Prototype Con ict Alerting System for Free Flight

The development of a prototype alerting system for a conceptual free  ight environment is discussed. The alerting logic is based on a probabilistic model of aircraft sensor and trajectory uncertainties that need not be Gaussian distributions. Monte Carlo simulations are used over a range of encounter situations to estimate con ict probability as a function of intruder position, heading, and speed, as determined through a datalink between aircraft. Additionally, the probability of con ict along potential avoidance trajectories is used to indicate whether adequate space is available to resolve a con ict. Intruder intent information, e.g.,  ight plan, is not included in the model but could be used to reduce the uncertainty in the projected trajectory. Four alert stages are deŽ ned based on the probability of con ict and on the avoidance maneuvers that are available to the  ight crew. Preliminary results from numerical evaluations and from a piloted simulator study at NASA Ames Research Center are summarized.