Airplanes use a variety of navigation systems. Large commercial jets, military aircraft and small, single-engine airplanes are equipped with some or all of the different types, including ADF, VOR, INS and GPS.
The Automatic Direction Finder resembles a compass with a large arrow in the center. The pilot selects the frequency of a non-directional beacon station, and the needle points to the station.
A Very High Frequency Omni Directional Range resembles a compass with a bar hanging down the middle. The pilot rotates the bar until the needle is centered, and that will guide the aircraft to the VOR ground station.
The Inertial Navigation System is set by the pilot before taking off. The pilot sets the coordinates of his present position, and using a variety of gyroscopes, the system will keep track of the aircraft's position throughout the flight.
The Global Positioning System uses a series of satellites that calculate the aircraft's position. The GPS unit provides a display that shows the plane's position on a map.
The most basic tool is the standard magnetic compass.
