On-vehicle information processor with map data and map data management

• US 6,397,144 B2
• Filed: 11/29/2000
• Issued: 05/28/2002
• Est. Priority Date: 11/30/1999
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakao, Yoshihisa, Takenaka, Shoichiro, Maegawa, Satoshi, Shimotani, Mitsuo, Umezu, Masaharu, Mikuriya, Makoto, Ikeuchi, Tomoya
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US09/725,208
• Publication Number:
  US 20010002456A1
• Time in Patent Office: 545 Days
• Field of Search: 701/206,207,208,209,210,211 340/995
• US Class Current: 701/208
• CPC Class Codes: G01C 21/387 Organisation of map data, e.g. version management or database structures

Abstract

An on-vehicle information processor is configured such that, when there is a request for access from application units to the same map data stored in a data management unit, a request analyzing unit maintains the map data unlocked so that the applications can access the map data.

Claims

1. An on-vehicle information processor for providing map information based on map data, comprising:

application processing means for providing map information based on map data and map management data;

a data reading unit for reading the map data and the map management data from a recording medium;

a data management unit for managing the map data and the map management data independently; and

a request analyzing unit for responding to a request from said application processing means to permit access from said application processing means to the map data and the map management data managed by said data management unit.

2. The on-vehicle information processor according to claim 1, wherein:

said data management unit acquires the map management data provided to said application means, so as to manage the map management data acquired;

said request analyzing unit reads the map management data from the recording medium via said data reading unit so as to supply the map management data thus read to said application means, when the map management data is required by said application means; and

said request analyzing unit supplies the map management data managed by said data management unit to said application means when the map management data is subsequently required by said application means.

3. The on-vehicle information processor according to claim 1, wherein said data management unit includes a map data cache and a control unit for controlling the map data cache.

4. The on-vehicle information processor according to claim 3, wherein the control unit in said data management unit controls the map data stored in said map data cache to be smaller in size than an upper limit.

5. The on-vehicle information processor according to claim 3, wherein said request analyzing unit grants access from a plurality of application means to the same map data stored in the map data cache.

6. The on-vehicle information processor according to claim 3, wherein:

the map data cache stores count information indicating number of application means accessing a storage area storing the map data, and

the control unit determines whether the map data stored in the map data cache that should be discarded, based on the count information stored in the map data cache.

7. The on-vehicle information processor according to claim 6, wherein:

the map data cache stores information relating to one of chronological sequence of storage of the map data and information indicating time of access to the map data, and

the control unit determines the map data stored in the map data cache that should be discarded, based on the information stored in the map data cache.