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HOW GPS works?
GPS is a complex and expensive
technology mainly used by military outfits. GPS works in a way
whereby it provides specially coded satellite signals that can
be processed in a GPS receiver, enabling the receiver to compute
position, velocity and time. Four GPS satellite signals are used
to compute positions in three dimensions and the time offset in
the receiver clock.
To locate the position, velocity
and time, GPS works in three segments: space, control, and user.
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The first segment, The Space
Segment, consists of a minimum of 24 operational satellites
in six circular orbits 20,200 km (10,900 NM) above the earth
at an inclination angle of 55 degrees with a 12 hour period.
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The Control Segment consists
of a master control station in Colorado Springs, with five
monitor stations and three ground antennas located throughout
the world.
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The User Segment consists
of the receivers, processors, and antennas that allow land,
sea, or airborne operators to receive the GPS satellite broadcasts
and compute their precise position, velocity and time.
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Exact process of GPS function can be broken
down into following steps:
First step is the most basic step that is the basis of GPS, known
as "triangulation" from satellites. For this step, it has to triangulate. It means a GPS receiver measures
distance using the travel time of radio signals. To measure travel time and distance, GPS uses various tricks and
careful monitoring. GPS needs very accurate timing which it achieves
with some tricks. Finally you must correct for any delays the signal experiences
as it travels through the atmosphere |
HOW GPS works?