1. Primary Model Category

Tool to create scripted 4D flight paths of pseudo aircraft.

2. Summary

The Robust Air Traffic Situation Generator (RATSG) is part of the MIT Aeronautical Systems Laboratory's part-task simulation facility. RATSG allows the user to design 4D flight plans (position and time) for a number of pseudo aircraft for use in simulation studies. Waypoints can be defined relative to fixed earth coordinates or relative to a subject aircraft. The pseudo aircraft can automatically change speed, altitude, or heading in order to assure that a desired air traffic situation occurs regardless of the actions of a human pilot. Although currently used in real-time, human-in-the-loop simulation studies, the tool could be used in fast-time traffic simulations as well.

3. Input Requirements

A Graphical User Interface is used to develop scenarios and flight plans. The user can specify the number and type of aircraft, aircraft call sign, transponder status, and whether the aircraft has TCAS. Additionally, aircraft initial states (position, altitude, heading, speed) and the 4D waypoints are defined either through a text input or graphically. Voice messages can be recorded and scripted to play at predetermined times to simulate VHF communications.

4. Outputs

When running, RATSG outputs pseudo aircraft state data in either real time or in fast time.

5. Major Assumptions

The aircraft use simple point-mass dynamics.

6. Computational Characteristics

Code exists (written in C and GL) for Silicon Graphics Indigo workstations. Typical run time in fast mode is 3 minutes for a 30 minute flight.

7. Modularity and Flexibility

The code is somewhat modular and has been exported to NASA Ames for use in developing traffic encounter scenarios.

8. Status

The model is still being used but is not under further development at this time.

9. Extent of Model Verification

The aircraft model uses simple performance numbers as parameters (e.g., best rate of climb, gross weight, roll rate). The values of these parameters are based on published aircraft performance data but have not been otherwise validated.

10. Principal Applications

Development of traffic encounter situations for human-in-the-loop simulations.

11. Availability

Available through MIT. Contact: Prof. John Hansman, (617)-253-2271, rjhans@mit.edu

12. Information for Model Evaluation

Johnson, E. N. and R. J. Hansman, "Multi-Agent Flight Simulation with Robust Situation Generation", MIT Aeronautical Systems Laboratory Report ASL-95-2, January, 1995.

13. Summary Evaluation

The Robust Air Traffic Situation Generator has been implemented on a graphical workstation that communicates with the MIT-ASL Advanced Cockpit Simulator, allowing specific traffic situations to be designed and used in experiments. Traffic encounters are scripted by the experimenter using 4D waypoints (position and time). These waypoints can be located relative to fixed earth coordinates or placed relative to the subject aircraft so that potential collision events can be simulated. VHF communications can be simulated by scripting pre-recorded voice for playback during simulation runs. During a simulation, the pseudo aircraft are automatically controlled through adaptive 4D waypoints to ensure that the traffic situation unfolds as desired even if the subject performs unexpected maneuvers. In addition, because the simulation is already built around 4D waypoints, a framework is already in place to examine advanced 4D traffic control issues with multiple aircraft.

Traffic can be simulated in real time or in a fast mode. A Graphical User Interface is used to design the traffic scenarios.