Map Matching - Pioneer AVIC-505 Owner's Manual

Handling large errors
If you use chains on your wheels for winter driving, or if you need to use the spare wheel, the
errors may appear to suddenly increase as a result of the different wheel diameter. To prevent
corruption of learning data that has been gradually built up about your vehicle, learning
automatically stops when such errors suddenly appear.
• If for any reason GPS signals cannot be picked up, learning and error correction are not possible. If
GPS positioning has been operating for only a short time, your vehicle's actual position and the
current location mark on the map may diverge considerably. Once GPS reception is restored,
accuracy will be recovered within about two hours.
• There are two learning memories, so the system can learn about and compensate for two different tyre
sets, such as summer and winter tyres. (See "Selecting a calibration memory" on page 111 for details.)

Map matching

As mentioned, the GPS and dead reckoning systems used by this Mobile 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 is able to correct your position by adjusting it to a nearby road. This
is called map matching.
With map matching
With no map matching