Handling Large Errors - Pioneer AVIC-F980DAB Operation Manual

Appendix

Handling large errors

Positioning errors are kept to a minimum by combining GPS,
dead reckoning and map matching. However, in some situa-
tions, these functions may not work properly, and the error may
become bigger.
When positioning by GPS is
impossible
 GPS positioning is disabled if signals cannot be received
from more than two GPS satellites.

In some driving conditions, signals from GPS satellites may
not reach your vehicle. In this case, it is impossible for the
system to use GPS positioning.
In tunnels or enclosed parking garages
Under elevated roads or similar structures
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When driving among high buildings
When driving through a dense forest or tall trees
 If a car phone or mobile phone is used near the GPS aerial,
GPS reception may be lost temporarily.
 Do not cover the GPS aerial with spray paint or car wax,
because this may block the reception of GPS signals. Snow
buildup can also degrade the signals, so keep the aerial
clear.
p If a GPS signal has not been received for a long time, your
vehicle's actual position and the current position mark on
the map may diverge considerably or may not be updated. In
such case, once GPS reception is restored, accuracy will be
recovered.
Conditions likely to cause noticeable
positioning errors
For various reasons, such as the state of the road you are trav-
elling on and the reception status of the GPS signal, the actual
position of your vehicle may differ from the position displayed on
the map screen.

If you make a slight turn.
 If there is a parallel road.
 If there is another road very nearby, such as in the case of an
elevated motorway.
 If you take a recently opened road that is not on the map.