Comparison of Aircraft Trajectory Predictor Capabilities and Impacts on Automation Interoperability

The U.S. NextGen air transportation system is expected to dramatically increase the amount of aircraft trajectory data shared between automation systems operating within the National Airspace System. To illustrate the strengths, weaknesses, and issues of sharing different types of trajectory data, lessons learned from previous work in comparing the capabilities of disparate trajectory predictors (TPs) was leveraged. An abstracted model of top-level internal TP processing, developed to compare the trajectory prediction capabilities of five state-of-the-art TPs, was presented. Detailed results comparing TP constraints, behavior models and math models were presented to illustrate how different TP modeling decisions create significant differences between TP capabilities. The abstracted top-level internal TP processing model was then used to discuss the potential effectiveness of two existing data sharing approaches, intent and 4D trajectory data sharing, and to propose a new approach, behavior model data sharing. Finally, an arrival aircraft conflict scenario used the TP comparison results to illustrate detailed examples of issues that can arise when sharing intent or 4D trajectory data between airborne FMS and ground-based separation assurance automation. The paper concludes that none of the three trajectory data sharing approaches is expected to be the best at achieving NAS automation interoperability under all possible situations and provides motivation for performing future, formal experiments to study the applicability of different data sharing approaches.