A Model-Based Approach Centred on Operational Procedures for the Development of Reliable and Usable Ground Segment Systems

Abstract

This paper deals with technologies, methods and tools for improving space operations. The work presented here builds upon previous research and development activities carried out on multimodal interaction techniques for ground segment systems. Within this project we defined and exploited formal description techniques for both the interactive part of the ground segment system (GSS) and the functional part. We report here an extension to the approach which encompasses two additional elements: operational procedures and operator training. 3 (among others) for the description of operational procedures). Furthermore, most of these two principal development processes are heavily based on documents (MS Word, Excel etc). Our contribution places the model-based approach at the centre of the development process. It is based on the use of the technique developed in 4 and 5 for the modelling of system elements (including satellite database, operational procedures description and the related GSS). The user-related elements are described using other modelling techniques (more adequate with respect to their idiosyncratic nature) such as task models 6 for describing operator activities. An important project objective lies in the definition of methods and tools supporting the cross verification of models i.e. the current system behaviour (both as described in the operational procedures and in the GSS) is compatible with the operators' behaviours and is in line with the training programme that has been designed and performed. Indeed, even if these various models seem, at first, independent, they correspond in fact to different views of the same complex socio-technical system. The study is concerned with the mapping of these 3 types of models with an aim of ensuring both their coherence (ensuring information that appears in several models is compatible) and their completeness (ensuring that all pertinent information is included in the model). This paper presents the application of the method on a typical command and control application of a Ground Segment System (GSS) at CNES. For confidentiality reasons, the exact satellite studied will not be cited in this paper. We emphasise the extensions to the previous approach in order to handle the specificities of GSS as well as the benefits in terms of cost reductions and reliability improvement. The following section II, presents a state of the art on model-based and formal approaches to training. Section III introduces our model-based approach for improving operator training while section IV introduces the case study based on the sending of a hazardous telecommand within a GSS. Section V presents our training approach and visions for safety, followed by sections VI and VII describing the system model (command and control application