2D-DOA Estimation Using L-shaped Distributed Augmented Nested Array

Abstract

In this paper, we investigate the problem of two-dimensional (2-D) direction of arrival (DOA) estimation in a distributed L-shaped array (LSA). The resolution of 2-D DOA estimation in distributed uniform L-shaped array is low, the number of available sources is limited by array elements and the estimation accuracy is susceptible to SNR. In order to promote the 2-D DOA estimation performance under distributed L-shaped array, this paper proposes a new L-shaped array geometry for 2-D DOA estimation based on the conjugate augmented property of signal second-order statistics. The proposed array structure is distributed augmented nested L-shaped array which every subarray is one-dimensional (1-D) distributed augmented nested array placed along y-axis and z-axis. By using Khatri-Rao product processing, the newly formed array possesses higher degree-of-freedom and number of virtual array apertures are more extended. Then, utilize spatial information and temporal information to construct a conjugate augmented spatial–temporal auto-correlation matrix for each orthogonal distributed subarray. With the redundancy removal and spatial smoothing, the rank of each covariance matrix is restored. Through analysis, each portion of the new formed virtual array can be used separately for 1-D azimuth and elevation angle estimation. Additionally, virtual cross-correlation matrix of two subarrays can accomplish angle-pairing procedure. Simulation results verify the effectivity of the proposed method in 2D-DOA estimation.