1 Introduction



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EUMETCast

1 Introduction

The EUMETSAT Data Distribution System (EUMETCast) utilises the services of a satellite operator and telecommunications provider to distribute data files using Digital Video Broadcast (DVB) to a wide audience located within the combined geographical coverage zone of the individual telecommunications satellites used to transmit the data to users.


The following EUMETSAT services are currently available via the EUMETCast system:


  • Meteosat-8 (formerly MSG-1) dissemination.

  • The EUMETSAT ATOVS Retransmission Service (EARS)

  • The Rapid Scanning Service (RSS)

  • DWDSat - Deutscher Wetterdienst forecast information

This document provides a general description of EUMETCast and the procedure for gaining access to information disseminated via this broadcast. The document is divided into the following sections:







  • Process for Receiving EUMETCast - including user station equipment requirements and installation procedure






2 EUMETCast System Overview
Within the current EUMETCast configuration, the multicast system provided is based on a client/server system developed by Tellique Kommunikationstechnik GmbH. The server side is implemented at the EUMETCast uplink site (Usingen, Germany), and the client side installed on the individual EUMETCast reception stations. Standard FTP is used on top of IP over the DVB multicast platform provided by the telecommunications providers.
Two telecommunications providers supply the DVB multicast distribution. Encoded data/product files are transferred via a dedicated communications line from EUMETSAT to the uplink facility where they are transmitted to a geostationary communications satellite for broadcast to user receiving stations. Each receiving station decodes the signal and recreates the user data/products according to a defined directory and file name structure.
The figure below shows how EUMETCast fits within the overall EUMETSAT Ground Segment architecture.



Figure 1 EUMETCast System Overview

3 EUMETCast Reception
A single reception station can receive any combination of the provided services. Data whose access is controlled in accordance with EUMETSAT Data Policy are encrypted, and decryption at the user station is carried out by an eToken decryption scheme.
The data is made available on the reception station as files organised and formatted according to the reception format. No changes are performed in the reception station.
3.1 Data Volume
Each DVB channel has a fixed bandwidth:


  • Channel 1 EARS & RSS 0.250 Mbps

  • Channel 2 MSG High Rate Channel 1.620 Mbps

  • Channel 3 Low Rate, Multi-Service Channel 0.386 Mbps

  • Channel 4 DWDSAT 0.256 Mbps

Channel 2 and 3 are fed into the C-Band turn-around service. The C-Band bandwidth is



2.7 Mbps.
Additional bandwidth can be made available. A maximum bandwidth will be constrained by different elements (number of channels, uplink server performance, transponder bandwidth, performance of the reception stations (DVB card, decryption, PC H/W & S/W)). Hence a maximum figure cannot be given, but duplication or tripling of the current bandwidth will be achievable with appropriate tuning of the various elements.
All files are available and accessible on the reception station within a few seconds of the reception of the last DVB packet.
4 EUMETCast Coverage
The geographic coverage of a DVB is determined by the characteristics of the spacecraft and its associated antenna beams. In the current operational configuration, EUMETCast reception is available in Ku-band (from November 2002) and C-band (from November 2003).
4.1 EUMETCast Coverage in Ku-band
For coverage in Ku-band, the spacecraft selected by the telecommunications provider, T-Systems, is the HotBird series operated by EUTELSAT. This has excellent coverage of Europe and the surrounding area, as shown in Figure 2 below. In the current Ku-band operational configuration, EUMETCast provides good coverage over the EUMETSAT Member and Cooperating States.


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