Wide swath range sweep SAR: gapless imaging of wide scenes that are not parallel to the satellite orbit

Abstract

ABSTRACT Spaceborne stripmap range sweep synthetic aperture radar (SS-RSSAR) can image regions of interest tilted with the satellite orbit and has great potential in reducing data rates and improving observation efficiency. However, the range sweep mode is designed for single-channel SAR, and its imaging range swath and azimuth resolution cannot be improved simultaneously. Moreover, the multi-interval sampling technique proposed for the range sweep SAR is based on the assumption that the echo signal window is narrower than the pulse repetition interval (PRI), which is not valid in the case of high-resolution wide-swath (HRWS) SAR. In order to apply the range sweep mode in HRWS SAR systems based on digital beamforming on receive, a new design method for variable PRI sequences is proposed in this paper. The simulation results prove that using the proposed PRI sequence, the concept-wide swath range sweep SAR (WS-RSSAR) system can image broader scenes unparalleled to the satellite orbit without lowering the azimuth resolution.