Pioneer AVIC-D1 Handling Large Errors, When the positioning by GPS is impossible, Map matching

❒ If you use chains on your wheels for winter

NAVI/AV	driving or put on the spare wheel, errors may
	suddenly increase because of difference in
	wheel diameter. The system detects the fact
	that the tire diameter has changed, and auto-
	matically replaces the value for calculating
	distance.
	❒ If the ND-PG1 is used or if your vehicle is oper-
	ating in Simple hybrid mode, the distance cal-
	culation value cannot be replaced
	automatically.

Map matching

As mentioned, the GPS and dead reckoning sys- tems used by this Navigation System are suscep- tible 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 posi-

Appendix	tion by adjusting it to a nearby road. This is called
	map matching.

With map matching

Without map matching

Handling Large Errors

Positioning errors are kept to a minimum by com- bining GPS, Dead Reckoning, and map match- ing. 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.

In tunnels or enclosed parking garages

Under elevated roads or similar

When driving among high buildings

When driving through a dense forest or tall trees

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