Improved Trajectory Prediction for Air Traffic Management by Simulation of Guidance Logic and Inferred Aircraft Intent using Existing Data-Link Technology

Abstract

§Trajectory Predictors (TPs) employed within Air Traffic Management (ATM) systems often do not have access to unambiguous aircraft intent information and need to make many assumptions on how the aircraft will operate. Especially in the descent phase of flight this large uncertainty makes it difficult for air traffic controllers to allow for efficient operations while providing separation and maintaining runway throughput. Future Air Navigation Systems (FANS) technology provides an existing means for Air Traffic Control (ATC) to extract the trajectory computed by the aircraft’s Flight Management System (FMS). While a logical choice appears for ATC to make direct use of this FMS derived trajectory, there are many arguments against this approach. The research presented in this paper combines data extracted from the FMS via FANS technology and data available to the ATM system to infer aircraft intent appropriate to the active aircraft guidance strategy. This methodology was applied to a sample of 413 flights performed by FANS-equipped Boeing 737-800 aircraft that conducted an unimpeded descent into Melbourne International Airport (Australia). Trajectories were predicted when the aircraft was about 20-40 nautical miles prior to Top of Descent (TOD). The resulting predictions were compared to those made at the same point in time by the aircraft’s FMS and by the TP employed by The Australian Advanced Air Traffic System (TAAATS). Only 12% of the TAAATS predictions for the Terminal Area entry were within the set requirement of 30 seconds accuracy. The aircraft’s FMS is much better with 92% containment. The proposed methodology proved to be even better with 97% containment. The improvement in trajectory prediction accuracy reported in this paper is solely achieved through the use of data-link systems that are operationally available today and does not require any new equipment to be fitted to aircraft.