Hänsel, F.; May, J.; Poliak, J.; Becker, U.; Schnieder, E.:
Satellite Based Low Cost Train Protection System for Secondary Railways Lines.
Proceedings of the International Symposium on Certification of GNSS Systems & Services - Cergal 2007, April 2007.


Present localisation methods in railway systems are based on trackside located technical equipment i.e. axle counters, track circuits etc. At best these equipments provide train position information with an accuracy of several 100 m, which suffice for existing protection systems but reduces the availability respectively track capacity. Furthermore these devices acquire enormous maintenance effort besides a poor adaptability to changes or innovative operational requirements. For modern railway protection systems as the ERTMS/ETCSystem for example a continuous – and if possible autonomous – vehicle localisation in connection with a train integrity validation with high accuracy, availability and safety is required in order to provide a modern and flexible train operation also in the future. But also in order to increase the track capacity on low-equipped secondary railway lines with in general little traffic a vehicle autonomous localisation is necessary to assure train protection with low costs. The basic idea of a project called “DemoOrt” consists of developing a platform with an onboard autonomous and vehicle autonomous technology which also integrates and uses available as well as innovative technologies whereas the main focus is on satellite based positioning (GPS, GALILEO and EGNOS). The system is designed to be highly available and will be provided for applications in safety matters bearing safety responsibility. The Paper will show a localisation system with its components as well as the existing approach for the hazard analysis using formal techniques required by the railway safety standards for a protection system on low density secondary lines.