A new and fast approach to correct distortion between the airborne frequency-modulated continuous wave synthetic aperture radar (FMCW SAR) real-time images is proposed in this letter. The main idea of the proposed method contains two parts. First, the rotation distortion, according to the adjacent subimages caused by the selection of the reference trajectory, is efficiently corrected by data reposition. Comparing with the conventional correction technique, the time consumption is dramatically reduced from 0.3 s to only 0.717 ms. Second, the residual offset error between the rotated subimages is analyzed and compensated in the first-step motion compensation. With the application of the proposed method, the distortion correction during FMCW SAR real-time imaging becomes realizable. The correction approach has been evaluated by an FMCW SAR system, and the obtained results verify the feasibility and effectiveness of the proposed method.
['Chengfei Gu', 'Wenge Chang', 'Xiangyang Li', 'Gaowei Jia', 'Xinqun Luan']
A New Distortion Correction Method for FMCW SAR Real-Time Imaging