Patent ID: 6542816
Filing Date: 2003-04-01
Classification: G01C

Abstract:
A communication navigation system which includes an information center and a vehicle mounted navigation apparatus, in which data concerning a recommended route from a current location of the navigation apparatus to a destination is transmitted from the information center to the navigation apparatus, and then route guidance is carried out by the navigation apparatus using the data transmitted from the information center, wherein the navigation apparatus comprises:road information storage means containing stored first road information including first road network data including a plurality of road links and first identification data of the first road information; data transmitting means for transmitting data of a current location and a destination of the navigation apparatus and the first identification data to the information center; data receiving means for receiving data of recommended route guidance information from the information center; route guidance data generating means for generating route guidance data based on the first road information stored in the road information storage means and based on the recommended route guidance information transmitted from the information center; and route guiding means for guiding a user of the navigation apparatus from the current location to the destination of the navigation apparatus using the route guidance data; and wherein the information center comprises: a database containing stored second road information including second road network data including a plurality of road links and second identification data of said second road information; data receiving means for receiving the transmitted data of the current location and the destination of the navigation apparatus and the transmitted first identification data; recommended route determining means for determining a recommended route, by extracting recommended road links from the second road network data stored in the database, from the current location to the destination received from the navigation apparatus, based on the second road information stored in the database; judging means for judging respectively whether or not each recommended road link along the recommended route is contained in the first road information, by comparing the first identification data transmitted from the navigation apparatus with the second identification data of the road information stored in the database; recommended route guidance information generating means for generating recommended route guidance information, based on the database, containing first enabling data enabling retrieval of first recommended road links from the road information storage means, the first recommended road links being those recommended road links judged to be contained in the first road information, and second enabling data enabling construction of second recommended road links, the second recommended road links being those recommended road links judged not to be contained in the first road information; and data transmitting means for transmitting said recommended route guidance information to the navigation apparatus.