Fourier-Based 2-D Imaging Algorithm for Circular Synthetic Aperture Radar: Analysis and Application

Circular synthetic aperture radar (CSAR) has become a research hotspot in the SAR community. Since the Fourier-based imaging methods of CSAR are underdeveloped, further developments have to be investigated. In this paper, the exact expression and property analysis of the spectrum of CSAR are presented first. It turns out that the challenges of the Fourier-based 2-D imaging processing of CSAR lie in the projection of spectrum from the slant plane into the ground plane. Correspondingly, a spectrum-projection method by matched filtering as well as the practical subaperture-based imaging flow of CSAR are proposed, during which the trajectory deviation has been taken into account. Simulation and experimental tests are carried out to measure the efficiency and accuracy of the proposed method. The corresponding results verify that the proposed signal model is correct and the presented imaging flow is a good candidate to produce well-focused CSAR imagery with much less time consumption.