Fast time-domain focussing for general bistatic low frequency ultra wide band SAR in elliptical polar coordinate

A novel fast time-domain approach called bistatic fast factorized backprojection algorithm (FFBPA) for general bistatic low frequency ultra wide band (UWB) synthetic aperture radar (SAR) imaging is proposed. This method is able to accurately dispose the azimuth-variance of range cell migrations and motion errors in general bistatic SAR imaging and achieve the imaging efficiency in parity with frequency-domain methods. It represents subimages in elliptical polar coordinates to reduce the number of operations. Taking into account motion errors, the sampling requirements of the elliptical subimages is deduced by analyzing the bistatic range error. The implementation and computational load of the bistatic FFBPA (BFFBPA) are discussed. Simulation results are shown to demonstrate the correctness of the theory analysis and the validity of the proposed method.