Research On Aircraft Conflict Detection And Resolution Under Four-dimensional Trajectory-based Operation

Aviation safety is the main task of air traffic management.In the current air traffic management system,aircraft separation maintenance task is performed by ground controllers through real-time monitoring and adjustment of aircraft state.At present,many scholars have conducted a lot of research on aircraft conf lict detection and resolution,and aircraft safety separation maintenance has formed a relatively systematic theory.At present,the next generation air traffic management system proposes the concept of four-dimensional trajectory-based operation.By sharing the four-dimensional aircraft trajectory in the whole air traffic system,it promotes collaborative decision-making among various parties including air traffic controller,airline and aircraft,and thus accurately manage and control aircraft trajectory,improve the effectiveness of spatial-temporal airspace resources.Under the four-dimensional trajectory-based operation,the task of aircraft separation maintenance will be transferred from the ground control to the aircraft crew,and the aircraft pilot will bear the main responsibility for maintaining the aircraft's safe separation.Thus,the freedom of aircraft pilots' autonomous trajectory planning increases,and poses new challenges to aircraft trajectory prediction,conflict detection and resolution.To solve the impact of the pilot intent uncertainty on aircraft trajectory planning under the next generation air traffic management system,this paper proposes the concept of the aircraft potential motion space based on time geography concept.Moreover,it studies the probabilistic trajectory prediction,conflict detection,and conflict resolution methods,and form a systematic aircraft probabilistic conflict detection and resolution method suitable for the next generation air traffic management systems.The achievement of this study is able to provide theoretical guidance for the implementation of the next generation air traffic management automation systems.Based on the in-depth exploration of the operation mode of the next generation air traffic management system,the applicability of the time geography concept to describe aircraft motion mode is analyzed.The concept and measurement method of the aircraft potential motion space is proposed to describe the space-time position that the aircraft may reach under the limitation of the four-dimensional flight plan.A framework and operational process for aircraft conflict detection and resolution system based on four-dimensional trajectory operation is proposed.Considering the pilot intent and the constraints of potential motion space,a probabilistic prediction of the future flight trajectory of the aircraft is achieved by modeling the visiting probability distribution within the potential motion space.By analyzing the factors affecting the potential motion space and the visiting probability distribution of the aircraft,it provides theoretical support for the formulation and adjustment of the four-dimensional flight plan.Based on the description of the potential motion space of the aircraft and the quantification of the visiting probability distribution of the aircraft,this paper propose corresponding conflict identification and conflicts probability estimation method to the three aircraft conflict scenarios: aircraft conflict with surrounding airspace,conflict between aircraft pairs,and multi-aircraft conflict,respectively.By analyzing the factors affecting the aircraft conflict probability,it provides a quantitative basis for the formulation and adjustment of the four-dimensional flight plan.Besides,the conflict risk assessment method is proposed and the theoretical framework of the conflict early warning system is established.This paper propose a strategical conflict resolution strategy based on flight plan adjustment.Based on the analysis of the objectives and constraints of aircraft trajectory planning under the four-dimensional trajectory-based operation,the ant colony algorithm is improved to make it suitable for the multi-aircraft conflict avoidance trajectory planning in the complex environment under the next generation conlict avoidance system.The validity of the theoretical aircraft conflict detection and resolution method is verified by a numerical simulation.The paper follows the overall research idea of "problem discovery-system proposed-theoretical research-simulation verification",aiming at constructing aircraft conflict detection and resolution methods applicable to the next generation air transportation system,and enriching the theoretical system of aircraft conflict avoidance,and providing theoretical guidance for the implementation of the next generation air transport management system.The proposed aircraft conflict detection and resolution framework can not only guide the development and improvement of aircraft conflict detection and resolution systems,but also help aircraft conflict resolution transit from tactical passive resolution to strategic active avoidance.Besides,it can also provide strategical support for air traffic control department in formulating and adjusting flight plans,providing conflict warning and conflict resolution decisions,as well as balancing airspace traffic volume,and thus promote coordinated air traffic management,ensure air traffic safety,and improve air transportation efficiency.