Prototype Conflict Alerting System for Free Flight

The development of a prototype alerting system for a conceptual free eight 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 coneict probability as a function of intruder position, heading, and speed, as determined through a datalink between aircraft. Additionally, the probability of coneict along potential avoidance trajectories is used to indicate whether adequate space is available to resolve a coneict. Intruder intent information, e.g., e ight plan, is not included in the modelbutcould beused toreducetheuncertaintyintheprojected trajectory. Fouralertstagesaredeenedbasedon the probability of cone ict and on the avoidance maneuvers that are availableto thee ight crew. Preliminary results from numerical evaluations and from a piloted simulator study at NASA Ames Research Center are summarized.