Validation and Optimization of a non-cooperative Sense and Avoid System

Abstract: To complement the established cooperative S&A system named TCAS which uses vertical avoid trajectories, Airbus Defence and Space developed a non-cooperative S&A System which favors lateral avoidance maneuvers. For this non-cooperative system, intruder aircraft are detected by radar before five different avoid trajectories are computed of which the best one is chosen. The presented work consists of the validation and optimization of this S&A System by simulating many different aircraft encounter scenarios. For validation purposes, the probability tables provided by the European Encounter Model (EEM) were used to compute the most probable aircraft encounters. As a result of the optimization process, the number of Near Mid-Air Collisions (NMACs) could be reduced significantly, and flight route constraints were included. More than 85,000 simulations were carried out to assess the performance of the system. The simulations revealed that the performance requirement for the S&A System, namely being at least as good as a human on-board pilot, could be fulfilled for encounter scenarios in which the ownship was flying level.