A New Method for Enhancing Azimuth Extent of Imaging for Space borne Sliding Spotlight SAR

摘要

The present paper describes a processing method for extending azimuth coverage for a space borne SAR operating in sliding spotlight mode. There are two major difficulties in processing such data, namely the large range cell migration (RCM) and the rapidly changing Doppler rate along the 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 corresponding phase compensation will convert the data to a strip-map one. However, in the resultant strip map data , the Doppler rate drifts along the azimuth and the drift is prominent as one moves away from spot centre. A re-sampling mechanism, applicable in both time and frequency domain, depending upon the matched filter domain, is suggested which enables strip map processing over a block of data with linearly drifting Doppler rate.