'A method for processing space borne sliding spotlight synthetic aperture radar signal for extended azimuth coverage

摘要

The invention provides a method of processing for extending azimuth coverage for a SAR operating in spaceborne sliding spotlight mode. Two major difficulties, in processing such data, namely large range cell migration (RCM) and rapidly changing Doppler rate along azimuth. This method assumes that the complete azimuth stretch will be processed in different blocks. Majority of RCM will be corrected in time domain by Bulk RCM correction and a corresponding phase compensation will convert the data to a strip-map one. However, in the resultant stripmap data, the Doppler rate drifts along the azimuth and the drift is prominent as one moves away from spot center. A resampling mechanism, Co applicable in both time and frequency domain, depending upon the matched filter domain, ,is suggested which enables stripmap processing over a block of data with linearly drifting Doppler rate.