Installation angle correction device and method for vehicle-mounted millimeter wave radar

Abstract

The embodiment of the application provides a kind of installation angle correction device and method of vehicle-mounted millimeter wave radar, the device includes: linear travel judging module, motor vehicle is in linear travel state during motor vehicle travel process judging;Target point identification module is used to determine effective target point;Quantity judging module, the quantity of the effective target point extracted in predetermined time is counted, and when the statistical data in predetermined time is greater than predetermined quantity threshold, linear fitting instruction is output, otherwise the statistical data is zero and repeat analysis instruction is sent;Linear fitting module is used to respond linear fitting instruction, and the expression of a target fitting straight line parallel to the travel direction of motor vehicle in linear travel state is obtained by fitting;Angle calculation and storage module, the target installation angle of vehicle-mounted millimeter wave radar is obtained by calculation.The embodiment can quickly and conveniently realize the correction of the installation angle of vehicle-mounted millimeter wave radar.

Description

Technical Field

[0001] This invention relates to the field of vehicle-mounted millimeter-wave radar technology, and in particular to an installation angle correction device and method for vehicle-mounted millimeter-wave radar. Background Technology

[0002] Currently, millimeter-wave radars are typically installed at the front and rear of motor vehicles to detect obstacles around the vehicle and assist the driver. When millimeter-wave radars are installed at the front and rear of a vehicle, their orientation is usually not directly in front of or behind the vehicle, but rather forms an angle with the vehicle's longitudinal direction. Therefore, it is usually necessary to calibrate and correct the installation angle of the millimeter-wave radar to ensure its accurate orientation when detecting target points.

[0003] One existing method for calibrating and correcting the installation angle of vehicle-mounted millimeter-wave radar typically involves offline calibration using a calibration object. The specific principle is as follows: A wave-absorbing material (e.g., a wave-absorbing wall or cotton) is placed at a predetermined distance from the end of the vehicle where the millimeter-wave radar is installed. Then, a calibration object (usually a triangular cone) is fixed between the wave-absorbing material and the vehicle. During calibration, the radar controller of the vehicle-mounted millimeter-wave radar controls the radar to emit millimeter waves towards the calibration object. The installation angle of the millimeter-wave radar is obtained by calculating the reflected wave from the calibration object.

[0004] However, the inventors found in practice that the above-mentioned method for calibrating and correcting the installation angle of vehicle-mounted millimeter-wave radar needs to be carried out in a specific calibration site, which is relatively complicated and increases production costs. In addition, the above-mentioned calibration and correction method has relatively high requirements for the accuracy of the installation position of the calibration object, and the accuracy of the final calculated installation angle is relatively poor. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide an installation angle correction device for vehicle-mounted millimeter-wave radar, which can quickly and conveniently calibrate the installation angle of vehicle-mounted millimeter-wave radar.

[0006] A further technical problem to be solved by the embodiments of the present invention is to provide a method for correcting the installation angle of a vehicle-mounted millimeter-wave radar, which can quickly and conveniently calibrate the installation angle of the vehicle-mounted millimeter-wave radar.

[0007] To address the aforementioned technical problems, the present invention first provides the following technical solution: a device for correcting the installation angle of a vehicle-mounted millimeter-wave radar, comprising:

[0008] The straight-line driving judgment module is used to analyze the driving state of the vehicle in response to the initial analysis command or the repeated analysis command, and output the angle correction command when it is determined that the vehicle is in a straight-line driving state.

[0009] The target point identification module is connected to the vehicle-mounted millimeter-wave radar and the straight-line driving judgment module respectively. It is used to analyze the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar in response to the angle correction command and calculate the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point.

[0010] The quantity judgment module is connected to the target point recognition module and the straight driving judgment module respectively. It is used to count the number of valid target points extracted within a predetermined time period, and output a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, it sets the statistical data to zero and issues the repeat analysis instruction.

[0011] A straight-line fitting module, connected to both the target point identification module and the quantity determination module, is used to respond to the straight-line fitting command by fitting each of the effective target points into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight-line fitting principle, and to determine the expression of the target fitting straight line; and

[0012] An angle calculation and storage module is connected to the straight line fitting module and the radar controller of the vehicle-mounted millimeter-wave radar, respectively. It is used to calculate the target installation angle of the vehicle-mounted millimeter-wave radar based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system, and to update the original installation angle stored in the radar controller using the target installation angle.

[0013] Furthermore, the line fitting module includes:

[0014] The preliminary fitting unit is used to respond to the line fitting command and, based on a predetermined line fitting principle, fit each of the effective target points into a preliminary fitting line parallel to the driving direction of the motor vehicle in a straight driving state, and determine the expression of the preliminary fitting line.

[0015] The distance calculation unit is used to calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line based on the expression of the preliminary fitted line;

[0016] An interference removal unit is configured to determine a distance filtering threshold for each effective target point based on a pre-stored correspondence table between the actual number of effective target points and a distance filtering threshold, and to perform distance filtering on each effective target point to remove effective target points whose actual point-to-line distance is greater than the distance filtering threshold; and

[0017] The secondary fitting unit is used to fit each of the effective target points after distance screening into a target fitting line parallel to the driving direction of the motor vehicle in a straight-line driving state, based on a predetermined straight-line fitting principle, and to determine the expression of the target fitting line.

[0018] Furthermore, the angle calculation and storage module includes:

[0019] A cyclic control unit is used to sequentially control the straight-line driving judgment module, target point recognition module, quantity judgment module, and straight-line fitting module to work cyclically until a predetermined number of target fitting straight lines and expressions of the target fitting straight lines are obtained; an angle calculation unit is used to calculate a preliminary installation angle of the vehicle-mounted millimeter-wave radar based on the expression of each target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system.

[0020] An angle processing unit is used to process all preliminary installation angles based on a sliding window method to obtain a target installation angle; and

[0021] An angle update unit is used to update the original installation angle stored in the radar controller using the target installation angle.

[0022] Furthermore, the straight-line driving judgment module calculates the actual turning radius of the vehicle by using the actual steering wheel angle and the vehicle's three-dimensional data or the actual yaw rate. When the actual turning radius is greater than a preset radius threshold, the module determines that the vehicle is in a straight-line driving state and outputs the angle correction command.

[0023] Furthermore, the principle of the predetermined straight line fitting is the least squares method.

[0024] On the other hand, in order to solve the above-mentioned further technical problems, the embodiments of the present invention provide the following technical solution: a method for correcting the installation angle of a vehicle-mounted millimeter-wave radar, comprising the following steps:

[0025] The straight-line driving judgment step responds to the initial analysis command or repeated analysis command to analyze the vehicle's driving state and outputs an angle correction command when it is determined that the vehicle is in a straight-line driving state.

[0026] The target point identification step involves analyzing the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar in response to the angle correction command, and calculating the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point.

[0027] The quantity judgment step counts the number of valid target points extracted within a predetermined time period, and outputs a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, the statistical data is set to zero and the repeat analysis instruction is issued.

[0028] The straight-line fitting step involves, in response to the straight-line fitting instruction, fitting each of the effective target points into a target fitted straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight-line fitting principle, and determining the expression of the target fitted straight line; and

[0029] The angle calculation and update steps involve calculating the target installation angle of the vehicle-mounted millimeter-wave radar based on the expression of the target fitted line and the positional relationship of the target fitted line in the radar coordinate system, and then using the target installation angle to update the original installation angle stored in the radar controller.

[0030] Furthermore, the line fitting step includes:

[0031] In response to the line fitting instruction, each of the effective target points is fitted into a preliminary fitted line parallel to the driving direction of the motor vehicle in a straight driving state based on a predetermined line fitting principle, and the expression of the preliminary fitted line is determined.

[0032] Calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line based on the expression of the preliminary fitted line;

[0033] Based on a pre-stored table showing the correspondence between the actual number of valid target points and the distance filtering threshold, the distance filtering threshold for each valid target point is determined. Distance filtering is then applied to each valid target point to remove those whose actual point-to-line distance is greater than the distance filtering threshold.

[0034] Based on the predetermined straight line fitting principle, each of the effective target points after distance screening is fitted into a target fitting straight line parallel to the driving direction of the motor vehicle in a straight driving state, and the expression of the target fitting straight line is determined.

[0035] Furthermore, the angle calculation and update steps include:

[0036] The straight-line driving judgment step, target point identification step, quantity judgment step, and straight-line fitting step are executed sequentially until a predetermined number of target fitted lines and the expression of the target fitted lines are obtained.

[0037] Based on the expression of each target fitting line and the positional relationship of the target fitting lines in the radar coordinate system, a preliminary installation angle of the vehicle-mounted millimeter-wave radar is calculated.

[0038] A target installation angle is obtained by processing all preliminary installation angles using the sliding window method; and

[0039] The original installation angle stored in the radar controller is updated using the target installation angle.

[0040] Furthermore, the straight-line driving judgment step specifically refers to: calculating the actual turning radius of the vehicle by means of the actual steering wheel angle and the three-dimensional data of the vehicle body or the actual yaw rate of the vehicle; when the actual turning radius is greater than a preset radius threshold, the vehicle is determined to be in a straight-line driving state and the angle correction command is output.

[0041] Furthermore, the principle of the predetermined straight line fitting is the least squares method.

[0042] After adopting the above technical solution, the embodiments of the present invention have at least the following beneficial effects: When the straight-line driving judgment module determines that the motor vehicle is in a straight-line driving state, it outputs an angle correction command. Then, when the motor vehicle is in a straight-line driving state, the target point recognition module analyzes the suspected target points around the motor vehicle body detected by the vehicle-mounted millimeter-wave radar, and calculates the difference between the radial velocity of the suspected target point and the actual driving speed of the motor vehicle. Since the radial velocity component of a long, elongated object that is absolutely stationary on the road surface around the motor vehicle is smaller and its moving speed is smaller the farther away it is from the motor vehicle, the lower the radial velocity component is. Therefore, when the difference is within a preset speed difference threshold range, the suspected target point is determined as a relatively stationary valid target point, which is used as a valid target point for straight-line fitting. Then, the quantity judgment module counts the number of valid target points determined within a predetermined time period. When the statistical data is greater than a predetermined quantity threshold, a straight-line fitting command is output. Otherwise, after resetting the statistical data to zero, a repeat analysis command is output to control the straight-line driving judgment module and the target point identification module to work again. This prevents sudden changes in the distance between the two during the determination of effective target points or the vehicle turning, ensuring that a sufficient number of effective target points can be obtained for subsequent straight-line fitting. Then, the straight-line fitting module fits each effective target point into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight-line fitting principle, and determines its expression. Finally, the angle calculation and storage module calculates the target installation angle of the vehicle-mounted millimeter-wave radar based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system, and uses the target installation angle to update the original installation angle stored in the radar controller. This allows for quick and convenient calibration and correction of the installation angle of the vehicle-mounted millimeter-wave radar during actual vehicle operation. Attached Figure Description

[0043] Figure 1 This is a schematic block diagram of an optional embodiment of the installation angle correction device for vehicle-mounted millimeter-wave radar of the present invention.

[0044] Figure 2 This is a schematic diagram illustrating the principle of identifying and determining a valid target point in an optional embodiment of the vehicle-mounted millimeter-wave radar installation angle correction device of the present invention.

[0045] Figure 3 This is a schematic diagram of the linear fitting module, which is an optional embodiment of the installation angle correction device for vehicle-mounted millimeter-wave radar of the present invention.

[0046] Figure 4 This is a schematic diagram illustrating the principle of performing two linear fittings in an optional embodiment of the vehicle-mounted millimeter-wave radar installation angle correction device of the present invention.

[0047] Figure 5 This is a schematic diagram of the angle calculation and storage module, which is an optional embodiment of the installation angle correction device for vehicle-mounted millimeter-wave radar of the present invention.

[0048] Figure 6 This is a flowchart of an optional embodiment of the installation angle correction method for vehicle-mounted millimeter-wave radar of the present invention.

[0049] Figure 7 This is a flowchart detailing the linear fitting step in an optional embodiment of the vehicle-mounted millimeter-wave radar installation angle correction device of the present invention.

[0050] Figure 8 This is a flowchart detailing the angle calculation and updating steps of an optional embodiment of the installation angle correction method for vehicle-mounted millimeter-wave radar of the present invention. Detailed Implementation

[0051] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only used to explain the present invention and are not intended to limit the present invention. Moreover, the embodiments and features in the embodiments of the present application can be combined with each other unless otherwise specified.

[0052] like Figure 1 As shown, an optional embodiment of the present invention provides an installation angle correction device for a vehicle-mounted millimeter-wave radar, comprising:

[0053] The straight-line driving judgment module 1 is used to analyze the driving state of the motor vehicle in response to the initial analysis command or the repeated analysis command, and output the angle correction command when it is determined that the motor vehicle is in a straight-line driving state.

[0054] The target point identification module 3 is connected to the vehicle-mounted millimeter-wave radar A and the straight-line driving judgment module 1 respectively. It is used to analyze the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar A in response to the angle correction command and calculate the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point.

[0055] The quantity judgment module 5 is connected to the target point recognition module 3 and the straight driving judgment module 1 respectively. It is used to count the number of valid target points extracted within a predetermined time period, and output a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, it sets the statistical data to zero and issues the repeat analysis instruction.

[0056] The straight-line fitting module 7, connected to the target point identification module 3 and the quantity determination module 5 respectively, is used to respond to the straight-line fitting command and, based on a predetermined straight-line fitting principle, fit each of the effective target points into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state, and determine the expression of the target fitting straight line; and

[0057] Angle calculation and storage module 9 is connected to the straight line fitting module 7 and the radar controller B of the vehicle-mounted millimeter-wave radar A, respectively. It is used to calculate the target installation angle of the vehicle-mounted millimeter-wave radar A based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system, and to update the original installation angle stored in the radar controller B using the target installation angle.

[0058] In this embodiment of the invention, the straight-line driving judgment module 1 outputs an angle correction command when it determines that the vehicle is in a straight-line driving state. Then, the target point recognition module 3 analyzes the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar A when the vehicle is in a straight-line driving state, and calculates the difference between the radial velocity of the suspected target points and the actual driving speed of the vehicle. Since the radial velocity component of objects that are absolutely stationary and elongated on the road surface around the vehicle (e.g., green belts, guardrails, curbs, etc.) is smaller and their moving speed is smaller the farther away they are from the vehicle (e.g., green belts, guardrails, curbs, etc.). Figure 2 As shown in the diagram, when the difference is within a preset speed difference threshold range, the suspected target point is determined as a relatively stationary valid target point, used as a valid target point for straight line fitting. Then, the quantity judgment module 5 counts the number of valid target points determined within a predetermined time period. When the statistical data is greater than the predetermined quantity threshold, a straight line fitting instruction is output; otherwise, the statistical data is reset to zero and a repeat analysis instruction is output to control the straight-line driving judgment module 1 and the target point identification module 3 to work again. This prevents sudden changes in the distance between the two vehicles or turning of the vehicle during the determination of valid target points, ensuring that a sufficient number of valid target points can be obtained for subsequent straight line fitting. Then, the straight line fitting module 7 fits each valid target point into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight line fitting principle, and determines its expression. Finally, the angle calculation and storage module 8 calculates the target installation angle of the vehicle-mounted millimeter-wave radar A based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system, and uses the target installation angle to update the original installation angle stored in the radar controller B. This allows for the quick and convenient calibration and correction of the installation angle of the vehicle-mounted millimeter-wave radar A during actual vehicle operation.

[0059] In specific implementation, such as Figure 2 As shown, calculating the target installation angle of the vehicle-mounted millimeter-wave radar A based on the expression of the target fitting line and the positional relationship of the target fitting line in the radar coordinate system specifically means: after knowing the expression of a target fitting line parallel to the vehicle's driving direction, the angle β between the target fitting line and the X-axis of the radar coordinate system can be calculated using the radar coordinate system of the vehicle-mounted millimeter-wave radar A; then, combining the plane trigonometric geometric relationships, the installation angle of the vehicle-mounted millimeter-wave radar A is... Furthermore, it is understood that the expression for the target fitting line and the coordinates of the effective target points are all parameters within the radar coordinate system. Additionally, to improve the fitting accuracy of the target fitting line, the predetermined time is typically set to 0.6 seconds. Moreover, the more effective target points obtained within 0.6 seconds, the better. Of course, to reasonably improve calibration efficiency and reduce the calculation process, the predetermined number threshold can be set within the range of 30-40. Furthermore, depending on the calibration and correction, the original installation angle stored in the radar controller B can correspond to zero or initial values ​​with relatively large errors. Additionally, the initial analysis command can be automatically generated when the vehicle-mounted millimeter-wave radar A is powered on, or manually input by the operator as needed to actively correct the installation angle.

[0060] In another optional embodiment of the invention, such as Figure 3 and Figure 4 As shown, the line fitting module 3 includes:

[0061] The preliminary fitting unit 30 is used to respond to the line fitting instruction and, based on a predetermined line fitting principle, fit each of the effective target points into a preliminary fitting line parallel to the driving direction of the motor vehicle in a straight driving state, and determine the expression of the preliminary fitting line.

[0062] The distance calculation unit 32 is used to calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line according to the expression of the preliminary fitted line;

[0063] Interference removal unit 34 is configured to determine the distance filtering threshold of the effective target points according to a pre-stored correspondence table between the actual number of effective target points and the distance filtering threshold, and to perform distance filtering on each effective target point to remove effective target points whose actual point-to-line distance is greater than the distance filtering threshold; and

[0064] The secondary fitting unit 36 ​​is used to fit each of the effective target points after distance screening into a target fitting line parallel to the driving direction of the motor vehicle in a straight driving state, based on a predetermined straight line fitting principle, and to determine the expression of the target fitting line.

[0065] In this embodiment, the preliminary fitting unit 30 first obtains an expression for a preliminary fitted line by fitting the actual coordinates of all valid target points. Then, it calculates the actual point-to-line distance between the valid target points and the preliminary fitted line. Based on the actual number of valid target points, it filters out valid target points with larger distances than the distance filtering threshold, thereby removing valid target points with relatively large errors. Finally, the secondary fitting unit 36 ​​performs secondary fitting based on the actual coordinates of each valid target point that has completed distance filtering to obtain the target fitted line, thereby effectively improving the fitting accuracy of the target fitted line.

[0066] In specific implementation, it can be understood that the correspondence between the actual number of effective target points and the distance filtering threshold can be as follows: for example, if the actual number is 10, then the distance filtering threshold is 5cm, that is, effective target points whose actual point-to-line distance is greater than 5cm are filtered out; or if the actual number is 20, then the distance filtering threshold is 10cm, that is, effective target points whose actual point-to-line distance is greater than 10cm are filtered out.

[0067] In yet another optional embodiment of the present invention, such as Figure 5 As shown, the angle calculation and storage module 9 includes:

[0068] The loop control unit 90 is used to sequentially control the straight driving judgment module 1, the target point recognition module 3, the quantity judgment module 5 and the straight line fitting module 7 to work in a loop until a predetermined number of target fitting lines and the expression of the target fitting lines are obtained;

[0069] Angle calculation unit 92 is used to calculate a preliminary installation angle of the vehicle-mounted millimeter-wave radar A based on the expression of each target fitting line and the positional relationship of the target fitting lines in the radar coordinate system.

[0070] Angle processing unit 94 is used to process all preliminary installation angles based on the sliding window method to obtain a target installation angle; and

[0071] Angle update unit 96 is used to update the original installation angle stored in the radar controller B using the target installation angle.

[0072] In this embodiment, multiple expressions for the target fitting lines are obtained by iterating repeatedly. Then, a preliminary installation angle is calculated based on the expression of each target fitting line. The sliding window method is then used to process all the preliminary installation angles to determine the optimal angle as the target installation angle. This avoids the situation where the installation angle obtained each time is inaccurate due to instantaneous vehicle body vibration, incomplete target, etc., and can effectively improve the accuracy of calibration.

[0073] It is understood that the sliding window method for processing each preliminary installation angle means maintaining the installation angle data within the predetermined window length, excluding preliminary installation angles (larger or smaller angles) outside the predetermined window length, and then averaging the remaining preliminary installation angles within the predetermined window length to obtain the target installation angle.

[0074] In another optional embodiment of the present invention, the straight driving judgment module 1 calculates the actual turning radius of the motor vehicle by the actual turning angle of the motor vehicle steering wheel and the three-dimensional data of the vehicle body or the actual yaw rate of the motor vehicle. When the actual turning radius is greater than a preset radius threshold, the motor vehicle is determined to be in a straight driving state and the angle correction command is output.

[0075] In this embodiment, the turning radius of the vehicle is calculated using the actual steering angle of the vehicle's steering wheel and the vehicle's three-dimensional data or actual yaw rate. Then, the turning radius is obtained using one of the two methods and compared with a preset radius threshold to determine whether the vehicle is in a straight-line driving state. The accuracy of the judgment is relatively high, which helps to improve the accuracy of the calibration.

[0076] In an optional embodiment of the present invention, the predetermined straight line fitting principle is the least squares method. In this embodiment, the least squares method is used as the straight line fitting method. The least squares method for straight line fitting is relatively simple, has relatively few data processing steps, and can effectively improve the efficiency of straight line fitting.

[0077] The process of calculating a straight line using the least squares method described above is as follows:

[0078] The expression for the target fitted line is set as y = ax + b (Formula 1);

[0079]

[0080] b = y - ax (Formula 3);

[0081] Where x and y are the abscissa and ordinate of the effective target point, respectively, and N is the actual number of effective target points.

[0082] Of course, in specific implementation, considering factors such as calibration accuracy and calibration efficiency, other methods such as gradient descent, Gauss-Newton method, or Levenberg-Marquardt (LM) algorithm can also be used for line fitting.

[0083] On the other hand, such as Figure 6 As shown in the figure, this embodiment of the invention further provides a method for correcting the installation angle of a vehicle-mounted millimeter-wave radar, including the following steps:

[0084] S1: Straight driving judgment step, responds to the initial analysis command or repeated analysis command to analyze the vehicle's driving state and outputs the angle correction command when it is determined that the vehicle is in a straight driving state.

[0085] S2: Target point identification step, in response to the angle correction command, analyze the suspected target points around the vehicle body detected by the vehicle millimeter-wave radar A and calculate the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point.

[0086] S3: Quantity judgment step, count the number of the effective target points extracted within a predetermined time period, and output a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, reset the statistical data to zero and issue the repeat analysis instruction.

[0087] S4: Line fitting step, responding to the line fitting instruction, fitting each of the effective target points into a target fitting line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined line fitting principle, and determining the expression of the target fitting line; and

[0088] S5: Angle calculation and update step: Based on the expression of the target fitted line and the positional relationship of the target fitted line in the radar coordinate system, calculate the target installation angle of the vehicle-mounted millimeter-wave radar A, and use the target installation angle to update the original installation angle stored in the radar controller B.

[0089] This invention, through the above method, outputs an angle correction command when it is determined that the vehicle is traveling in a straight line. Then, while the vehicle is traveling in a straight line, it analyzes the suspected target points around the vehicle body detected by the onboard millimeter-wave radar A, and calculates the difference between the radial velocity of the suspected target points and the actual speed of the vehicle. Since the radial velocity component of any absolutely stationary, elongated objects on the road surface around the vehicle (e.g., green belts, guardrails, curbs, etc.) is smaller and their moving speed is lower the further away they are from the vehicle (e.g., green belts, guardrails, curbs, etc.), the lower their moving speed (e.g., ...). Figure 2 As shown in the diagram, when the difference is within a preset speed difference threshold range, the suspected target point is determined as a valid target point and used as a valid target point for straight line fitting. Then, the number of valid target points determined within a predetermined time period is counted. When the statistical data is greater than a predetermined threshold, a straight line fitting command is output. Otherwise, the statistical data is reset to zero and a repeat analysis command is output to re-perform straight-line driving judgment and target point identification. This prevents sudden changes in the distance between the vehicle and the target point during the determination of the valid target point or the vehicle turning, ensuring that a sufficient number of valid target points can be obtained for subsequent straight line fitting. Then, based on the predetermined straight line fitting principle, each valid target point is fitted into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state, and its expression is determined. Finally, the target installation angle of the vehicle-mounted millimeter-wave radar A is calculated based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system. The original installation angle stored in the radar controller B is updated using the target installation angle. Thus, the installation angle of the vehicle-mounted millimeter-wave radar A can be quickly and conveniently calibrated and corrected during the actual operation of the vehicle.

[0090] In an optional embodiment of the present invention, such as Figure 7 As shown, step S4 includes:

[0091] S41: In response to the line fitting instruction, based on a predetermined line fitting principle, fit each of the effective target points into a preliminary fitted line parallel to the driving direction of the motor vehicle in a straight driving state, and determine the expression of the preliminary fitted line; S42: Calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line according to the expression of the preliminary fitted line;

[0092] S43: Determine the distance filtering threshold for each valid target point based on a pre-stored correspondence table between the actual number of valid target points and the distance filtering threshold; perform distance filtering on each valid target point to remove valid target points whose actual point-to-line distance is greater than the distance filtering threshold; and

[0093] S44: Based on the predetermined straight line fitting principle, fit each of the effective target points after distance screening into a target fitting straight line parallel to the driving direction of the motor vehicle in a straight driving state, and determine the expression of the target fitting straight line.

[0094] In this embodiment, an expression for a preliminary fitted line is obtained by first fitting the actual coordinates of all valid target points. Then, the actual point-to-line distance between the valid target points and the preliminary fitted line is calculated. Next, valid target points with larger errors are filtered out based on a distance screening threshold determined by the actual number of valid target points, thereby removing valid target points with relatively large errors. Finally, a second fitting is performed based on the actual coordinates of each valid target point that has completed distance screening to obtain the target fitted line, thereby effectively improving the fitting accuracy of the target fitted line.

[0095] In an optional embodiment of the present invention, such as Figure 8 As shown, step S5 includes:

[0096] S51: Execute steps S1 to S4 sequentially until a predetermined number of the target fitted lines and the expression of the target fitted lines are obtained;

[0097] S52: Based on the expression of each target fitting line and the positional relationship of the target fitting lines in the radar coordinate system, a preliminary installation angle of the vehicle-mounted millimeter-wave radar A is calculated respectively;

[0098] S53: A target installation angle is obtained by processing all preliminary installation angles using the sliding window method; and

[0099] S54: Update the original installation angle stored in the radar controller B using the target installation angle.

[0100] In this embodiment, multiple expressions for the target fitting lines are obtained by iterating repeatedly. Then, a preliminary installation angle is calculated based on the expression of each target fitting line. The sliding window method is then used to process each preliminary installation angle to determine the optimal angle as the target installation angle. This avoids the situation where the installation angle obtained each time is inaccurate due to instantaneous vehicle body vibration, incomplete target, etc., and can effectively improve the calibration accuracy.

[0101] In an optional embodiment of the present invention, step S1 specifically refers to: calculating the actual turning radius of the motor vehicle by means of the actual steering wheel angle and the three-dimensional data of the vehicle body or the actual yaw rate of the motor vehicle; when the actual turning radius is greater than a preset radius threshold, determining that the motor vehicle is in a straight-line driving state and outputting the angle correction command.

[0102] In this embodiment, the turning radius of the vehicle is calculated using the actual steering angle of the vehicle's steering wheel and the vehicle's three-dimensional data or actual yaw rate. Then, the turning radius is obtained using one of the two methods and compared with a preset radius threshold to determine whether the vehicle is in a straight-line driving state. The accuracy of the judgment is relatively high, which helps to improve the accuracy of the calibration.

[0103] In an optional embodiment of the present invention, the predetermined straight line fitting principle is the least squares method. In this embodiment, the least squares method is used as the straight line fitting method. The least squares method for straight line fitting is relatively simple, has relatively few data processing steps, and can effectively improve the efficiency of straight line fitting.

[0104] If the functions described in the embodiments of this invention are implemented as software functional modules or units and sold or used as independent products, they can be stored in a computing device-readable storage medium. Based on this understanding, the parts of the embodiments of this invention that contribute to the prior art or the technical solutions can be embodied in the form of software products. These software products are stored in a storage medium and include several instructions to cause a computing device (which may be a personal computer, server, mobile computing device, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks. The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably.

[0105] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the scope of protection of the present invention.

Claims

1. A device for correcting the installation angle of a vehicle-mounted millimeter-wave radar, characterized in that, The device includes: The straight-line driving judgment module is used to analyze the driving state of the vehicle in response to the initial analysis command or the repeated analysis command, and output the angle correction command when it is determined that the vehicle is in a straight-line driving state. The target point identification module is connected to the vehicle-mounted millimeter-wave radar and the straight-line driving judgment module respectively. It is used to analyze the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar in response to the angle correction command and calculate the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point. The quantity judgment module is connected to the target point recognition module and the straight driving judgment module respectively. It is used to count the number of valid target points extracted within a predetermined time period, and output a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, it sets the statistical data to zero and issues the repeat analysis instruction. A straight-line fitting module, connected to both the target point identification module and the quantity determination module, is used to respond to the straight-line fitting command by fitting each of the valid target points into a target fitting straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight-line fitting principle, and to determine the expression of the target fitting straight line; and An angle calculation and storage module is connected to the straight line fitting module and the radar controller of the vehicle-mounted millimeter-wave radar, respectively. It is used to calculate the target installation angle of the vehicle-mounted millimeter-wave radar based on the expression of the target fitting straight line and the positional relationship of the target fitting straight line in the radar coordinate system, and to update the original installation angle stored in the radar controller using the target installation angle. The line fitting module includes: The preliminary fitting unit is used to respond to the line fitting command and, based on a predetermined line fitting principle, fit each of the effective target points into a preliminary fitting line parallel to the driving direction of the motor vehicle in a straight driving state, and determine the expression of the preliminary fitting line. The distance calculation unit is used to calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line based on the expression of the preliminary fitted line; An interference removal unit is configured to determine a distance filtering threshold for each effective target point based on a pre-stored correspondence table between the actual number of effective target points and a distance filtering threshold, and to perform distance filtering on each effective target point to remove effective target points whose actual point-to-line distance is greater than the distance filtering threshold; and The secondary fitting unit is used to fit each of the effective target points after distance screening into a target fitting line parallel to the driving direction of the motor vehicle in a straight-line driving state, based on a predetermined straight-line fitting principle, and to determine the expression of the target fitting line.

2. The installation angle correction device for vehicle-mounted millimeter-wave radar as described in claim 1, characterized in that, The angle calculation and storage module includes: The loop control unit is used to sequentially control the straight driving judgment module, target point recognition module, quantity judgment module and straight line fitting module to work in a loop until a predetermined number of target fitting straight lines and the expression of the target fitting straight lines are obtained; An angle calculation unit is used to calculate a preliminary installation angle of the vehicle-mounted millimeter-wave radar based on the expression of each target fitting line and the positional relationship of the target fitting lines in the radar coordinate system. An angle processing unit is used to process all preliminary installation angles based on the sliding window method to obtain a target installation angle; and An angle update unit is used to update the original installation angle stored in the radar controller using the target installation angle.

3. The installation angle correction device for vehicle-mounted millimeter-wave radar as described in claim 1, characterized in that, The straight-line driving judgment module calculates the actual turning radius of the vehicle by using the actual steering wheel angle and the vehicle's three-dimensional data or the actual yaw rate. When the actual turning radius is greater than a preset radius threshold, the module determines that the vehicle is in a straight-line driving state and outputs the angle correction command.

4. The installation angle correction device for vehicle-mounted millimeter-wave radar as described in claim 1, characterized in that, The principle of the predetermined straight line fitting is the least squares method.

5. A method for correcting the installation angle of a vehicle-mounted millimeter-wave radar, characterized in that, The method includes the following steps: The straight-line driving judgment step involves responding to the initial analysis command or repeated analysis command to analyze the vehicle's driving state and outputting an angle correction command when it is determined that the vehicle is in a straight-line driving state. The target point identification step involves analyzing the suspected target points around the vehicle body detected by the vehicle-mounted millimeter-wave radar in response to the angle correction command, and calculating the difference between the radial velocity of each suspected target point in the radar coordinate system and the actual driving speed of the vehicle. When the absolute value of the difference is within the preset speed difference threshold range, the corresponding suspected target point is determined as a valid target point. The quantity judgment step counts the number of valid target points extracted within a predetermined time period, and outputs a straight line fitting instruction when the statistical data within the predetermined time period is greater than a predetermined number threshold; otherwise, the statistical data is set to zero and the repeat analysis instruction is issued. The straight-line fitting step involves, in response to the straight-line fitting instruction, fitting each of the effective target points into a target fitted straight line parallel to the driving direction of the vehicle in a straight-line driving state based on a predetermined straight-line fitting principle, and determining the expression of the target fitted straight line; and The angle calculation and update steps involve calculating the target installation angle of the vehicle-mounted millimeter-wave radar based on the expression of the target fitted line and the positional relationship of the target fitted line in the radar coordinate system, and then using the target installation angle to update the original installation angle stored in the radar controller. The line fitting step includes: In response to the line fitting instruction, each of the effective target points is fitted into a preliminary fitted line parallel to the driving direction of the motor vehicle in a straight driving state based on a predetermined line fitting principle, and the expression of the preliminary fitted line is determined. Calculate the actual point-to-line distance between each of the effective target points and the preliminary fitted line based on the expression of the preliminary fitted line; Based on a pre-stored table showing the correspondence between the actual number of valid target points and the distance filtering threshold, the distance filtering threshold for each valid target point is determined. Distance filtering is then applied to each valid target point to remove those whose actual point-to-line distance is greater than the distance filtering threshold. Based on the predetermined straight line fitting principle, each of the effective target points after distance screening is fitted into a target fitting straight line parallel to the driving direction of the motor vehicle in a straight driving state, and the expression of the target fitting straight line is determined.

6. The method for correcting the installation angle of a vehicle-mounted millimeter-wave radar as described in claim 5, characterized in that, The angle calculation and update steps include: The straight-line driving judgment step, target point identification step, quantity judgment step, and straight-line fitting step are executed sequentially until a predetermined number of target fitted lines and the expression of the target fitted lines are obtained. Based on the expression of each target fitting line and the positional relationship of the target fitting lines in the radar coordinate system, a preliminary installation angle of the vehicle-mounted millimeter-wave radar is calculated. A target installation angle is obtained by processing all preliminary installation angles using the sliding window method; and The original installation angle stored in the radar controller is updated using the target installation angle.

7. The method for correcting the installation angle of a vehicle-mounted millimeter-wave radar as described in claim 5, characterized in that, The straight-line driving judgment step specifically refers to: calculating the actual turning radius of the vehicle by using the actual steering wheel angle and the vehicle's three-dimensional data or the actual yaw rate of the vehicle; when the actual turning radius is greater than a preset radius threshold, determining that the vehicle is in a straight-line driving state and outputting the angle correction command.

8. The method for correcting the installation angle of a vehicle-mounted millimeter-wave radar as described in claim 5, characterized in that, The principle of the predetermined straight line fitting is the least squares method.

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