IMproving the Performance of the Railways through an EGNSS Safety Service
Background & Objectives
The use of an EGNSS receiver in combination with other sensors could result in the provision of accurate and reliable positioning which would translate into an overall improvement of the rail system.
Galileo is Europe’s Global Navigation Satellite System (GNSS) providing an accurate, guaranteed global positioning service under civilian control. Galileo is operational since the Initial Service declaration at the end of 2016. Full Operational Capability is expected to be reached along 2020. As part of the main services provided by Galileo, the Galileo High-Accuracy Service (HAS) shall provide in the near future a high-accuracy positioning and synchronisation information.
EGNOS, the European Satellite-Based Augmentation System (SBAS), includes a Safety-of-Life (SoL) service providing the necessary level of integrity, continuity and accessibility to meet the demands of safety-critical applications. In the future, EGNOS V3 will provide a Dual-Frequency Multi-Constellation (DFMC) service as well based on augmentation of both GPS and Galileo on the L1/E1 and L5/E5a signals, but it will also maintain a legacy augmentation service of GPS L1.
Railway applications would greatly benefit from a multi-constellation approach, due to the challenging environments (e.g. tunnels, urban scenarios) which might cause masking, multipath, and non-line-of-sight effects.
The main tasks of the project are the following:
- Identify what are the current safety, legal and regulatory constraints as well as the standardisation framework in the rail sector at European level.
- Analyse the main technologies used nowadays for Positioning, Navigation and Timing (PNT) in the rail domain and try to predict their foreseen evolution with respect to EGNSS penetration in the rail sector within the timeframe 2022-2035.
- Develop a new integrity concept for the onboard unit (OBU), to be nested within the ETCS (European Train Control System), for safety critical applications and define the associated requirements that a GNSS receiver of an OBU and an antenna shall comply with. Determine the minimum requirements that shall be verified during a test campaign to validate the new integrity concept.
- Characterise, in terms of performance, the EGNSS safety service tailored to the rail domain considering several scenarios and operational conditions. Two service definitions will be considered: the short-term, which includes the replacement of virtual balises, and the long-term, with the objective to improve the overall performance of the safety service to address more demanding rail applications.
- Estimate whether or not the new proposed service offered by the EGNSS and applicable to the rail sector will be beneficial to:
- GNSS receiver manufacturers
- Rail users: infrastructure managers, rail operators
- EGNSS safety service provider
- Assess the different steps towards the implementation for the new EGNSS rail safety service, indicating risks and associated mitigations as well as the key decisions to be taken.
- Support the EC in the dissemination activities.
Work performed & results
The study aims to define a new integrity concept based on EGNSS services and tailored to the rail sector for safety applications. The “EGNSS-based rail safety service” will be validated by the rail and GNSS stakeholders, including:
- Infrastructure Managers
- Railway Operators
- Rail System Integrators
- GNSS Receiver manufacturer
- EGNSS Service Providers (ESP)
Indeed, ERTMS is gradually being rolled-out within European countries. In fact, some countries have already decided to accelerate the transition from their own legacy systems to the new standards on their whole national networks: this is the case for Belgium, Denmark, Luxembourg, Sweden, Switzerland and Norway.
The integration of EGNSS functions within ERTMS, while ensuring backwards compatibility and interoperability with existing ERTMS equipment, is twofold:
- It will enable to minimise the number of physical balises on trackside in the long-term, thus reducing the initial capex costs, ongoing maintenance costs and preventing from vandalism.
- And the use of EGNSS signals combined with other sensors (e.g. inertial sensors, radar, odometer and cameras) may enable improved train positioning performance levels. For example, it might improve the positioning performance through enhanced odometry.
In addition, the rail sector is one of the key target transport domains where EGNSS can play a crucial role, bringing benefits for train localisation and other safety-critical rail applications.
The results will be added at a later stage.
Disclaimer: The project results represent the views of the consortium. They do not necessarily represent the views of the European Commission and they do not commit the Commission to implementing the results.