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GSC Sentinel-2 PDGS OCD - Emits - ESA

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o Report generation frequency and coverage<br />

<strong>ESA</strong> UNCLASSIFIED – For Official Use<br />

<strong>GSC</strong> <strong>Sentinel</strong>-2 <strong>PDGS</strong> <strong>OCD</strong><br />

Issue 1 Revision 2 (draft) - 25.07.2010<br />

GMES-GSEG-EOPG-TN-09-0008<br />

page 249 of 350<br />

This operation scenario is used for the configuration of the DRX function when deployed in a<br />

<strong>Sentinel</strong>-2 assigned data reception centre. Firstly the configuration will cover the <strong>Sentinel</strong>-2A<br />

spacecraft and then complemented when additional spacecrafts are added to the mission.<br />

6.1.2.2 Load of the Acquisition Schedule<br />

This scenario accounts for the autonomous loading of <strong>Sentinel</strong>-2 acquisition schedule<br />

according to the DRX configuration. The acquisition schedule comprises the data reception<br />

and front-end processing activities.<br />

The following steps are identified for this operation scenario:<br />

1) The DRX function autonomously gathers the new acquisition schedule (containing the<br />

spacecraft TLEs, the AOS & LOS events, and the front-end processing events) as<br />

provided by the MPL function;<br />

2) The DRX function autonomously loads the acquisition schedule to enable the data<br />

reception and front-end processing activities. Accordingly the acquisition and front-end<br />

agendas are updated ready to be activated shortly preceding the planned AOS. The<br />

antenna that will support the reception is pre-selected for each planned reception;<br />

3) The DRX function alerts in case of conflict with a previous planning (e.g. operations<br />

conflict with another mission).<br />

The acquisition schedule is generated by the MPL function as part of the mission plan<br />

generation activities. The MPL function supplies it to all the involved ground-stations. In a<br />

second step, the acquisition schedule is updated by the MPL function and supplied to the<br />

ground stations according to the availability of more accurate orbit ephemeris.<br />

6.1.2.3 Current Pass Data-Reception and Real-Time ISP Supply<br />

This scenario accounts for the autonomous data acquisition, front-end processing and realtime<br />

data supply. The DRX function acquires and decodes the mission data (science,<br />

ancillary & X-Band HKTM) downlinked from the satellites during a given pass, process it and<br />

distribute it in real-time towards the data consumers (i.e. the DPC function). The Instrument<br />

Source Packets supply towards the data consumers is started in real-time as soon as there is<br />

new data of the current pass available (i.e. not waiting until the pass has been completed but<br />

on-the-flow).<br />

This scenario also accounts for the local archiving of the acquired data and processed data at<br />

VCDU level discriminated by the VCID (science nominal, NRT and RT; ancillary and HKTM<br />

data respectively) according to the archiving strategy defined in the DRX function<br />

configuration scenario.<br />

The following steps are identified for this operation scenario:<br />

1) According to the acquisition schedule (cf. 6.1.2.2), the data reception activities are<br />

activated shortly before the planned AOS event. The antenna selected for acquisition<br />

is moved to the AOS position using the applicable TLE and signal search is activated<br />

enabling tracking on the RF carrier signal with the associated antenna movement until<br />

the planned LOS;<br />

© <strong>ESA</strong><br />

The copyright of this document is the property of <strong>ESA</strong>. It is supplied in confidence and shall not be reproduced, copied or<br />

communicated to any third party without written permission from <strong>ESA</strong>.

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