Global Positioning System is a really popular navigation system that is used by a large amount of people today. This system gives a possibility to define the location and velocity of the objects at any place on Earth, including polar territories, almost in all weather conditions, and in outer space to one hundred kilometers above Earth. The developer of Global Positioning System is the United States Department of Defense that has realized this system.
The location is identified by the principle of measuring the distance from the spot with the definite coordinates to an object. The distance is calculated by the delay time of the signal diffusing from the sending satellite to the receiving of it by a GPS antenna. 3-D coordinates can be defined when GPS receiver will know the distance to 3 satellites and the time of the Global Positioning System. And to detect a receiver's coordinates and altitude it has to use minimum 4 satellites' signals. The control over the satellites from Earth is implemented in the control station that is situated in Schriever base, Colorado.
GPS receivers are often applied nowadays by civil persons, sailors, rescuers and the police for location and velocity definition of diverse objects. Handheld GPS systems are being sold in diverse stores and they are built in mobile phones, personal computers and onboarders. GPS receiver gives you a possibility to define geographical coordinates of the receiver's situation at the present moment. The maximum accuracy is from three to five meters and with the correction radio signal from Earth it is to 1 millimeter.