Geopositional system

Since prehistoric times, people have been trying to figure out a reliable way to tell where they are and how to get to their destination. But did we discover it? Definitely! And that is the GPS.
TheGlobal Positioning System (GPS) is navigation and precise-positioning that can determinate and show you your exact position on Earth anytime, anywhere, in any weather.
GPS has three essentialelements: the space segment, the user segment, and the control segment. The space segment consists of a constellation of 24 satellites (and about six "spares"), each in its own orbit, also each satellitegenerates radio signals continuously sent you the ground stations that allow a receiver to estimate the satellite location and distance between the satellite and the receiver. The receiver uses themeasurements to calculate where on or above Earth the user is located. The user segment consists of receivers, which you can hold in your hand or mount in a vehicle, like your car. These receiversdetect, decode, and process GPS satellite signals. The control segment consists of ground stations (six of them, located around the world) that make sure the satellites are working properly. The mastercontrol station at Schriever Air Force Base, near Colorado Springs, Colorado, runs the system.
The signal that is emitted by the satellite travels to the ground at the speed of light. Even at thisspeed, the signal takes a measurable amount of time to reach the receiver. The difference between the time when the signal is received and the time when it was sent, multiplied by the speed of light,enables the receiver to calculate the distance to the satellite. . To calculate its precise latitude, longitude, and altitude, the receiver measures the distance to four separate GPS satellites. By usingfour satellites, the receiver calculates both its position and the time.
some people use it keeping track of your car in case of theft, Some to reach any destination in shortest time by using...