Modified imaging method for high resolution wide swath spaceborne SAR based on nonuniform azimuth sampling

With the increasing demands for higher resolution and wider swath in many applications of Synthetic Aperture Radar (SAR), sliding spotlight mode has been presented. Here the antenna pattern is steered towards a fixed point to increase the synthetic aperture length and consequently in a better resolution. Currently, the image processing algorithms for sliding spotlight mode are almost based on the equivalent slant range model (ESRM). A great challenge has to be faced in signal processing of sliding spotlight mode. The ESRM, which is used for signal processing, may cause a Doppler parameter mismatch phenomenon and making an image quality decline at the edge of the scene when the swath coverage gets larger. In this paper, a modified imaging method based on nonuniform azimuth sampling is presented. First, a nonuniform azimuth sampling method is developed to compensate the Doppler parameter mismatch phenomenon. Second, a modified imaging method is proposed. Simulations are performed to validate the presented algorithm.