21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-6.2.1

A SOFT DYNAMIC PROGRAMMING APPROACH FOR ON-LINE AIRCRAFT 4D-TRAJECTORY OPTIMIZATION

Hagelauer P.
Aerospatiale, France

Keywords: aircraft 4d-trajectory optimization

During the last decade, Flight Management Systems (FMS) have been introduced on board modem aircraft to reduce operational costs, and flight profiles have been optimized in order to minimize fuel and time-related costs. Today, the integration of next generation Flight Management Systems in the future air traffic management (ATM) environment requires the development of new capabilities and among them, on-line real-time 4D trajectory generation has become mandatory. This paper presents a method based on dynamic programming to generate optimal 4D-trajectories. This approach is applied to a partial formulation of the problem which deals with what is accomplished today by empirical means on modem transport aircraft. Numerical simulations, which consider realistic case studies for an AIRBUS A340 aircraft, show that this approach leads to a reduction in global costs and that computer time is compatible with on-board application requirements. Considering the future evolution of air navigation requirements (FANS, Free Flight concept), a more complex formulation of the optimization problem, which includes multiple and window-type time constraints, is considered. The previous approach is extended leading to an increase in the solution search space which is then compensated by adding heuristics based on specialized knowledge and by using neural networks to accelerate aircraft performance calculations.

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