How GPS Works

The basis of GPS technology is precise time and position information. Using atomic clocks (accurate to within one second every 70,000 years) and location data, each satellite continuously broadcasts the time and its position. A GPS receiver receives these signals, listening to three or more satellites at once, to determine your position on Earth.

By measuring the time interval between the transmission and the reception of a satellite signal, GPS receivers calculate the distance between the user and each satellite. Using the distance measurements of at least three satellites in an algorithm computation, the GPS receiver arrives at an accurate position fix.

The position information in a GPS receiver may be displayed as latitude and longitude or as other types of coordinates.