2-D DOA estimation based on discrete fractional Fourier transform for L-shaped nested array

Abstract

Yielding better estimation performance for two-dimensional (2-D) direction-of-arrival (DOA) estimation at limited snapshots and low signal-to-noise ratios (SNRs) has recently attracted increasing attention. Aiming at this, a 2-D DOA estimation algorithm based on discrete fractional Fourier transform and Taylor expansion approximation (DFRFT-TEA) for the L-shaped nested array (LsNA) is proposed. Specifically, the discrete fractional Fourier transform (DFRFT) method is first introduced to generate the initial estimated angles, then the Taylor expansion approximation (TEA) method is utilized to compensate the angular offsets to obtain the fine estimated angles, and finally the pair-matching of the fine estimated angles is achieved by the permutation matrix. The findings of the numerical simulation show that the DFRFT-TEA algorithm not only has favorable DOA estimation performance under finite snapshots and low SNRs but also can be adapted to DOA estimation for the underdetermined scenario. Furthermore, the proposed DFRFT-TEA algorithm provides superior estimation performance in comparison to the existing algorithms.