An interpolation-free FFBP algorithm for spotlight SAR processing

In this paper, an interpolation-free fast factorized back-projection (IF-FFBP) algorithm is proposed for high-resolution spotlight synthetic aperture radar (SAR) processing. Different from the original FFBP utilizing two-dimensional image-domain interpolation for sub-aperture fusion, IF-FFBP finishes the image merging steps using chirp-z transform and circular shifting. Under the restriction of the applicable scope, IF-FFBP yields enhanced efficiency over the 4 times upsampling interpolation based FFBP, and keeps the high precision simultaneously. Finally, Real-data experiment verifies the efficiency superiorities of the FIM-FFBP.