Ground Control Points and L1C Images Extracted from the Copernicus Sentinel-2 Global Reference Image

The Copernicus Sentinel-2 Global Reference Image (GRI) was originally designed with the main goal of being used by the Ground Segment Level-1 processor to geometrically refine the Sentinel-2 data. The usage of the GRI has enabled a real improvement of the Sentinel-2 data geometric performance. Indeed, both absolute geolocation and relative (multi-temporal) performances have significantly improved and meet the requirements.It is expected that the use of the GRI could be then beneficial to other missions than Sentinel-2. In this framework and driven by user’s needs, ESA decided to freely give access to the scientific community to the entire GRI. Moreover, in order to facilitate the use of the GRI, a set of Level-1C images and a database of Ground Control Points (Level-1B and Level-1C geometries) have been derived from the Level-1B Sentinel-2 GRI. This paper recalls the characteristics of this Calibration/Validation GRI databases as well as the validations performed.