Intelligent executive guidance agent for general aviation aircraft under free flight

Abstract

Conflict detection and resolution is a critical capability for the realization of free flight, a new concept of air traffic management that allows pilots to select their own flight paths and airspeeds in real time. A particularly demanding situation within this environment occurs when multiple traffic and weather conflicts arise simultaneously. A solution that forms the basis for this thesis is an agent based hierarchical system that attempts to provide optimal and conflict free flight path guidance in these multiple conflict situations. An intelligent executive guidance agent, acting as a high-level arbitrator, receives guidance information from a previously designed lower-level weather agent and a traffic detection and collision avoidance agent. When the flight path guidance from the two-lower level agents conflicts, the executive agent arbitrates by considering the spatial and temporal characteristics of the conflicting guidance. It classifies them as either tactical or strategic in nature, and then prioritizes them according to a pre-defined rule base of conflict priorities. The arbitration function thus acts as a fuzzy controller, and gradually switches the guidance between the weather agent and traffic agent, providing conflict free flight path guidance, as the aircraft flies in and out of dangerous regions. Results of test cases presented in the thesis demonstrate that the approach and algorithm can successfully resolve combined weather and traffic conflicts in real-time, subject to realistic imposed constraints. The severity of conflicting flight paths was managed within acceptable levels, and the ultimate recommended conflict free flight path is generally between those originally proposed by the weather and traffic agents. The algorithm does not exhibit any critical failures during cases tested, and proved robust and reliable. The proposed agent based hierarchical system, when integrated with a simplified flight management system coupled with a heading command and hold autopilot, offers an effective and reliable guidance and navigation system for generating safe, alternate flight paths in conflict situations.