Maximum detection range (nautical miles)
Maximum lookahead time (seconds)
Gauge Repeatability and Reproducibility (Gage R&R)
Measured aircraft speed (knots).
The detection and false alarm rates, although implemented in the code, are not used in the current demonstration version of the model; that is, as noted above, we assume for present purposes a detection rate of 100 percent and a false alarm rate of zero percent.
Either the maximum detection range or the maximum lookahead time should be zero – but not both of them. This way, whichever is not zero will be used for calculating the other. Gage R&R is a standard characteristic of all sensors, from tape measures to chromatographs, and represents the percentage of deviation of the reading of the sensor from the value being measured. A good realistic value of GR&R is 10 percent or less. The measured aircraft speed is updated at each time step of AircraftOnRoute.
Controllers
The logic and procedures of air traffic controllers for this scenario are described in detail in Chapter V. There are two sectors in the simulation, EXTERNAL and SUBJECT, each with its own air traffic controller agent.
For the EXTERNAL sector, we use the RFSController agent, which, much like RFSPilot, has very limited capabilities as compared to the higher fidelity MIDAS-Controller. It performs handoffs and handles messages sent via the communication channel. Its vocabulary of messages is very limited, but expandable, and it matches the RFSPilot’s vocabulary. In addition, if there is less than 1000 feet vertical separation between two aircraft trajectories and their lateral separation is projected to conflict, RFSController commands one or both of them to change speed.
The controller gets information on the name, present position, heading, and speed of all aircraft in its sector either from a surveillance agent or, if there is no surveillance agent available to it, from the simulation’s vehicle list. It does not perform any actions in situations when the pilot issues a PIREP or SensorPIREP message; however, it does receive and translate this message appropriately.
For the SUBJECT sector, RFSController is used as a wrapper for the MIDAS-Controller agent, so that as soon as the aircraft is handed off into the sector, all control functions, including interactions with the pilots – MIDAS-FlightCrew and RFSPilots – are determined by MIDAS-Controller. At the same time, RFSController continues monitoring the radar and determining which aircraft are to be handed off into the next sector.
Handoffs by RFSController occur in the following manner. When RFSController receives a greeting message from an aircraft entering its sector, it immediately (in terms of simulation time) adds this aircraft to its control list and starts monitoring it.
At each simulation update step, then, RFSController monitors the surveillance agent’s data and determines the distance of each aircraft on its control list to the nearest link between two neighboring points on the sector boundary. When this distance becomes smaller than this RFSController’s point identification error tolerance, RFSController sends a “Good Bye” handoff message to the aircraft containing the name of the next sector's channel (i.e., radio frequency).
Upon receipt of the handoff message, the aircraft removes itself from the channel it is on, registers with the next channel, and sends the greeting to the next sector’s controller. If the aircraft has reached its last waypoint (end of its route), then RFSController in charge of this aircraft sends the “Good Bye” message to the aircraft, but without the next channel name. This causes the aircraft to remove itself from the present channel, but it does not register with another channel. Upon sending the “Good Bye” message – with or without the name of the next channel – RFSController removes the aircraft from its control list and, if there was no next channel name sent, destroys the aircraft object.
中國航空網(wǎng) www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：DEVELOPMENT OF FAST-TIME SIMULATION TECHNIQUES(28)
