Analysing Sanity of Requirements for Avionics Systems (Preliminary Version)
This work addresses the need for improved requirement clarity and correctness in safety-critical avionics systems, representing an incremental advancement in formal verification methods.
The paper tackles the problem of detecting flaws in formalized software requirements for avionics systems by proposing new sanity checking techniques, including consistency and redundancy checking that identify all inconsistencies and a semi-automatic completeness evaluation, with experimental evaluation in an industrial environment and a case study on an aeroplane control system.
In the last decade it became a common practice to formalise software requirements to improve the clarity of users' expectations. In this work we build on the fact that functional requirements can be expressed in temporal logic and we propose new sanity checking techniques that automatically detect flaws and suggest improvements of given requirements. Specifically, we describe and experimentally evaluate approaches to consistency and redundancy checking that identify all inconsistencies and pinpoint their exact source (the smallest inconsistent set). We further report on the experience obtained from employing the consistency and redundancy checking in an industrial environment. To complete the sanity checking we also describe a semi-automatic completeness evaluation that can assess the coverage of user requirements and suggest missing properties the user might have wanted to formulate. The usefulness of our completeness evaluation is demonstrated in a case study of an aeroplane control system.