Symmetric Displaced Coprime Planar Array for Two-Dimensional Direction-of-Arrival Estimation

Recently, sparse planar arrays have been developed to improve the two-dimensional (2D) direction-of-arrival (DOA) estimation performance by their superiorities in the degree of freedom (DOF), array aperture and mutual coupling over uniform planar arrays. In this paper, we devise a new sparse planar array, termed symmetric displaced coprime planar array (SDCPA), for estimating the 2D DOAs. The SDCPA configuration consists of three sparse uniform rectangular arrays with a certain horizontal and vertical displacement, implying that there are two bilaterally symmetric displaced coprime planar arrays (CPAs) with one shared subarray. Under any number of sensors, the sensor positions of a SDCPA can be expressed in a closed form. We also derive the optimal displacement factors to achieve the maximum number of consecutive coarray lags, which can be analytically calculated. Compared with the conventional CPAs, the SDCPA configuration possesses a higher number of uniform DOF and less mutual coupling effects. Numerical results demonstrate its superiority over several existing sparse planar arrays.