Refined ECS algorithm for high-resolution spaceborne spotlight SAR data processing

A refined extended chirp scaling (ECS) algorithm for high-resolution spaceborne spotlight synthetic aperture radar (SAR) imaging is presented. The squint range equivalent model is selected, which is more suitable for spaceborne geometrical relationships than the broadside range model. Based on the squint range equivalent model, the derivation of the algorithm is presented. The refined azimuth scaling factors are given. The refined azimuth scaling factor decreases azimuth time expansion and improves the efficiency of azimuth processing. Besides, a subaperture approach is introduced. Finally, the validity of the refined algorithm is tested by computer simulation.