OFDM SAR multiple targets image reconstruction using MUSIC-LSE algorithm

Abstract

In Synthetic Aperture Radar (SAR) image reconstruction, the quality of the image depends on the range and cross range resolution to resolve multiple target positions. If the distance between the targets is less than both SAR resolutions, the radar imaged them as one single target. To overcome this challenge, Orthogonal Frequency Division Multiplexing (OFDM) SAR has been proposed to improve the image resolution. However the image quality degrades in lower boundary conditions. In this paper, we propose the use of Multiple Signal Classification (MUSIC) algorithm to estimate the signal Direction of Arrival (DoA) and Least Square Estimation (LSE) algorithm to estimate the phase history. The Cross-range Profile Reconstruction (CPR) is reconstructed using the phase history and combined with Range Profile Reconstruction (RPR) to form the image. Simulation results show that the proposed MUSIC-LSE SAR approach gives a higher image resolution compared to the LSE-SAR imaging. The approach also shows that by estimating the signal DoA and then apply LSE, the radar can separate the targets even at distances below the range and cross-range resolution without necessarily increasing the bandwidth.