When it comes to railway signalling in Europe, the integrity delivered by EGNOS can be the enabler for safe train localisation provided by E-GNSS. EGNOS offers improved precision of positioning for free, which further contributes to the efficiency of train localisation in the European Railway Traffic Management System (ERTMS).
For now, mainly due to a difficult rail environment, safety-relevant GNSS-based solutions don’t meet the positioning requirements specified by the ERTMS standard. In the future, however, with the currently under development EGNOS V3 multi-frequency/multi-constellation, augmentation will improve accuracy and reliability of the positioning information. By 2020, Galileo will be fully deployed and will deliver an independent civilian infrastructure with robust positioning and timing services and a high degree of performance.
According to a presentation from Peter Gurnik, Technical Affairs Manager for UNIFE, an industry association representing the European Rail Supply Industry, GNSS reduces costs when used with the European Train Control System (ETCS): The ultimate objective is to reduce the cost of ETCS trackside by reducing the number of bailises in the track, which would also increase availability and reduce exposure to theft and vandalism. More so, according to the presentation, in order to minimise the impact on ETCS, the concept of ‘virtual balises’ was developed, in which a GNSS-based positioning system confirms a train’s position at defined reference points.
Adapting to Rail
Since EGNOS was designed to answer aviation requirements, some features are not applicable unless specifically adapted for railways. To assist in this adaptation and improve GNSS services for rail, there is ongoing support through the Horizon 2020 funding programme and, previously, via the FP7 programme.
For example, the GSA is working with Next Generation Train Control, a three-year FP7 research project in coordination with UNIFE, to analyse the commonalities and differences of current major train control systems. The common functions of these systems are then used as the basis for Next Generation Train Control system specifications. Through this project, satellite positioning was identified as an emerging technology to be integrated into future train controls.
Satellite Technology for Advanced Railway Signalling (STARS), a Horizon 2020 project under the 2nd Galileo call, has been favourably evaluated and is another example of how GNSS services can assist in rail applications. This project aims to fill the gap between the need for safety critical applications and E-GNSS services through a characterisation of the railway environment and of GNSS performance assessments in that environment. Through the project, a universal approach to predict the achievable GNSS performance in a railway environment will be developed, especially for safety critical applications.
“Though there is work to be done to adapt EGNOS to railways, the future is promising,” says GSA Market Development Officer Daniel Lopour. “With the help of partners like UNIFE, and research through new, innovative projects, GNSS services are on the way to making rail more affordable and efficient for cities, and more accurate and safer for everyone.”
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