Detection of occurrence of horizontal displacement of radar axis, determination of amount of axis displacement, and correction of axis displacement

• US 20030034913A1
• Filed: 08/09/2002
• Published: 02/20/2003
• Est. Priority Date: 08/15/2001
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: Asanuma, Hisateru, Kishida, Masayuki
• Granted Patent: US 6,750,811 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4056 specially adapted to FMCW
• CPC Class Codes: G01S 7/4091 during normal radar operation
• CPC Class Codes: G01S 7/4972 Alignment of sensor

Abstract

The occurrence of an axis displacement in a horizontal direction in a vehicle-to-vehicle distance controlling radar is detected, the amount of the axis displacement is determined, and an azimuth angle is corrected using the thus determined amount of the axis displacement. The frequency with which vehicle-to-vehicle distance control is released or re-set is measured and, if the frequency is higher than a threshold, it is determined that the axis is displaced. The amount of the axis displacement is determined from the angle of the locus of a stationary target. The azimuth angle of the target is corrected using the thus determined axis displacement angle.

Claims

1. A method of detecting an occurrence of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising the steps of:

measuring a frequency with which vehicle-to-vehicle distance control being performing using said radar is released or re-set; and

determining that an axis of said radar is displaced in the horizontal direction when said measured control release or re-set frequency is higher than a predetermined threshold.

2. A method of determining an amount of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising the steps of:

recognizing that a target detected by said radar is a stationary target; and

determining the amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target.

3. A method as claimed in claim 2, wherein the axis displacement amount determining step includes the substep of determining the amount of the axis displacement from a slope of the locus.

4. A method of correcting an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising the steps of:

recognizing that a target detected by said radar is a stationary target;

determining an amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target; and

correcting azimuth angle of said target by using said determined amount of the axis displacement in the horizontal direction.

5. A method as claimed in claim 4, wherein the axis displacement amount determining step includes the substep of determining the amount of the axis displacement from a slope of the locus.

6. An apparatus for detecting an occurrence of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

means for measuring a frequency with which vehicle-to-vehicle distance control being performing using said radar is released or re-set; and

means for determining that an axis of said radar is displaced in the horizontal direction when said measured control release or re-set frequency is higher than a predetermined threshold.

7. An apparatus for determining an amount of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

means for recognizing that a target detected by said radar is a stationary target; and

means for determining the amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target.

8. An apparatus as claimed in claim 7, wherein the axis displacement amount determining means includes means for determining the amount of the axis displacement from a slope of the locus.

9. An apparatus for correcting an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

means for recognizing that a target detected by said radar is a stationary target;

means for determining an amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target; and

means for correcting azimuth angle of said target by using said determined amount of the axis displacement in the horizontal direction.

10. An apparatus as claimed in claim 9, wherein the axis displacement amount determining means includes means for determining the amount of the axis displacement from a slope of the locus.

11. A computer program product for detecting an occurrence of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

computer code that measures a frequency with which vehicle-to-vehicle distance control being performing using said radar is released or re-set; and

computer code that determines that an axis of said radar is displaced in the horizontal direction when said measured control release or re-set frequency is higher than a predetermined threshold.

12. A computer program product for determining an amount of an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

computer code that recognizes that a target detected by said radar is a stationary target; and

computer code that determines the amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target.

13. A computer program product as claimed in claim 12, wherein the axis displacement amount determining code includes computer code that determines the amount of the axis displacement from a slope of the locus.

14. A computer program product for correcting an axis displacement in a horizontal direction in a radar mounted on a vehicle, comprising:

computer code that recognizes that a target detected by said radar is a stationary target;

computer code that determines an amount of the axis displacement in the horizontal direction, based on a locus of said target recognized as being the stationary target; and

computer code that corrects azimuth angle of said target by using said determined amount of the axis displacement in the horizontal direction.

15. A computer program product as claimed in claim 14, wherein the axis displacement amount determining code includes computer code that determines the amount of the axis displacement from a slope of the locus.