Analysis of the Monotonic Lagrangian Grid as an Air Traffic Simulation Tool

Abstract

A new research platform, the Air Traffic Monotonic Lagrangian Grid, has been developed to serve as a simulation tool for easy and fast testing of various air traffic system concepts. The underlying algorithm is the Monotonic Lagrangian Grid, which is a fast nearest-neighbors interaction algorithm used for sorting and tracking many moving and interacting objects. The nodes of the Monotonic Lagrangian Grid represent the locations of individual aircraft, and the grid moves at each time step as the aircraft move. The model is used to simulate a 24 h period of air traffic flow in the National Airspace System, during which there are 41,594 flights, and this requires only 79 s of wall-clock time on a single processor of a 1.3 GHz Altix. An analysis is presented of the number of nearest-neighbor nodes that must be checked to ensure adequate separation among aircraft. An investigation of the effect of removing waypoints from aircraft trajectories indicates that this may result in a significant reduction in total flight time. Finally, the model is compared with the traditional Latitude—Longitude grid approach, in which the airspace volume is partitioned into fixed stationary grid cells. Results of the comparison indicate that the main advantage of the Monotonic Lagrangian Grid method is that it is a general sorting algorithm that can sort on multiple properties, providing more computational efficiency.