Car navigation map update system and car navigation terminal

• US 6,546,334 B1
• Filed: 06/28/2000
• Issued: 04/08/2003
• Est. Priority Date: 06/29/1999
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Izumi, Heikan, Fukuchi, Yushi, Abukawa, Masahiro
• Primary Examiner(s): NGUYEN, THU V
• Application Number:
  US09/604,970
• Time in Patent Office: 1,014 Days
• Field of Search: 701/23-26, 701/200-203, 701/207-210, 701/212, 340/988, 340/990-995, 342/357.13, 707/200, 707/203, 707/205, 707/511
• US Class Current: 701/208
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A car navigation map update system includes map update data delivery equipment and one or more car navigation terminals. The map update data delivery equipment includes a map update data broadcasting section for broadcasting map update data by radio waves. Each car navigation terminal receives the broadcast map update data, stores the map update data in a map update data storing medium, and utilizes the map update data in connection with map information data prestored in a map data recording medium. This enables the terminals to collect latest map data using a receiver already installed in the car navigation terminals without adding a data transmitter, thereby solving a problem of a conventional car navigation system which requires a data transmitter installed in the car navigation terminal for sending a message to a host to obtain the map update data, and hence complicates the configuration and increases the cost of the system.

Claims

1. A car navigation map update system comprising:

map update data delivery equipment including a map update data management section for managing a database containing rewritable map data, and a map update data broadcasting section for broadcasting map update data rewritten by the map update data management section;

a car navigation terminal that receives the map update data broadcast by said map update data delivery equipment, stores the map update data in a map update data storing medium, and utilizes the map update data stored in the map update data storing medium in connection with map information data stored in a map data recording medium to form at least a partial map;

said car navigation terminal forms an entire map by assembling partial map areas that are small subdivisions of map areas, and update the map on a partial map area basis by attaching an area identifier and a version number to each of the partial map areas; and

wherein said car navigation terminal comprises a received data processor, and

said received data processor compares the area identifiers and version numbers of the received map update data with those of the map information data stored in the map data recording medium and with those of the map update data stored in the map update data storing medium;

additionally stores a received map update data block into the map update data storing medium, when the received map update data block has a version number that is newer than that of a corresponding map information data block stored in the map data recording medium, and has an area identifier that disagrees with area identifiers of all map update data blocks on the map update data storing medium, and rewrites a map update data block on the map update data storing medium by a newly received map update data block, when the received map update data block has area identifier that agrees with that of the map update data block stored in the map update data storing medium, and has version number that is newer than that of the map update data block stored in the map update data storing medium.

2. The car navigation map update system according to claim 1, wherein said car navigation terminal comprises a map generator, and wherein said map generator retrieves map update data and map information data associated with designated map areas from said map update data storing medium and from said map data recording medium, and generates map data with replacing the map information data by the map update data in the designated map areas.

3. The car navigation map update system according to claim 1, wherein said map update data broadcasting section broadcasts the map update data repeatedly.

4. The car navigation map update system according to claim 1, further comprising a map update data update terminal, wherein said map update data storing medium is removably attached to said car navigation terminal, and the map update data update terminal rewrites the map update data on the map update data storing medium.

5. The car navigation map update system according to claim 1, wherein said map update data delivery equipment comprises instead of said map update data broadcasting section an entire map data broadcasting section for broadcasting all latest map data managed by said map data management section.

6. A car navigation terminal comprising:

a map information data recorder for recording map data in a map data recording medium in advance;

a receiver for receiving map update data broadcast by radio waves;

a map update data storage for storing map update data;

a map generator for combining map information data recorded in said map data recording medium with the map update data stored in said map update data storage;

a display unit for displaying combined map data; and

wherein said car navigation terminal comprises a received data processor, and wherein said received data processor compares the area identifiers and version numbers of the received map update data with those of the map information data stored in the map data recording medium and with those of the map update data stored in the map update data storage;

additionally stores a received map update data block into the map update data storage, when the received map update data block has a version number that is newer than that of a corresponding map information data block stored in the map data recording medium, and has area identifier that disagrees with area identifiers of all map update data blocks on the map update data storage, and rewrites a map update data block on the map update data storage by the newly received map update data block, when the received map update data block has area identifier that agrees with that of a map update data block stored in the map update data storage, and has version number that is newer than that of the map update data block stored in the map update data storage.

7. A method for updating a navigation map in a vehicle comprising:

managing a database containing rewritable map data so as to rewrite map update data,

broadcasting the rewritten map update data to a vehicle navigation terminal,

storing the broadcast map update data in a map update data storing medium,

forming at least a partial map using the stored map update data in connection with map information data stored in a map data recording medium,

assembling at least two partial map areas that are small subdivisions of map areas to form an entire map,

updating the entire map on a partial map area basis by attaching an area identifier and version number to each of the partial map areas,

comparing the area identifiers and the version numbers associated with the received map update data with the area identifiers and version numbers associated with the map information data and the area identifiers and version numbers associated with the stored map update data,

storing the received map update data into the map update data storing medium if the received map update data includes a map update data block whose version number is newer than that of a corresponding map information data block stored in the map data recording medium and whose area identifier disagrees with the area identifiers of all map update data blocks on the map update data storing medium, and

rewriting a map update block on the map update data storing medium using the received map update data if the received map update data includes a map update data block whose area identifier agrees with that of the map update data block stored in the map update data storing medium and whose version number is newer than that of the map update data stored in the map update data storing medium.

8. The method according to claim 7, further comprising:

retrieving map update data and map information data associated with designated map areas from the map update data storing medium and from the map data recording medium, and

generating map data by replacing the map information data by the map update data in the designated map areas.

9. The method according to claim 7, wherein the step of broadcasting further includes broadcasting the map update data repeatedly.

10. The method according to claim 7, wherein the map update data storing medium is removably attached, the method for rewriting a map update data block comprising rewriting the map update data block on the removably attached map update data storing medium.

11. The method according to claim 7, wherein the step of broadcasting further includes broadcasting all latest map data managed during map data management.

12. A method for providing navigation in a vehicle, the method comprising:

recording map information data in advance in a map data recording medium,

managing a database containing rewritable map data so as to rewrite map update data,

broadcasting the rewritten map update data to a vehicle navigation terminal,

receiving the broadcast map update data,

storing the received map update data in a map update data storing medium,

forming at least a partial map using the stored map update data in connection with map information data stored in the map data recording medium,

assembling at least two partial map areas that are small subdivisions of map areas to form an entire map,

updating the entire map on a partial map area basis by attaching an area identifier and version number to each of the partial map areas,

comparing the area identifiers and the version numbers associated with the received map update data with the area identifiers and version numbers associated with the map information data and the area identifiers and version numbers associated with the stored map update data in the map update data storing medium,

storing the received map update data into the map update data storing medium if the received map update data includes a map update data block whose version number is newer than that of a corresponding map information data block stored in the map data recording medium and whose area identifier disagrees with the area identifiers of all map update data blocks on the map update data storing medium, and

rewriting a map update block on the map update data storing medium using the received map update data if the received map update data includes a map update data block whose area identifier agrees with that of a map update data block stored in the map update data storing medium and whose version number is newer than that of the map update data stored in the map update data storing medium.