Abstract: A communication route guidance system provides exchange of data between an information center and each of a plurality of mobile units such as vehicles. The information center has the latest road data and searches it to prepare recommended route guidance data in response to a request from the mobile unit. The reccommended route guidance data is divided into a plurality of data segments, each usable as an independent guidance instruction in the mobile unit. The mobile unit has stored therein road data similar to the road data in the information center and determines if data communication with the information center is available. In a case where the mobile unit can not communicate with the information center, the mobile unit prepares route guidance based on the road data stored in the mobile unit. It thereby becomes possible to guide the user even in the case that the mobile unit can not communicate with the information center.

Abstract: A navigation system includes a navigation center and at least one moving body. The navigation center of the navigation system comprises memory means for storing navigation information; updating means for constantly updating the navigation information stored in the memory means; route searching means for setting a route from a current position of the moving body to a destination on the basis of the newest navigation information updated by the updating means; dividing means for dividing the searched route into at least two portions; extracting means for extracting navigation data concerning at least a head portion of the divided route from the memory means; transmitting means for transmitting to the moving body the extracted navigation data; and control means.

Abstract: In a communications navigation system, data is transmitted and received between a navigation base apparatus provided at a navigation base and each of a plurality of navigation apparatuses provided in moving bodies such as vehicles using communication. A determining section of the navigation base apparatus determines untraveled route portion by comparing user's information stored in a user information storage with information of a recommended route provided by a route search section. The navigation base apparatus extracts necessary route/guidance information for untraveled route portion determined by the determining section from route/guidance data stored in a database, and then transmits the extracted route/guidance data to the navigation apparatus identified by the identification information. The route/guidance information may be transmitted to the navigation apparatus in the form of segmented data.

Abstract: A navigation system includes a navigation center and a plurality of navigation apparatuses each of which has a data storage that stores various information. In this navigation system, data (coordinate data of each of traveling intersections) concerning a recommended route is transmitted from the navigation center to the navigation apparatus, and then route guidance is carried out in the navigation apparatus using the data received from the navigation center. In the case where the navigation apparatus has intersection data for an intersection specified by the data received from the navigation center, the navigation apparatus extracts the intersection data for the intersection from the data storage. Further, in the case where the navigation center does not have intersection data for an intersection specified by the data received from the navigation center, the navigation apparatus establishes the intersection as a newly-built intersection on the recommended route.

Abstract: Disclosed is a communicatory navigation system including an information center (150), at least one navigation unit (100) each mounted on a vehicle and communication means for allowing bi-directional data communication between the information center and the navigation unit. Data transmission from the navigation unit to the information center is made during a period of communication that begins when the navigation unit become communicable with the information center and ends when the bi-directional data communication therebetween is disconnected. The navigation unit is provided with a drive route history memory area (131) and an instrument operation history memory area (132), and data in these memory areas are transmitted to the information center, together with the vehicle current position data and the destination position data.

Abstract: A commucations navigation system in which data is transmitted and received between a navigation base apparatus provided at a navigation base and a vehicle navigation apparatus provided in a vehicle using communication. The vehicle navigation apparatus is adapted to transmit at least data concerning the current position of the vehicle and the destination thereof to the navigation base apparatus, and the navigation base apparatus stores navigation data in its data base and is adapted to determine a recommended route based on the transmitted data of the current position of the vehicle and the destination thereof and then extract data of the recommended route from the navigation data stored in the data base and transmit the extracted data to the navigation apparatus.

Abstract: Disclosed is a communicatory navigation system including an information center (150), at least one navigation unit (100) each mounted on a vehicle and communication means for allowing bi-directional data communication between the information center and the navigation unit. Data transmission from the navigation unit to the information center is made during a period of communication that begins when the navigation unit become communicatable with the information center and ends when the bi-directional data communication therebetween is disconnected. The navigation unit is provided with a drive route history memory area (131) and an instrument operation history memory area (132), and data in these memory areas are transmitted to the information center, together with the vehicle current position data and the destination position data.