DOA Estimation for UCA in the Presence of Mutual Coupling via Error Model Equivalence
Weiwei Hu, Qiang Wang · IEEE Wireless Communications Letters · 2019
In this letter, a direction-of-arrival (DOA) estimation method for a uniform-circular-array (UCA) with mutual coupling is presented. Due to the mutual coupling model of UCA, the actual steering vector in the mode domain is considered to correspond to a virtual uniform-linear-array (ULA) with gain-phase errors. This consideration indicates the calibration for mutual coupling in UCA can be transformed to that for gain-phase errors in the ULA: the gain errors are estimated with the main diagonal of the actual covariance matrix of the virtual ULA, and the phase errors are obtained via the Toeplitz structure of the ideal covariance matrix. In addition, due to the property of the ULA, there is an ambiguity in the estimation of the phase errors, which is analyzed and eliminated via least-square-method. Ultimately, the DOA and the coefficient of mutual coupling are estimated using estimating- signal-parameter-via-rotational-invariance-techniques and rank- reduction theory, respectively. The proposed method works on line without multidimensional parameter search. Furthermore, it avoids the ambiguity of the DOA estimation and simulations verify its effectiveness.