1. There are always at least 24 active GPS satellites orbiting the Earth though there are more than 30 at present out there. The first set of 24 satellites was sent up in 1989
2. The idea of Geo Positioning System or Global Positioning System came from LORAN and Decca Navigation System, which were used during World War II. They helped in the navigation of ships and planes at a long range
3. GPS system uses the principle of Doppler Effect to trace locations as the change in frequency of signals from the GPS satellites helps in identifying locations
4.GPS was first used by US for military purposes to fulfil their need of a global navigation system during the cold war
5. Before Global Positioning System came into existence, navigation system of Navy was being used. However, high speed air force operations demanded a better navigation system that led them to think of navigation using satellites
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6. GPS was called Navstar in the beginning and the first Navstar satellite was launched in 1978. However, the first fully developed GPS satellite was launched only in 1989
7. In 1983, a Korean Airlines flight was shot down by Soviet Union since the flight entered the Soviet airspace. As a result, President Ronald Reagan let Global Positioning System go public for free, which was till then confined to military purposes alone
8.Even after GPS went public, the high quality GPS signals were confined to military purposes only. On May 1, 2000, the restriction was taken off and more accurate signals were available for public use.
9. Introduction of Global Positioning System in automobiles happened in 1996
10. GPS isn’t just about navigation. Every Global Positioning System satellite has multiple atomic clocks and the signals sent out by the satellite includes the time. The signals help the GPS receiver determine the time in 100 billionths of a second and these are used to synchronise time in a cell phone network
11. At present, Global Positioning System is a part of everyday gadgets ranging from mobiles phones to cars
12. The popularity of Global Positioning System is such that there are even GPS shoes available in the market. These have been created to locate Alzheimer’s patients in case they get lost.