Recent Findings on the Sentinel-1 Geolocation Accuracy using the Australian Corner Reflector Array

Abstract

Synthetic Aperture Radar (SAR) satellites observe range and azimuth geometric accuracies at the low centimeter level. The accuracy of geolocation is driven by several aspects, e.g. orbit determination, SAR image processing, or atmospheric error correction. Our paper concentrates on the Sentinel-1 mission and the compensation of the platform motion effects in the geolocation, which were found to limit the best possible geolocation capabilities of Sentinel-1. The key to advance the geolocation results is the rigorous compensation of the bistatic effect in azimuth, and the correction of the Doppler-induced shifts in range. First results for Sentinel-1 at the Australian reflector Array consisting of 40 Corner Reflector (CR) show consistent improvement in the geolocation (1 sigma) to 6 cm in range and 28 cm in azimuth for both spacecrafts when using the Interferometric Wide swath (IW) product.