Basics of GPS:
GPS works when signals gets transmitted from satellites in space and get received by receivers on or near Earth. Timing is used to determine the distance of each satellite which gives the knowledge of satellite positions on earth. The satellites also transmit information about their positions and the receiver becomes able to calculate the distance from the satellite to the receiver. A fully operational GPS satellite system features 24 operational satellites and the satellites are in one of the six orbits. Each orbit has four satellites at 55 degree to the equatorial plane. It ensures that between five to eight satellites can be accessed any time at any point on the Earth.
If GPS receivers are economically manufactured then they can provide information to within a number of metres. GPS receivers are now fitted to motor vehicles and private individuals also use these receivers to a large extent these days. Primarily GPS is used for military navigation system.
Know about GPS satellites and receivers:
Satellites keep orbiting above the Earth and heavy controls are kept on these satellites as if these satellites are at error, then the final results will also be mistaken. An atomic clock is kept in the satellites to ensure accurate time signals. GPS satellites have a design life of ten years but still spares are held in orbit so that unexpected failures don't cost much. GPS receivers use digital signalling processing techniques. Transmissions from satellites are done through spectrum technology and the signals are correlated by signal processors to recover data. The GPS receivers in use must be kept in open as they can't operate inside buildings.
How GPS receivers work:
GPS receivers follow certain processes in their functions. 2-D Trilateration, 3-D Trilateration and GPS calculations are some of the processes that GPS receivers follow while functioning. Radio waves are used in GPS receivers for electromagnetic energy. At a particular time the satellite begins transmitting a long digital pattern and when the signal reaches the receiver its transmission of the pattern lags a bit. This measurement can be done through clocks and nanoseconds on those clocks, rather atomic clocks.
GPS control network:
GPS satellites are monitored and controlled from the ground and contact with each satellite is highly required to maintain the level of performance. Information from remote stations is passed to the main operational centre at Colorado Springs and then proper assessment of the information is done. Orbit and clock performance are closely monitored.
GPS signal basics and signal data:
GPS satellites transmit variety of signals and there are two main frequencies which are used in the transmission of the GPS signal. GPS signal carries three types of data: Pseudo-random code, Ephemeris data and Almanac data.
GPS Applications:
As we said earlier, GPS is primarily used as military navigational assistance. American Department of Defense runs GPS but now it's applied for several commercial purposes all across the globe like aircraft navigation, ship navigation and any kind of location information. Cost effective GPS receivers are available these days and they are integrated into satNav systems in motor vehicles so that navigation becomes easy without any additional map.
GPS has brought a revolution in global navigation as before its arrival, navigation systems were limited to local spheres without any kind of accuracy or flexibility.
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