Storage device, navigation device, and map database creation method

• US 9,506,760 B2
• Filed: 07/29/2013
• Issued: 11/29/2016
• Est. Priority Date: 08/02/2012
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Sakakibara, Hiroaki
• Primary Examiner(s): Butler, Rodney
• Assistant Examiner(s): BRUSHABER, FREDERICK M
• Application Number:
  US14/411,981
• Publication Number:
  US 20150149082A1
• Time in Patent Office: 1,219 Days
• Field of Search: 701/461
• US Class Current: 1/1
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01C 21/387 Organisation of map data, e.g. version management or database structures
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

A storage device includes a map database having at least two specified sub-blocks and at least one non-specified sub-block. Each specified sub-block is correlated to a measurement position coordinate obtained from an external server by a measurement. The measurement position coordinate of each specified sub-block is stored in the storage device. The non-specified sub-block is directly or indirectly sandwiched by the two specified sub-blocks along a road. A measurement position coordinate of the non-specified sub-block is stored in the storage device when a distance between the measurement position coordinate and an estimation position coordinate of the non-specified sub-block is equal to or longer than a predetermined distance, and the measurement position coordinate of the non-specified sub-block is not stored in the storage device when the distance between the measurement position coordinate and the estimation position coordinate of the non-specified sub-block is shorter than the predetermined distance.

Claims

1. A map database storage device for a navigation apparatus of a vehicle, the map database storage device comprising:

a processor; and

a map database storage coupled to the processor, the map database storage storing therein a map database, wherein

the map database includes a plurality of link data of a plurality of links that correspond to a plurality of roads, and each of the plurality of links connects two adjacent nodes,

the map database includes at least two specified sub-blocks and at least one non-specified sub-block,

each of the two specified sub-blocks is correlated to a measurement position coordinate obtained from an external source, the measurement position coordinate is a position coordinate obtained by a measurement,

the map database further includes (i) the measurement position coordinate of each of the two specified sub-blocks, and (ii) the plurality of link data for specifying a position coordinate of the non-specified sub-block, the plurality of link data and the measurement position coordinates are stored in different storage locations from each other in the map database,

the non-specified sub-block is directly or indirectly sandwiched by the two specified sub-blocks along one of the plurality of roads,

the processor is configured to

store, in the map database storage, a measurement position coordinate of the non-specified sub-block when a distance between the measurement position coordinate of the non-specified sub-block and an estimation position coordinate of the non-specified sub-block is determined to be equal to or longer than a predetermined distance, the measurement position coordinate of the non-specified sub-block is obtained from the external source and the estimation position coordinate of the non-specified sub-block is calculated by a proportion calculation based on the measurement position coordinates of the two specified sub-block, and

not store, in the map database storage, the measurement position coordinate of the non-specified sub-block when the distance between the measurement position coordinate of the non-specified sub-block and the estimation position coordinate of the non-specified sub-block is determined to be shorter than the predetermined distance.

2. The map database storage device according to claim 1,

wherein, in an island-shaped area, which is an area having an island shape and includes the sub-blocks positioned along the road, the two specified sub-blocks are positioned at respective ends of the island-shaped area.

3. The map database storage device according to claim 1, wherein

the processor is further configured to determine the predetermined distance based on a maximum capacity of a memory region of the map database storage for storing the measurement position coordinate of each of the two specified sub-blocks and the non-specified sub-block, and the predetermined distance decreases with an increase of the maximum capacity of the memory region.

4. A navigation device determining a position coordinate of an object sub-block based on measurement position coordinates stored in a map database of a map database storage device, wherein the map database of the map database storage device includes:

a plurality of link data of a plurality of links that correspond to a plurality of roads, and each of the plurality of links connects two adjacent nodes,

at least two specified sub-blocks and at least one non-specified sub-block;

each of the two specified sub-blocks is correlated to a measurement position coordinate obtained from an external source, the measurement position coordinate is a position coordinate obtained by a measurement;

the map database further includes (i) the measurement position coordinate of each of the two specified sub-blocks, and (ii) the plurality of link data for specifying a position coordinate of the non-specified sub-block, the plurality of link data and the measurement position coordinates are stored in different storage locations from each other in the map database;

the non-specified sub-block is directly or indirectly sandwiched by the two specified sub-blocks along one of the plurality of roads;

the map database storage stores a measurement position coordinate of the non-specified sub-block when a distance between the measurement position coordinate of the non-specified sub-block and an estimation position coordinate of the non-specified sub-block is determined to be equal to or longer than a predetermined distance, the measurement position coordinate of the non-specified sub-block is obtained from the external source and the estimation position coordinate of the non-specified sub-block is calculated by a proportion calculation based on the measurement position coordinates of the two specified sub-block; and

the map database storage does not store the measurement position coordinate of the non-specified sub-block when the distance between the measurement position coordinate of the non-specified sub-block and the estimation position coordinate of the non-specified sub-block is determined to be shorter than the predetermined distance,

the navigation device comprising;

a processor cooperative with the map database storage, the processor is configured to

determine, in an existence determination section, whether the measurement position coordinate of the object sub-block is stored in the map database;

calculate, in a position coordinate estimation section, the position coordinate of the object sub-block by a proportion calculation based on the measurement position coordinates of the two specified sub-blocks positioned along the road, the object sub-block being sandwiched between the two specified sub-blocks in a contacted manner or in a non-contacted manner; and

determine, in a position coordinate determination section, the measurement position coordinate of the object sub-block as the position coordinate of the object sub-block when the existence determination section determines that the measurement position coordinate of the object sub-block is stored in the map database, and the position coordinate determination section further determines the estimation position coordinate of the object sub-block as the position coordinate of the object sub-block when the existence determination section determines that the measurement position coordinate of the object sub-block is not stored in the map database.

5. The navigation device according to claim 4, further comprising

the map database storage that stores the map database.

6. The navigation device according to claim 4, wherein the processor is further configured to,

for an island-shaped area, which is an area having an island shape and includes the sub-blocks positioned along the road, position the two specified sub-blocks at respective ends of the island-shaped area.

7. The navigation device according to claim 4, wherein the processor is further configured to

determine the predetermined distance based on a maximum capacity of a memory region of the map database storage for storing the measurement position coordinate of each of the two specified sub-blocks and the non-specified sub-block, and the predetermined distance decreases with an increase of the maximum capacity of the memory region.

8. A map database creation method to create a map database for a navigation apparatus of a vehicle, comprising:

storing, by a processor, in a map database stored on a map database storage device, (i) measurement position coordinates of at least two specified sub-blocks, and (ii) a plurality of link data of a plurality of links that correspond to a plurality of roads, the plurality of link data and the measurement position coordinates are stored in different storage locations from each other in the map database, each of the plurality of links connecting two adjacent nodes, the measurement position coordinates being provided by an external source and being obtained by a measurement, the two specified sub-blocks being included in an island-shaped area on an electronic map and the island-shaped area further including a plurality of non-specified sub-blocks positioned along one of a plurality of roads, the non-specified sub-blocks being sandwiched by the two specified sub-blocks that are positioned on respective ends of the island-shaped area along the one of the plurality of roads, the measurement position coordinates of the at least two specified sub-blocks being used for specifying a position coordinate of each of the plurality of non-specified sub-blocks;

calculating, by the processor, an estimation position coordinate of each of the non-specified sub-blocks by a proportion calculation based on the measurement position coordinates of the two specified sub-blocks;

when a distance between an estimation position coordinate of an object sub-block and a measurement position coordinate of the object sub-block is determined to be equal to or longer than a predetermined distance, storing, by the processor, in the map database stored on the map database storage, the measurement position coordinate of the object sub-block as the position coordinate of the object sub-block, the object sub-block being one of the non-specified sub-blocks, the estimation position coordinate of the object sub-block being calculated by the proportion calculation and the measurement position coordinate of the object sub-block being obtained from the external source; and

when the distance between the estimation position coordinate of the object sub-block and the measurement position coordinate of the object sub-block is determined to be shorter than the predetermined distance, skipping the storing of the measurement position coordinate of the object sub-block.

9. The map database creation method according to claim 8, further comprising

positioning, by the processor, for an island-shaped area, which is an area having an island shape and includes the sub-blocks positioned along the road, the two specified sub-blocks at respective ends of the island-shaped area.

10. The map database creation method according to claim 8, further comprising

determining, by the processor, the predetermined distance based on a maximum capacity of a memory region of the map database storage for storing the measurement position coordinate of each of the two specified sub-blocks and the non-specified sub-block, and the predetermined distance decreases with an increase of the maximum capacity of the memory region.