A Flight Trajectory Model for a Pc-based Airspace Analysis Tool

This paper documents a method for rapid generation of aircraft flight trajectories. Rapid generation of flight trajectories is important for simulation models of air traffic that involve large numbers of aircraft, especially if complex interdependencies exist between flights and short simulation run times are required. Among the many aircraft trajectory models that have been developed, one generally observes a tradeoff between modeling detail provided by the model and its computational speed. Models that provide detailed trajectories typically require simulation run times on the order of one second per trajectory. Faster models often trade modeling detail for greater simulation speed. The model presented here was developed for applications that require simulation speeds on the order of one thousand trajectories per second and modeling detail to simulate typical flight operations in airspace close to major airports known as Terminal Radar Approach Control (TRACON) airspace. The computational speed of the model results from a discrete event simulation approach. It generates continuous speed and altitude profiles based on a small set of 31 trajectory parameters that are defined for each aircraft type based on aircraft performance data. The model provides detailed flight trajectories by synchronizing the discrete events that define model trajectories with significant events of typical flight operations and methodically adjusting the size of variable simulation time steps. The time steps, chosen in accordance with common piloting procedures and flight events, are categorized in ten flight phases. This paper introduces the concept of flight phases to group flight events and their associated trajectory parameters and presents a discrete-event flight trajectory model that is based on aircraft performance and centered on piloting procedures.