טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentGekht Daphna Olga
SubjectTactical Re-planning Algorithms for 4D Contracts in
Air-Traffic Control
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Moshe Idan
Full Thesis textFull thesis text - English Version


Abstract

Continuous growth in the air traffic density, mainly over Europe and the U.S., raises serious concerns about the ability of the current air traffic control system to accommodate the predicted load of aircraft. Current air traffic control system, mainly based on human controllers, is reaching its limits. In order to meet the traffic demand predictions, a development of new concepts in air traffic control is required. Those concepts should be more automated and rely less on human involvement.


One of such new concepts involves air-traffic management using four dimensional (4D) contracts. According to this approach, all the air traffic is pre-planned and optimized in advance in four dimensions: 3D location and time. Before take-off each aircraft is provided with a flyable conflict-free flight plan that accounts for aircraft performance, airline requirements, weather forecast, and any other relevant air traffic aspects. The flight plan, called a 4D contract, consists of a 4D bone trajectory and margins. The margins are introduced in order to keep sufficient separation between the airborne aircraft and to provide the guidance and control systems of the aircraft with some freedom when following those contracts.


During flight, the aircraft is responsible to comply with its 4D contract. Whether, for any reason, the aircraft cannot respect its prescribed 4D contract, it has to request a new contract from the ground air traffic management system. Since at this stage the aircraft are already airborne, the new 4D contracts should be re-computed in a matter of minutes.


In this work an algorithm for re-planning of the 4D contracts within the mentioned time limitations is developed. The update task is treated as an optimization problem minimizing the influence of the contract change on the surrounding traffic. To increase the efficiency of the algorithm, only the relevant neighboring traffic is considered during the re-planning process. The proposed re-planning algorithm is described in this thesis and numerical examples are used to demonstrate its performance.