New Approach for SAR Doppler Ambiguity Resolution in Compressed Range Time and Scaled Azimuth Time Domain

A new approach is addressed for Doppler ambiguity resolution. This method exploits the fact that, in compressed range time and special scaled azimuth time domain, all the trajectories exhibit the same slope, which is proportional to the Doppler ambiguity number. The method can directly estimate the ambiguity number without a priori knowledge on the baseband Doppler centroid. It is confirmed that this approach is robust to the partially exposed strong targets in azimuth, ground slowly moving targets and the motion variation of platform in realistic scenarios. Results of real measured data processing show that this method works well in medium- to high-contrast scenes and can basically (not always) provide the right estimate in low-contrast scenes.