Nufft-Based Algorithm for Bistatic Sar Imaging Via Cooperative High-Orbit and Low-Orbit Satellites

Compared to the monostatic geosynchronous synthetic aperture radar (GEO SAR), GEO bistatic SAR can provide finer spatial resolution and higher signal-to-noise ratio (SNR) with lower system complexity, which leads the GEO-LEO (low earth orbit) SAR be a hot research topic. In this paper, an imaging scheme using cooperative high-orbit and low-orbit satellites is proposed. Firstly, the bistatic range history is extended by Taylor series, and then two-dimensional non-uniform fast Fourier transform (2D-NUFFT) is presented to formulate a bistatic SAR image in the range-velocity domain. The effectiveness of the proposed imaging scheme for GEO-LEO bistatic SAR is verified by simulation data for multi-point targets.