(1) The geographic information technology used by the car navigator is (global positioning system), which includes three parts: (space part, satellite constellation ground control part-ground monitoring system, user equipment part-signal receiver).
(2) If the position of the vehicle is to be determined, at least (3) satellites shall be used.
(3) The system can provide users with accurate three-dimensional coordinates, and "three-dimensional" refers to (longitude, latitude and altitude).