appendix 3 - european space agencyemits.esa.int/emits-doc/estec/edrs-appendix3.pdf · 2010. 1....

Ref: D/TIA/2008-12152/CE App3

Date: 27/06/2008 Issue: 1 rev 0 Page: 1 of 7

Appendix 3

EDRS

European Data Relay Satellite System

Preliminary EDRS end-to-end System

Architecture

European Space research and Technology Centre (ESTEC)

European Space Agency

Keplerlaan 1, P.O. BOX 299, 2200 AG Noordwijk, The Netherlands



This document describes a possible EDRS end to end architecture. The illustrative information provided in this appendix should not be considered as mandatory requirements. It is a starting point for further consideration by the respondent to the AO in order to alter/complement this scheme within the same budget envelope. The end-to-end architecture is depicted in Figure 1. For illustration purposes, the GMES SENTINEL scenario is considered in order to provide an overview of a truly end to end architecture involving the user elements. The main elements of the EDRS architecture and associated functions are:

• The ISL terminals, LCTs on board the SENTINEL satellites, transmitting the scientific

data acquired by the observation instruments on board the SENTINEL satellites.

• The in orbit EDRS GEO Payloads providing a real time communication link between the SENTINEL satellites and the EDRS receiving ground stations. Possibly also providing data repatriation and dissemination capabilities.

• The EDRS ground stations receiving the data from the EDRS GEO payloads

• The EDRS Satellite Control Centre(s) (SCC) in charge of the operation and monitoring of

the in orbit EDRS GEO payloads.

• The EDRS Mission and Operation Centre (MOC) receiving GMES service requests and translating those requests into an overall EDRS system configuration.



GMES Pocessing and

Archiving Centeres

SENTINELS 1 & 2

Requests

EDRS Mission & Operation Centre

EDRS GEO Payloads

EDRS Ground Station

EDRS Ground Station

TM/TC

EDRS Data

EDRS Satellite Control Centre

GMESMission Management

Center

GMES SENTINELRequests

GMES Pocessing and

Archiving Centeres

SENTINELS 1 & 2

Requests


EDRS GEO Payloads

EDRS Ground Station

EDRS Ground Station

TM/TC



Center

EDRS Data

GMES SENTINELRequests

Figure 1 : EDRS end to end architecture

The way the EDRS system interfaces with the user infrastructure is described using a typical sequence of actions from the request of the service to its delivery. GMES User Mission Management Centre originates a “service request” to the EDRS MOC. The MOC sends configuration commands:

• through the SCC for the EDRS GEO Payloads configuration,

• to the GMES Mission Management Centre for the configuration of the LCT on board the

SENTINEL satellite. (through and under the responsibility of the GMES SENTINEL Satellite Control Centre).

• To the EDRS relevant ground stations (either directly or via the GMES MOC)

The data from the EDRS Ground stations is then transferred to the Processing and Archiving Centres (PACs) from where processed data is disseminated to the final User. The EDRS operator is not responsible for the GMES Mission Management Centre nor for the PACs.



This overall architecture will remain similar for most of the user scenarios. The actual flow of information and interfaces however is subject to changes depending on the types of services and users. With regards to the GMES case, complementary missions such as data repatriation and dissemination can also be provided through the EDRS system providing the GMES SENTINEL system with an all in one service package and rendering the offer more attractive. The following figure includes these additional services:

GMES PACs

SENTINELS 1 & 2

GMES X band Station

Requests

Data Repatriation

Final users


EDRS GEO Payloads

EDRS Ground Stationmain EDRS

Ground Stationred

TM/TC

EDRS Data

Data Dissemination

EDRS Rx User Stations


EDRS Data Dissemination

SENTINEL 3


CenterTerrestrial

50% traffic +redundancy

50% traffic

GMES PACs

SENTINELS 1 & 2

GMES X band Station

Requests

Data Repatriation

Final users


EDRS GEO Payloads

EDRS Ground Stationmain EDRS

Ground Stationred

TM/TC

Data Dissemination

EDRS Rx User Stations


EDRS Data

EDRS Data Dissemination

SENTINEL 3


CenterTerrestrial

50% traffic +redundancy

50% traffic

Figure 2 : EDRS end to end architecture including data repatriation/dissemination

services

For non technical reasons, it is currently considered that not all the SENTINEL data will through the EDRS optical data relay link (about 50%). The repatriation mission therefore consists in carrying the remaining data at the X band stations back to the PACs through a satellite link solution. The dissemination mission consists in serving some of end users of the processed data also through a satellite link. This allows the GMES system to rely and procure all the services from a single entity: the EDRS service provider.



The mains elements of the EDRS architecture are grouped into segments:

• The EDRS space segment including the GEO in orbit infrastructure

• The EDRS ground segment including the EDRS Mission and Operation Centre, the EDRS

SCC facilities on the ground, and the EDRS ground stations (including those required the repatriation and dissemination missions).

• The EDRS User segment including the EDRS ISL terminal on board the user platform

(SENTINEL in the GMES case) The first element of the EDRS space segment is composed of two “Piggy-back A and B” payloads to be embarked and flown on board two commercial geostationary satellites by the end of 2012. Once in orbit, the piggy-back payloads (of approximately 100 Kg each) will provide an operational DRS capability for the most urgent usage (GMES) through the optical link but also includes a Ka band ISL capability (on Piggy back payload A only to back up the already existing capability on ARTEMIS). The utilisation of piggy-back is economically attractive and cost-effective and is possibly the only means to guarantee reliable (with appropriate Quality of Service (QoS)) DRS service provision by 2012. The second element of the EDRS space segment is a “Dedicated satellite C” providing both optical and Ka band ISL capabilities as well as a specific complementary mission (data repatriation and dissemination for GMES). The development of the Dedicated Satellite shall be initiated in parallel with the “Piggy-back payloads” but will be launched at the end of 2013. With a dedicated DRS satellite, added in late 2013, the baseline system will be capable of fully covering all DRS needs and requirements from ESA and other commercial/institutional users, with the exception of S-band related services (essentially required by launchers). The dedicated satellite is foreseen to be based on a Small-GEO class platform (300 Kg / 3 kW payload). Additionally, the Dedicated satellite can be tailored to meet military/security needs since the EDRS operators has full ownership and therefore full control of the dedicated satellite. This aspect is considered key for the EDRS operator to be able to provide services to military entities (who represent a strong candidate for use of DRS services). Finally the Dedicated Satellite will embark operator’s own payloads. These are typically commercial and governmental communication payloads (Ka-band steerable spot beams). These payloads will top-up the dedicated satellite platform so that the full platform capabilities can be utilized (and launch cost optimized).



With regards to the ground segment, the Mission and Operation Centre will include two main functions. The first is to act as a single interface point with the EDRS customers hence receiving service requests and also performing the associated service monitoring/accounting/billing as agreed in the various Service Level Agreements. The second main function consists in defining the overall EDRS system configuration accordingly to the services requests received. The Satellite Control Centre function is typically the monitoring and controlling the space segment. The SCC function will likely be implemented at already existing premises of satellite operators. The EDRS ground stations includes the receiving stations for data relayed by the EDRS space segment but can also include transmit and receive stations specific to complementary missions such repatriation and dissemination for the GMES. The share of ownership and control of the EDRS ground stations will need to be defined with the relevant EDRS customer. Some may want to procure an end to end solution including the provision and operation of the station under the EDRS operator responsibility. In other cases, other customers may just want to procure transponder capacity and operate the telecom links themselves. Preliminary design assessment A preliminary technical assessment of the EDRS system was performed focussing on the ESA DRS needs only. The results of this assessment are therefore indicative only. Additional requirements from other EDRS potential customers should be considered by the EDRS operator in order to perform an overall EDRS design iteration. High level information on the results of this iteration shall be provided in the answer to this AO (payload/satellite/launch configuration, antenna size, overall mass and power consumption/dissipation, technology identification)

Piggy-back payload A This payload includes an optical and Ka band ISL capability with a Ka band feeder link over Europe. The optical link function is considered mono-directional (return link (RTN) from SENTINEL to Ground only) as there is no rapid tasking or TM/TC requirements from the GMES. The Optical Link data rate is imposed at 520 Mbps (at SENTINEL data level) in order to minimize design impact of the SENTINEL satellites. The Ka band ISL is bi-directional. The Ka band ISL RTN link is size with up to 2 carriers of 150 Mbps, the FWD link is based on a lower rate of a few 10s of Mbps. The Optical terminal is based on the 1064nm wavelength Laser technology, the Ka band ISL is implement through a single feed antenna with a 2 meter (TBC) reflector that should be fully steerable. The feeder link operates in the Ka band through a global European coverage provided by a single beam 0.7 m antenna (TBC). The overall payload mass is estimated at 115kg with an overall power consumption of 675W. The repeater architecture includes standards receive and transmit chains, the main advanced technological elements are the optical terminal, and the necessary high rate modulator of the for the optical data relay mission.



Piggy-back payload B This payload corresponds to the payload B but without the Ka band ISL capability, hence an optical data relay mission only (mono directional optical ISL and Ka band feeder downlink). The overall payload mass is estimated at 80kg with an overall power consumption of 500W.

Dedicated satellite C This element of the Ground segment consists in a full satellite based on a small class platform (300 kg / 3000 W payload). The payloads considered for the dedicated satellite are identical to the piggy back payload A plus a repatriation/dissemination mission payload for the GMES needs plus an own operator payload. The repatriation/dissemination mission is considered in Ka band and re-uses the already existing Ka band feeder link European coverage antenna. The repatriation/distribution mission therefore translates into a Ka band repeater with the tradition receive and transmits sections. A total of 3 to 4 active transponders are expected to be necessary. Excluding the operator own payload, the payload mass is estimated at 130 kg with a 1200 W power consumption, leaving some available mass and power resource for the operator own payload (170 kg and 1800 W).

EDRS ground stations The characteristics of the ground station will be specific to the customer mission, in the GMES case, a 4 to 5 antenna is expected to be required to receive both the feeder downlink and the repatriation data at the PAC premises (in Ka band for both cases). The same station also include a transmit function for the dissemination mission. Additional 4 to 5 m antenna Ka band transmit stations collocated with X band stations are also envisaged for the repatriation mission. Finally end user Rx Ka band stations of 80 to 90 cm are considered for the dissemination mission across Europe. The DVB-S2 standard is considered as baseline for those links. There is currently no technological challenge on the design of the EDRS ground stations except possibly for the very high rate Rx demodulators possibly required for receiving the feeder downlink.

appendix 3 - european space agencyemits.esa.int/emits-doc/estec/edrs-appendix3.pdf · 2010. 1....

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