System Performance Characteristics of Centralized and Decentralized Air Traffic Separation Strategies

Abstract

This work investigates the system performance characteristics of centralized and decentralized strategies for air traffic separation. A centralized separation strategy and two decentralized separation strategies, implemented as constant-speed heading-change maneuvers, were simulated for randomized horizontal traffic patterns at various traffic densities. Human decision-making of controllers and pilots was not modeled. The centralized strategy represents a controller-oriented separation system generating co-ordinated resolution advisories that emphasize system-level stability. The decentralized strategies represent user-oriented separation systems generating independent resolution advisories that emphasize aircraft-level efficiency. Results from numerical experiments indicate that system stability and efficiency both degrade as traffic density increases, for all separation strategies. Although decentralized separation strategies can give rise to a significant domino effect, the corresponding system efficiency is comparable to that of a benchmark centralized strategy (designed to suppress the domino effect) at traffic densities below a threshold value that is significantly higher than current peak en route densities. Introducing even a limited stability emphasis (look-ahead capability) into the decentralized strategy can significantly reduce the domino effect and the resulting efficiency drop at very high traffic densities.