Sparsity-driven bandwidth factorisation autofocus of high-resolution squint SAR imagery reconstructed by FFBP

In large squint high-resolution cases, smearing introduced by path deviation and air turbulence in synthetic aperture radar (SAR) imagery reconstructed via fast factorised backprojection algorithm (FFBP) will exist along space variant oblique angles. To refocus the blurred FFBP imagery, a motion phase error estimation and compensation methodology based on range bandwidth factorisation is proposed in this study. Motion phase error is estimated based on lower resolution data and then sparsity-driven combination is performed to derive the high-resolution refocused imagery. Extended point target simulation can verify the bandwidth-factorisation-based autofocus algorithm.