Multi-aircraft Trajectory Optimization for Continuous Descent Arrivals

IT is a known fact that aircraft noise and fuel emissions are the most constraining factors for the growth of aviation. Continuous Descent Arrivals (CDAs) provide significant reductions in fuel consumption and noise footprint on the ground, by following idle thrust descent and eliminating low altitude leveling off. However, limitations such as unpredictability of the trajectory and separation management for CDAs prevent wide-spread implementation. The thesis focuses on overcoming some of these limitations. Optimal control theory is used to optimize the descent trajectory of the aircraft by using fuel and time as the performance index. The problem is formulated as amulti-phase optimal control and is solved by using a pseudospectral method. The theory is also the backbone of General Pseudospectral OPtimal Control Software (GPOPS). The main focus of the thesis is to enable multi-aircraft trajectory optimization for CDAs and ensure sufficient separation between all aircraft along the entire trajectory by implementing the separation algorithm. The possibility of using both distance based and the time based separation is explored in detail. It is demonstrated using Amsterdam Schiphol (AMS) airport’s real-time inbound flight data that it is feasible to apply the separation algorithm to separate aircraft along the entire lateral path while still being able to performCDAs during the peak and non-peak periods. All the limitations pertaining to the separation algorithmare analyzed and discussed in detail. By addressing some of these shortcomings, the simulation environment can be improved to bring itmore close to a real-time scenario. Although a lot of other factors have to be considered for a practical wide-spread implementation, success of this method will result in the aircraft trajectory being more predictable to the ground controller, effectively addressing one of the major shortcomings of CDAs. On a more important note, the success of this method will also result in reduced noise footprint and fuel consumption by aircraft, benefiting both the environment and airlines.Aerospace EngineeringControl & Operation