Distance Measuring Equipment (DME)

Distance measuring equipment (DME) is a transponder-based radio navigation technology that measures the slant range distance between an aircraft and a ground station by timing the propagation delay of UHF radio signals. It is often paired with a VOR to provide both bearing and distance for a precise position fix.

Key Points

• •Measures slant range (direct line-of-sight distance), not horizontal ground distance.
• •Slant range error is most pronounced when flying at high altitudes directly over the station.
• •Used to establish fixes and make off-track corrections in conjunction with other navigation aids.

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