Abstract:In Circular Synthetic Aperture Radar(CSAR), the range equation between radar and ground moving target is complicated because the radar platform flies around the circumference of the observation scene, and there is a complex coupling relationship between range direction parameters and azimuth direction parameters of target, which makes it difficult to estimate the range velocity of moving target independently. A method for estimating the range velocity of moving target in terahertz CSAR based on sub-aperture division is proposed. By selecting a suitable angle of sub-apertures, sub-aperture division is performed on CSAR. Under the condition of sub-aperture, the decoupling between the range velocity of moving target and other parameters can be realized by small angle approximation, and the range velocity of moving target can be accurately estimated, which can achieve accurate relocation of moving target. The effectiveness of the proposed algorithm is verified by simulation and measured data.