Global Positioning System :: Space Satellites Technology Essays

Global Positioning System Did you know that there are 24 GPS satellites in orbit at this moment? The 24 satellites cost an estimated $12 billion to build and launch. Each satellite weighs about 1,735 lb and takes 12 hours to orbit the Earth once. They are in orbit about 12,500 mi above the Earth. The first GPS satellite was launched in 1978 followed by the launching of the first Block 2 satellite, second generation of GPS satellites, in 1989. GPS stands for Global Positioning System, which is a worldwide radio navigation system. It is a network made up of 24 satellites which orbit the earth and allow a person to receive information about their location. These satellites will allow to pin point your exact location and calculate your coordinates. Now with the advancement in technology, you can make 6measurements of where you are to the nearest centimeter. So GPS allows to determine your precise longitude, latitude and altitude anywhere in the planet. GPS works through handheld GPS units which are easily available anywhere. Nowadays with the advancement in technology they are being used not only in ships and airplanes, but are now built into cars as well. This helps a driver if they get lost. As for the hand held units, they are great for hikers or those who travel on foot or bikes. It wont be soon before GPS will become as basic as telephones. As mentioned before, there is a network of 24 satellites that orbit the Earth. It is required to have at least four of them above the horizon. Usually though, there are around eight satellite’s available. GPS works using these satellites to measure the distances between places by means of radio waves. Distance is calculated by the amount of time taken by signal to travel from satellite to receiver. This time can be calculated using two kinds of clocks. An atomic clock or an quartz clock. An atomic clock would be extremely precise for this operation, however with its high cost it is not feasible to use. So then with its high costs, atomic clocks are only employed in satellites.