Nets-within-nets to model innovative space system architectures

Abstract

This paper focuses on a nets-within-nets approach to model, simulate and evaluate innovative space system architectures. Indeed, as military Earth observation space systems are more and more subjected to a wide spectrum of emerging space threats and attacks, it is necessary to devise new architectures and to assess their performance and their threat-tolerance. We will consider networked constellations of autonomous microsatellites - or Autonomous Networked Constellations (ANCs) - in which several heterogeneous interacting entities (satellites and ground stations), ruled by the space dynamics laws, rely on resources (functions or sub-systems) to achieve the overall Earth observation mission. Petri nets are well adapted for modeling ANCs as they feature event-triggered state changes and concurrent communication accesses. The ANC model is based on Renew 2.2 which we use to deal with top-down, bottom-up and horizontal synchronizations so as to represent state propagations from an entity to its nested resources and vice-versa, and from an entity to another one. A model and simulation of a simple ANC subjected to threats are given and discussed. © 2012 Springer-Verlag.