4D Air Traffic Control for Non-4D-Equipped Aircraft

 M. R. Jardin

 jardin@osprey.arc.nasa.gov

 NASA Ames Research Center

 MS 210-9

 Moffett Field, CA 94035
 Abstract

A method for designing a nonlinear compensator to help air 
traffic controllers and pilots to accurately and efficiently 
control aircraft to buffered 4-dimensional (4D) trajectories is 
presented in this paper. The main technical challenge is to develop 
a control algorithm that efficiently achieves 4D control for 
aircraft that is accurate enough to meet airport capacity and 
safety requirements while minimizing the number of tactical control 
clearances that need to be issued by the air traffic controller. 
The approach is to soften 4D trajectory clearances by allowing 
aircraft to be within a well-defined error buffer region around the 
trajectory and to then use phase-plane techniques to determine how 
to keep the aircraft within the buffer with a minimum number of 
control advisories. In addition to the nonlinear advisory-
minimization function, an optimal model-based wind and airspeed 
estimator is used within the compensator to remove bias errors in 
these quantities so that zero steady-state error can be achieved.