Hybrid-system simulation for national airspace system safety analysis

Analysis of large, complex systems requires simulations of hybrid-system dy namics (i.e., dynamics best described by a combination of continuous-time a nd discrete-event models) and their interactions. To serve as valuable rese arch tools, such simulations must also be computationally efficient, readil y modifiable, capable of simulating systems using models of a wide range of fidelity, and easily reconfigurable to simulate parts or all of the system of interest. The development of a simulation architecture meeting these cr iteria is described. Issues with its development are described conceptually , and its application to safety analysis of the national airspace system is discussed. In particular, an object-oriented approach to hybrid-system sim ulation is detailed, and computationally efficient methods of updating the simulation are described and compared. New asynchronous with resynchronizat ion methods of timing individual objects are applied in an example, demonst rating a significant improvement in simulation efficiency.