Assessment of Galileo Key Dependability and Safety Parameters: A Simulation-Based Approach

Bertil A. Oving

Abstract:	For Galileo, a need for means for analyzing performance of the navigation system with focus on dependability (reliability, availability and maintainability) and - to some extend - safety aspects has been identified by the European Space Agency (ESA). NLR has supported Galileo Industries (GaIn) with dependability analyses, such as Functional Hazard Analysis (FHA), Failure Mode Effect and Criticality Analysis (FMECA) and Fault Tree Analysis (FTA), on Galileo system level. The above-mentioned analysis methods each are useful for a particular problem area. They, however, also have their limitations. Most important drawback is that they are not capable of handling complex, dynamic systems, such as Galileo. For instance, a dependability characteristic for the time-to-alert simply requires the use of dynamic simulations where the time is an explicit parameter. To target the dependability objectives, a modeling and simulation concept based on Dynamically Colored Petri Nets (DCPN) is introduced in this paper to support dependability analysis on stochastic failures and statistic analysis in relation to top-level hazards. This tool is considered to provide an important, if not essential, contribution to the assessment of Galileo as a system with among others- safety critical user communities.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	1307 - 1314
Cite this article:	Oving, Bertil A., "Assessment of Galileo Key Dependability and Safety Parameters: A Simulation-Based Approach," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 1307-1314.
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