Airspace Concept

1
Airspace Concept Evaluation System- State of
Development POC Kee Palopo Kee.Palopo_at_nasa.gov
10 December 2008
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Outline

• Process
• Requirements
• Development
• ACES 6.0 (Near-term Capabilities)
• Studies Using ACES
• Planned ACES Development

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Requirements Process

• Project Driven (milestones and principal
  investigators)
• Review
• Branch and Division
• Start with Research Question
• Experiment Plan
• Meetings
• Workshops and Conferences
• Request For Proposals

4
Development Phases
Build N
Build N1
Requirements
One Year
FAA, Glenn, JPDO, Langley, Others
Main Build
includes enhancement and maintenance
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ACES 6.0

• Communication, Navigation, and Surveillance (CNS)
  models with uncertainty
• Advanced Airspace Concept (AAC)
• Pre-computed schedule of sector capacities
• Dynamic Sub-sector Assignment
• Swappable Trajectory Generator
• Traffic Management Advisor
• ACES-FACET

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Studies Using ACES

• S. Karahan, S. Zelinski, Creating Convective
  Weather Scenarios for Simulating Weather
  Reroutes, AIAA Modeling and Simulation
  Technologies Conference and Exhibit, AIAA
  2007-6557 Hilton Head, South Carolina Aug. 20-23,
  2007
• R. Windhorst, H. Erzberger, Fast-Time Simulation
  of an Automated Conflict Detection and Resolution
  Concept, 6th AIAA Aviation Technology,
  Integration and Operations Conference (ATIO),
  Wichita, Kansas, Sept. 25-27, 2006

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Studies Using ACES (contd)

• S. Zelinski, L. Meyn, Validating the Airspace
  Concept Evaluation System for Different Weather
  Days, AIAA Modeling and Simulation Technologies
  Conference and Exhibit, Keystone, Colorado, Aug.
  21-24, 2006
• K. Palopo, R. Windhorst, B. Musaffar, M. Refai,
  Economic and Safety Impacts of Flight Routing in
  the National Airspace System, 7th AIAA ATIO
  Conference, Belfast, Northern Ireland, Sept.
  18-20, 2007

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Studies Using ACES (contd)

• G. Chatterji, Y. Zheng, Impact of Airport
  Capacity Constraints on National Airspace System
  Delays, 7th AIAA ATIO Conference, Belfast,
  Northern Ireland, Sep. 18-20, 2007
• S. Sahlman, Description and Analysis of a High
  Fidelity Airspace Model for the Airspace Concept
  Evaluation System, AIAA Modeling and Simulation
  Technologies Conference and Exhibit, Hilton Head,
  South Carolina, Aug. 20-23, 2007

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Ongoing Studies Using ACES

• Nation-wide Separation Assurance using AAC
• Single-center NAS-wide
• 42K flights 24 hours
• 25 hours on one high-end Mac
• Wind-Optimal Study
• Annual basis
• 1X traffic
• 4 hours on 7 Linux machines
• Plot by airlines

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Conflicts Types and Resolution Order

• Auto resolver is designed to resolve three types
  of conflicts
• Loss of separation conflicts
• Weather conflicts
• Arrival sequencing conflicts
• An aircraft may be involved with all three types
  at the same time

Source Dr. Heinz Erzberger
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Conflicts Types and Resolution Order (contd)

• Auto resolver resolves conflicts in the following
  sequence
• Weather conflicts
• Arrival sequencing conflicts
• Loss of separation conflicts

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Flow Chart for Algorithm
Input Conflict Pair
Formulas and logic for calculating simplified
resolution traj.
Resolution Maneuver Generator
4D Trajectory Synthesizer
Heavy duty numerical calculations
Traj. completed?
No
Yes
Check traj. for conflicts
Conflicts detected ?
Yes
Res. Traj. accepted
No
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Resolution Process
Current list of conflicts
Updated at regular intervals
Pick next conflict for resolution
Priority based on time to first loss
Generates multiple resolutions for each aircraft
special rules for weather conflicts
Resolution algorithm
Continue this loop until all conflicts are
resolved
Weather conflict?
Yes
No
Secondary conflict?
Yes
No
Update flight plan
Current flight plan is replaced with resolution
flight plan
Execute resolution
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AAC Remarks

• An algorithm that generates resolution
  trajectories for the full spectrum of possible
  conflicts has been designed
• Simultaneously resolves conflicts with convective
  weather, loss of separation conflicts and
  sequencing conflicts.
• Algorithm comprises a mix of rule-based
  procedures and analytical formulas.
• ACES has proven to be a valuable tool for
  development and analysis of algorithm

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AAC Remarks (contd)

• Real time controller and pilot interactive
  simulations have demonstrated high degree of
  controller and pilot acceptance at up to 3x
  traffic levels.
• Web-based documentation of software has been
  developed to assist in technology transfer to
  users

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Another Separation Assurance Study

• Trajectory prediction uncertainties for AAC
• Aircraft weight
• Descent profile
• Wind uncertainty
• Maneuver initiation delays
• Aircraft-based AAC
• Multi-center AAC

Source Dr. Todd Lauderdale
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Trajectory Prediction Uncertainties
Predicted
Actual
Actual
Predicted

• Can introduce uncertainties into the trajectory
  used for conflict prediction
• Uncertainties can be controlled and understood

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Aircraft-Based AAC
r

• Each aircraft is aware of all aircraft in the
  sensor range r
• Each aircraft uses AAC to resolve conflicts of
  which they are aware

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Aircraft-based AAC Unresolved Conflicts
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Aircraft-based AAC Time to First Loss
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Aircraft-based AAC- Run Time
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Multi-Center AAC

• AAC can run in multiple centers simultaneously
• A buffer of control and visibility can be
  established around each center

ZOB AAC
ZID AAC
ZDC AAC
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Planned ACES Development

• Integrate enhanced terminal model TME/STLE into
  ACES 7-11
• Port and Enhance Weather Agent
• Enhance Traffic Flow Management (TFM)
• Other Model Enhancements
• Metric Enhancements (Dynamic Density, Complexity,
  and AAC)

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Planned ACES Development (contd)

• Miscellaneous Supporting Tools
• Terminal Area and Airport Surface Editor
• ACES Viewer Development with Air Force Research
  Laboratory
• ACES Toolbox Enhancements

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STLE Surface Modeling
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Automated Terminal Area Node-link Generator
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Example TAASE Editor View
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Enhanced Terminal Modeling

• Airport Air Traffic Control
• Model 4D Traffic Movement on Surface
• Determine runway takeoffs/landing and gate
  entries/exits
• Airport TFM Generate TFM Landing Restrictions
• TRACON TFM Propagate Arrival Fix Crossing
  Restrictions

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Enhanced Terminal Modeling (contd)

• TRACON Air Traffic Control
• Model 4D Traffic Movement through Terminal
  Airspace
• Determine Airport Landing/Departure Fix Crossings
• Flight 4D Trajectory for Terminal/En Route
  Airspace

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Airport Air Traffic Control

• Surface 4D route/re-route planning with/without
  Required Time of Arrivals
• Surface 4D route/re-route and clearance limit
  assignment
• Surface domain representation Gate, Ramp,
  Taxiway, Runway
• Gate assignment and occupancy management
• Ramp and Taxiway intersection transit control
  with gridlock resolution

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Airport Air Traffic Control (contd)

• Takeoff runway assignment
• Runway takeoff/landing/taxi crossing transit
  control
• Surface transit Required Time of Arrival
  conformance monitoring/alerting
• Surface traffic state monitoring/alerting

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Airport Air Traffic Control (contd)

• Autonomous flight movement with aircraft in-trail
  self-separation
• Acceleration/Deceleration
• Nominal Roll/Stochastic speed assignment subject
  to speed limit

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Airport Traffic Flow Management

• Gate assignment and occupancy time prediction
• Runway assignment prediction
• Surface 4D route prediction with/without Required
  Time of Arrivals
• Traffic Flow Management Runway takeoff/landing
  planning
• Takeoff-time Traffic Flow Management Restriction
  generation

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Airport ATC/TFM Utilities

• Gate selector
• Runway selector
• Surface prescribed route assigner
• Surface shortest path calculator
• Air Traffic Control Runway takeoff/landing planner

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TRACON Air Traffic Control

• Terminal airspace 4D route/re-route planning
  with/without Required Time of Arrivals
• Terminal airspace 4D route/re-route and clearance
  limit assignment
• Landing runway assignment
• Airspace fix transit control
• Airspace transit Required Time of Arrivals
  conformance monitoring/alerting
• Airspace traffic state monitoring/alerting

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TRACON Traffic Flow Management

• Terminal airspace 4D route prediction
  with/without Required Time of Arrivals
• Arrival/Departure fix crossing planning
• Airports operating conditions forecasting
• Airports runway configuration planning
• Arrival fix crossing-time Traffic Flow Management
  Restriction propagation

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MPAS Improvements

• Make stable at aircraft minimum speed
• Model short flights and low-altitude tower en
  route flights
• Integrate Flight Management System generated
  vertical trajectories to meet restrictions
• Support holding patterns
• Pluggable

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Flight Management System

• Generate vertical trajectories from route, time,
  speed, and altitude restrictions
• Model vertical profiles for jet, turboprop, and
  piston aircraft
• Interface with surface movement model at the
  runway threshold
• Pluggable

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Concluding Remarks

• Requirements are gathered from project
  investigators and researchers and incorporated
  into development
• Studies go on in parallel
• ACES is in active development at one-year cycles
• Main trunk
• Branches of parallel development