Continuous Pulse Repetition Interval Variation For Highly Squint High-Resolution Spotlight Sar Imaging

Highly squint Synthetic Aperture Radar (SAR) is a competitive candidate for intelligence surveillance and disaster monitoring because of its capacity for multi-angle information acquisition and high spatial resolution. However, large Range Cell Migration (RCM) results in a considerably long receive window and an extremely large volume of invalid data, which burdens the computational load and severely reduces the efficiency of image processing. The existing method is designed to remove range walks using continuous Pulse Repetition Interval (PRI) variation. When a high-resolution system is required, the range curvature is apparent. This paper proposes a novel strategy to remove the RCM of a reference point accurately using continuous PRI variation for highly squint high-resolution spotlight spaceborne SAR. Additionally, the proposed strategy avoids contamination by transmit and nadir interferences. The simulation results show that the proposed method achieves improved data volume reduction performance compared with the existing method.