GB-ArcSAR Imaging Based on Optimized Construction of Reference Plane

Due to the specific arc-scanning way of ground-based arc-scanning synthetic aperture radar (GB-ArcSAR) to synthesize aperture, when a target's height is large enough and deviates much from the reference imaging plane, the image defocus would occur since that the target's range migration trajectory cannot be completely compensated. This article makes a theoretical analysis of the reasons for GB-ArcSAR imaging defocus, when it is utilized to observe those targets with large height differences, i.e., large elevation angles, from the imaging plane. A quantitative relationship between the imaging defocus level and the elevation angle is deduced with the simulation of an ideal target. Aiming at solving the problem of imaging defocus, an optimized imaging method of GB-ArcSAR based on the reference plane construction is proposed. A series of reference planes with different inclination angles or starting ranges are constructed and utilized for radar imaging separately. The minimum entropy criterion is then taken to search for the optimal plane. The qualitative and quantitative comparisons of the simulated and experimental datasets with other methods both prove the effectiveness of the proposed method.