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GPS was originally only used only for military purposes, but in 1980, a new GPS can be used for civilian purposes. Although GPS satellites worth hundreds of millions of dollars, but everyone can use it for free. The satellites were owned by the Ministry of Defence (the Department of Defense), the United States who first introduced starting in 1978. GPS can be used anywhere within 24 hours. The position of the GPS unit will be determined based on points of degrees of latitude and longitude coordinates. GPS satellites first launched in 1978, In the development of the GPS many more. In 1994 there were 24 satellite GPS. Now the GPS satellites that operate already more than 30 pieces. GPS satellite age average of 10 years, so when they are past 10 years, it should be routine maintenance or replacement. GPS satellite weight average 2000 ± pounds (± 1 ton), the width of the solar panel is ± 17 feet / ± 5 meters, power transmission. GPS satellites orbiting at an altitude of approximately 12,000 miles of Earth's surface. This position is ideal because the satellite can reach a wider coverage area. These satellites will always be a position that can reach all the areas above the earth's surface so as to minimize the occurrence of blank spots (areas not covered by the satellite coverage). Each satellite can circumnavigate the globe in just 12 hours. Very quickly, so that the GPS satellites can always reach your position anywhere on the earth's surface.