Radio Direction Finder (RDF)
Since February 2017 air traffic controllers at EUROCONTROL’s Maastricht Upper Area Control Centre (MUAC) can rely on a new technology to further improve their situational awareness. In densely occupied airspace, the Radio Direction Finder (RDF) assists the controllers in rapidly identifying which aircraft is transmitting on the frequency. This is particularly useful in dense sectors where controllers handle up to 25 aircraft at any one time.
The area of the origin of a voice transmission appears clearly on the controller’s integrated Human Machine Interface (HMI) - in a white circle - and is totally independent of conventional radar or GPS-based aircraft localising techniques. This feature helps to reduce call sign confusion helps to catch read-backs from wrong aircraft or crossed transmissions (aircraft simultaneously or an aircraft transmitting at the same time as the controller). RDF also facilitates the controller's work by reducing drastically the scanning time of the radar screen necessary to find the calling aircraft track, in particular when the aircraft is outside the radar screen since you still get the direction where the aircraft called from and you can display again the position of the 'last calling station'.