Radar calibration

Patent metadata

Field	Value
Publication number	US-11378668-B2
Application number	US-202016807608-A
Country	US
Kind code	B2
Filing date	Mar 3, 2020
Priority date	Mar 3, 2020
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

A calibration system for a radar sensor and a method of using the system are disclosed. The method may comprise (a) receiving, from a first sensor in a vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor; (b) receiving, from a radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor; (c) repeating the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor; (d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determining corresponding positions of the calibration target; and (e) using the corresponding positions of the calibration target, determining radar calibration parameters.

First claim

The invention claimed is:

1. A method, comprising:
(a) receiving, from a first sensor in a vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor;
(b) receiving, from a radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor;
(c) repeating the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor, wherein the steps of (a) receiving the plurality of global navigation satellite system (GNSS) parameters from the first sensor in the vehicle, (b) receiving the plurality of radar parameters, from the radar sensor in the vehicle, and (c) repeating the receiving of the plurality of global navigation satellite system (GNSS) parameters and the plurality of radar parameters at additional unique terrestrial positions of the first sensor, are repeated to receive a threshold quantity of unique terrestrial positions;
(d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determining corresponding positions of the calibration target; and
(e) using the corresponding positions of the calibration target, determining radar calibration parameters.

2. The method of claim 1 , wherein (e) further comprises:
determining the radar calibration parameters using a first transformation matrix relative to a frame of reference of the first sensor and using a second transformation matrix relative to a frame of reference of the radar sensor.

3. The method of claim 2 , wherein at least one of the first or second transformation matrices is a rotation matrix.

4. The method of claim 3 , wherein (e) further comprises: determining a plurality of Euclidean differences using the corresponding positions of the calibration target.

5. The method of claim 4 , wherein (e) further comprises: determining a summation of the plurality of Euclidean differences; and determining the radar calibration parameters using an optimization function that determines a set of radar calibration parameters that minimize the summation.

6. The method of claim 5 , wherein the set of radar calibration parameters comprise either: an x-parameter, a y-parameter, and a yaw-parameter.

7. The method of claim 5 , further comprising: determining an upper bound or a lower bound of each of the radar calibration parameters.

8. The method of claim 1 , further comprising: programming a computer or the radar sensor with the radar calibration parameters.

9. The method of claim 1 , wherein the calibration target is fixed during (b) and (c).

10. The method of claim 1 , wherein the first sensor is within a threshold distance of the calibration target during (b) and (c).

11. The method of claim 1 , wherein the radar sensor is a two-dimensional (2D) radar sensor or a three-dimensional (3D) radar sensor, wherein the first sensor is one of a Global Positioning System (GPS) device or a Global Navigation Satellite System (GLONASS) device.

12. The method of claim 1 , wherein the calibration target is a corner reflector.

13. A calibration system for a radar sensor in a vehicle, comprising:
a first sensor in the vehicle;
a calibration target; and
a computer, comprising one or more processors and memory storing instructions executable by the one or more processors, the instructions comprising to:
(a) receive, from a first sensor in the vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor;
(b) receive, from the radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor;
(c) repeat the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor, wherein the steps of (a) receiving the plurality of global navigation satellite system (GNSS) parameters from the first sensor in the vehicle, (b) receiving the plurality of radar parameters, from the radar sensor in the vehicle, and (c) repeating the receiving of the plurality of global navigation satellite system (GNSS) parameters and the plurality of radar parameters at additional unique terrestrial positions of the first sensor, are repeated to receive a threshold quantity of unique terrestrial positions;
(d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determine corresponding positions of the calibration target; and
(e) using the corresponding positions of the calibration target, determine radar calibration parameters.

14. The system of claim 13 , wherein (e) further comprises to:
determine the radar calibration parameters using a first transformation matrix relative to a frame of reference of the first sensor and using a second transformation matrix relative to a frame of reference of the radar sensor.

15. The system of claim 14 , wherein (e) further comprises to: determine a plurality of Euclidean differences using the corresponding positions of the calibration target.

16. The system of claim 15 , wherein (e) further comprises to: determine a summation of the plurality of Euclidean differences; and determine the radar calibration parameters using an optimization function that determines a set of radar calibration parameters that minimize the summation.

17. The system of claim 16 , wherein the set of radar calibration parameters comprise either: an x-parameter, a y-parameter, and a yaw-parameter.

18. The system of claim 13 , wherein the instructions further comprise to:
program a computer or the radar sensor with the radar calibration parameters.

19. The system of claim 13 , wherein the calibration target is fixed during (b) and (c).

Assignees

• Ford Global Tech Llc

Inventors

• Krishnan Krishanth
• Lee Sangjin
• Vora Ankit Girish
• Agarwal Siddharth

Classifications

• G01S7/4082

  using externally generated reference signals, e.g. via remote reflector or transponder · CPC title

• G01S7/4004 Primary

  of parts of a radar system · CPC title

• G01S2013/932

  using own vehicle data, e.g. ground speed, steering wheel direction · CPC title

• G01S13/34

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S13/865

  Combination of radar systems with lidar systems · CPC title