Title
In-Depth Verification of Sentinel-1 and TerraSAR-X Geolocation Accuracy Using the Australian Corner Reflector Array
Abstract
This article shows how the array of corner reflectors (CRs) in Queensland, Australia, together with highly accurate geodetic synthetic aperture radar (SAR) techniques-also called imaging geodesy-can be used to measure the absolute and relative geometric fidelity of SAR missions. We describe, in detail, the end-to-end methodology and apply it to TerraSAR-X Stripmap (SM) and ScanSAR (SC) data and to Sentinel-1 interferometric wide swath (IW) data. Geometric distortions within images that are caused by commonly used SAR processor approximations are explained, and we show how to correct them during postprocessing. Our results, supported by the analysis of 140 images across the different SAR modes and using the 40 reflectors of the array, confirm our methodology and achieve the limits predicted by theory for both Sentinel-1 and TerraSAR-X. After our corrections, the Sentinel-1 residual errors are 6 cm in range and 26 cm in azimuth, including all error sources. The findings are confirmed by the mutual independent processing carried out at University of Zurich (UZH) and German Aerospace Center (DLR). This represents an improvement of the geolocation accuracy by approximately a factor of four in range and a factor of two in azimuth compared with the standard Sentinel-1 products. The TerraSAR-X results are even better. The achieved geolocation accuracy now approaches that of the global navigation satellite system (GNSS)-based survey of the CRs positions, which highlights the potential of the end-to-end SAR methodology for imaging geodesy.
Year
DOI
Venue
2021
10.1109/TGRS.2019.2961248
IEEE Transactions on Geoscience and Remote Sensing
Keywords
DocType
Volume
Geodesy,radar remote sensing,spaceborne radar,synthetic aperture radar
Journal
59
Issue
ISSN
Citations 
2
0196-2892
0
PageRank 
References 
Authors
0.34
0
9
Name
Order
Citations
PageRank
Christoph Gisinger1617.53
Adrian Schubert2366.16
Helko Breit336875.29
Matthew C. Garthwaite452.46
Ulrich Balss522929.57
Martin Willberg601.01
David Small716222.04
Michael Eineder843972.07
Nuno Miranda9234.78