Astronomical principles of satellite positioning

The Global Navigation Satellite Systems (GNSS) dominate the positioning technologies at the beginning of this millennium. The new concept, already common in all users'segments, refer to those radio-navigation systems providing highly precise time and position information, continuously and globally, disregarding the weather status. In the present paper, a comparison between the principles of celestial navigation and satellite navigation is intended, offering additional reasoning to conclude that the roots of the global satellite navigation systems are connected to the classical principles of celestial navigation.