The Systematic Processing and Reprocessing Services are part of the ESA Copernicus Ground Segment and are resonsible for the exploitation of the instrument data. They are managed by ESA's Centre for Earth Observation also known as the European Space Research Institute (ESRIN) in Frascati, Italy. The Systematic Processing and Reprocessing Services operationally generate the user products and distribute processed Level-1C and Level-2A products.

The ESA Copernicus Groud Segment is composed of:

• Data Acquisition (ACQ)
• Systematic Processing and routine quality control (PR)
• On demand production (ODP)
• Auxiliary Data Gathering (ADG)
• Precise Orbit Determination (POD)
• Data Preservation (Long Term data Archiving (LTA))
• Data Access including Data Distribution (DD)
• E2E Operations performance monitoring
• Flight Operations Services (FOS) includes the facilities responsible for mission control (mission planning, production planning), quality control (calibration, validation, quality monitoring, instrument performance assessment), precise orbit determination, user services interface and acquisition, processing and archiving.

Real-time sensed data as well as data played back from on-board saved data are downlinked directly to ground or via the European Data Relay Satellite (EDRS), received, down-converted, demodulated and transferred to the processing facilities for systematic generation and archiving of Level-0 and Level-1/2 data products.

The ESA Copernicus Ground Segment is expected to receive and process 2.4 TBytes of compressed raw data per day for the two satellites in addition to data from all other ESA missions. MSI Level-0 data are processed to produce Level-1 and Level-2 products applying all the necessary processing algorithms and formatting techniques.

The ESA Copernicus Ground Segment is distributed over several core centres components including Core Ground Acquisition Stations, Systematic Processing and Reprocessing Services, Processing and Archiving Centres (PAC), Mission Performance Centres (MPC) and Precise Orbit Determination (POD) facilities.

• Acquisition Stations: the network of X-band core ground stations located in Alaska, USA, Matera, Italy, Maspalomas, Spain and Svalbard, Norway, are responsible for data acquisition and near real-time transfer of CADU (Channel Data Access Units) to the Processing Services (PS).
• Data Preservation (Long Term data Archiving (LTA)): LTAs perform long-term data archiving, data access and systematic non-time critical data processing. Archiving and long-term preservation of data produced by the ESA Copernicus Ground Segment - as well as POD data - is ensured for all Level-0 data and for a set of configurable systematic higher level products.
• Mission Performance Centres: MPCs are responsible for calibration, validation, quality control and end-to-end system performance assessment. The MPCs include expert teams for specific cal/val, off-line quality control and algorithm correction activities.
• Precise Orbit Determination: POD facilities make use of the GNSS receiver data on-board the SENTINEL satellites to deliver the orbital information needed for generation of mission products.

Figure 1: SENTINEL-2 Receiving Stations and Off-line Processing and Archiving Centres

Coordination between the centres is provided through the Payload Data Management Centre (PDMC) at ESRIN in Frascati, Italy.

SENTINEL-2 products are provided to the user through online access. Near real-time dissemination is allocated to the receiving stations and less time-critical data dissemination is allocated to the assembly, processing and archiving centres.