Pioneer CNDV-50MT - Manual (Page 115)

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Map matching
As mentioned, the GPS and dead reckoning
systems used by this Navigation System are
susceptible to certain errors. Their calculations
may, on occasion, place you in a location on the
map where no road exists. In this situation, the
processing system understands that vehicles
travel only on roads, and can correct your
position by adjusting it to a nearby road. This is
called map matching.
Handling Large Errors
Positioning errors are kept to a minimum by
combining GPS, Dead Reckoning, and map
matching. However, in some situations, these
functions may not work properly, and the error
may become bigger.
When the positioning by GPS is
impossible
• If signals cannot be received from more than
two GPS satellites, GPS positioning does not
take place.
• 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.
With map matching
Without map matching
In tunnels or enclosed parking garages
Under elevated roads or similar
When driving among high buildings
MAN-CNDV-50MT-EN.book Page 113 Wednesday, May 4, 2005 1:49 PM