A vehicle information system which includes an in-vehicle system 105 and
a centralized server system 120. The in-vehicle system communicates with
the server system using a wireless communication link 110, such as over
a cellular telephone system. A position system, such as a set of GPS satellites
140, provides positioning signals that are used by the in-vehicle systems,
and optionally by the centralized server system to increase the accuracy of position
estimates. In one version of the system, an operator specifies a destination to
an in-vehicle system which validates the destination. The in-vehicle system transmits
specification of the destination to a server system 125 at the centralized
server. The server system computes a route to the destination and transmits the
computed route to the in-vehicle system. The in-vehicle system guides the operator
along the route. If the in-vehicle system detects that the vehicle has deviated
from the planned route, it replans a new route to the destination using an in-vehicle
map database.
