The Sentinel core ground segment allows all Sentinel data to be systematically acquired, processed and distributed. It includes elements for monitoring and controlling the Sentinel satellites and for downloading, processing and disseminating the data to users. It also has mechanisms for monitoring and controlling the quality of data products, as well as for data archiving. Infrastructure is 'distributed', meaning that various centres are in different locations but linked together and coordinated. Despite the complexity of the system, users are offered a single virtual access point for locating and downloading products.
The main facilities of the Sentinel core ground segment are:
- The Flight Operations Segment (FOS) - responsible for all flight operations of the Sentinel satellites, including monitoring and control, execution of all platform activities and commanding of the payload schedules.
- The Core Ground Stations - where the Sentinel data are downlinked and products are generated in near real-time. A network of X-band ground stations allows the downlink of all Sentinel data. These are complemented by the utilisation of the European Data Relay Satellite (EDRS) for additional downlink of Sentinel data to EDRS ground stations.
- The Processing and Archiving Centre's (PACs) - where systematic non-time critical data processing is performed. All data products are archived for online access by users. A network of PACs supports all processing and archiving of Sentinel data.
- The Mission Performance Centres (MPCs) - responsible for calibration, validation, quality control and end-to-end system performance assessment. The MPCs include expert teams for specific calibration/validation, off-line quality control, algorithm correction and evolution activities.
- The Sentinel Precise Orbit Determination (POD) facility - makes use of the GNSS receiver data on the Sentinels to deliver the orbital information needed to generate the data products.
- The Copernicus Space Component Wide Area Network (CSC WAN) - allows all products and auxiliary data to be carried across the various ground segment facilities and provides disseminated data products to end users.
All Sentinel data are systematically processed up to the designated level and according to different timelines, ranging from near real-time to non-time critical, available typically within 3-24 hours of being sensed by the satellite.