Motion Compensation for Terahertz Synthetic Aperture Radar Based on Subaperture Decomposition and Minimum Entropy Theorem

In this paper, a motion compensation method based on subaperture decomposition and minimum entropy theorem is proposed for terahertz (THz) synthetic aperture radar (SAR). The full aperture is decomposed into a series of subapertures and the motion errors of the platform are parameterized with constant azimuth velocity and the radial acceleration in each subaperture. Motion parameters estimation based on the minimization of the image entropy for each subaperture is developed in an iterative fashion. With the estimated motion parameters, the phase errors caused by the non-ideal movement of the platform over the full aperture can be reconstructed, and the compensation of the motion errors can be successfully accomplished for the THz SAR to obtain the well-focused images. Simulation and the experimental results based on a 0.3THz vehicle borne SAR verify the effectiveness of the proposed method for THz SAR motion compensation.