Circular SAR optimization imaging method about buildings based on the principle of high SNR

Abstract

CSAR (Circular SAR) achieves 360° observation on the target by circular moving and beam controlling of platform, obtaining all-round scattering information and having significant advantages in the aspect of building geometric feature description. According to the buildings scattering feature and shape feature, this paper puts forward a CSAR optimization imaging method about buildings based on the principle of high SNR. The method establishes the electromagnetic scattering model of buildings to simulate the CSAR echo and image by using FEKO, a software of electromagnetic simulation. Furthermore, comparing and analysing the imaging result with the case of scattering isotropic, we conclude the best range of azimuth angle of coherent accumulation when the building CSAR imaging has fine SNR. Due to the scattering direction of buildings is unknown in the actual scene, CSAR 360° echo is divided into a plurality of sub apertures, overlapping each other in small angle. Finally, imaging for every sub aperture, all-round composite image is obtained by extracting the maximize value of each pixel in every sub aperture images. Validating by P band CSAR data processing, the proposed CSAR imaging method is superior to the traditional full coherent accumulation CSAR imaging method, which can realize high SNR imaging of buildings.