GSC Sentinel-2 PDGS OCD - Emits - ESA

GSC Sentinel-2 PDGS OCD
Issue 1 Revision 2 (draft) - 25.07.2010
GMES-GSEG-EOPG-TN-09-0008
page 128 of 350
Orbit N-1 descending part
Orbit N descending part
Downlink Plan
MSI packet store playback timeline
CGS-A
CGS-B
Regular with-
Memory-Freed
Stop
Regular with-
Memory-Freed
Stop
MMFU commands
MMFU playback
command timeline
RT- with-
Memory-Freed
Stop +
Regular with-
Memory-Freed
Stop
Regular with-
Memory-Freed
Stop
Nominal
NRT
Nominal
NRT
Nominal
MMFU record command timeline
NRT
Nominal
HLOP-driven acquisition plan
NRT NRT Nominal ocean
NRT
MSI imaging timeline
RT
MSI data recovered
at core stations
CGS-A
CGS-B
Figure 4-19: MMFU Baseline Commanding Scenario for MSI
To avoid unnecessary NRT/Nominal transitions, the recording timeline will be optimised such
that Nominal-NRT-Nominal transition patterns are removed whenever the inner NRT fragment
is downlinked within the same playback segment as its adjacent Nominal observations (cf.
case of the first NRT segment in Figure 4-19).
4.5.4.2.2.2 MMFU Scene Overlap Management
As introduced in section 4.3.8.2, the management of the MMFU memory will generate
discontinuities in the timeline received at every CGS. To simplify the PDGS operations in
handling those discontinuities in view of MSI data processing, the MMFU design is being
adapted as described in [RD-41] to allow, via appropriate commanding, to artificially
introduce three redundant MSI scenes covering every timeline discontinuity.
This functionality will be used by the PDGS mission planning function as follows:
○ The Scene Rewind flag will be activated at every interruption of Playback-Regular-
With-Memory-Freed operations provided the MMFU memory is not emptied at the term
of the playback (cf. case-A in the figure depicted below);
ESA UNCLASSIFIED – For Official Use
© ESA
The copyright of this document is the property of ESA. It is supplied in confidence and shall not be reproduced, copied or
communicated to any third party without written permission from ESA.