It is a satellite based navigation system which allows ground users to determine their exact location, velocity, and time 24 hours a day, in all weather conditions, all over the world. It is maintained and developed by the U.S. Department of Defense, and was basically designed to assist soldiers and military vehicles, but after some decades it made accessible to anyone having a GPS receiver. It is widely used to track vehicles and follow the best route from one place to another place by Airlines, shipping firms, courier companies, drivers etc.
The first GPS was developed in the 1960s to assist the ships of the US Navy in navigating the oceans more accurately. The first system started with five satellites which enabled ships to check their location once every hour.
In order to receive the information GPS device will first establish a connection with 3 to 4 satellites. GPS satellite broadcasts a message, including the location of the receiver. GPS receiver combines the message from different satellites to calculate the exact position using the process called triangulation.
