Research Progress on Spaceborne High-resolution Wide-swath Staggered SAR Imaging Technology

One of the future development trends in spaceborne synthetic aperture radar (SAR) is to have the capabilities for high-resolution and wide-swath imaging, but due to constraints imposed by minimum antenna area requirements, there is an inherent conflict between high-resolution and wide-swath imaging. To resolve this contradiction, various advanced SAR operational modes for high-resolution wide-swath imaging have been proposed. Among those, the Staggered SAR technique, which combines multiple elevation beams technology with variable pulse repetition frequency (PRF) technology, has emerged as a focal point of interest for scholars worldwide in the new generation of SAR systems. High-resolution wide-swath imaging is achieved by the multiple elevation beams technology using broad illumination and multi-channel echo reception in the range dimension; the variable pulse repetition interval (PRI) is used by the PRF technology to continuously shift the positions of blind areas, overcoming the fixed range gaps between sub-swaths caused by constant PRI and enabling gapless wide-swath imaging. Based on the spaceborne high-resolution wide range Staggered SAR system, the imaging modes, key technologies and derivative modes are analyzed in this paper, and a prospective outlook on future development trends is also offered.