Efficient DOA Estimation for Coprime Array via Inverse Discrete Fourier Transform

In this paper, we propose an inverse discrete Fourier transform (IDFT)-based direction-of-arrival (DOA) estimation algorithm for coprime array, where both DOAs and power of the sources can be efficiently estimated with an increased number of degrees-of-freedom. Specifically, the IDFT is generalized to realize the transformation between the defined angular-spatial domain and the spatial domain. With such a relationship, the IDFT is directly implemented on the second-order virtual signals characterized by the angular-spatial frequencies, and it is proved that both the DOAs and the sources power can be estimated from the resulting spatial response. Meanwhile, the window method and the zero-padding technique are sequentially incorporated to alleviate the spectral leakage and improve the estimation accuracy, respectively. The direct IDFT solution presents a remarkably reduced computational complexity as compared to the existing algorithms exploiting coprime array, and the simulation results validate the effectiveness of the proposed DOA estimation algorithm.