Fast factorized back projection algorithm for spotlight bistatic forward-looking low frequency UWB SAR

Spotlight bistatic forward-looking synthetic aperture radar (BFSAR) is a valid tool in the precise surveillance and attacking mission. Because the low frequency ultrawideband (UWB) spotlight BFSAR has the complicated range-azimuth coupling, diverse imaging geometry, and long synthetic aperture, etc., the application of frequency-domain algorithms is limited. In this paper, an extended fast factorized back-projection (FFBP) algorithm is presented to focus the low frequency UWB spotlight BFSAR data. First, the imaging geometry and signal model are established, and the idea of implementation of continuous surveillance and moving target indication (MTI) is presented. Then, the phase error of the FFBP algorithm for processing the spotlight BFSAR data is analyzed, and the implementation of the proposed FFBP algorithm is given. Finally, the simulation experiment is carried out to prove the validity of the proposed approach.