VOR (VHF Omnidirectional Range)

A VOR (VHF Omnidirectional Range) is a ground-based radio navigation aid that transmits a signal allowing an aircraft's receiver to determine its magnetic bearing, or radial, from the station. A VOR broadcasts on 360 usable radials, each corresponding to a magnetic bearing outward from the station, which an aircraft's Course Deviation Indicator (CDI) or Horizontal Situation Indicator (HSI) displays.

Pilots use VORs both to track directly to or from a station and to fix their position by taking bearings from two or more stations (a VOR cross-fix). Many VORs are co-located with DME (Distance Measuring Equipment), letting a pilot determine both a bearing and a distance from a single station.

While GPS has largely superseded VOR for primary navigation, the FAA retains a reduced but permanent VOR network (the Minimum Operational Network) as a backup for GPS outages, and VOR navigation, orientation, and radial interception remain directly tested on FAA knowledge exams.