GSC Sentinel-2 PDGS OCD - Emits - ESA

ESA UNCLASSIFIED – For Official Use
GSC Sentinel-2 PDGS OCD
Issue 1 Revision 2 (draft) - 25.07.2010
GMES-GSEG-EOPG-TN-09-0008
page 75 of 350
Other constraints related to EDRS, the OCP and their overall operability for the Sentinels has
led to setting up a number of assumptions (cf. section 4.1) and derived constraints (cf.
sections 4.3.8.6 and 4.3.11).
4.3.2.3 PDGS Physical Layout and Evolutions
As a matter of fact, the CGS network and complementary centres that will support the PDGS
operations is at this stage not settled.
The non a-priori knowledge at the time of design of the ground-infrastructure that will be
selected to support PDGS operations imposes a highly flexible, modular and scalable solution
to be used on-time considering its settled effective characteristics (e.g. CGS network and
accessibility via networks, ground network bandwidth, major user sites, etc) and allowing for
future evolutions.
The operation constraints specifically related to the future choice of the CGS network are
described separately in paragraph 4.3.10. They highlight the impacts of the CGS network
selection and sizing on the mission performance regarding data timeliness.
An initial CGS network will be settled according to the effective timeliness required.
Regarding evolutions of these requirements, it is expected that the phase-in of EDRS will
alleviate most constraints in this respect. As a backup solution, the PDGS shall have the
required flexibility to accommodate additional X-Band ground-stations or to modify the initial
setting to match the new requirements.
Regarding networking and data-transportation, specific drivers directed by technology
evolutions have been highlighted in section 4.3.6 for consideration and trade-off;
In addition, strategic drivers are highlighted such as the maximum reuse of existing European
infrastructure in the LTDP area, to exploit synergy with the long-term archiving already
performed for other EO missions.
4.3.2.4 Evolutions through Third-Party Collaborations
As introduced in section 4.2.7, the GSC operation concepts foresee the operations of a core
PDGS supported by collaborative entities operated separately and in harmony with the core
system towards the common objectives of the GSC. In this extended framework, collaborative
partners outside of the GSC framework will contribute to enhancing the global system
performance.
Although out of the strict scope of the PDGS, the enabling of such collaborative opportunities
for Sentinel-2 shall be considered within the perimeter of the PDGS operation concepts as
possible evolutions.
4.3.2.5 Local Station Network
As introduced in section 4.2.7, the mission calls for the capability to downlink real-time MSI
data directly from the Sentinel-2 spacecrafts X-Band interface to a network of LGSs owned,
managed and operated outside of the GSC framework. At this time, this local station network
is unknown as depending on dedicated agreements to be set-up between partner
organisations and the Sentinel-2 MMA.
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