GPS is the Global Positioning System. GPS uses satellite technology to enable a terrestrial terminal to determine its position on the Earth in latitude and longitude.
GPS receivers do this by measuring the signals from three or more satellites simultaneously and determining their position using the timing of these signals.
GPS operates using trilateration. Trilateration is the process of determining the position of an unknown point by measuring the lengths of the sides of an imaginary triangle between the unknown point and two or more known points.
In the GPS system, the two known points are provided by two GPS satellites. These satellites constantly transmit an identifying signal.
The GPS receiver measures the distance to each GPS satellite by measuring the time each signal took to travel between the GPS satellite and the GPS receiver.
The formula for this is:Distance = Velocity * Time
Velocity of the GPS signal is the speed of light, approximately 300,000 Km/s.
GPS transmissions occur on a frequency of 1575.42 and 1227.60 Mhz. Both of these frequencies are within the L Band.
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