Poliak, J.; Hänsel, F.; Marais, J.:
First steps towards GALILEO validation for railways.
Proceedings of the International Symposium on Certification of GNSS Systems & Services - Cergal 2007, Braunschweig, April 2007.


Satellite-based positioning systems are promising solutions for the future of railways as they can satisfy most of the requirements because of independence to national systems or because they are embedded solutions instead of infrastructure equipments. The main challenge for a good penetration of the domain will be to prove that performance answer to railway requirements in real railway conditions of use in particular for safety related applications especially on low density secondary lines.

In the first part of this paper, we will present a state of the art that compares railway requirements for positioning and Galileo specifications. Both communities are using their own definitions and their own language. In order to help them to understand themselves and make railways accept Galileo as a reliable system, we will describe the two certifications usages. The second part of the paper will concentrate on the proposal of a methodology in order to validate the GALILEO performance in a real railway environment. The work to perform will be written in the context of the already existing GALILEO certification process. From the railway point of view, a GALILEO receiver will be used as an already certified equipment. However, what will have to be validated is the good reception in typical railway environments. These typical environments will have to be defined and described. This work will use the PREDISSAT tool developed at INRETS that analyses reception conditions extracted from a video record along lines. The iVA tool, CaRail will allow us to compare measurements to an experimental reference platform. The combination of both tools will give some important information for precise performance analyses. This work will be performed in close contact with railway managers via the UIC working group. Their support is obvious to propose clear answers, and scenarios as close as possible from the real conditions of use. The certification processes will have to be explained in order to convince users and find a common language between the two communities, part of a common chain.