Pioneer AVIC-D3 Owner's Manual - Page 139

NAVI/AV 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. With 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. Without map matching In tunnels or enclosed parking garages Under elevated roads or similar structures Appendix When driving among high buildings When driving through a dense forest or tall trees 137