To ensure EU-wide interoperability, real-time, precise train positioning and high levels of safety, ERTMS could switch to EU space solutions. EUSPA-funded project CLUG, has made concrete steps towards providing a cost-efficient train tracking solution based on satellite technology together with other sensors and data.
Travelling around Europe by train comes with a lot of benefits. It is a great way to get a sense of the country you are visiting just by looking outside of the window while it is also a comfortable means of transport that enables you to make new acquaintances with fellow travelers. What’s more, rail is one of the most environmentally friendly modes of transport. In the EU, rail is responsible for less than 0.5% of transport-related greenhouse gas emissions. This makes it one of the most sustainable forms of passenger and freight transport.
Knowing the exact position of a train is at the heart of rail operations across the Union. Real-time train localisation allows passengers to know whether their train is delayed but also aids rail operators in train traffic management. The European Railway Traffic Management System (ERTMS), is a major industrial project being implemented by the European Union, which will create an interoperable railway system in Europe that is more efficient and safer.
To ensure EU-wide interoperability, real-time, precise train positioning and high levels of safety, the ERTMS currently relies on a series of costly ground instruments. In the coming years, this is set to change and ERTMS could switch to EU space solutions. EUSPA-funded project CLUG, has made concrete steps towards providing a cost-efficient train tracking solution based on EU satellite technology together with other sensors and data.
Project CLUG at a glance
Experienced rail operators and infrastructure managers came together to define a set of specifications and operational scenarios that meet the stringiest safety needs of the rail sector. The specifications are used by the architects of the CLUG consortium who are currently in the process of rolling out the system.
The project’s goal is to assess the creation of a failsafe Train Localisation On Board Unit (TLOBU) that will be interoperable across the entire European railway network. The TLOBU will provide trains and railway operators with critical information such as positioning and velocity, complemented by acceleration, heading and attitude for non-safe applications.
At the end of the project, and based on the experience gained during the demonstration phase, the consortium will be able to collect and review data that will help rail operators and industry to gain insights and push towards a new version of the ERTMS standards.
How does it work?
The proposed solution is based on multi-sensor fusion using measurements from a GNSS receiver, an Inertial Measurement Unit (IMU) and a tachometer with the support of a digital map of the rail tracks.
The localisation system consists of a data fusion algorithm associated with an integrity algorithm, ensuring the SIL4 level of safety of the main outputs of the TLOBU. The integrity algorithm uses EGNOS, the European Satellite Based Augmentation System.
Data from the TLOBU are transmitted to specific train safety functions such as the European Vital Computer (EVC), part of the Automatic Train Protection function (ATP). In parallel, the fusion algorithm is also providing other outputs to other train functions that do not require a SIL4 level of safety, such as Train Management System (TMS) or the passenger information system.
The system architecture and algorithms are defined by Airbus Defence & Space, and NAVENTIK. Both companies are providing two different solutions for the fusion algorithms, whereas the integrity concept is defined by Airbus Defence & Space. This concept is based on the EGNOS services; however, the currently available services have only been defined for aviation means and requires specific refinements to be optimised for rail environments. This EGNOS service is the cornerstone of the integrity concept of CLUG to reach the necessary SIL4 level of safety. Airbus D&S detailed this EGNOS service for rail in specific deliverables, which will be published in the coming months.
Using EU space technology in the railway sector not only increases safety but can significantly reduce maintenance and other operational costs. This new approach for train localisation is set to improve the current system based on balise readers. The goal of the TLOBU is to ultimately replace the current localisation system, and thus to promote and accelerate the deployment of ERTMS in Europe by introducing more accurate train localisation. Such an innovative system should also help drastically reduce the ground equipment, currently ensuring the safe train localisation, such as axel counters and track circuits. Although one of the goals is to decrease as much as possible the use of balises along the tracks, the system will still make use of some balises to help maintain a precise and safe position in GNSS-denied environments such as tunnels and train stations.
About project CLUG
The Horizon 2020 consortium consists of ten companies from four European countries (France, Germany, Switzerland and Spain): three Rail Operator or Infrastructure Manager (SNCF, DB Netz and SBB), two rail industrials (CAF and Siemens), one major European aerospace company (Airbus D&S), one research institute related to aeronautics (ENAC), one certification organism (NavCert), and two localisation experts (FDC and NAVENTIK).
Visit the project’s website to find out more.
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