Editing VHF omnidirectional range (section)

===History===
Developed from earlier [[Visual Aural Radio Range]] (VAR) systems. The VOR development was part of a U.S. civil/military program for Aeronautical Navigation Aids.<ref name=":0" /> In 1949 VOR for the azimuth/bearing of an aircraft to/from a VOR installation and UHF DME<sub>(1950)</sub><ref name=":1" /> and the first ICAO Distance Measuring Equipment standard,<ref name=":2" /> were put in operation by the U.S. CAA (Civil Aeronautics Administration). In 1950  ICAO standardized VOR and DME<sub>(1950)</sub> in Annex 10 ed.1.<ref name=":2" />

The VOR was designed to provide 360 courses to and from the station, selectable by the pilot. Early [[vacuum tube]] transmitters with mechanically rotated antennas were widely installed in the 1950s, and began to be replaced with fully [[Solid state (electronics)|solid-state]] units in the early 1960s. DVOR were gradually implemented They became the major radio navigation system in the 1960s, when they took over from the older radio beacon and [[Low frequency radio range|four-course (low/medium frequency range) system]]. Some of the older range stations survived, with the four-course directional features removed, as non-directional low or medium frequency radiobeacons ([[Non-directional beacon|NDB]]s).
{{Gallery
|height=75
|width=75
|align=right
|title=Aeronautical chart VOR pictograms
|File:Pictogram VOR.svg|VOR
|File:VOR-DME.svg|VOR/DME
|File:Pictogram VORTAC.svg|VORTAC
}}
A worldwide land-based network of "air highways", known in the US as [[Victor airways]] (below {{convert|18000|ft|m|abbr=on|disp=or}}) and "jet routes" (at and above 18,000 feet), was set up linking VORs. An aircraft can follow a specific path from station to station by tuning into the successive stations on the VOR receiver, and then either following the desired course on a Radio Magnetic Indicator, or setting it on a [[course deviation indicator]] (CDI) or a [[horizontal situation indicator]] (HSI, a more sophisticated version of the VOR indicator) and keeping a course pointer centered on the display.

As of 2005, due to advances in technology, many airports are replacing VOR and NDB approaches with RNAV (GNSS) approach procedures; however, receiver and data update costs<ref name="AOPA2005">{{cite web | author=Airplane Owners and Pilots Association | date=March 23, 2005 | url=http://www.aopa.org/whatsnew/air_traffic/gps_databases.html | title=Inexpensive GPS Databases | work=AOPA Online | publisher=Airplane Owners and Pilots Association | access-date=December 5, 2009 | archive-date=June 21, 2010 | archive-url=https://web.archive.org/web/20100621152318/http://www.aopa.org/whatsnew/air_traffic/gps_databases.html | url-status=live }}</ref> are still significant enough that many small general aviation aircraft are not equipped with GNSS equipment certified for primary navigation or approaches.