uniform linear array (ULA) structure is presented. The proposed method is based on the joint iterative subspace optimization (JIO) and the auto-calibration of mutual coupling. Given an initial coupling vector, reduced-rank correlation matrix is estimated with the JIO approach, followed by iterative joint estimation of DOA and coupling with an auto-calibration algorithm. Simulation results show that both the proposed method and the existing auto-calibration method have similar performance in terms of DOA root mean square error, while the complexity of the proposed method is much lower than that of the auto-calibration approach due to the reduced rank.