Further Information
Accuracy & error calculation
Regarding Precision Accuracy
Since the GPS satellites are controlled by the US Department of Defense
they do have a very high level of accuracy, however a multipath due to
reflections from buildings and so on could cause errors to occur.
Regarding the Properties of the GPS ElectroMagnetic Waves and Signal Reception
If there are any obstacles between the GPS antenna and the GPS
satellite, electromagnetic-waves cannot be received from the satellite.
It is also impossible to use GPS positioning in the following locations as
at least three simultaneous electromagnetic-waves are necessary to
take measurements.
Also, if there are any obstacles around the GPS antenna,
electromagnetic-waves cannot be received from the satellite.
• In tunnels
• If the immediate area is enclosed by
large objects such as skyscrapers
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