In this time and age, you probably have heard about GPS. Chances are you've seen what the device looks like on television and in James Bond films on the widescreen. But the design of the GPS came after the development of other navigation equipment such as the LORAN and the Decca Navigator of the 1940s.
The Global Positioning System which is more commonly known as GPS is, at present, the only fully functional Global Navigation Satellite System (GNSS). This means that more then twenty GPS satellites are currently orbiting the Earth. These satellites send signals to various GPS receivers providing information like location, speed and direction which are pertinent in basic navigation.
The first GPS was launched in the late 70s. Since then, it has developed into a very important piece of equipment not only in the field of navigation but has directly improved the providing of other services as well. GPS technology has been used in map-making and land surveying as well as determining calamity struck areas, identifying hungry stricken nations, and the like. GPS has become a scientific tool to aid studies on earthquakes, volcano eruptions, storm and hurricane formations, and other naturally occurring phenomena.
GPS was first developed by the United States Department of Defense. At first it had a very long name. The device was known as NAVSTAR GPS which is short for Navigation Satellite Timing and Ranging Global Positioning System. The military still holds the control over the satellite constellation being used by GPS users. It takes millions of dollars to maintain and operate. Even so, the general public are able to use GPS technology.
How does it work? Basically,
GPS uses a technique called trilateration. A
GPS receiver will calculate its position in reference to three or more
GPS satellites. The receiver will measure the distance between the satellites and the time delay of the transmission and receipt of the radio signal. Plus, signals being sent carry information about the satellites' location. With this information, the
GPS receiver is then able to compute its current position.
A current GPS is made up of three major segments, in particular the space segment or SS, a control segment or CS, and a user segment or US. The SS refers to the GPS satellites, or Space Vehicles (SV) that are orbiting the Earth. The control segment refers to ground control stations which monitor GPS satellites and its services. When it comes to the user segment, GPS signals are received by a number of channels