Applying simulation to the design and performance evaluation of integrated modular avionics

For the last few years, civil airborne equipment systems complexity never stops growing. This is due to addition of new functions, stemmed from technological progress, but above ail, architecture of actual avionics systems don't meet evolution criteria. Mastering such an increasing complexity needs new architectural concepts mainly based on modular design, generic resources and multiplexed communication buses. These new architectures, such as Integrated Modular Avionics (IMA) architecture, rely on the definition of standardized hardware and software. Like many others domains, complexity of IMA real-time and modular architecture forces organizations to look to new design tools, enabling platform designer, applications developer and system integrator to describe and evaluate different implementation choices. First stage consists in modeling an avionics system as a whole (hardware and software). Modeling allows expression of real-time characteristics of applications and also modular description of the target architecture. Architecture components behavior is described by a dynamic model allowing simulation of the IMA system. Second stage consists in simulating applications execution on the IMA platform to validate the system by verification of some properties and by performance analysis. Timing charts are used to display the sequence of tasks execution, communication, and operating systems calls. They show how the software architecture will fit within the timing constraints and identify any system architecture design weakness.