Motor vehicle position recognizing system

• US 20020143442A1
• Filed: 09/27/2001
• Published: 10/03/2002
• Est. Priority Date: 03/27/2001
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Uehara, Naohisa
• Granted Patent: US 6,618,653 B2
• Time in Patent Office: Days
• US Class Current: 701/23
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

A motor vehicle position recognizing system which can ensure high accuracy for an arithmetic processing for determining a vehicle position in a transverse direction of a road by minimizing error involved in the arithmetic processing by suppressing occurrence of discontinuity even when a magnetic sensor whose output is destined for the arithmetic processing is changed over to another one. The system includes magnetic markers (1) laid on a road surface at predetermined locations for forming a magnetic field zone, a plurality of vehicle-onboard magnetic sensors (2) for detecting the intensity of the magnetic field zone formed by the magnetic markers (1), a vehicle position arithmetic means (3A) for arithmetically determining a position (Phr) of the motor vehicle in the transverse direction as a vehicle position on the basis of the field intensities detected by the magnetic sensors (2), and a vehicle position correcting means (6) for correcting an arithmetically determined value of the position of the motor vehicle as determined by the vehicle position arithmetic means (3A).

Claims

1. A motor vehicle position recognizing system, comprising:

signal zone forming means laid on a road surface at least at one predetermined location for forming a signal zone of a predetermined signal strength;

a plurality of signal strength detecting means mounted on a motor vehicle traveling on said road surface and disposed at a plurality of positions along a transverse direction substantially orthogonal to a traveling direction of said motor vehicle for detecting the signal strength of said signal zone;

vehicle position arithmetic means for arithmetically determining a position of said motor vehicle in a transverse direction as a vehicle position on the basis of the signal strength detected by at least one of said plural signal strength detecting means;

detecting means changeover means for changing over the signal strength detecting means whose output is used for an arithmetic operation for determining said vehicle position in dependence on maneuvering of said motor vehicle; and

vehicle position correcting means for correcting an arithmetically determined value of the position of said motor vehicle as determined arithmetically by said vehicle position arithmetic means in response to the changeover operation of said signal strength detecting means.

2. A motor vehicle position recognizing system according to claim 1,

wherein said vehicle position correcting means is so designed as to correct the arithmetically determined value of the position of said motor vehicle in response to the changeover operation of said signal strength detecting means so that the arithmetically determined values of the positions of said motor vehicle as determined arithmetically before and after said changeover of said signal strength detecting means, respectively, assume substantially midpoints between arithmetically determined values based on the signal strengths detected by said individual signal strength detecting means before and after the changeover of said signal strength detecting means, respectively.

3. A motor vehicle position recognizing system according to claim 1,

wherein said vehicle position correcting means is so designed as to correct said arithmetically determined value of the position of said motor vehicle so that coincidence is found among said vehicle positions determined on the basis of said detection signal strengths, respectively, when coincidence is detected among detection signal strengths derived from the outputs of said plural signal strength detecting means, respectively.

4. A motor vehicle position recognizing system according to claim 1,

wherein said signal zone forming means is constituted by magnetic markers for generating magnetic fields of a predetermined intensity, and

wherein said plurality of signal strength detecting means are constituted by a plurality of magnetic sensors for detecting said magnetic field intensities.

5. A motor vehicle position recognizing system according to claim 4,

wherein said vehicle position correcting means is so designed as to correct the arithmetically determined value of the position of said motor vehicle in response to the magnetic sensor changeover operation performed by said detecting means changeover means so that the arithmetically determined values of the positions of said motor vehicle as determined arithmetically before and after said changeover of said magnetic sensors, respectively, assume midpoints between arithmetically determined values based on the signal strengths detected by said magnetic sensors before and after the changeover of said magnetic sensors, respectively.

6. A motor vehicle position recognizing system according to claim 4,

wherein said vehicle position correcting means is so designed as to correct said arithmetically determined value of the position of said motor vehicle so that coincidence is found among said vehicle positions determined on the basis of said detected magnetic field intensities, respectively, when coincidence is detected among the detected magnetic field intensities derived from the outputs of said plurality of magnetic sensors, respectively.

7. A motor vehicle position recognizing system according to claim 6,

wherein said plurality of magnetic sensors are so designed as to detect magnetic field intensity in a vertical direction of said motor vehicle, and

wherein said vehicle position correcting means is so designed as to correct said arithmetically determined value of the position of said motor vehicle so that coincidence is found among the vehicle positions determined on the basis of the detected magnetic field intensities detected by said plurality of magnetic sensors, respectively, when coincidence is detected among the vertical field intensities derived from the outputs of said plurality of magnetic sensors, respectively.

8. A motor vehicle position recognizing system according to claim 7, further comprising:

fault decision means for determining a fault of said magnetic sensor,

wherein said fault decision means is so designed as to determine that said magnetic sensor suffers a fault when the arithmetically determined values of the position of said motor vehicle differ at least by a predetermined value notwithstanding that coincidence is found among said detected vertical field magnetic intensities before and after changeover of said magnetic sensors.

9. A motor vehicle position recognizing system according to claim 6,

wherein said plurality of magnetic sensors are so designed as to detect magnetic field intensity in a horizontal direction of said motor vehicle, and

wherein said vehicle position correcting means is so designed as to correct said arithmetically determined value of the position of said motor vehicle so that coincidence is found among the vehicle positions determined on the basis of the detected magnetic field intensities as detected by said plurality of magnetic sensors, respectively, when coincidence is detected among the horizontal field intensities derived from the outputs of said plurality of magnetic sensors, respectively.

10. A motor vehicle position recognizing system according to claim 9, further comprising:

fault decision means for determining a fault of said magnetic sensor,

wherein said fault decision means is so designed as to determine that said magnetic sensor suffers a fault when the arithmetically determined values of the position of said motor vehicle differ at least by a predetermined value notwithstanding that coincidence is found among said detected horizontal field magnetic intensities before and after changeover of said magnetic sensors.

11. A motor vehicle position recognizing system according to claim 4,

wherein said vehicle position correcting means is so designed that when said magnetic marker exists underneath one of said plural magnetic sensors, said vehicle position correcting means corrects the arithmetically determined value of said vehicle position such that the vehicle position determined on the basis of the detected field intensity derived from the output of said one magnetic sensor coincides with the vehicle position determined on the basis of the detected field intensity derived from the output of the magnetic sensor located adjacent to said one magnetic sensor.

12. A motor vehicle position recognizing system according to claim 11,

said plurality of magnetic sensors being so designed as to detect magnetic field intensity in the horizontal direction of said motor vehicle,

wherein said vehicle position correcting means is so designed that unless the horizontal field intensity is determined by one of said plurality of magnetic sensors, said vehicle position correcting means decides that said magnetic marker exists underneath said one magnetic sensor.

13. A motor vehicle position recognizing system according to claim 11,

wherein when the position of said magnetic marker as arithmetically determined on the basis of the detected field intensity derived from the output of one of said plurality of magnetic sensors coincides with the position of said one magnetic marker, decision is made that said magnetic marker exists underneath said one magnetic sensor.

14. A motor vehicle position recognizing system according to claim 11,

wherein said vehicle position arithmetic means is so designed that when said magnetic marker exists underneath said one magnetic sensor, said vehicle position arithmetic means arithmetically determines the correction factor so that the arithmetically determined value of said vehicle position as determined arithmetically on the basis of the field intensity detected by the magnetic sensor located adjacent to said one magnetic sensor coincides with a distance between said magnetic sensors.

15. A motor vehicle position recognizing system according to claim 14, further comprising:

fault decision means for making decision as to whether said magnetic sensor suffers a fault,

wherein said fault decision means is so designed as to decide that said magnetic sensor suffers a fault when said correction factor departs from a predetermined value range.

16. A motor vehicle position recognizing system according to claim 14,

wherein said vehicle position correcting means is so designed as to correct the arithmetically determined value of the vehicle position such that the vehicle positions determined arithmetically on the basis of the detected field intensities derived from the outputs of said plurality of magnetic sensors, respectively, coincide with one another.

17. A motor vehicle position recognizing system according to claim 16,

wherein said vehicle position arithmetic means is so designed as to arithmetically determined said correction factor such that a sum of absolute values of the arithmetically determined values of said vehicle positions determined on the basis of the detected field intensities derived, respectively, from the outputs of two of said plurality of magnetic sensors coincides with the distance between said magnetic sensors.

18. A motor vehicle position recognizing system according to claim 17, further comprising:

fault decision means for making decision as to whether said magnetic sensor suffers a fault,

wherein said fault decision means is so designed as to decide that said magnetic sensor suffers a fault when said correction factor departs from a predetermined value range.