Study on the Geometric Distortion Correction Algorithm for Circular-Scanning SAR Imaging

The images generated by a circular-scanning synthetic aperture radar (SAR) can provide precise guiding information though image-matching post-processing, which necessitates their high precision in geometry. However, due to the irregular motion of the radar platform and the circular scanning antenna beam, the inevitable geometric distortion in the focused images is necessarily to be corrected. In this paper, a two-dimensional geometric distortion correction algorithm based on projection transformation between the scatterers and the images is presented, in condition of focusing the subimages using linear range-Doppler algorithm. The geometric distortion in any subimage obtained at any squint angle within 360 degrees can be effectively corrected. The point-target simulation results are provided to demonstrate the validity of the proposed method.