Polarimetric CSAR Image Quality Enhancement Using Joint Sub-aperture Processing

Polarimetric circular synthetic aperture radar (CSAR) can obtain the 360° full-azimuth polarization information of target. Due to the anisotropy of most manmade targets, there are great differences in the polarization scattering characteristics at different observation angles. However, full-aperture processing is the coherent accumulation imaging of the full-azimuth polarimetric data directly, which may result in the failure of obtaining the target’s polarization characteristics at each azimuth. Focus on this issue, a polarimetric CSAR imaging method using joint sub-aperture processing is proposed. The proposed method mainly contains three steps. Firstly, the polarimetric data is divided into multiple sub-aperture data since manmade targets usually exhibit scattering anisotropic properly. Then, the sub-aperture images are obtained using the back projection (BP) algorithm. Finally, the joint processing image is obtained via combining the maximum SPAN value among all sub-aperture images. The effectiveness of the proposed method is validated using the simulated data of civilian vehicle. Compared with the full-aperture images, the sub-aperture images achieve better image contrast and lower image entropy. In this vein, the image quality of the polarimetric CSAR from the proposed method is enhanced.