Optimising a Validation and Verification Strategy for Autonomous Software Systems

摘要

ESA’s Cosmic Vision objectives [1] unambiguously dictate a requirement for future science missions to enjoy an unprecedented degree of autonomy. Among the many challenges to be overcome in realising such a mission will be the need to evolve an appropriate software Verification and Validation (V&V) Strategy. This strategy will need to balance the demand for rigorous assurance against the need to take a pragmatic approach to programme and cost drivers. This paper has been developed to provide the space community with a robust baseline for discussion of the subject ‘Optimising a V&V Strategy for Autonomous Software Systems’ ? We refer to a realistic mission scenario based upon the Aurora ExoMars Rover Autonomous Navigation requirements. The challenges (expressed in the context of the V&V challenge) implicit in these requirements are summarised. ? We present a comprehensive summary description of contemporary candidate V&V tools and methodologies which could conceivably be deployed in support of the design and implementation of a solution to our selected scenario. It should be noted that our scenario is deliberately ‘loosely’ interpreted – it is used to guide our selection of candidate tools and in no way do we carry out an exhaustive analysis. These tools are described in a narrative review in terms of: ? The program and cost implications implicit in the deployment of these tools. ? The technical strengths and weakness of each tool? We propose a logical strategy for the selection and deployment of these tools, and make reference to what might be regarded as some strategic guidelines. ? We suggest development, with ESA, of a framework within which Autonomy Levels are defined, along with the associated process and functional objectives. This would be a similar approach to that adopted for Safety and Security. We anticipate that this paper will be a welcome contribution to debate in the fields of design and implementation of: ? Autonomous rendez-vous, Soft landing, Rover navigation guidance navigation and control. ? Emulation of the highly autonomous avionics systems of interplanetary spacecraft.