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PSEUDO AIRCRAFT SYSTEMS
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Overview

Pseudo Aircraft Systems (PAS) is a computerized flight dynamics and piloting system designed to provide a high fidelity, multi-aircraft, real-time simulation environment to support air traffic control research. PAS is comprised of three major software components that run on a network of computer workstations:

Simulation Manager
The Simulation Manager, the heart of the system, runs on a single workstation. It serves as the control center for the overall aircraft simulation. It provides the computer link between the PAS network and the Air Traffic Control system. The Simulation Manager also contains the kinematic models of the individual aircraft comprising the simulated traffic scenario. The kinematic models process commands to produce aircraft state variables which are used to generate the simulated radar track data, the primary output of the system.
PAS Pilot Manager
The Pilot Manager serves as an interface between each Pilot Station and the Simulation Manager and also as an administrator for the set of Pilot Stations. It relays commands from all of the Pilot Stations to the Simulation Manager and, conversely, aircraft state data from the Simulation Manager to the appropriate Pilot Station.
Pilot Station
The Pilot Station software runs on a set of workstations that serve as both input devices and information display devices for operators called pseudopilots. Each pseudopilot controls a number of individual aircraft by issuing commands in response to verbal instructions from air traffic controllers, much as an actual pilot controls his aircraft. The commands are pre-defined strings of alphanumeric characters that are entered using a standard workstation keyboard or transmitted electronically from the air traffic control system (datalink commands).
Each Pilot Station controls a specific sector in the simulated airspace. If reductions in pseudopilot work load are necessary, up to four Pilot Stations can be assigned to each sector. When used in this manner, the program automatically distributes the aircraft in a sector uniformly among the number of assigned Pilot Stations so that each one controls only certain aircraft within the assigned sector.
Each component is operated and controlled by its own custom designed Graphical User Interface (GUI). Functionality is distributed among the components to allow the system to execute fast enough to support real-time operations.

PAS workstations are linked by an Ethernet Local Area Network, and standard UNIX socket protocol is used for data transfer. Air traffic controllers, staffing the Air Traffic Control System, issue clearances to PAS operators through a voice communication system. These operators, called pseudopilots, accomplish the controllers' instructions through keyboard input and mouse interaction at PAS pilot stations. PAS supports multiple pilot positions each of which pilots multiple aircraft. PAS also provides aircraft flight plans and state information to the Air Traffic Control System. The following graphic illustrates the setup of the network.

Diagram of the PAS Network. Click on the D-link for a detailed description.D

PAS was designed as a template-type system to enhance flexibility and allow rapid modeling of new test conditions. New airspace regions, wind conditions, aircraft types or traffic scenarios can be implemented by altering the data only; the algorithms remain unchanged. As currently structured, PAS software imposes no limit on the number of aircraft or the number of airports that can be simulated.

PAS contains sophisticated and realistic aircraft models and piloting logic which results in complex maneuvering and navigational capabilities. New features and improved capabilities are continually added to PAS to support ongoing and future Air Traffic Control system development.

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PAS Simulation Manager

The Simulation Manager, the heart of the PAS system, serves as the control center for the overall aircraft simulation. It provides the computer link between the PAS network and the Air Traffic Control system. The Simulation Manager also contains the kinematic models of the individual aircraft comprising the simulated traffic scenario. The kinematic models process commands to produce aircraft state variables which are used to generate the simulated radar track data, the primary output of the system.

The main functions of the Simulation Manager are:
  • Simulation control and management
  • Aircraft modeling
  • Communication management between PAS and the Air Traffic Control system
Aircraft models and piloting logic are combined within the PAS Aerodynamics process, a component of the Simulation Manager. Kinematic models representing both commercial transports and private aircraft are available. Each aircraft in the scenario is modeled independently. Aircraft acceleration is computed in three dimensions based upon external forces, integrated twice and transformed to the appropriate coordinate system to represent the aircraft's radar track.

The piloting logic within the PAS Aerodynamics process is a complex control algorithm that guides each aircraft along the desired flight path in response to commands from the pseudopilots. This piloting logic processes pseudopilot commands to generate appropriate inputs to an aircraft model and monitors the resulting aircraft motion. Additional control adjustments may be generated to nullify the error between the desired and the actual flight path.

The graphical user interface for the Simulation Manager is comprised of a Flight Data Table and a Control Frame. The Flight Data table is a list of aircraft about to become active in the simulation and those aircraft that are currently active. The format is that of FAA standard Flight Progress Strips in both the TRACON and Enroute format. The majority of the information is static but portions are dynamic in nature. For example, the information in the altitude field of the Fight Progress Strip will change as the altitude of the aircraft changes. The Control Frame allows the research engineer to modify the simulation during run-time. Some of the options that are available are the ability to create aircraft on-the-fly, to delay aircraft release time, and to remove aircraft.

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PAS Pilot Manager

The Pilot Manager provides executive control over a set of Pilot Stations and communication services for the components of the PAS network. It links the Simulation Manager and the Pilot Stations by passing aircraft state data one direction, and aircraft commands the other.

The Pilot Manager is an executive Pilot Station. In addition to the capabilities of a normal Pilot Station, it can command any active aircraft, not just those assigned to a specific sector. The Pilot Manager also performs administrative functions, such as managing the transfer of control responsibility for individual aircraft from Pilot Station to Pilot Station (called a "handoff" in Air Traffic Control jargon).

In operational mode, the Pilot Manager Run Frame and three icons representing the executive Pilot Station appear on the screen. With the three icons opened, the Pilot Manager has the look and operations of a Pilot Station but with control of all aircraft.

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PAS Pilot Stations

The Pilot Station software runs on a set of workstations that serve as both input devices and information display devices for operators called pseudopilots. Each pseudopilot controls a number of aircraft by issuing commands in response to verbal instructions from air traffic controllers, much as an actual pilot controls his aircraft. The commands are pre-defined strings of alphanumeric characters that are entered using a standard workstation keyboard or transmitted electronically from the air traffic control system (datalink commands).

Each Pilot Station controls a specific sector in the simulated airspace. If reductions in pseudopilot work load are necessary, up to four Pilot Stations can be assigned to a sector. The program will automatically distribute the aircraft uniformly among the Pilot Stations assigned that sector.

Numerous commands are available to the pseudopilot to initiate aircraft maneuvering. For example:
  • Vectoring commands change heading, altitude or airspeed
  • Scheduling commands reassign a flight path or establish the aircraft on a nonradar route
  • Special commands establish holding patterns, missed approaches, runway or airport assignment changes and handoffs
The Pilot Station graphical user interface is made up of the Instrument Panel, the Radar Display and the Pilot Messages window. The Instrument Panel displays aircraft state information and receives command input. Overall situational awareness is provided by the Radar Display, which is a map-like plan view of the local airspace. Command error and aircraft status information are presented in the Message window. Aircraft are assigned only to one Pilot Station and are controlled by that particular Pilot Station. Each Pilot Station can, and typically does, have multiple aircraft assigned to it.

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Last Updated: October 13, 2016

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