VOR/DME

DME was a modification of World War II-era navigation systems like Gee-H, and began development in 1946.

[5] During the mid-1960s, ICAO began the process of introducing a standardized radio navigation system for medium-area coverage on the order of a few hundred kilometres.

A number of proposals were submitted, including ones based solely on angle measurements like VOR, solely on distance measures like DME, combinations, or systems that output a location directly, like Decca Navigator and Loran-C. VOR/DME eventually won the standardization effort, due to a number of factors.

One was that the direct measurement systems like Loran were generally much more expensive to implement (and would be into the 1980s) while Decca had problems with static interference from lightning strikes because of its low 70 to 129 kHz frequency.

With VOR/DME, measurement from a single station reveals an angle and range, which can be easily drawn on a chart.