Navigation device and map data updating method thereof

1. A navigation device comprising:

a map database storing map data divided into predetermined update units, each update unit corresponding to a region obtained by dividing a map into a plurality of regions and each update unit respectively including identification information identifying the corresponding region and version information indicating a present update version;

receiving means for receiving, via a communication network, update data generated in update units corresponding to the update units of the map data, each generated unit of update data including difference information indicating an update content of the generated update data as a difference with the map data of the corresponding update unit stored in the map database, identification information identifying the corresponding region for the unit of update data, and version information indicating a post-update update version;

reading means for reading the update data from a recording medium storing a plurality of units of the update data; and

updating means for performing a differential update of the map data stored in the map database using the update data received by the receiving means or read by the reading means,

wherein, when performing an update of the map data using the update data stored on the recording medium, the updating means extracts the update data units having identification information that matches the identification information of the update units of map data stored in the map database and having version information indicating a later update version than the update version of the update units of map data stored in the map database from the plurality of units of the update data stored on the recording medium, and performs a differential update of the update units of map data using the extracted update data units.

2. The navigation device according to claim 1 , wherein, when a plurality of update data units having the identification information that matches the identification information of the map data and having version information indicating a later update version than the update version of the map data exist, the updating means performs the differential update of the map data on the basis of the version information of the respective update data units such that the update data is applied in order from the update data unit having the oldest update version.

3. The navigation device according to claim 2 , wherein the version information of an update data unit indicates an identical update version in relation to a plurality of update data units generated at an identical generation time but having different update map data.

4. The navigation device according to claim 3 , wherein, in addition to the version information, update data units include past version information indicating a past update version of the update data relating to the update map data.

5. The navigation device according to claim 2 , wherein, in addition to the version information, update data units include past version information indicating a past update version of the update data relating to an update unit of map data stored in the map database.

6. The navigation device according to claim 2 , wherein the recording medium stores update data for a plurality of map data update units included in a predetermined geographical area as update subjects in all update versions generated within a predetermined time period.

7. The navigation device according to claim 1 , wherein the version information of an update data unit indicates an identical update version in relation to a plurality of update data units generated at an identical generation time but having different update map data.

8. The navigation device according to claim 7 , wherein, in addition to the version information, update data units include past version information indicating a past update version of the update data relating to an update unit of map data stored in the map database.

9. The navigation device according to claim 8 , wherein the recording medium stores update data for a plurality of map data update units included in a predetermined geographical area as update subjects in all update versions generated within a predetermined time period.

10. The navigation device according to claim 7 , wherein the recording medium stores update data for a plurality of map data update units included in a predetermined geographical area as update subjects in all update versions generated within a predetermined time period.

11. The navigation device according to claim 1 , wherein, in addition to the version information, update data units include past version information indicating a past update version of the update data relating to an update unit of map data stored in the map database.

12. The navigation device according to claim 1 , wherein the recording medium stores update data for a plurality of map data update units included in a predetermined geographical area as update subjects in all update versions generated within a predetermined time period.

13. A map data updating method for a navigation device, wherein, when a differential update is performed on map data using update data received via a communication network or read from a recording medium in a navigation device having a map database that stores map data divided into predetermined update units, each update unit corresponding to a region obtained by dividing a map into a plurality of regions and each update unit respectively including identification information identifying the corresponding region and version information indicating a present update version,

the update data are generated in update data units corresponding to the update units of the map data stored in the map database so as to include difference information indicating an update content of update subject map data as a difference with map data of the corresponding update unit stored in the map database, identification information identifying the corresponding region for the unit of update data, and version information indicating a post-update update version, and

when an update of the map data is performed by reading the update data from the recording medium storing a plurality of units of update data, the update data having identification information that matches the identification information of the update units of map data stored in the map database and having version information indicating a later update version than the update version of the update units of map data stored in the map database are extracted from the plurality of units of the update data stored on the recording medium, and a differential update of the update units of map data in the map database is performed using the extracted update data.