Sentinel-2: presentation of the CAL/VAL commissioning phase

Abstract

In partnership with the European Commission and in the frame of the Copernicus program, the European Space Agency (ESA) has developed the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbits. Sentinel-2 will offer a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). The first sentinel 2A has been launched on June 22nd, 2015, from Kourou, French Guyana. In this context, the Centre National d’Etudes Spatiales (CNES) supports ESA to insure the cal/val commissioning phase, for Image Quality aspects. This paper provides first, an overview of the Sentinel-2 system after the launch. Then the articles focuses on the means implemented and activated in CNES to perform the In Orbit Commissioning, the availability and performances of the different devices involved in the ground segment : the GPP in charge of producing the level 1 files, the “radiometric unit” that processes sensitivity parameters, the “geometric unit” in charge of fitting the images on a reference map, MACCS that will produce Level 2A files (computing reflectances at the Bottom of Atmosphere) and the TEC-S2 that will coordinate all the previous software and drive a database in which will be gather the incoming Level 0 files and the processed Level 1 files.