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30. September 2013


  • The project aims to develop and validate a new satellite-based platform (both for navigation and communications) suitable for the Train Control and Management System.
  • This platform addresses the needs and requirements of the Railway Infrastructure Administrations, Train Operators and Industrial System Integrators, which are interested to exploit the satellite assets for increasing the performance of existing train control and management systems.

Description in details:

Using satellite techniques for the train control systems is derived from a promising demand from both international and European Community markets, which are setting new priorities on the ERTMS-ETCS technology roadmap.

The adoption of new satellite techniques for the train system is carrying on much faster in Australia, USA and Russia than in Europe, where most of the demands focus on the local-regional railway lines.

GNSS localization and new telecommunication techniques are going to be introduced into the ERTMS-ETCS platform.
Five main target market areas (Australia, USA, Russia, Europe) have been identified and for each of them user requirements have been derived. A standard platform should be defined, which can be customized for each of these five target market areas.

Depending on the specific market area, three existing satellite localization systems, i.e. GPS, GLONASS and GALILEO, can be used.
The proposed general architecture of the train control and management system is shown in the following figure:



The Space Segment includes:

  • GNSS constellations
  • SATCOM satellite communication system

The User Segment includes:

  • Onboard devices for localization, communication and automatic train protection
  • Wayside logic into the IXL and the RBC
  • Custom GBAS Local Reference Station (LRS) and Tracking Area Lds Server (TALS)
  • Fixed and mobile communication networks

The Ground Segment includes:

  • Public SBAS services
  • IP backbone for communication toward the User Segment

The function of train positioning is performed by the following elements:

  • GNSS constellations (GPS, GLONASS, Galileo) and a public SBAS (EGNOS)
  • On board location unit (GNSS receiver, LDS equipment and a database including the map of the track)
  • Custom augmentation network (LRS and TALS)

The main task of the space segment is to provide reference satellite signals needed for the computation of train positions, as well as to distribute real time corrections related to satellite ephemerides, clock offsets, propagation delays and Signal in Space (SIS) integrity. Additionally the satellite segment provides communication links between trains and remote control centers. The DLR Institute of Communications and Navigation is mainly involved in the satellite communications tasks, and in the design of a direct train-to-train collision avoidance system.

One of the major objectives and final outputs of the 3InSat project is a technology demonstration in Sardinia (Italy). The objective of the technology demonstration with respect to the telecommunications (TLC) component is to gather performance indicators related to delay, jitter, effective bitrate and packet loss rate.

During this trial, two TLC architectures will be demonstrated:

  • Train-hosted picocell with satellite backhauling: A Cab emulator terminates at a GSM/3G modem. Data traffic is either routed through a train-hosted GSM picocell (linked via satellite to the control centre) or a terrestrial GSM/3G network.
  • Wired sat modem: A cab emulator terminates at an Integrated Services Router. Traffic is either routed through a satellite modem and satellite backbone or the GSM/3G port of the Integrated Services Router using terrestrial networks.

The LRS networks play a role similar to the EGNOS RIM subsystem. In fact, it will be mainly deployed only on those areas out of the EGNOS footprint. In essence, processing of satellite signals received at known locations allows to estimate the error sources affecting train positioning and to detect possible GNSS faults. Compared to the actual EGNOS, the major differences consist of a denser spatial deployment of the LRSs, compensating for milder requirements (and lower cost) on the GNSS receiver clocks and the use of the wireless network employed for train signaling even for augmentation data distribution.

To enhance the capabilities of systemic satellite fault detection, as well as to detect possible faults of LRSs themselves, their outputs are jointly processed by a Track Area LDS Safety (TALS) server.

In order to reduce the probability that any Misleading Information caused by hardware/software failure would produce a dangerous situation, the Location Determination System of the on-board unit adopts a multisensor solution that combines the information provided by the GNSS LDS subsystem with localization data provided by classical Odometric subsystem, denoted as ODO LDS, that processes tachometer data as well as inertial sensor packages.


  • Ansaldo STS is a world market leader for the supply of signalling and TLC solutions
  • TriaGnoSys is a very competent techonology provider for mobile communications, which has developed the concept of a mobile cell for the aeronautical service
  • RFI is the Italian railways administrator that is the potential user of the satellite-based train control system
  • Radiolabs is a no-profit research organisation with expertise in the mobile communications and satellite-based applications for the localizer and augmentation networks
  • TUDC is an accredited laboratory for GNSS applications in the rail domain and safety analysis with EGNOS and Galileo
  • Italcertifier is an independent assessor for the certification process, which has been involved since early 2000 on the GNSS working groups for rails and trials in Italy

Dr.-Ing. Sandro Scalise
Deutsches Zentrum für Luft- und Raumfahrt (DLR)

Institut für Kommunikation und Navigation
, Satellitennetze
Tel: +49 8153 28-2856

Fax: +49 8153 28-2844

E-Mail: Sandro.Scalise@dlr.de
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