The basic principles of aircraft navigation are identical and similar to basic general navigation, which includes the process of planning, recording, and controlling the movement of an aircraft from one place to another. The techniques used for navigation in the air will depend on whether the aircraft is flying under visual flight rules (VFR) or instrument flight rules (IFR). In the latter case, the pilot will navigate exclusively using instruments and radio navigation aids such as Automatic Direction Finder (ADF) and Non-directional Beacon (NDB), Very High Frequency Omni-directional Range (VOR), Distance Measuring Equipment (DME), Instrument Landing System (ILS), Microwave Landing System (MLS), Global Positioning System (GPS) or as directed under radar control by air traffic control. In the VFR case, a pilot will largely navigate using dead reckoning methods that combined with visual observations style known as pilotage, with reference to appropriate maps.