GPS Measurement 1-8
GPS Measurement
GPSGPS is the acronym for Global Positioning System.
The MMCS uses GPS satellites that orbit the Earth
in space at an altitude of approximately 20,000km.
Electromagnetic waves from at least three of these
satellites are received on the Earth by the system,
making it possible to learn the current position.
Map MatchingWhen traveling with just the GPS, there may be errors
in the current position display. In such case, “map
matching” is the function that compensates for this
error by assuming that vehicles travel on roads and
placing the current position on a nearby road.
GPS antenna positionThe position of the vehicle is determined from the
weak electromagnetic waves from GPS satellites
received by the GPS antenna.
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NOTESince it may not be possible to accurately display the
vehicle position if the electromagnetic waves from
the GPS satellite are blocked, be sure to obey the
following:
carbon to the window glass.
antenna.
GPS antenna.
Situations where accurate measurement is not
possible
In situations such as the following, accurate
measurement may not be possible.
The US Tracking and Control Center controls the
satellites. Sometimes the electromagnetic waves are
stopped during upgrades or repairs to the system.
NOTEsatellites by placing objects on or around the GPS
antenna.
of the GPS antenna, as it could prevent accurate
measurement.
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