Imaging algorithm for high resolution spaceborne spotlight/sliding spotlight SAR

For high resolution spaceborne spotlight/sliding spotlight SAR, it is essential to consider the error of the range equation and signal azimuth spectrum aliasing, both of which are caused by the long illuminate time. In order to address these issues, we present an imaging algorithm for high resolution spaceborne spotlight/sliding spotlight SAR. Firstly, it utilizes "curve orbit compensation" to compensate for range space variation error prior to RCMC, thereby avoiding defocusing issues resulting from the error of the range equation. Secondly, through the use of the "extended TSA", variations in Doppler center frequency and Doppler frequency rate with instantaneous range frequency are employed for azimuth pre-processing, effectively overcoming problems associated with azimuth spectrum aliasing. Simulation results for point targets demonstrate the effectiveness of the proposed algorithm.