When people talk about GPS, they usually mean a Global Positioning Satellite receiver. The GPS is a constellation of 27 Earth orbiting satellites. This system of satellites was originally developed by the military, and then opened to the public.
The 3-4,000 pound satellite, circle the earths globe, at about 12,000 miles, making 2 complete rotations a day. A GPS receiver job is to locate four or more of these satellites, figure out the distance to each, and use this information to define on location. The GPS receives the location of the satellites. By Knowing how faraway a satellite is, the receiver also knows know it is located on some imaginary sphere somewhere at the satellite. It then determines the size of several spheres, one for each satellite. The receiver is located where the two spheres intersect.The accuracy of the GPS depends on the type of receiver. Most hand held have a 10 to 20 meter accuracy. Other receivers use a method called differential GPS to obtain a much higher accuracy. Observation made by the stationary receiver are used to correct positions recorded by the revolving units, which offer a greater accuracy, greater than 1 meter.Today, GPS is still being used by the military. Hunter have grab onto the idea. Have a deer you are unable to drag out of the woods, tag it and relocate with the GPS. For several years, This GPS system, basically used for emergency, now used for mapping, auto help, unlocking doors and engine trouble.
The 3-4,000 pound satellite, circle the earths globe, at about 12,000 miles, making 2 complete rotations a day. A GPS receiver job is to locate four or more of these satellites, figure out the distance to each, and use this information to define on location. The GPS receives the location of the satellites. By Knowing how faraway a satellite is, the receiver also knows know it is located on some imaginary sphere somewhere at the satellite. It then determines the size of several spheres, one for each satellite. The receiver is located where the two spheres intersect.The accuracy of the GPS depends on the type of receiver. Most hand held have a 10 to 20 meter accuracy. Other receivers use a method called differential GPS to obtain a much higher accuracy. Observation made by the stationary receiver are used to correct positions recorded by the revolving units, which offer a greater accuracy, greater than 1 meter.Today, GPS is still being used by the military. Hunter have grab onto the idea. Have a deer you are unable to drag out of the woods, tag it and relocate with the GPS. For several years, This GPS system, basically used for emergency, now used for mapping, auto help, unlocking doors and engine trouble.
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