Overview: Taxiway Model

Motivation

  • Safety of systems of systems (such as the airspace) results from the distributed situation awareness of the individual actors (e.g., Pilots, ATC, etc.)

  • To best understand this distributed situation awareness of systems of systems, we need ways to represent it in a simulation

  • The taxiway model provides a simple systems model of an airport taxiway we can use to understand distributed situation awareness

Model Structure {.smaller}

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The taxiway model has three main agent types:

  • Helicopter, which lands and takes off from a helipad

  • Aircraft, which lands at a runway, taxis to a gate, and takes off from a runway

  • ATC, which coordinates operations

These agents interact via the flows:

  • Ground, a MultiFlow tracking the map as well as agent assignments/allocations

  • Location, a MultiFlow tracking the position/velocity of each route, and

  • Requests, a CommsFlow tracking messages between ATC and assets ::: ::: {.column width=”45%”} ::: ::::

Environment

In this environment, aircraft cycle between In Air, landing, gate, and takeoff locations while helicopters cycle between In Air and helipad locations

Hazard Simulation - Incorrect Requests {.smaller}

Below, we model the situation of Air Traffic Control issuing an incorrect approval to land that is not caught by uav2 due to a poor sight (no_sight fault).

As shown, in this scenario, the uav2 lands on an occupied airstrip, causing a crash, and further aircraft are blocked from attempting to land.

Note that while the simulation continues to play out with landings/takeoffs, this would normally cause a shutdown of airport operations.

Analysis of Distributed Situation Awareness {.smaller}

Distributed Situation awareness in fmdtools can be represented as graphs of information connecting the various agents, as shown below.

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At t=20, the map has an overbooked location, while ua2 and ma3 have crashed into each other due to the wrong_land_command issued by atc. ::: ::: {.column width=”55%”} {height=250}

This graph shows the extend of the faults effect on communications at time t=10, where the in-air aircraft now have been given duplicate landing commands ::: ::::

Conclusions

  • The taxiway model showcases how fmdtools can be used to model distributed situation awareness in a complex system-of-systems

Further reading:

  • Irshad, L., & Hulse, D. (2025). Toward Early Design Modeling and Simulation of Distributed Situation Awareness. Journal of Computing and Information Science in Engineering, 25(6), 061001.

  • paper_jcise_dsa.ipynb