Abstract:

The sliding spotlight frequency modulated continuous wave synthetic aperture radar (FMCW-SAR) combines the advantages of sliding spotlight mode and that of FMCW-SAR, by means of which it is possible to acquire the microwave images with an azimuth resolution better than that obtained in the strip-map case and with an imaged area larger than that achieved in the spotlight operation. The long azimuth coherently integrated time, the serious range cell migration and the importance of motion compensation with high resolution imagery on the small carrier are analyzed. The signal model of sliding spotlight FMCW-SAR is established and the range Doppler spectrum of the echo signal is analyzed, then a subaperture algorithm that compensates RCM with Chirp-Z transform is presented. The subaperture recombination of the sliding spotlight mode which not only overlaps coherently the sub-apertures to achieve full resolution, but also adjoins them to output the continuous scene, is different from that of the spotlight operation. The validity and feasibility of the proposed algorithm are verified by the processed result of simulation data.