Terminal area trajectory synthesis for air traffic control automation

Research into air traffic control automation at Ames Research Center has led to the development of the Center-TRACON Automation System (CTAS). The component of CTAS used in the TRACON (i.e. terminal) area is the Final Approach Spacing Tool (FAST). FAST is designed to help air traffic controllers produce a safe, efficient, and expeditious flow of traffic. A key performance factor of the CTAS system is the ability to calculate accurate trajectories. The trajectories in CTAS for aircraft in both the terminal and en-route areas are calculated in the Trajectory Synthesizer (TS). This paper describes the trajectory generation algorithm in the terminal area and suggests some modifications that will improve its performance. Trajectories calculated from the current algorithm and a modified algorithm adapted from a validated en-route TS algorithm are compared. Both algorithms are very accurate (four to six percent error) when calculating estimated time of arrival compared to the actual time of arrival. The current algorithm has large (greater than 10 percent) differences from the validated en-route algorithm in calculating advisories, such as speed changes. This is acceptable for the current CTAS system which continually updates advisories, but will create problems for the future planned combination of CTAS with airborne flight management systems