Fast factorised backprojection algorithm in elliptical polar coordinate for one-stationary bistatic very high frequency/ultrahigh frequency ultra-wideband synthetic aperture radar with arbitrary motion

The precise disposal of azimuth variance of range cell migrations and motion errors in the one-stationary bistatic very high frequency/ultrahigh frequency ultra-wideband synthetic aperture radar imaging is a real challenge for efficient frequency-domain algorithms, but can be precisely managed by time-domain approaches. In this study, a novel bistatic fast factorised backprojection (BFFBP) algorithm is presented, which can deal with these two effects accurately and achieve the computational performance in parity with frequency-domain algorithms. First, the imaging geometry with arbitrary motion in elliptical polar coordinate is provided, and the analytical expression of the bistatic backprojection algorithm in this coordinate system is derived, which provides a theory basis for the proposed algorithm. Then, based on the subaperture imaging geometry, the sampling requirements considering motion errors is deduced, which offers the optimal tradeoff between the imaging quality and computational speed. The advantage of using elliptical polar coordinate system for implementing the BFFBP algorithm is analysed. Finally, the implementation and computational burden of the BFFBP algorithm are discussed. Simulation results are shown to prove the correctness of the theory analysis and validity of the proposed approach.