Despite several GNSS based solution have been proposed, to modernize the ERTMS-ETCS European Train Control System, till now a certifiable solution compliant with the CELENEC SIL-4 requirements and accepted by the rail stake-holders does not exist. In this paper we present a roadmap for the the development of GNSS applications as a contribution to the validation and certification process. The achievement of a certifiable solution that can be used in the rail domain in the shortest time as possible will have to re-use the expertise of the aviation sector for safety of life applications. A pillar of our roadmap is the Rail Test Range deployed in the Sardinia Island, in Italy, in the framework of the ERSAT project. Considering the importance of the performance assessment in the certification process, particular attention is devoted in the paper to the analytical evaluation of the impact of the SIS hazards on the estimation error of the train separation distance, and then on Integrity (in terms of Protection Levels and Tolerable Hazard Rate) and Availability, when a variable block length management is introduced. Previous models considered just one train at time.
Neri, A., Rispoli, F., & Salvatori, P. (2015). The Perspective of Adopting the GNSS for the Evolution of the European Train Control System (ERTMS): A Roadmap for a Standardized and Certifiable Platform. In Proceedings of the 28th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2015) (pp.542-552).