Aircraft Sequencing Problem Near Terminal Area Final Term Project Presentation Sepehr Sarmadi Dec. 10 th 2002 System definition System users & objectives Terminal area: A cylindrical-shaped region with varying radius and altitude centered around an airport. Airlines and passengers
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Aircraft Sequencing Problem Near Terminal Area
Final Term Project Presentation
Dec. 10th 2002
System users & objectives
A cylindrical-shaped region with varying radius and altitude centered around an airport.
Airlines and passengers
Size is determined by the range of the airport’s radar and communication coverage.
An area where aircraft begins its landing maneuver
Decision making strategies to compute
Aircraft Sequencing Problem (ASP)
The problem of sequencing aircraft near the terminal area to satisfy some of the “system objectives” stated before
Aircraft category &
Both components must be completed in a few seconds as the nature of the real time ASP demands
ASP, DP approaches (1)
ASP is a special case of the famous Traveling Salesman Problem
TSP in a complete directed graph
Hamilton problem Equivalent to LLT version of ASP
But still DP approaches (or any other combinatorial approach) are computationally prohibitive in practice
ASP, DP approaches (2)
DP algorithm solution time for TSP
A time saving technique
classifying arriving aircraft into a few categories (n) generally based on landing velocity and weight
For m1=m2=m3=5, n=3, N=15:
Dynamic updating for a simple example*
*Source: Dear, Roger, PhD thesis, MIT, 1976
Min delay and Max throughput strategies fail in practice
The only practical solution to ASP must involve a compromise.
“Constrained Position Shifting” methodology is a very successful compromise.
CPS Limits the maximum number of position shifts (forwards or backwards) with respect to FCFS
CPS in practice (1)
Almost all major airports around the world still implement the FCFS strategy to avoid additional controller’s workload
The “CTAS” system in Denver and Dallas/Ft. Worth and the “COMPAS” system in Frankfurt include algorithms for assisting controllers do CPS with a maximum position shift of 1 or 2.
CTAS was conceived and is being prototyped at the NASA Ames Research Center. In 1991 it was chosen by the FAA as the future automation system for the terminal area
COMPAS was developed in the early 1980’s in Germany. One of the project goals was to plan an optimal sequence of the arriving aircraft from different arrival routes to make best use of the existing runway capacity
CPS in practice (2)*
On February 15, 1999, the Passive Final Approach Spacing Tool (pFAST) began sixteen hour per day operational use (covering over 80% of the arrival rushes) at the Dallas/Fort Worth (D/FW) TRACON.
*Source: NASA website
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