A Global Positioning System (GPS) usually means a GPS receiver. It is a constellation of 24 Earth-orbiting satellites. The U.S. military has developed and implemented this satellite network as a military navigation system. However, later it was opened up to everybody else. Each of this solar-powered satellite circles the globe at about 20,200 kilometers and make two complete rotations every day. The orbits of these satellites are arranged so that at any time, anywhere on Earth, there are at least four satellites “visible” in the sky. A GPS receiver locates four or more of these satellites, calculates the distance to each and uses this information to analyze its own location.
In order to calculate a location the GPS receiver depends on two things:
- The location of at least three satellites above a person; and
- The distance between a person and each of these satellites
The GPS receiver figures both by analyzing high frequency, low-power radio signals from the GPS satellites. It then figures out how far the signal has traveled, how much time it has taken and how long it took the signal to arrive. The receiver and the satellite then work together to make this measurement. The length of the delay is equal to the signal’s travel time and the receiver multiplies this time by the speed of light to determine how far the signal traveled. It is assumed that the signal traveled in a straight line and it is the distance from receiver to satellite. The most crucial function of a GPS receiver is to pick up the transmissions from satellites and combine the information in these transmissions with information in an electronic atlas, all in order to figure out the receiver’s position on Earth.
Once the GPS receiver makes this calculation, it can exhibit the latitude, longitude, altitude, and country grid to tell the current position of the device using GPS system. In order to make the navigation user-friendlier, most GPS receivers install this collected data into map files stored in the memory of the device. With the help of maps stored in the receiver’s memory or by connecting it to a computer that can hold more detailed maps in its memory, a person can see the detailed map of his area and find the way using the receiver’s latitude and longitude readouts. Along with this information the GPS receiver also provides valuable information like odometer, speedometer, time span and average speed of an installed GPS device.
A standard GPS receiver displays the correct place on a map at any particular location. Additionally, it also traces a path across the map as the person moves. By leaving the receiver on, a person can stay in constant communication with GPS satellites to see how his location is changing.
Max Adams is the publisher of http://www.infospotters.com - An ever growing collection of articles, tips, hints and ideas from all over the World. Here you can find facts on hundreds of subjects including sports, entertainment, technology and relationships.
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