Wide-Angle CSAR Imaging Based on the Adaptive Subaperture Partition Method in the Terahertz Band

Abstract

Based on the assumption of isotropic scattering, a wider angle aperture can provide improved resolution of synthetic aperture radar images. However, due to the limited angular persistence of scatterers for high-resolution terahertz radar, traditional imaging techniques make aspect-dependent scatterers blur. In this paper, a novel wide-angle circular synthetic aperture radar (CSAR) imaging technique is investigated on the basis of the adaptive subaperture partition method in the terahertz band, with the objective to enhance object reconstruction. The proposed algorithm captures the scattering characteristics of aspect-dependent scatterers, which is applied to adaptively divide the full aperture into multiple subapertures. Because the subapertures are approximately consistent with the scattering persistence angles of aspect-dependent scatterers, the real reflectivity characteristics of objects are better kept in the composite two-dimensional CSAR images obtained with the noncoherent combination of the subaperture images on the basis of the generalized likelihood ratio test imaging approach. Real data results have verified the effectiveness of the proposed algorithm.