Imaging Algorithm of High Squint Spotlight SAR Based on Azimuth Deramp and Nonlinear Frequency Scaling(NFS)
基于方位deramp和NFS大斜视聚束SAR成像算法

To eliminate the azimuthal spectral folding of spotlight Synthetic Aperture Radar (SAR) and the serious coupling between range and azimuth in high squint mode, an algorithm based on azimuth deramp and Nonlinear Frequency Scaling (NFS) is proposed. First, azimuth deramp operation eliminates the azimuthal spectral folding. Then nonlinear frequency scaling compensating the azimuth phase with the range scale variation is adopted to fulfill the focusing of the swath. Simulation results illustrate that it can eliminate azimuthal spectral folding, possess high precision and satisfy the imaging quality of high squint spotlight SAR and large scene swath.