Improved Two-step Imaging Method for Sliding Spotlight SAR

Sliding spotlight SAR often suffers from Doppler ambiguity due to its wide Doppler bandwidth. The commonly processing method currently is the two-step algorithm, which uses deramp preprocessing to remove Doppler ambiguity and then uses commonly SAR imaging algorithms for imaging. However, under certain conditions, deramp processing can cause ambiguity in the azimuth time domain. The conditions for Doppler ambiguity and time-domain ambiguity are proposed, and the improved two-step imaging method for sliding spotlight SAR is proposed to achieve sliding SAR imaging without azimuth time domain and frequency domain ambiguity.