Pioneer AVIC-D1 Owner's Manual - Page 112

NAVI/AV ❒ If you use chains on your wheels for winter 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 automatically replaces the value for calculating distance. ❒ If the ND-PG1 is used or if your vehicle is operating in Simple hybrid mode, the distance calculation value cannot be replaced automatically. 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. In tunnels or enclosed parking garages With map matching Under elevated roads or similar Appendix Without map matching When driving among high buildings When driving through a dense forest or tall trees 110