119
-EN
Information
Fluctuation of the Current Position or
Tracks
The fluctuation can be made smaller by combining the GPS, the self-
contained navigation, and the map matching. However, these functions
may not operate correctly according to conditions, and fluctuation may
be considerable.
•
When only the radio waves of two GPS satellites or less can
be received, the positioning by GPS cannot be performed.
•
When the vehicle is in the following places, positioning by
GPS cannot be performed because the radio waves of the
GPS satellite are interrupted and cannot be received.
•
In the following cases, the radio waves of the GPS satellites
may be temporarily not be receivable due to radio
interference.
– When using a satellite phone or mobile phone near the GPS
antenna.
•
In the following cases, the GPS satellite signals may not be
receivable.
– A roof rack is used (GPS antenna installed on roof of car).
– A metallic object is near the GPS antenna (GPS antenna
installed inside car).
– A window film that contains metal is installed in the car (GPS
antenna installed inside car).
•
GPS satellites are managed by the United States Department
of Defence, and may transmit positional data that the satellite
intentionally shifted. The fluctuation of the positioning grows
at such time.
•
Measure the current position with the fluctuation of approx.
10 to 100 m when performing three dimension positioning.
The fluctuation of the two dimension positioning grows a little
in the case of three dimension positioning.
•
Insufficient accuracy may result when the location of GPS
satellites is unfavourable (when the satellites are in similar
direction or similar height). (When radio waves from two or
more satellites immediately above the vehicle and a very limit
horizon in north, south, east, and west is received, the best
accuracy is obtained for GPS positioning.)
•
For the accuracy of GPS positioning, the fluctuation in the
direction of height grows a little compared with the horizontal
direction.
Since satellite signals from around the earth’s opposite
hemisphere cannot be received, height comparison cannot
be sufficiently performed.
•
When you have driven a Y-junction with a small angle
•
When the roads are adjacent (such as expressway and
service road).
Fluctuation by GPS Positioning not
Acceptable
In tunnels and indoor
parking lots
Locations surrounded
by tall buildings
Locations surrounded
by tall trees
On the bottom level of
double-decker
motorways
When GPS satellite is low on
the horizon (angle below 10°),
obstructions sometimes make
normal reception impossible
Fluctuation by GPS Satellites
Other Fluctuations
