Coarray-domain iterative direction-of-arrival estimation with coprime arrays

In this paper, we consider source direction-of-arrival (DOA) estimation with coprime arrays via coarray domain processing. We present two Fourier-based iterative methods which address the non-uniformity of the corresponding difference coarray, thereby permitting exploitation of all offered degrees-of-freedom. The proposed approaches are based on the fast iterative interpolated beamforming (FIIB), which is a low-complexity algorithm for DOA estimation using uniform linear arrays. The first method specifically accounts for the non-uniformity of the coarray in the FIIB algorithm. The second approach modifies the FIIB to estimate the contributions of the missing elements, thus emulating a uniform coarray. We show that both methods achieve asymptotically unbiased DOA estimates. Extensive simulation results are provided to demonstrate the effectiveness of the proposed approaches.