An international radio system of short-range navigation VOR defines the magnetic bearing of a/c relative to VOR radio beacons located in all regions of the world. An international radio system of instrument landing ILS using metric radio waves is an internationally acknowledged landing system along with GLS and MLS.

ILS ensures approach and landing in most airports according to I, II and III ICAO DME categories.

An international radio system of short-range navigation DME defines the slant distance of a/c to DME radio beacons in all regions of the world.

DNE system can operate separately from VOR system providing the data about the slant distance of a/c to several DME radio beacons simultaneously.