GPS, or Global Positioning System, is a satellite-based navigation system that allows users to pinpoint their exact location and track their movement. The system is run by the US government and is open to anyone with a GPS receiver.

The GPS system is made up of three parts: satellites that orbit the Earth, ground control stations that track and maintain the satellites, and GPS receivers that users carry with them.

GPS satellites orbit the Earth at an altitude of about 12,000 miles (20,000 kilometers) and transmit signals to the ground. These signals contain information about the satellite's location as well as the time the signal was transmitted.

A GPS receiver determines its own location by utilizing signals from multiple satellites. The receiver detects signals from multiple satellites and uses the time stamp on each signal to calculate the distance between them. The receiver can triangulate its own position by comparing the distance to multiple satellites.

The location is determined through a process known as trilateration, in which the distances between three or more GPS satellites are used to pinpoint a 2D location (latitude and longitude). 3D location (latitude, longitude, and altitude) is obtained using elevation data from at least four satellites.

After determining its location, the GPS receiver can provide that information to the user in the form of coordinates (latitude and longitude) or even addresses or points of interest. Some GPS receivers can be integrated into cars to provide verbal directions to a specific location, as well as in navigation apps on smartphones, tablets, or smartwatches to assist users in navigating to a desired location.