Global positioning system (GPS) receiver being held in a hand. The system uses a network of satellites that orbit the Earth. Each of these sends out signals about its position and the time. The receiver uses the signals from at least four satellites simultaneously to calculate its latitude,longitude and altitude,as well as the local time | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Percival, Steve |
Taille de l’image : | 5238 px × 3507 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |