Airport gate assignment optimization with operational safety constraints

This thesis presents an original research on solving the airport gate assignment problem with the practical constraints and considerations. The aim of the PhD work is to develop effective and efficient methods for assigning flights to gates so as to achieve smooth ground operations. The first task of the PhD study focuses on improving robust gate assignment by minimizing the dispersion of gate idle time periods, with the consideration of adding operational safety constraints to avoid the potential hazard of aircraft collision caused by gate apron operational conflicts. Then, a flexible gate assignment strategy is proposed allowing the use of gate pairs to accommodate large aircraft, to solve the capacity saturation problem for early-built airports under the over-constrained scenario. The flexible gate assignment problem is formulated as an integer programming model with an objective of minimizing remote assignments and aircraft-gate mismatch. The improvements of applying flexible gate assignment strategy have been demonstrated by massive testing on examples and realistic flight schedule data from two hub airports as well. However, it takes very long to solve the model optimally. Therefore, different methods for decomposing the large scale problem have been applied to solve the problem efficiently. A dynamic approach in dealing with the uncertainties of actual flight information is implemented under a rolling horizon framework. The results provide feasible and efficient gate reassignment plans for different deviations of scheduled flight information.