Gps.

The Global Positioning System (GPS), originally NAVSTAR GPS,[1] is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force.[2] It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.[3] Obstacles such as mountains and buildings block the relatively weak GPS signals.