A modified chirp-scaling algorithm for spaceborne squinted sliding spotlight SAR data processing

A modified chirp scaling (CS) algorithm for processing spaceborne squinted sliding spotlight synthetic aperture radar (SAR) data is proposed in this paper. For squinted sliding spotlight mode, both the squint angle and azimuth beam steering make the spectral aliasing in azimuth. To solve this problem, the linear range cell migration correction (LRCM) and De-rotation are adopted firstly. Then a modified CS kernel is proposed to focus the data. What´s more, the azimuth nonlinear CS (NCS) method is used to solve the limited depth-of-azimuth-focus (DOAF) problem caused by the first step. Finally, the geometric distortion is corrected in the range frequency domain. The effectiveness of the proposed algorithm is validated by simulation results.