Optimal Aircraft Conflict Resolution in Free Flight Using Simulated Annealing and Genetic Alogorithms

Abstract

Limitations of the existing Air Traffic Control (ATC) systems lead to problems like congestion in airspace, delays and improper detection of conflicts between the aircraft, and their resolution. The current trend is to shift from this centralized system to an autonomous one in which the assurance of separation depends on the aircraft themselves. This concept is termed as Free Flight. In the present study we deal with the optimal resolution of conflicts between three aircraft in level flight on intersecting routes. A geometric approach has been employed to resolve the conflicts using only speed changes of the aircraft. Three objective functions are proposed to obtain the best conflict free trajectories, which penalize the aircraft for the number of speed changes and/or the extent of the speed changes. Using stochastic methods for optimization viz. Simulated Annealing (SA) and Genetic Algorithms (GA), optimal conflict avoidance speed changes have been obtained. The resulting speed change sequences for the aircraft generated using SA and GA exhibit comparable trends and values. The solutions obtained are optimal not only in the context of the magnitude of speed change but also in the number of deviations from the original speed values.