Plain English Meaning
A radio tool in the aircraft that constantly tells the pilot how far they are, in nautical miles, from a chosen ground station.
Full Definition
An airborne and ground-based radio navigation system that measures the slant-range distance in nautical miles between an aircraft and a selected ground station. The aircraft transmits paired pulses to the ground station, which replies after a fixed delay; the airborne receiver measures the round-trip time and converts it into a distance readout in the cockpit. DME ground stations are typically co-located with VOR or ILS facilities and operate in the UHF band.
Context Anchor
Seen on navigation displays, , and descriptions that use DME distances from a navigation station.