Access to the Copernicus Sentinel-2 Global Reference Image (GRI)

We are pleased to inform that the Copernicus Sentinel-2 Global Reference Image (GRI) is now available.

The ESA Ground Segment uses the Copernicus Sentinel-2 GRI in the Sentinel-2 Level-1 processing chain in order to geometrically calibrate the data before distribution to users. Specifically, the GRI is used to improve the absolute geo-location accuracy and the multi-temporal co-registration of Sentinel-2 data through a processing step called “geometric refinement”.

The GRI was initially generated as a set of as-cloud-free-as-possible mono-spectral (central band B04, 10m resolution) Sentinel-2 Level-1B products, whose geometrical model had been previously improved. That version is referred as Multi-Layer Copernicus Sentinel-2 GRI in L1B and is the one currently used by the ESA Ground Segment to systematically generate the Sentinel-2 data:

1. Multi-Layer Copernicus Sentinel-2 GRI in Level-1B;

Starting from the Multi-Layer Copernicus Sentinel-2 GRI in L1B, the following additional three versions of the GRI were generated:

2. Multi-Layer Copernicus Sentinel-2 GRI in Level-1C ;
3. Copernicus Sentinel-2 GRI as Database of Ground Control Points (GCPs) in Level-1B ;
4. Copernicus Sentinel-2 GRI as Database of Ground Control Points (GCPs) in Level-1C .

All the four Copernicus Sentinel-2 GRI versions have the same coverage, i.e., land and coastal areas worldwide (except high latitude areas), including most of the islands.

Usage of the Copernicus Sentinel-2 GRI allows to constrain the geometric model of satellite data, i.e., not only for the Sentinel-2 mission but also for other satellite missions generating data up to 50m spatial resolution.

Access to the four versions of the Copernicus Sentinel-2 GRI (i.e., as L1B and L1C Multi-Layer and as L1B and L1C Databases of GCPs) and to the associated documentation (Product Handbooks and Validation Reports) for download is available via the ESA Sentinel Online webpage