Multi-Objective Optimization of CDO Trajectory in a Flexible Airspace Structure

Continuous Descent Operations (CDO) can significantly reduce fuel burn and noise impact by keeping arriving aircraft at their cruise altitude for longer and then having a continuous descent at near-idle thrust with no level-flight segments. Designing concise, efficient and flexible arrival routes for high-level automation in generating conflict-free and economical trajectories, is a cornerstone for fully achieving CDO in high-density traffic scenarios. In this research, inspired by the Point Merge (PM), we design the Inverted Crown-Shaped Arrival Airspace (ICSAA) and its operational procedures in the terminal area to deliver Omni-directional CDO. In order to generate alternative optimal conflict-free trajectories for upcoming aircraft in an efficient manner, we established a multi-objective trajectory optimization model solved by Non-dominated Sorting Genetic Algorithm with Elitist Strategy (NSGA-Ⅱ). The Parote solutions of minimal fuel consumption and trip time were achieved in single aircraft and highly complex multi-aircraft scenarios. Results validated the effectiveness and acceptable computational cost (less than 5min in extremely high-density scenarios) of proposed algorithm. In addition, ICSAA seems to be a promising structure that could promote the application of CDO for its operational flexibility and capacity.