Misalignment detection for a vehicle radar sensor

Patent metadata

Field	Value
Publication number	US-10948569-B2
Application number	US-201716096773-A
Country	US
Kind code	B2
Filing date	Apr 27, 2017
Priority date	Apr 29, 2016
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A vehicle radar system (2) that is arranged to detect a plurality of objects outside a vehicle (1) and that includes a radar detector (3) and a processing unit arrangement (4). The processing unit arrangement (4) is arranged to obtain at least one total detection angle (φdT, φdT′) relative an x-axis (7) and at least one corresponding detected target Doppler velocity (vDoppler) relative the radar detector (3) for each detected object (5, 6; 10, 11). Each detected object is classified as moving or stationary, and a relation is determined between the stationary detections and the total number of detections. The processing unit arrangement (4) further is adapted to determine whether the radar detector (3) is misaligned based on the relation, where the total detection angle (φdT, φdT′) equals the sum of a known mounting angle (φm) between the x-axis (7) and the radar detector's mounting direction (8), and a detection angle (φd, φd′). The present disclosure also relates to a corresponding method.

First claim

The invention claimed is:

1. A vehicle radar system arranged to detect a plurality of objects outside a vehicle, the radar system comprising; a radar detector and a processing unit arrangement, the processing unit arrangement being arranged to obtain a total detection angle relative an x-axis and at least one corresponding detected target Doppler velocity relative to the radar detector for the plurality of objects during a certain time interval, the processing unit arrangement is adapted to classify the plurality of objects as one of a moving object or a stationary object relative a surrounding environment, and to determine a relation between a number of the plurality of objects that has been classified as one of the stationary object and a total number of detections, where the processing unit arrangement further is adapted to determine whether the radar detector is misaligned based on the relation, where a total detection angle equals the sum of a known mounting angle between the x-axis and a mounting direction of the radar detector, and a correct or a misaligned detection angle.

2. A vehicle radar system according to claim 1 further comprising, the processing unit arrangement is adapted to calculate a percentage fraction by dividing the number of the plurality of objects that has been classified as one of the stationary object with the total number of detections, where the processing unit arrangement further is adapted to compare the percentage fraction with a threshold value, and to determine that the radar detector is misaligned when the percentage fraction falls below the threshold value.

3. A vehicle radar system according to claim 2 further comprising, the processing unit arrangement is adapted to compare the percentage fraction with the threshold value based on accumulated results of a certain number of radar cycles, where each of the radar cycles is one observation phase in which the radar detector acquires data, processes the data on several signal processing levels and sends out available results.

4. A vehicle radar system according to claim 2 further comprising, the processing unit arrangement is adapted to compare the percentage fraction with the threshold value for one or more different host vehicle velocity windows.

5. A vehicle radar system according to claim 1 further comprising, the processing unit arrangement is adapted to classify the plurality of objects as one of the moving object or one of the stationary object relative to the surrounding environment by determining if the detected target Doppler velocity equals a calculated radial velocity and if that is the case, to classify the plurality of objects as one of the stationary object, where the processing unit arrangement is adapted to calculate a calculated radial velocity as a cosine for the total detection angle times a negative host vehicle velocity.

6. A vehicle radar system according to claim 1 further comprising, the processing unit arrangement is adapted to classify the plurality of objects as one of the moving object or one of the stationary object relative to the surrounding environment by determining whether the detected target Doppler velocity equals zero for the total detection angle that equals 90° and if that is the case, to classify the object as one of the stationary object.

7. A vehicle radar system according to claim 1 further comprising, the processing unit arrangement is adapted to only consider a detection of the plurality of objects having the total detection angle that have an absolute value that exceeds a predetermined angular cut value.

8. A vehicle radar system according to claim 1 further comprising, the processing unit arrangement is adapted to deactivate at least one safety function or to send an error message to a driver of the vehicle if the radar detector is determined to be misaligned.

9. A method for estimating a misalignment of a vehicle radar detector in a vehicle radar system that is used for detecting a plurality of objects outside a vehicle, where the method comprises the steps of;
obtaining at least one total detection angle relative an x-axis and at least one corresponding detected target Doppler velocity relative to the radar detector for detected objects of the plurality of objects during a certain time interval;
classifying the plurality of objects as one of a moving object or a stationary object relative a surrounding environment;
determining a relation between a number of the plurality of objects that has been classified as one of the stationary object and a total number of detections; and
determining whether the radar detector is misaligned based on the relation,
where a total detection angle equals the sum of a known mounting angle between the x-axis and a mounting direction of the radar detector, and a correct or misaligned detection angle.

10. The method according to claim 9 wherein the method further comprises the steps of:
calculating a percentage fraction by comparing a number of the plurality of objects that has been classified as one of the stationary object with the total number of detections;
comparing the percentage fraction with a threshold value; and
determining that the radar detector is misaligned when the percentage fraction falls below the threshold value.

11. The method according to claim 10 further comprising; the steps of comparing the percentage fraction with the threshold value based on an accumulated result of a certain number of radar cycles, where each of the radar cycles is one observation phase in which the radar detector acquires data, processes the data on several signal processing levels and sends out available results.

12. The method according to claim 10 further comprising, the steps of comparing the percentage fraction with the threshold value for different host velocity windows.

13. The method according to claim 9 further comprising; classifying the of plurality objects as one of the moving objects or one of the stationary object relative to the surrounding environment by determining if the detected target Doppler velocity equals a cosine for the total detection angle times a negative host vehicle velocity, and if that is the case, classifying the detected object as one of the stationary object.

14. The method according to claim 9 further comprising, the steps of classifying the plurality of objects as one of the moving object or one of the stationary object relative to the radar system by determining whether the detected target Doppler velocity equals zero for the total detection angle that equals 90°, and if that is the case, classifying the plurality of objects as one of the stationary object.

15. The method according to claim 9 further comprising, the steps of only considering a detection of the plurality of objects having the total detection angle that has an absolute value that exceeds a predetermined angular cut value.

Assignees

• Autoliv Dev
• Zhou Yi
• Unverdorben Christopher
• Maas Michael
• Veoneer Sweden Ab

Inventors

• Zhou Yi
• Unverdorben Christopher
• Maas Michael

Classifications

• G01S7/403

  in azimuth, i.e. in the horizontal plane · CPC title

• G01S7/4026 Primary

  Antenna boresight · CPC title

• G01S13/931 Primary

  of land vehicles · CPC title

• G01S13/52

  Discriminating between fixed and moving objects or between objects moving at different speeds · CPC title

• G01S2013/93271

  in the front of the vehicles · CPC title