Trajectory Synthesis for Air Traffic Automation

Trajectory synthesis algorithms that are key to the center ‐terminal radar approach control automation system (CTAS) developed at NASA Ames Research Center for air trafe c control automation are discussed. CTAS generates computer advisories based on synthesized trajectories that help controllers to produce a safe, efe cient, and expeditious e ow of trafe c over the extended terminal area. Trajectories are synthesized from initial aircraft positionsto ametering e x orrunway, depending on airspace.Thehorizontal pathisconstructed e rstfrom specie ed waypoints using straight lines and constant-radius turns. The vertical trajectory is divided into a series of e ight segments. Three types of e ight proe les are dee ned by connecting selected segments in a predetermined order: fast, nominal, and slow. Each proe lecan produce a certain rangeof arrivaltimes. A second-order Runge ‐Kutta scheme is used for integrating a set of simplie ed point-mass equations to generate vertical trajectories. Then, an iterative scheme is employed to determine the speed that meets a specie ed arrival time. Several special case trajectories are also explained. Two e ight scenarios are used to illustrate the use of trajectory synthesis algorithms.