US-12625232-B2 - Calibration process for vehicular radar sensing system

US12625232B2US 12625232 B2US12625232 B2US 12625232B2US-12625232-B2

Abstract

A method for calibrating a radar system includes disposing the radar sensor at a vehicle and disposing an object at a first location relative to the vehicle. Using sensor data captured by the radar sensor with the object at the first location, a first location of the object relative to the radar sensor is determined. The object is moved along an intended principal axis of sensing for the radar sensor from the first location to a second location. Using sensor data captured by the radar sensor with the object at the second location, a second location of the object relative to the radar sensor is determined. Using the first determined location of the object and the second determined location of the object, a misalignment of the radar sensor is determined. The radar system is calibrated based at least in part on the misalignment.

Inventors

Denis Belokurov
Sebastian Breunig
Alexej Bohr

Assignees

MAGNA ELECTRONICS INC.

Dates

Publication Date: 20260512
Application Date: 20231109

Claims (20)

1 . A method for calibrating a vehicular radar system, the method comprising: obtaining a vehicle comprising a radar sensor of the vehicular radar system, the radar sensor sensing exterior of the vehicle, wherein the radar sensor has a principal axis of sensing, and wherein the radar sensor has a misalignment representing a difference between the principal axis of sensing of the radar sensor and an intended principal axis of sensing for the radar sensor; positioning an object at a first location relative to the radar sensor on the intended principal axis of sensing for the radar sensor, wherein the first location has a first distance between the object and the radar sensor; capturing, via the radar sensor, sensor data with the object at the first location; determining, via processing by a data processor of sensor data captured by the radar sensor with the object at the first location, a first sensed location of the object relative to the radar sensor; changing the location of the object relative to the radar sensor along the intended principal axis of sensing for the radar sensor from the first location to a second location relative to the radar sensor, wherein the second location has a second distance between the object and the radar sensor that is different than the first distance between the object and the radar sensor; capturing, via the radar sensor, sensor data with the object at the second location; determining, via processing by the data processor of sensor data captured by the radar sensor with the object at the second location, a second sensed location of the object relative to the radar sensor; determining the misalignment of the radar sensor based at least in part on the first sensed location of the object and the second sensed location of the object; and calibrating the vehicular radar system based at least in part on the determined misalignment of the radar sensor.
2 . The method of claim 1 , wherein calibrating the vehicular radar system comprises storing, at memory included in the vehicle, a correction value based on the determined misalignment of the radar sensor.
3 . The method of claim 1 , wherein determining the misalignment of the radar sensor comprises (i) determining a first linear equation based on the first sensed location, (ii) determining a second linear equation based on the second sensed location and (iii) solving the first linear equation and the second linear equation.
4 . The method of claim 1 , further comprising changing the location of the object relative to the radar sensor along the intended principal axis of sensing for the radar sensor to a third location relative to the radar sensor and determining, via processing by the data processor of sensor data captured by the radar sensor with the object at the third location, a third sensed location of the object relative to the radar sensor, and wherein determining the misalignment of the radar sensor is based in part on the third sensed location.
5 . The method of claim 1 , wherein the object comprises a spherical reflector.
6 . The method of claim 1 , wherein the object comprises a virtual object generated using a virtual radar target generator, and wherein changing the location of the object relative to the radar sensor comprises simulating movement of the virtual object.
7 . The method of claim 1 , wherein changing the location of the object relative to the radar sensor along the intended principal axis of sensing for the radar sensor from the first location relative to the radar sensor to the second location relative to the radar sensor comprises moving the vehicle along the intended principal axis of sensing for the radar sensor relative to the object.
8 . The method of claim 1 , wherein the intended principal axis of sensing for the radar sensor is parallel to a longitudinal axis of the vehicle.
9 . The method of claim 1 , wherein the intended principal axis of sensing for the radar sensor is parallel to the ground.
10 . The method of claim 1 , wherein the misalignment of the radar sensor comprises an azimuth misalignment.
11 . The method of claim 1 , wherein the misalignment of the radar sensor comprises an elevation misalignment.
12 . A method for calibrating a vehicular radar system, the method comprising: obtaining a vehicle comprising a radar sensor of the vehicular radar system, the radar sensor sensing exterior of the vehicle, wherein the radar sensor has a principal axis of sensing, and wherein the radar sensor has an azimuth misalignment representing a difference between the principal axis of sensing of the radar sensor and an intended principal axis of sensing for the radar sensor; positioning a first object at a first location relative to the radar sensor on the intended principal axis of sensing for the radar sensor, wherein the first location has a first distance between the first object and the radar sensor; capturing, via the radar sensor, sensor data with the first object at the first location; determining, via processing by a data processor of sensor data captured by the radar sensor with the first object at the first location, a first sensed location of the first object relative to the radar sensor; positioning a second object at a second location relative to the radar sensor on the intended principal axis of sensing for the radar sensor, wherein the second location has a second distance between the second object and the radar sensor that is different than the first distance between the first object and the radar sensor; capturing, via the radar sensor, sensor data with the second object at the second location; determining, via processing by the data processor of sensor data captured by the radar sensor with the second object at the second location, a second sensed location of the second object relative to the radar sensor; determining the azimuth misalignment of the radar sensor based at least in part on the first sensed location of the first object and the second sensed location of the second object; and calibrating the vehicular radar system based at least in part on the determined azimuth misalignment of the radar sensor.
13 . The method of claim 12 , wherein the first object and the second object are different objects.
14 . The method of claim 12 , wherein positioning the second object at the second location comprises moving the first object from the first location to the second location.
15 . The method of claim 12 , wherein calibrating the vehicular radar system comprises storing, at memory included in the vehicle, an azimuth correction value based on the determined azimuth misalignment of the radar sensor.
16 . The method of claim 12 , wherein determining the azimuth misalignment of the radar sensor comprises (i) determining a first linear equation based on the first sensed location, (ii) determining a second linear equation based on the second sensed location and (iii) solving the first linear equation and the second linear equation.
17 . The method of claim 12 , wherein the intended principal axis of sensing for the radar sensor is parallel to a longitudinal axis of the vehicle.
18 . A method for calibrating a vehicular radar system, the method comprising: obtaining a vehicle comprising a radar sensor of the vehicular radar system, the radar sensor sensing exterior of the vehicle, wherein the radar sensor has a principal axis of sensing, and wherein the radar sensor has an elevation misalignment representing a difference between the principal axis of sensing of the radar sensor and an intended principal axis of sensing for the radar sensor; positioning an object at a first location relative to the radar sensor on the intended principal axis of sensing for the radar sensor, wherein the first location has a first distance between the object and the radar sensor; capturing, via the radar sensor, sensor data with the object at the first location; determining, via processing by a data processor of sensor data captured by the radar sensor with the object at the first location, a first sensed location of the object relative to the radar sensor; changing the location of the radar sensor relative to the object along the intended principal axis of sensing for the radar sensor from the first location to a second location relative to the object wherein the second location has a second distance between the object and the radar sensor that is different than the first distance between the object and the radar sensor; capturing, via the radar sensor, sensor data with the object at the second location; determining, via processing by the data processor of sensor data captured by the radar sensor with the object at the second location, a second sensed location of the object relative to the radar sensor; determining the elevation misalignment of the radar sensor based at least in part on the first sensed location of the object and the second sensed location of the object; and calibrating the vehicular radar system based at least in part on the determined elevation misalignment of the radar sensor.
19 . The method of claim 18 , wherein the object comprises a spherical reflector.
20 . The method of claim 18 , wherein the intended principal axis of sensing for the radar sensor is parallel to the ground.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application claims priority of U.S. provisional application Ser. No. 63/385,651, filed Dec. 1, 2022, and U.S. provisional application Ser. No. 63/383,299, filed Nov. 11, 2022, which are hereby incorporated herein by reference in their entireties. FIELD OF THE INVENTION The present invention relates generally to a vehicle sensing system for a vehicle and, more particularly, to a vehicle sensing system that utilizes one or more radar sensors at a vehicle. BACKGROUND OF THE INVENTION Use of radar sensors in vehicle sensing systems is common and known. Examples of such known systems are described in U.S. Pat. Nos. 9,146,898; 8,027,029 and/or 8,013,780, which are hereby incorporated herein by reference in their entireties. SUMMARY OF THE INVENTION A method for calibrating a vehicular radar system includes disposing a radar sensor of the vehicular radar system at a vehicle. The radar sensor senses exterior of the vehicle and has a principal axis of sensing. The radar sensor has a misalignment representing a difference between the principal axis of sensing of the radar sensor and an intended principal axis of sensing for the radar sensor. The method includes disposing an object at a first location relative to the radar sensor on the intended principal axis of sensing for the radar sensor. The first location has a first distance between the object and the radar sensor. The method includes capturing, via the radar sensor, sensor data with the object at the first location. The method also includes determining, via processing by a data processor of sensor data captured by the radar sensor with the object at the first location, a first sensed location of the object relative to the radar sensor. The method includes moving the object along the intended principal axis of sensing for the radar sensor from the first location to a second location relative to the radar sensor. The second location has a second distance between the object and the radar sensor that is different than the first distance between the object and the radar sensor. The method includes capturing, via the radar sensor, sensor data with the object at the second location. The method also includes determining, via processing by the data processor of sensor data captured by the radar sensor with the object at the second location, a second sensed location of the object relative to the radar sensor. The method also includes determining the misalignment of the radar sensor based at least in part on the first sensed location of the object and the second sensed location of the object. The method includes calibrating the vehicular radar system based at least in part on the determined misalignment of the radar sensor. These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicle with a sensing system that incorporates a radar sensor; FIG. 2 is a schematic view of a radar calibration system for azimuth calibration of the sensing system of FIG. 1; and FIG. 3 is a schematic view of a radar calibration system for elevation calibration of the sensing system of FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle sensing system and/or driver assist system and/or driving assist system and/or object detection system and/or alert system operates to capture sensing data exterior of the vehicle and may process the captured data to detect objects at or near the vehicle and in the predicted path of the vehicle, such as to assist a driver of the vehicle or a control for an autonomous vehicle in maneuvering the vehicle in a forward or rearward direction. The system includes a processor that is operable to receive sensing data from one or more sensors and provide an output, such as an alert or control of a vehicle system. Referring now to the drawings and the illustrative embodiments depicted therein, a vehicle 10 (FIG. 1) includes an driving assistance system or sensing system 12 that includes at least one radar sensor unit, such as a forward facing radar sensor unit 14 (and the system may optionally include multiple exterior facing sensors, such as cameras, radar, or other sensors, such as a rearward facing sensor at the rear of the vehicle, one or more corner sensing sensors such as corner-mounted radar sensors, and/or a sideward/rearward facing sensor at respective sides of the vehicle), which sense regions exterior of the vehicle. The sensing system 12 includes a control or electronic control unit (ECU) that includes a data processor that is operable to process data captured by the radar sensor(s). The sensing system may also include a radar sensor that includes a plurality of transmitters that transmit radio signals via a plurality of antennas. The radar sensor also includes a plurality of receivers that receive radio signals