Payload Data Ground Segment (PDGS)
The Payload Data Ground Segment (PDGS) is responsible for exploitation of the instrument data. The PDGS is operated from ESA's Centre for Earth Observation also known as the European Space Research Institute (ESRIN) in Frascati, Italy. The PDGS operationally generates the user products and distributes raw Level-0 products, processed Level-1 products and derived Level-2 products.
The PDGS 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 PDGS is expected to receive and process 0.6 TBytes of uncompressed raw data per day for the two satellites in addition to data from all other ESA missions. All S3-instrument Level-0 data are processed to produce Level-1 and Level-2 products applying all the necessary processing algorithms and formatting techniques.
The PDGS is distributed over several core centres including Core Ground Stations (CGS), Processing and Archiving Centres (PAC), Mission Performance Centres (MPC) and Precise Orbit Determination (POD) facilities.
Core Ground Stations
The X-band core ground station located in Svalbard, Norway, is responsible for data acquisition and near real-time processing.
Processing and Archiving Centres
PACs perform long-term data archiving, data access and systematic non-time critical data processing. Archiving and long-term preservation of 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-3 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-3 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 centers.