EFFECT OF UNCERTAINTY ON EN ROUTE DESCENT ADVISOR (EDA) PREDICTIONS

K. Tysen Mueller, Richard Bortins, David R. Schleicher, Doug Sweet, and
Richard A. Coppenbarger


Abstract

The En Route Descent Advisor (EDA) is one of the Center TRACON Automation 
System (CTAS) decision support tools under development at the NASA Ames 
Research Center.  EDA generates maneuver advisories for arrival aircraft 
to meet scheduled arrival times at the arrival meter fix, sometimes 
20-25 minutes ahead of the aircraft's scheduled meter fix arrival time. 
This work determined the sensistivity of the EDA advisories to system
uncertainties, including initial condition, environmental, and aircraft 
performance data errors. Using a Monte Carlo simulation that incorporates 
a Matlab Trajectory Synthesizer (TS) simulation, the sensitivities of the 
EDA predicted trajectory to these data error sources were obtained. The 
key metric is the meter fix crossing time error since this metric directly
measures the performance of EDA. This performance analysis involved a 
minimum of 200 Monte Carlo trials per error parameter. In addition to 
the single aircraft performance analysis, the impact of aircraft 
prediction errors on conflict detection between closely-spaced
aircraft was also explored. These Monte Carlo performance analyses 
determined how robust the EDA advisories are to input parameter 
uncertainties.