Comparison of Trajectory Synthesis Algorithms for Monitoring Final Approach Compression

Abstract

This study analyzes the performance of aircraft in-trail separation monitoring algorithms using 480,000 flights on the final approach courses of 25 major airports in the National Airspace System. While compression monitoring is expected to help air traffic controllers achieve and maintain higher arrival rates, the trajectory prediction requirements for it are not well understood. To address this gap, analytical trajectories were constructed from flight plan and track data for flights arriving at the 14 major and 11 satellite airports of the 8 busiest terminal areas. Three types of analytical trajectory models were compared. These trajectory models were a constant speed model, and two heuristic deceleration models. The trajectory prediction accuracy and separation prediction accuracy of each of these models were calculated for all aircraft pairs along the final approach course. The results were used to rank the overall performance of the various trajectory models in terms of the true and false alerts by the compression monitoring algorithms. The best performing trajectory model enforced the landing speed constraint, used a landing speed based upon weight class, and did not adjust the landing speed by airport elevation. All of the trajectory models exhibited significantly more false alarms when excess in-trail separation was less than 0.5 nm.