MIT AATT Model Project

TAAM: Total Airspace & Airport Modeller

(5/14/96, KK)

1. Primary Model Category

Full Air Traffic system simulation.

2. Summary

TAAM (Total Airspace & Airport Modeller) is a large scale detailed fast-time simulation package for modeling entire air traffic systems, developed by The Preston Group (TPG) in cooperation with the Australian Civil Aviation Authority (CAA).

TAAM can be used as a planning tool or to conduct analysis and feasibility studies of ATM concepts. TAAM can simulate most ATM functions in detail and can provide scenario generation for real-time ATC simulators. The simulations cover the entire gate to gate ATM process, generally in more detail than competing models.

A TAAM simulation consists of a collection of user provided data relevant to the problem at hand and its modeling requirements. TAAM takes as input the air traffic schedule, environment description, aircraft flight plans, air traffic control and output control rules. It uses them in performing airport and airspace usage, conflict detection and resolution, and aggregate metrics calculations with its internal algorithms and user defined rulebases.

TAAM modules include an interactive graphical fast-time simulation tool which provides the user with a 2D or 3D view of the airpace or airport; a real-time air traffic monitoring tool with simulation capability; and a reporting tool which can be used to generate graphs and tables from data generated by the simulation. Simulations can be interrupted and restarted and key aspects of the model, such as conflict resolution and airport resource usage are controlled by rulebases which may be edited by the user during a simulation run. 'Live' graphical display of the simulation can be selected and customizable reporting is available. The simulation can also be run unattended in batch mode, with no graphics. During the simulation, statistics are gathered by the reporting program and written to a report file. This file is used by the Report Presentation Facility to construct the text and graphical reports desired by the user.

Competing models: ASIM, SIMMOD, RAMS.

3. Input Requirements

As TAAM is a large scale simulation of an Air Traffic system, comprehensive input data files describing the entire Air Traffic system are needed. The level of detail can be varied for better modeling of critical areas. The inputs are the following:

  • Airport Descriptions
  • Airspace Route and Sector Layouts
  • Geographical Features
  • Air Traffic Control Rules
  • Airport Usage Rules
    • wake turbulence and other standards
    • SIDs/STARs/route selections etc.
  • Traffic Timetables
  • Aircraft Trajectories and Routes
  • Aircraft Performance Characteristics
  • Conflict Detection and Resolution strategies

Default input files for a large proportion of these are available. Most data entry for building the environment model and operation rules is interactive and various data entry tools are available:

  • 2D/3D graphical editor (CAD tool) for entering and editing graphical data such as airport layouts, airspace sectors, etc.
  • Data entry and validation tool for entering and maintaining data such as waypoints, routes, etc.
  • Other data entry tools e.g. a digitizer for digitizing paper maps, and an external data converter for importing maps in AutoCAD(TM) format and Jeppesen(TM) data.

4. Outputs

These are in general aggregated metrics and can be reported on system or sector wide basis.

  • System delays
  • Conflicts: counts by degree of severity, whether successfully resolved or not
  • Airport movements, delays, operations on taxiways and runways, runway occupancy
  • Airspace operation metrics such as usage of routes, sectors, fixes and coordination
  • Noise contours
  • Total fuel burnt
  • Costs: aggregate, fuel, non-fuel
  • Controller workloads
  • Individual Aircraft flight profiles
  • Scenario generation e.g. for real-time ATC simulators or other playback
  • "Show Logic" diagnostics which gives the operator an insight into TAAM's decision making process
  • Text messages (extent and content user selectable) which contain further details of TAAM events
  • Errors

A 2D or 3D graphical visualization of the simulation can also be generated. The graphical output can be viewed in several windows simultaneously, each window having an independent 2D or 3D view with the scale ranging from 30 m to 40,000 km.

5. Major Assumptions, Limitations

Hazardous weather, or special use airspace cannot yet be modeled dynamically. Weather modeling was limited to winds aloft in sectors, but according to TPG the user can now input SIGMETs and TAAM can determine which aircraft, and when, will be affected by these severe weather areas. Conflict detection and resolution is selectable but may not resolve all conflicts.

6. Computational Characteristics

Hardware: Sun SPARCstation 20, 75Mhz cpu with 288MB memory and two 1.05GB hard-disks. Minimum requirements depend on the size of simulation to be run. Speed of simulation is strongly dependent on the scale (flights/day) and computation time varies approximately with the square of the number of aircraft(real + ghost) in the simulation. Depending on the hardware used and the options enabled, TAAM can simulate airspaces up to the size of the entire continental United States. On the machine described above, a 16,000 flights for a day simulation takes about 24 hours to complete. Capacity improvements continue to be made.

TPG quotes the following benchmarks for the latest TAAM version:

  • 20,000 flights a day, conflict detection/resolution enabled: 17 hours on a typical SPARC20.
  • 35,000 flights a day, conflict detection/resolution disabled: less than 4 hours on the same machine.
Graphical visualization is available. The user can switch between 2D and 3D mode at will, and has full control over the view. Simulation runs can be seen from any angle, from `God's eye' view to `worm's eye' view. Zoom is continuous from looking at the whole world to a single aircraft, with any stage in-between. Screen dumps can be made of any view. The simulation can also be run unattended, with no graphics. The user has full control over the simulation; he can at any time stop the simulation, make changes to airport operation or various aspects of the airspace, and restart the simulation.

7. Modularity and Flexibility

TAAM is available as an executable with customizable input and output files. Rulebases of most aspects are reconfigurable and can be edited even during simulation runs. Linking with other programs is possible via input and output files. Additional packages allow linking with other ATM programs such as the FAA's Integrated Noise Model.

8. Status

Version 2.x of TAAM is available with a number of optional modules Additionally, TAAM is available as TAAM Airport, TAAM TMA, and TAAM Enroute, with reduced range/functionality.

9. Extent of Model Verification

Comparisons with FAA studies on some aspects of new ATM concepts have been performed showing comparable results. The simulation model has been verified by many users on a variety of scenarios. Aircraft movement in 4 dimensions can be fine tuned to get within 3%-4% of actual aircraft profiles. The same accuracy can be obtained for airport movement rates and other characteristics.

10. Principal Applications

Complete system simulation of present and proposed ATM systems and concepts. For example comparison between system performance using ATC preferred routes and Great Circle routes.

TAAM has a broad user base and many studies have been conducted many over the last 4-5 years, ranging from adding a couple of gates to designing London TMA procedures to total redesign of national airspace.

The principal areas of application have been:

  • Airport capacity (gate, taxiway, runway capacity)
  • Planning airport improvements, extensions
  • De-icing
  • Noise impact
  • Impact of severe weather
  • Design of terminal area procedures (SIDs/STARs)
  • Design of terminal area ATC sectors
  • Controller workload assessment
  • Impact of new ATC rules, e.g. reduced vertical separation
  • Systemwide delays
  • Cost/benefit studies

11. Availability

The software is available from:

The Preston Group Pty Ltd.
488 Victoria St.
Richmond, VIC 3121,
Australia

12. Information for Model Evaluation

Datta, K. and G. Schultz, "An Evaluation of TAAM for Free Flight Modeling", Draft Report, Sverdrup Technology Inc., NASA Ames Research Center Moffet Field CA 94035

Hank Wojcicki, TAAM homepage at ERAU:
http://erau.db.erau.edu/~taam/taam.html

Alexander Klein
email:sak@tpg.tpg.oz.au

13. Summary Evaluation

TAAM is one of the large scale fast-time simulations for entire Air Traffic Systems. It provides a high level of detail and realism although there are some limitations. TAAM is undergoing futher development and The Preston Group is currently working on version 3. TAAM is currently the most fully featured ATM simulation available and with further enhancement could be incorporated into a system of models for the evaluation of concepts such as Free Flight.

TAAM is a 4D flight path simulation and allows greater realism than mesh based simulations such as SIMMOD. It is possible to simulate dynamic re-routing, e.g. to avoid conflicts with other aircraft although it is not apparent whether it is sufficient to model complete Free-Flight. Hazardous weather can be input as SIGMETs and TAAM can determine which aircraft will be affected by these severe weather areas. Conflict avoidance capabilities are somewhat limited. Conflicts are detected by ghost aircraft flying the look-ahead time ahead on the prescribed flight-path. When TAAM evaluates a conflict avoidance action, it checks that the action resolves the predicted conflict between the given two aircraft, and does not lead to conflicts with other aircraft in the vicinity. If both requirements are not fulfilled, TAAM rejects the action and tries another one. TAAM cannot move more than one aircraft at a time and avoidance of one conflict can result in others that are not resolved.

TAAM Users

The following organisations are major users of TAAM [TPG]:

Europe:
DFS (German Federal Aviation Service)
NATS / British CAA
STCA (French Directorate General of Civil Aviation)
Swisscontrol
NLR (Dutch National Aerospace Laboratory)
Aerospatiale
Thomson-CSF

USA:
FedEx
Lockheed Martin
NASA
Boeing
Continental Airlines
Embry-Riddle Aeronautical University
FAA Potomac MCF
FAA Southern Region / Crown Communications
New York Port Authority

Asia:
ENRI, Japan (Electronic Naviation Research Institute)
Airservices Australia (former CAA)
CRC Research Institute (a subsidiary of Itochu)

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