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Satellite positioning set to enhance train localisation

Satellite positioning set to enhance train localisation

Sep 22, 2024

As Europe’s railways expand, their safety and efficiency depend increasingly on knowing every train’s position.

Traditional train detection systems use devices mounted along the rails, such as track circuits and axle counters

Trains also communicate track positions and distance travelled, thanks to Eurobalises and odometers

The Challenge

To achieve even greater accuracy and real-time localisation of trains by improving onboard positioning technology – using Global Navigation Satellite Systems (GNSS), such as the EU’s Galileo.

How we do this?

Shift2Rail delivered six Technical Demonstrators, defining an interoperable solution for Satellite-Based FailSafe Train Positioning (FSTP) that brings together:

1. Virtual Balises (VB);

2. a Stand-Alone FSTP system.

Researchers produced a Roadmap and Migration Strategy exploring:

  • ways to include fail-safe, interoperable train positioning solutions in future European Train Control System (ETCS) Technical Specifications for Interoperability (TSIs);
  • the need to integrate Satellite-Based FSTP systems in current and future Control-Command and Signalling (CCS) systems.

Virtual Balise-Based train positioning solutions

How does it work?

Positioning information is sent to a train through GNSS signals, supported by extra sensors, instead of relying only on physical balises along the track

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An onboard Virtual Balise Reader processes the GNSS signals and compares the GNSS coordinates with the list of coordinates onboard

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The reader reports the corresponding virtual balise to the Eurocab (a train-based computer), when the coordinates stored for it are reached

Solution

VB technology using GNSS to enhance positioning information for a train

VB solution in a real ERTMS/ETCS environment on non-urban lines, using European Geostationary Navigation Overlay Service

Ensuring interoperability between regional and main railway lines, for an FSTP solution plus VBs in a real ERTMS/ ETCS environment

Technology Readiness Level

5 (technology validated in a relevant environment)

5 (technology validated in a relevant environment)

4 (technology validated in a lab)

Key findings

Incorporating track data into the onboard algorithm can be a crucial factor in enhancing safety and
accuracy

Integration of satellite technology with standard positioning systems proved feasible, supporting:

  • interoperability
  • Reliability, Availability, Maintainability and Safety requirements

Implemented algorithm robust enough to cope with environmental disturbances to train positioning. Further runs on different lines are still necessary

Who benefits

Infrastructure managers

Railway operators

Stand-alone fail-safe train positioning solutions

Solution

Real-time demo (integrated GNSS, IMU, tachometer and a Digital Map) with an algorithm

Positioning algorithm (multi-sensor acquisitions with an emulator of EGNOS DFMC)

Real-time implementation (dual channel of GNSS, IMU or Inertial Measurement Unit, speed sensors and Digital Map)

Key findings

Showed feasibility of a positioning system of around 20 metres fixed error

Can result in error values below 3 metres

Challenging GNSS conditions affected precision of speed estimates

Who benefits

Infrastructure managers

Railway operators

Benefits of satellite-based train positioning

Calling on highly accurate real-time information from Virtual Balises on trains, supported by other sensors and technologies, these innovations can:

 

  • improve the localisation of trains
  • enhance rail safety, reliability and efficiency
  • enable the removal of trackside train-detection systems, reducing maintenance and driving major cost savings for infrastructure managers
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