Lu, D.; Grasso Toro, F.; Schnieder, E.:
Hazard Analysis of a Satellite-based Localisation Unit for Train.
WCRR 2013 - World Congress on Railway Research, Sydney, Australien, November 2013.


GNSS (Global Navigation Satellite Systems) have been in a struggle battle. GPS (Global Positioning System), GLONASS, GALILEO, BEIDOU these four GNSS are either rolling out or ready for civil applications such as road transportation and so on. To achieve more detailed restricted and more specific safety-related applications by the use of GNSS, the accreditation and certification process have to implement on any GNSS applications. Thus, the analysis of the hazards for the Satellite-based Localisation Unit for Train (SaLUT) has to be fulfilled, since SaLUT is a safety-related localisation unit for the railway train control system. To analysis the hazards, a formal method should be applied. Among the popular formal methods, Petri net is chosen to model SaLUT behaviours. Besides, the stochastic Petri net (SPN) can model the system behaviour with probability distributions on each event. For SPN analysis, the certain parameters can be tested and generated from the real data which was collected in High Tatra Mountains in Slovakia in 2008 by DemoOrt project. With the data, the performance of GNSS in this specific railway line can be evaluated, hazard mode can be identified and the corresponding hazard rate can be estimated. Based on the model and data, the methodology for analysing the hazard and corresponding hazard rate of GNSS for railway safety-related applications is proposed through the combination of Petri net and reliability block diagram interpretation.