Determination and visualization of uncertainties in 4D-trajectory prediction

Abstract

Future air traffic management relies on trajectory forecasting for higher safety, efficiency and environmental friendliness. The quality of trajectory predictions is subject to errors from a variety of sources. These errors in parameters cause inaccuracies in the calculations of the flight trajectories. Therefore the implementation of the future trajectory-based air traffic management requires decision support tools as well as reporting tools to analyze and predict uncertainties in actual flight paths. The Institute of Flight Guidance of the German Aerospace Center (DLR) is one of the leading establishments in the field of air traffic management and conducts research with focus on trajectories based on simulation systems. These simulations are strongly focused on generating scientific data which are evaluated subsequent to the campaign. To be able to evaluate the simulations, we developed a concept for the calculation and visualization of the trajectory prediction uncertainty. The concept is implemented as a component into DLR’s evaluation environment “Extensible Workflow Management for Simulations (EWMS) and validated using simulation scenarios. The most important factors for trajectory prediction, which are analyzed for the theoretical concept, are meteorological parameters (wind, temperature), aircraft performance (weight, speed) and navigation performance. Finally, the study applies error analysis to a sample collection of over 2,000 flights under various environmental conditions. The uncertainty of an aircraft position can be described in terms of temporal or spatial metrics by three-dimensional ellipsoids. For the processing in computer scientific systems the error data are classified and the possibilities of visualization in diagrams and geo systems are evaluated. For the representation of scalar errors charts generated by JFreeChart-Tool are suitable. NASA World Wind is used for the geographical visualization of trajectories and their errors. The concept implemented in EWMS enables the user to load fast-time simulation results from the TrafficSim-tool, calculate and compare trajectory uncertainties, and to visualize the results in diagrams as well as in the 3D NASA World Wind environment. The developed calculation and visualization routines provide the ability to analyze trajectory-based air traffic management concepts, as well as support decision-making in air traffic control.