Two-Dimensional Direction-of-Arrival Estimation for Co-Prime Planar Arrays: A Partial Spectral Search Approach

In this paper, we investigate the issue of 2-D direction-of-arrival (DOA) estimation of multiple signals in co-prime planar arrays, where phase ambiguity problem arises due to the large distance between adjacent elements for each subarray. According to the co-prime characteristic, the ambiguity problem can be eliminated by searching for the common peaks of the spatial spectrum of each subarray, where the spectrum search involves a tremendous computation burden. In this paper, we exploit the property that all the ambiguous peaks for each DOA are uniformly distributed in a new transformed domain. Relying on the linear relations, we propose a partial spectral search (PSS)-based estimation method, where it involves a limited search over only a small sector. Therefore, the proposed PSS method is very computationally efficient. Numerical results are provided to verify the effectiveness of the proposed method over the state-of-the-art methods, in terms of both computational complexity and estimation accuracy.

I. Introduction

Direction-of-arrival (DOA) estimation of multiple narrow-band sources is a common problem arising in areas including radar, sonar, wireless communications and other applications [1], [2]. Over the past decades, various methods have been developed to estimate DOAs [3]–[6]. Most of the existing studies on DOA estimation using array processing have focused primarily on uniform linear array geometry for the simplicity and mathematical tractability, while the appropriate non-uniform array geometry enables to achieve substantially improved resolution performance [7], [8].