A modified back-projection algorithm for imaging Geo-referenced SAR data

GR-strip (Geography-Referenced stripmap) imaging mode is a new imaging mode of SAR (Synthetic Aperture Radar), it is very different from the normal stripmap imaging mode. Operating in this mode, trajectory of aircraft can be un-parallel to swath, thus a higher flexibility is obtained due to the reduces of limitation for radar trajectory. Meanwhile, the characteristic of unlimited swath in azimuth orientation is also reserved in this mode. However, the shortest slant ranges are variant in GR-strip SAR for different points along azimuth direction on the strip and the resolution in azimuth is space-variance correspondingly. This cannot be solved by conventional SAR imaging algorithms. This article focused on two parts, the first part is the introduction of GR-strip SAR, the second part is a modified back-projection algorithm which is applicative to GR-strip SAR.