Road information sensing system, method and program

• US 8,370,028 B2
• Filed: 04/18/2007
• Issued: 02/05/2013
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamada, Kazunao
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Khatib, Rami
• Application Number:
  US11/787,910
• Publication Number:
  US 20070250263A1
• Time in Patent Office: 2,120 Days
• Field of Search: 701/1, 701/36, 701/45, 701/49, 701/200, 701/205, 701/207, 701/208, 701/209, 701/213, 701/300, 701/116, 701/117, 701/400, 701/408, 701/409, 701/426, 701/445, 701/446, 701/448, 701/469, 701/495, 701/518, 701/519, 701/527, 701/534, 340/901, 340/903, 340/988, 340/995.1, 340/995.18, 340/995.24, 340/995.25
• US Class Current: 701/49
• CPC Class Codes: B60Q 1/085 due to special conditions, e.g. adverse weather, type of road, badly illuminated road signs or potential dangers B60Q1/10, B60Q1/12, B60Q1/1423 take precedence
• CPC Class Codes: B60Q 2300/112 Vehicle speed
• CPC Class Codes: B60Q 2300/134 Yaw
• CPC Class Codes: B60Q 2300/146 Abnormalities, e.g. fail-safe
• CPC Class Codes: B60Q 2300/322 Road curvature
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01C 3/00 Measuring distances in line of sight; Optical rangefinders tapes, chains or wheels for measuring length G01B3/00; active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves, G01S17/48

Abstract

A GPS sensor senses a current position of a vehicle. A map database stores map data. A controller obtains road information of a road ahead of the vehicle from the map data based on the sensed current position of the vehicle. Then, the controller measures a distance from the vehicle to a predetermined object, which serves as a sensing subject, on the road when the obtained road information is predetermined road information. Then, the controller outputs the measured distance as control information of the vehicle.

Claims

1. A road information sensing system on a vehicle, comprising:

means for sensing a current position of the vehicle;

means for storing map data;

means for obtaining road information of a road ahead of the vehicle from the map data based on the current position of the vehicle;

means for measuring a distance from the vehicle to one predetermined object selected from a plurality of predetermined objects on the road only when the road information is predetermined road information, which is contained in the map data and indicates one of a curve in the road, a railway crossing, a tunnel and an intersection located on the road ahead of the vehicle on a map of the map data;

means for computing a predicted error which indicates a degree of accuracy of the current position of the vehicle;

means for determining a degree of reliability of the current position of the vehicle based upon the computed predicted error;

means for outputting the distance and the degree of reliability of the current position of the vehicle as control information of the vehicle; and

means for controlling a device of the vehicle based on the control information including both the distance and the degree of reliability of the current position of the vehicle;

wherein

the measuring means changes the one predetermined object based on the road information.

2. The road information sensing system according to claim 1, wherein the outputting means also outputs a measurement time at which the distance is measured with the measuring means, as the control information.

3. The road information sensing system according to claim 1, wherein the measuring means measures the distance from the vehicle to the one predetermined object on the road through use of a radar.

4. The road information sensing system according to claim 1, wherein the controlling means controls a headlight of the vehicle as the device of the vehicle in such a manner that an optical axis of the headlight is adjusted based on the control information.

5. The road information sensing system according to claim 1, further comprising means for setting the one predetermined object according to the obtained road information, which is obtained with the obtaining means.

6. The road information sensing system according to claim 1, wherein the controlling means varies an amount of control of the device based on the degree of reliability of the current position of the vehicle.

7. The road information sensing system according to claim 1, wherein the one predetermined object is one of a crossing bar, a signboard and a traffic light.

8. A road information sensing method comprising:

sensing a current position of a vehicle;

obtaining road information of a road ahead of the vehicle from map data based on the current position of the vehicle;

setting a predetermined object from a plurality of predetermined objects based on the obtained road information

measuring a distance from the vehicle to the predetermined object on the road only when the road information is predetermined road information, which is contained in the map data and indicates one of a curve in the road, a railway crossing, a tunnel and an intersection located on the road ahead of the vehicle on a map of the map data;

computing a predicted error which indicates a degree of accuracy of the current position of the vehicle;

determining a degree of reliability of the current position of the vehicle based upon the computed predicted error;

outputting the distance and the degree of reliability of the current position of the vehicle as control information of the vehicle; and

controlling a device of the vehicle based on the control information including both the distance and the degree of reliability of the current position of the vehicle.

9. A computer program embodied on a computer readable medium to perform the method of claim 8.

10. The road information sensing method according to claim 8, wherein the step of measuring the distance from the vehicle to the predetermined object includes using radar to measure the distance from the vehicle to the predetermined object.

11. The road information sensing method according to claim 8, wherein the step of controlling the device of the vehicle includes controlling a headlight of the vehicle as the device of the vehicle in such a manner that an optical axis of the headlight is adjusted based on the control information.

12. The road information sensing method according to claim 8, wherein the step of controlling the device of the vehicle includes varying an amount of control of the device of the vehicle based upon the degree of reliability of the current position of the vehicle.

13. The road information sensing method according to claim 8, wherein the step of setting the predetermined object sets the predetermined object to one of a crossing bar, a signboard and a traffic light.