Wenkang Liu, Guang-Cai Sun, Xiang-Gen Xia, Jianlai Chen, Liang Guo, Mengdao Xing
IEEE Transactions on Geoscience and Remote Sensing
Image formation of large scenes is still challenging in medium-earth-orbit (MEO) synthetic aperture radar (SAR) due to the existence of severe 2-D space variance. In this paper, the properties of space variance are analyzed in detail, and then a variable-coefficient fourth-order range model is adopted to model the space-variant range history of every target in a large scene accurately. A method integrating a modified chirp scaling algorithm with joint time-Doppler resampling is proposed to address the range-variant range cell migration, as well as the azimuth-variant frequency-modulation rate and higher order Doppler parameters. The computational burden and alternative implementation approaches are also discussed. Finally, processing of simulated data for MEO SAR with 2-m resolution is presented to validate the proposed algorithm.
W Liu, GC Sun, XG Xia, J Chen, L Guo, M Xing - IEEE Transactions on Geoscience and Remote …, 2018