DEVICE FOR ASCERTAINING A MISALIGNMENT OF A DETECTION UNIT FASTENED ON A VEHICLE

• US 20170261600A1
• Filed: 03/03/2017
• Published: 09/14/2017
• Est. Priority Date: 03/11/2016
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Maennicke, Nils Stefan, Wetoschkin, Igor, Reiher, Marcus Steffen
• Granted Patent: US 10,422,857 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• 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 7/4091 during normal radar operation

Abstract

A method and a device for ascertaining a misalignment of at least one detection unit fastened on a vehicle with respect to the intended sensor main beam direction. The device includes at least one detection unit which emits signals and receives partial signals which have been reflected on objects, and ascertains the distance and the azimuth angle of the reflecting objects, and further includes an evaluation unit, to which the ascertained positions of the at least one detection unit are forwarded, and the determination of a misalignment takes place in the evaluation unit by comparing the stored alignment of the sensor main beam direction and the ascertained angle of the object extension with respect to the sensor main beam direction, this taking place under the assumption that the vehicle is moving on average, in parallel to the object extension, for the period during which the misalignment is ascertained.

Claims

1. A device for ascertaining a misalignment of at least one detection unit fastened on a vehicle with respect to an intended sensor main beam direction, the device comprising:

at least one detection unit which emits signals and receives partial signals which have been reflected on objects, and ascertains a distance and an azimuth angle of the reflecting objects; and

an evaluation unit to which the ascertained distance and azimuth angle are forwarded, wherein the determination of a misalignment takes place in the evaluation unit by comparing stored alignment of the sensor main beam direction and an ascertained angle of an object extension with respect to a sensor main beam direction, and under the assumption that the vehicle is moving on average in parallel to the object extension for a period during which the misalignment is ascertained.

2. The device as recited in claim 1, wherein the detection unit is a radar sensor which operates in the microwave range or the millimeter-wave range.

3. The device as recited in claim 1, wherein multiple detection units are mounted on the vehicle.

4. The device as recited in claim 3, wherein the detection areas of adjacent detection units at least partially overlap.

5. The device as recited in claim 3, wherein knowledge of the instantaneous misalignment angle of a detection unit is utilized for ascertaining the misalignment angle of an adjacently situated detection unit.

6. A method for ascertaining a misalignment of at least one detection unit fastened on a vehicle with respect to an intended sensor main beam direction, the method comprising:

emitting signals, by at least one detection unit, and receiving partial signals reflected on objects;

ascertaining a distance and an azimuth angle of the reflecting objects, the ascertained distance and azimuth angle of the objects being forwarded to the at least one detection unit with the aid of an evaluation unit, wherein the determination of a misalignment takes place in the evaluation unit by comparing stored alignment of the sensor main beam direction and an ascertained angle of an object extension with respect to a sensor main beam direction, and under the assumption that the vehicle is moving on average in parallel to the object extension for a period during which the misalignment is ascertained.

7. The method as recited in claim 6, wherein, in order to ascertain the misalignment angle, a comparison of the stored alignment of the sensor main beam direction and the ascertained angle of the object extension with respect to the sensor main beam direction is carried out by ascertaining a difference angle between a vehicle longitudinal axis and the sensor main beam direction, and, from this, subtracting the angle value at which the detection unit ascertains the reflected partial signals of the transmission signals reflected on the extended object.

8. The method as recited in claim 7, wherein the misalignment is ascertained when specific object situations are detected.

9. The method as recited in claim 8, wherein the specific object situation is one of:

a detection of an extended object next to the host vehicle on the right in a direction of travel of the host vehicle;

a detection of an extended object next to the host vehicle on the left in the direction of travel;

or

a detection of extended objects next to the host vehicle on the left and on the right in the direction of travel.

10. The method as recited in claim 9, wherein an extended object is inferred when one of a guardrail, a concrete wall, a bridge railing, or a tunnel wall, is detected.

11. The method as recited in claim 6, wherein the ascertained misalignment angle is utilized for correcting an instantaneously measured object angle.

12. The method as recited in claim 6, wherein a shutoff of the detection unit takes place when the ascertained misalignment angle exceeds a predefined threshold value.

13. The method as recited in claim 11, wherein the misalignment angle used for correcting the instantaneously measured object angle is ascertained with the aid of a long-term filtering of measured values.

14. The method as recited in claim 12, wherein the misalignment angle to be ascertained for the shutoff is ascertained with the aid of a short-term filtering of the measured values.

15. The method as recited in claim 6, wherein positions of stationary objects detected in a range having the highest measuring quality are utilized for ascertaining a misalignment.

16. The method as recited in claim 15, wherein a detection unit has the highest measuring quality in a subarea of a detection area where the detection unit has at least one of:

i) the greatest range, and ii) the highest angular accuracy.

17. The method as recited in claim 6, wherein, when multiple detection units are mounted on a vehicle, whereby when the detection areas of adjacent detection units at least partially overlap, knowledge of the instantaneous misalignment angle of a detection unit is utilized for ascertaining the misalignment angle of an adjacently situated detection unit.