Specification of sampled data system timing parameters for hard-real-time avionics systems

The specification of hard-real-time (HRT) parameters involves the discipline of sampled data control theory and consideration of the practical capabilities of avionics processor technology. Historically the process has evolved through phases of rate-scrubbing and algorithm modifications (i.e. smoothing, filtering) and is a compromise between the simplicity of high performance prediction from high rate selection and practical processing capability. The specification process is addressed in this paper and guidelines are derived on the basis of sampled data theory. These guidelines introduce scientific discipline into what has historically been an iterative refinement process and insures that RunTime Environment (RTE) requirements are not over specified