Radio navigational equipment provides signpost in the sky, enabling pilots who fly by instrument to stay on course in any weather.The three most important ground-based navigational aids are VOR, DME and ILS:
- VHF Omni-Directional Range (VOR) equipment is an ultra-short wave navigational aid used mainly in airways and close traffic areas of the airports. With the corresponding airborne equipment, the course can be determined from and to the VOR beacon.
- Distance-Measuring Equipment (DME) shows the pilot the distance to a specified touchdown point on the runway or to a navigational transmitter.
- Instrument Landing Systems (ILS) allow safe landings even during very bad visibility. The ILS consists of a localiser, a glide path and a DME. With the help of a cross-pointer instrument, IFR pilots receive exact position of their aircraft during the final approach (the last 15 km before landing), compared to the ideal landing centre line, the optimum glide path as well as the distance from the runway threshold.
Satellite-based procedures are growing in importance and skyguide is developing, in collaboration with other partners, new satellite-based navigation procedures. Such procedures have already been successfully implemented, for example at Zurich airport and in the approach to Inselspital in Bern.