This paper aims at presenting the research work of formalisation of dependability-related localisation attributes within the framework of the European project QualiSaR. Processing of natural language is used with the aim of creating a structure of dependability and safety-related terms for evaluating automated systems in general and satellite positioning performances more specifically. The attribute hierarchy developed is managed by the help of iglos, an NLP tool (Natural Language Processing). The standardisation objective of this research work consists of making a proposal for an international standard, which describes satellite-based system quality criteria understandable by transportation communities.