# Commission Implementing Decision (EU) 2018/621 of 20 April 2018 on the technical specifications for the Copernicus space component pursuant to Regulation (EU) No 377/2014 of the European Parliament and of the Council (Text with EEA relevance), Division 3.5: European Data Relay System (EDRS)

Extent: E+W+S+N.I.

The European Data Relay System (EDRS) service shall provide the capability for the acquisition of Sentinels data complementary to the X-band core ground stations, allowing to support in particular quasi-real time observation needs (QRT is defined as products having timeliness of less than 1 hour). In particular EDRS shall provide the following capabilities:
(a) introduce flexibility in the overall data acquisition scenario leading to an increased availability of Sentinel data;
(b) allow to downlink data to ground while the Sentinels are outside the visibility of the X-band core ground stations;
(c) in combination with the X-Band core station network, support and improve the end to end availability and reliability of data provision to the end user;
(d) provide additional flexibility to accommodate Copernicus security-related requirements by ‘protecting’ the mission data reception via the encrypted EDRS Ka-band downlink.
The use of the EDRS service in support of the Sentinel-1 and Sentinel-2 missions shall provide further opportunities for product timeliness improvements, including beyond the current formal Near-Real Time commitment, defined as product timeliness of three hours.
EDRS shall allow performing fast downlink of data acquired outside the X-Band core stations visibility. Data shall be downlinked in pass-through mode via EDRS when observing such areas. This should in turn enhance the achieved product timeliness associated to core products. In addition, this should allow collaborative partners to generate products in QRT/NRT.
EDRS should be used to downlink a high percentage of data recorded in memory, outside X-band core stations visibility. This will in turn increase the volume of data downlinked and thus the volume of NRT data generated by the CSC ground segment.
The main functional tasks performed by the EDRS service shall be:
(a) sentinel-1 and -2 satellites data transmission via Optical (Laser) link between the OCP on-board the LEO satellites and the equivalent unit on-board the GEO satellites (EDRS-A and EDRS-C);
(b) mission data relay between the GEO satellites and the Ka-band ground receiving terminals;
(c) mission Data reception, decommutation and provision to the service interface point, including data circulation network.
The service shall be relevant to Sentinel-1 and Sentinel-2 missions (other Sentinels shall not carry on-board the necessary Optical Communication Payload). The geographical coverage area for downloading the Sentinel data to the EDRS receiving stations shall cover Europe as a minimum.
The service provided by EDRS shall be procured via a dedicated Service level Agreement contract, managed according to a set of stringent performance indicators.

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Source: https://www.legislation.gov.uk/eudn/2018/621/annex/division/3/division/3.5 (the official version)
Page: https://openlegislation.uk/eu-decision-2018-621/annex/division-3/division-3.5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.