A robust DOA estimation algorithm for uniform linear array in the presence of mutual coupling

It is well known that the mutual coupling between array elements is inversely related to their separation and may be negligible for elements separated by a few wavelengths, and at the same time the coupling between any two equally spaced sensors is approximately the same. Moreover, following the principle of reciprocity, the mutual coupling can always be expressed by a symmetric matrix. Consequently, a banded symmetric Toeplitz matrix provides a satisfactory model for the mutual coupling of ULA (Uniform linear array). In this paper, a robust subspace-based direction-of-arrival (DOA) estimation algorithm in the presence of mutual coupling is proposed for ULA. Based on the banded symmetric Toeplitz matrix model for the mutual coupling of ULA, the new algorithm provides a favorable DOA estimates and exploits no knowledge of the sensor mutual couplings. More importantly, an accurate estimate of mutual coupling matrix can also be achieved simultaneously for array calibration.