Advanced Design Tools for Evaluating Fault-Tolerant Systems

As mission critical avionics systems increase in complexity, the evaluation of their performance and reliability will become more difficult. We propose to select and to integrate a group of reliability and performance analysis tools, specifically designed to handle the fault-tolerant operational aspects of the next generation avionics architectures. These tools will support both hardware and software evaluation and will be developed in the Ada programming language. The reliability analysis will use a customized CARMS program (computer-aided rate modelling and simulation), with an interactive graphical and spreadsheet interface. The performance analysis tools will use Petri net analysis and Monte Carlo simulation methods. An embedded Ada expert system will help to guide the proper method selection and to control the evaluation and sensitivity analyses. Personal computers will be used for the initial prototyping and simulation. We expect that the availability of these tools will permit earlier evaluation of the effectiveness of the selected architecture, and thus avoid the need for later changes in the design. Our earlier experience with the PAVE PILLAR avionics architecture, embedded expert system design, and fault-tolerant system analysis and simulation methods will provide a sound foundation for this project.