An efficient approach for double sliding spotlight bistatic synthetic aperture radar focusing

With a satellite as a transmitter, spaceborne-airborne bistatic synthetic aperture radar (SA-BiSAR) uses an airborne platform as a receiver to get the back scatting echo of the scene. In order to maximize the beam-overlapping region, a double sliding spotlight mode is proposed recently. It is often required that the receiver operate in inverse sliding spotlight mode (TOPS mode) and the transmitter work in sliding spotlight mode. As the system working in double sliding spotlight mode, the imaging geometry suffers from severe spatial variance in range and azimuth dimensions. Based on chirp scaling method and nonlinear chirp scaling (NLCS) imaging algorithm, an imaging method of SA-BiSAR system is proposed in this paper. Finally, the proposed imaging algorithm is validated by several simulation results.