Map evaluation system and map evaluation method

• US 7,831,389 B2
• Filed: 02/19/2007
• Issued: 11/09/2010
• Est. Priority Date: 02/20/2006
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamada, Kazunao
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Amin; Bhavesh V
• Application Number:
  US11/708,160
• Publication Number:
  US 20070198177A1
• Time in Patent Office: 1,359 Days
• Field of Search: None
• US Class Current: 701/221
• CPC Class Codes: G01C 21/30 Map- or contour-matching

Abstract

An absolute position detector of a navigation device detects an absolute position of a vehicle. An on-map position of the vehicle is acquired based on the detected absolute position to be on a road map indicated by map data stored in the navigation device. Absolute positions detected by the absolute position detector are stored in association with on-map positions acquired based on the detected absolute positions as travel track information when the vehicle travels. An error of the map data as a reliability degree of the map data is set by comparing the travel track information with the map data.

Claims

1. A map evaluation system comprising:

a map data storage unit configured to store map data indicating a road map;

an absolute position detector configured to detect an absolute position of a vehicle by receiving electric waves from satellites;

an on-map position acquisition unit configured to acquire an on-map position of the vehicle using the detected absolute position, the on-map position being based on a road map indicated by the stored map data;

a track storing unit configured to store, as travel track information, absolute positions detected by the absolute position detector in association with on-map positions acquired by using the detected absolute positions when the vehicle travels;

a map reliability degree setting unit configured to set as a reliability degree of the map data, an error of the map data relative to the travel track information by comparing the travel track information with the map data; and

a track reliability degree setting unit configured to set a reliability degree of the travel track information based on a detection accuracy of the detected absolute position, the detection accuracy being variable based on a state where the absolute position is detected;

wherein

the track storing unit stores the set reliability degree of the travel track information in association with the travel track information, and

the map reliability degree setting unit sets the reliability degree of the map data only using travel track information which has a reliability degree exceeding a predetermined reference value.

2. The map evaluation system of claim 1, further comprising:

a track storing determination unit configured to determine whether a travel track of the vehicle is allowed to be stored based on the on-map position,

wherein the track storing unit stores the travel track information when it is determined that the travel track is allowed to be stored.

3. The map evaluation system of claim 2,

wherein the on-map position acquisition unit acquires the on-map position by performing an amendment to the detected absolute position to match with the road map indicated by the stored map data, and

wherein the track storing determination unit determines that the travel track is allowed to be stored when the amendment. to the detected absolute position is larger than a predetermined determination reference.

4. The map evaluation system of claim 2,

wherein the track storing determination unit determines that the travel track is allowed to be stored when the on-map position is within a region predetermined in the road map.

5. The map evaluation system of claim 1, further comprising:

a communications unit configured to communicate with an external server, which manages the map data, and to transmit the reliability degree of the map data to the external server.

11. The map evaluation system of claim 1, wherein an estimated error of the absolute position of the vehicle decreases as the number of satellites increases.

6. A map evaluation method for setting a reliability degree of map data in a map data storage unit, the method comprising:

detecting an absolute position of a vehicle by using an absolute position detector by receiving electric waves from satellites;

acquiring an on-map position of the vehicle by using the detected absolute position, the on-map position being based on a road map indicated by the stored map data;

storing, as travel track information, absolute positions detected by the absolute position detector in association with on-map positions acquired by using the detected absolute positions when the vehicle travels;

setting as a reliability degree of the map data, an error of the map data relative to the travel track information by comparing the travel track information with the map data; and

setting a reliability degree of the travel track information based on a detection accuracy of the detected absolute position, the detection accuracy being variable based on a state where the absolute position is detected;

wherein

the set reliability degree of the travel track information is stored in association with the travel track information, and

the reliability degree of the map data is set only using travel track information which has a reliability degree exceeding a predetermined reference value.

7. The map evaluation method of claim 6, further comprising:

determining whether a travel track of the vehicle is allowed to be stored based on the on-map position,

wherein the travel track information is stored when it is determined that the travel track is allowed to be stored.

8. The map evaluation method of claim 7,

wherein the on-map position is acquired by performing an amendment to the detected absolute position to match with the road map indicated by the stored map data, and

wherein it is determined that the travel track is allowed to be stored when the amendment to the detected absolute position is larger than a predetermined determination reference.

9. The map evaluation method of claim 7,

wherein it is determined that the travel track is allowed to be stored when the on-map position is within a region predetermined in the road map.

10. The map evaluation method of claim 6, further comprising:

transmitting the reliability degree of the map data by using a communications unit to an external server, which manages the map data.

12. The map evaluation method of claim 6, further comprising storing an estimated error of the absolute position of the vehicle wherein the estimated error decreases as the number of satellites increases.