Discrete Speed in Vertical Flight Planning

Vertical flight planning concerns assigning optimal cruise altitude and speed to each trajectory-composing segment, such that the fuel consumption is minimized, and the arrival time constraints are satisfied. The previous work that assigns continuous speed to each segment leads to prohibitively long computation time. In this work, we propose a mixed integer linear programming model that assigns discrete speed. In particular, an all-but-one speed discretization scheme is found to scale well with problem size with only negligible objective deviation from using continuous speed. Extensive experiments with real-world instances have shown the practical effectiveness and feasibility of the proposed speed discretization approach.