Method and system for determining the pointing angle of a moving object

Patent metadata

Field	Value
Publication number	US-10816344-B2
Application number	US-201815914208-A
Country	US
Kind code	B2
Filing date	Mar 7, 2018
Priority date	Mar 7, 2018
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

An illustrative example method of tracking a moving object includes determining an initial pointing angle of the object from a tracking device, determining an estimated position of a selected feature on the object based upon the initial pointing angle, determining a velocity vector at the estimated position, determining a lateral acceleration at the estimated position based upon the velocity vector and a yaw rate of the object, determining a sideslip angle of the selected feature based on the lateral acceleration, and determining a refined pointing angle of the object from the determined sideslip angle.

First claim

We claim:

1. A method of tracking a moving object, the method comprising:
determining an initial pointing angle of the object from a tracking device;
determining an estimated position of a selected feature on the object based upon the initial pointing angle;
determining a velocity vector at the estimated position;
determining a lateral acceleration at the estimated position based upon the velocity vector and a yaw rate of the object;
determining a sideslip angle of the selected feature based on the lateral acceleration; and
determining a refined pointing angle of the object from the determined sideslip angle.

2. The method of claim 1 , comprising
determining a difference between the initial pointing angle and the refined pointing angle; and
(i) when the difference satisfies a selected criterion, using the refined pointing angle as the pointing angle of the object; or
(ii) when the determined difference does not satisfy the selected criterion,
setting the initial pointing angle to be the same as the refined pointing angle; and
repeating the steps of
determining the estimated position of the selected feature on the object,
determining the velocity vector at the estimated position,
determining the lateral acceleration at the estimated position,
determining the sideslip angle of the selected feature,
determining the refined pointing angle of the object, and
determining the difference between the initial pointing angle and the refined pointing angle

until the difference satisfies the selected criterion.

3. The method of claim 2 , wherein the selected criterion indicates convergence between the initial pointing angle and the refined pointing angle.

4. The method of claim 1 , wherein
the object is a vehicle having a front wheel axle and a rear wheel axle; and
the selected feature is a center of the rear wheel axle.

5. The method of claim 4 , wherein the pointing angle indicates a direction along which the vehicle is traveling.

6. The method of claim 1 , wherein determining the initial pointing angle of the object from the tracking device comprises
determining a heading angle of a centroid of the object from the tracking device; and
setting the initial pointing angle to be the same as the heading angle.

7. The method of claim 6 , wherein determining the estimated position of the selected feature on the object based upon the initial pointing angle comprises
determining a vector describing a relationship between a position of the centroid and the selected feature in terms of a coordinate system that is fixed relative to the object;
rotating the vector by a rotation matrix that is based on the initial pointing angle; and
determining the estimated position from a difference between the position of the centroid and the rotated vector.

8. The method of claim 7 , wherein determining the velocity vector at the estimated position comprises
determining a kinematic relationship between centroid and the selected feature; and
using the yaw rate and the kinematic relationship to determine the velocity vector.

9. The method of claim 8 , wherein
the velocity vector comprises an x component and a y component; and
determining the refined pointing angle of the object, comprises
subtracting the determined sideslip angle from a tan 2 of the y and x components.

10. The method of claim 6 , wherein determining the estimated position of the selected feature on the object based upon the initial pointing angle comprises assuming that the selected feature is located at a center of a rear face of the object.

11. A system for tracking a moving object, the system comprising:
a tracking device configured to detect the moving object; and
a processor configured to:
determine an initial pointing angle of the object based on information from the tracking device;
determine an estimated position of a selected feature on the object based upon the initial pointing angle;
determine a velocity vector at the estimated position;
determine a lateral acceleration at the estimated position based upon the velocity vector and a yaw rate of the object;
determine a sideslip angle of the selected feature based on the lateral acceleration; and
determine a refined pointing angle of the object from the determined sideslip angle.

12. The system of claim 11 , wherein the processor is configured to:
determine a difference between the initial pointing angle and the refined pointing angle; and
(i) when the difference satisfies a selected criterion, use the refined pointing angle as the pointing angle of the object; or
(ii) when the determined difference does not satisfy the selected criterion,
set the initial pointing angle to be the same as the refined pointing angle; and
repeatedly
determine the estimated position of the selected feature on the object,
determine the velocity vector at the estimated position,
determine the lateral acceleration at the estimated position,
determine the sideslip angle of the selected feature,
determine the refined pointing angle of the object, and
determine the difference between the initial pointing angle and the refined pointing angle

until the difference satisfies the selected criterion.

13. The system of claim 12 , wherein the selected criterion indicates convergence between the initial pointing angle and the refined pointing angle.

14. The system of claim 11 , wherein
the object is a vehicle having a front wheel axle and a rear wheel axle; and
the selected feature is a center of the rear wheel axle.

15. The system of claim 14 , wherein the pointing angle indicates a direction along which the vehicle is traveling.

16. The system of claim 11 , wherein the processor is configured to determine the initial pointing angle of the object by
determining a heading angle of a centroid of the object based on the information from the tracking device; and
setting the initial pointing angle to be the same as the heading angle.

17. The system of claim 16 , wherein the processor is configured to determine the estimated position of the selected feature on the object based upon the initial pointing angle by
determining a vector describing a relationship between a position of the centroid and the selected feature in terms of a coordinate system that is fixed relative to the object;
rotating the vector by a rotation matrix that is based on the initial pointing angle; and
determining the estimated position from a difference between the position of the centroid and the rotated vector.

18. The system of claim 17 , wherein the processor is configured to determine the velocity vector at the estimated position by
determining a kinematic relationship between centroid and the selected feature; and
using the yaw rate and the kinematic relationship to determine the velocity vector.

19. The system of claim 18 , wherein
the velocity vector comprises an x component and a y component; and
the processor is configured to determine the refined pointing angle of the object by subtracting the determined sideslip angle from a tan 2 of the y and x components.

20. The system of claim 16 , wherein the processor is configured to determine the estimated position of the selected feature on the object by assuming that the selected feature is located at a center of a rear face of the object.

Assignees

• Delphi Tech Llc
• Aptiv Tech Ltd

Inventors

• Schiffmann Jan K
• Dang Wenbing
• Vishwajeet Kumar
• Nagaraja Keerthi Raj
• Schiffmann Franz P

Classifications

• G01S2013/9324

  Alternative operation using ultrasonic waves · CPC title

• G01S13/68

  for angle tracking only · CPC title

• G01S15/931

  of land vehicles · CPC title

• G01P13/025

  indicating air data, i.e. flight variables of an aircraft, e.g. angle of attack, side slip, shear, yaw · CPC title

• G01S15/66

  Sonar tracking systems · CPC title