Mazda ZOOM-ZOOM BT-50, Owner'S Manual

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NAVIGATION (Models with NAVI)
Accuracy & Error Calculation
Precision accuracy
Since the GPS satellites are controlled by the US Department of Defense, they provide
a very high level of accuracy, however, a multipath due to reflections from buildings
and so on could cause errors to occur.
Properties of GPS electromagnetic waves and signal reception
If there are any obstacles between the GPS antenna and the GPS satellite, it will not
be possible to receive electromagnetic waves 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.
Furthermore, if there are any obstacles around the GPS antenna, it will not be possible
to receive electromagnetic waves from the satellite.
• In tunnels
• If the immediate area is enclosed by large objects such as skyscrapers
• In underground buildings and indoor parking lots
• In places with many overgrown trees, etc.
• Under elevated roads
• Roads at the base of cliffs and caves
NOTE
• Because the GPS satellite is in orbit around the earth, the reception status of
electromagnetic waves changes depending on their position at that point in time,
even if your vehicle is in the same place. Furthermore, electromagnetic waves from
satellites near the horizon can be easily influenced by surrounding obstacles.
• At times, the accuracy of satellites under the control of the US Department of
Defense will drop intentionally.