A vehicle-mounted radar self-calibration method, calibration system, vehicle-mounted radar and vehicle
By obtaining driving information and collecting reference target information in the vehicle control system, and using over-determined equation calculations for vehicle-mounted radar angle calibration, the problem of relying on specific sites and drivers in the prior art is solved, and the automatic self-direction during vehicle driving is realized Calibration improves accuracy and efficiency and enhances driving safety.
Patent Information
- Application Number
- CN202211069349.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-02
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2042-09-02
AI Technical Summary
The existing vehicle-mounted radar self-calibration method relies on specific sites and targets, with driver participation, poor accuracy and inefficiency, and cannot perform self-calibration in normal working mode.
By obtaining vehicle driving information, determining whether the calibration conditions are met, collecting reference target information and using the over-determined equation set to calculate the least squares solution for radar angle calibration, so as to achieve automatic self-calibration during driving without affecting the normal function of the radar.
It realizes continuous self-checking and calibration of radar installation angle during vehicle driving, improves calibration accuracy and efficiency, reduces labor and material costs, and enhances driving safety.
Smart Images
Figure CN115421112B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of vehicle-mounted radars, and in particular to a vehicle-mounted radar self-calibration method, a calibration system, a vehicle-mounted radar and a car. Background Art
[0002] With the widespread application of autonomous driving, the performance requirements for sensors are constantly increasing, requiring millimeter-wave radars to achieve more accurate positioning of obstacles in their detection area, and accurate installation angles are the basis for accurate positioning. When the radar is installed on a vehicle, the installation angle is in line with the design specifications. However, during vehicle use, due to factors such as body vibration, loose installation structure, and accident deformation, the radar installation angle may deviate significantly from the preset value. At this time, the radar needs to have the function of self-checking and calibrating the installation angle during customer use. The current self-calibration algorithms of millimeter-wave radars mostly use a method of placing specific targets on a specific road section. For example, the patent (CN112666532A) discloses a vehicle-mounted millimeter-wave radar self-calibration method based on metal of a specific shape, which includes the following steps: sufficient stationary metal targets are set on the calibration track: metal triangular cones or multi-faceted triangular cones; dynamic calibration is completed within one ignition / power-on cycle; the vehicle's driving speed is maintained between 10km / h and 30m / h; before the calibration process begins, the vehicle is stationary on a flat road and the calibration process is activated, and then it is freely accelerated to the above speed range and the vehicle speed is maintained at a steady and straight speed; a diagnostic command is initiated through the on-board diagnostic instrument when the vehicle is stationary, and then the calibration progress is monitored through the vehicle calibration status instruction light; according to the above requirements, the vehicle is driven normally on the lane until the calibration is completed.
[0003] The existing technology has the following technical problems: 1. The vehicle-mounted radar not only depends on the specific site, road section and specific target, but also depends on the driving level of the driver, and the material and manpower costs are high; 2. The vehicle-mounted radar self-calibration is only executed through instructions in the diagnostic mode. The radar cannot be self-calibrated in the normal working mode. When the radar leaves the scene, the self-calibration algorithm cannot continue, and the scene applicability is poor; 3. The self-calibration accuracy is poor. Summary of the invention
[0004] In view of this, the purpose of the present invention is to provide a vehicle-mounted radar self-calibration method, a calibration system, a vehicle-mounted radar and a vehicle, which can realize continuous self-inspection and calibration of the radar installation angle during vehicle driving without affecting the normal function execution of the radar, thereby ensuring the use accuracy and calibration efficiency of the vehicle-mounted radar and making driving safer.
[0005] Specifically, the present invention provides a vehicle-mounted radar self-calibration method, the method comprising:
[0006] S1: Obtain current vehicle driving information and determine whether the vehicle driving information satisfies a first calibration condition; if so, proceed to S2 to enter the vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program.
[0007] S2: Only when the vehicle driving information meets the second calibration condition, the vehicle-mounted radar is controlled to collect N reference target information, and the least square solution of the vehicle-mounted radar angle is calculated using the overdetermined equation group. , according to the least squares solution A final calibration angle is calculated, and the vehicle-mounted radar self-calibration is performed according to the final calibration angle, where N is a natural number greater than 2.
[0008] In the above technical solution, the vehicle driving information includes the driving speed, yaw angular velocity, wheel speed, etc., and it is judged from the parameters of the above various vehicle motion states whether the vehicle is in the driving state and the vehicle speed is greater than the preset speed, and the vehicle yaw angular velocity is less than the preset angular velocity. This process is acquired by the first calibration unit embedded in the vehicle control system end, in which the threshold values of the relevant parameters are preset accordingly. The vehicle driving state is judged by whether each parameter reaches the corresponding threshold value, and it is judged whether to enter the vehicle radar self-calibration program.
[0009] The reference target information collected by the vehicle-mounted radar is to select a reference object that is stationary relative to the radar in the vehicle's driving environment, and obtain the radial velocity and angle of the reference object relative to the vehicle-mounted radar. This process is obtained by the acquisition unit embedded in the vehicle control system end. The obtained reference target information will be sent to the second calibration unit for calculation, and the obtained results will be self-calibrated.
[0010] Furthermore, the S1 includes: setting the first calibration condition to a driving mode, and entering the vehicle-mounted radar self-calibration procedure only when the current vehicle driving information is in the driving mode.
[0011] In the above technical solution, a first calibration condition is preset in the first calibration unit at the vehicle control system end. When the information obtained by the first calibration unit reaches the first calibration condition, it is determined that the vehicle is in driving mode, thereby entering the vehicle-mounted radar self-calibration program. It can be seen that the vehicle-mounted radar self-calibration program will automatically start after the vehicle starts driving, and the radar self-calibration algorithm is executed throughout the entire vehicle driving process, thereby ensuring the accuracy and efficiency of the vehicle radar calibration and making driving safer.
[0012] Further, the step S2 includes: setting the second calibration condition to the vehicle speed When the vehicle reaches the second calibration condition, the vehicle radar collects reference target information within a preset range, and the reference target information at least includes the radial velocity of a reference object in the environment that is stationary relative to the vehicle radar. and angle ; The vehicle-mounted radar collects N reference target information each time it detects a frame of reference target.
[0013] In the above technical solution, the first calibration unit at the vehicle control system end presets the second calibration condition, which at least includes the yaw angular velocity. When the yaw angular velocity of the vehicle is less than a certain threshold, it is judged that the vehicle is in a straight-line driving state. At this time, the acquisition unit of the module at the vehicle control system end starts to collect reference target information within a preset range, wherein the preset range may be within the detection range of the vehicle-mounted radar itself, and can ensure the accuracy of the reference target information, which is generally 1.5 meters and can be set according to the performance of the vehicle-mounted radar itself, and the reference target may be trees, signboards, street lights or fences around the vehicle;
[0014] On the one hand, this process is different from the current method that relies on specific equipment or specific road sections and environmental targets. This method does not rely on specific equipment, road sections and environmental targets. It selects reference targets in real time according to the road where the vehicle is located, making the self-calibration of the vehicle-mounted radar more timely. On the other hand, collecting multiple reference target information for calculation further improves the accuracy of self-calibration.
[0015] Furthermore, the step S2 further includes:
[0016] The radar angle calibration coordinates are constructed with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis. The overdetermined equation group is calculated based on the N reference target information. The formula is:
[0017] .
[0018] make , ;but .
[0019] make , , ,but ; where N=2,...,n. The least squares solution is : .
[0020] Vehicle radar calibration angle : .
[0021] In the above formula, is the vehicle driving speed; It is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; It is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y axis; is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction.
[0022] In the above technical solution, curve fitting is performed on N reference target information through the least squares method to calculate the approximate value of the complex function. This process can predict the change of radar angle during vehicle driving and improve the accuracy of self-calibration.
[0023] Further, the least squares solution The final calibration angle is calculated, and the method further includes: constructing a radar angle calibration coordinate with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis, and dividing the radar angle calibration coordinate into multiple groups of angle intervals according to the resolution; continuing to iterate the steps S1 and S2, and calibrating each vehicle-mounted radar according to the angle interval. After the preset time or the preset number of groupings is reached, the group with the largest number of groups is selected to obtain the average value to obtain the final calibration angle.
[0024] In the above technical solution, the self-calibration angle space from -90° to 90° can be adjusted according to the resolution Arithmetic division into lengths of 180 Multiple groups of angle intervals are used to calibrate the angle of each vehicle-mounted radar according to the angle interval. Grouping, when the least squares solution of a single algorithm execution result When outputting, Add 1. After completing M times of algorithm execution, select the group with the largest number and take the average to obtain the final calibration angle. This process is a further screening of the reference target information, which further ensures the accuracy of the vehicle-mounted radar self-calibration.
[0025] Furthermore, the self-calibration of the vehicle-mounted radar according to the final calibration angle also includes: setting a tolerance range for the vehicle-mounted radar calibration angle, calculating the difference between the final calibration angle and the original calibration angle, and determining whether the difference is within the tolerance range; if the difference is within the tolerance range, correcting the difference so that the radar continues to work normally; otherwise, stopping the radar and reporting the risk.
[0026] In the above technical solution, by setting the tolerance range of the vehicle-mounted radar calibration angle, the radar angle is checked and corrected under specific conditions, thereby achieving continuous calibration of the installation angle while the vehicle is driving, saving manpower and material resources.
[0027] As another preferred embodiment, the present invention further provides a calibration system using the above-mentioned vehicle-mounted radar self-calibration method, wherein the calibration system at least comprises:
[0028] The first calibration unit is used to obtain current vehicle driving information and determine whether the vehicle driving information meets a first calibration condition; if so, enter the vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program.
[0029] The acquisition unit is used to control the vehicle-mounted radar to acquire N reference target information and send it to the second calibration unit only when the vehicle driving information meets the second calibration condition.
[0030] The second calibration unit is used to calculate the least squares solution of the vehicle radar angle using an overdetermined equation set based on N reference targets , according to the least squares solution A final calibration angle is calculated, and the vehicle-mounted radar self-calibration is performed according to the final calibration angle, where N is a natural number greater than 2.
[0031] In the above technical solution, the first calibration unit, the acquisition unit and the second calibration unit are run on the vehicle control system in the form of a script or application or any other compatible form. The first calibration unit, the acquisition unit and the second calibration unit communicate and interconnect with each other to realize self-calibration of the vehicle-mounted radar. This method can cover various types of vehicles and has wide applicability.
[0032] Furthermore, it also includes:
[0033] The vehicle-mounted radar collects N reference target information each time it detects a frame of reference target.
[0034] The radar angle calibration coordinates are constructed with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis. The overdetermined equation group is calculated based on the N reference target information. The formula is:
[0035] .
[0036] make , ;but .
[0037] make , , ,but ; where N=2,...,n. The least squares solution is : .
[0038] Vehicle radar calibration angle : .
[0039] In the above formula, is the vehicle driving speed; It is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; It is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y axis; is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction.
[0040] Iteratively calculate the vehicle-mounted radar calibration angle After reaching the preset time or the preset number of groupings, the calibration angle of each vehicle radar is divided into angle intervals. The data are grouped and the group with the largest number is selected to take the average value to obtain the final calibration angle.
[0041] As another preferred embodiment, the present invention further provides a vehicle-mounted radar, which is used to collect reference target information, and a vehicle-mounted radar self-calibration method as described above is used through the reference target information to achieve calibration of the vehicle-mounted radar angle.
[0042] As another preferred embodiment, the present invention also provides a car, comprising a vehicle-mounted radar installed at any location of the car, and a computer-readable storage medium communicatively connected to the vehicle-mounted radar, wherein a computer program is stored on the computer-readable storage medium; the computer program is controlled and executed by one or more processors to implement a vehicle-mounted radar self-calibration method as described above.
[0043] Compared with the prior art, the present invention has the following beneficial effects:
[0044] The vehicle-mounted radar self-calibration program will automatically start after the vehicle starts driving. The radar's self-calibration algorithm will be executed throughout the vehicle's driving process. It can continuously perform self-inspection and calibration of the radar installation angle during vehicle driving without affecting the normal function execution of the radar, ensuring the use accuracy and calibration efficiency of the vehicle-mounted radar, making driving safer.
[0045] 1. This method does not rely on specific equipment, road sections and environmental targets. It selects reference targets in real time according to the road where the vehicle is located, making the self-calibration of the vehicle-mounted radar more timely. On the other hand, collecting multiple reference target information for calculation further improves the accuracy of self-calibration.
[0046] 2. The first calibration unit, the acquisition unit and the second calibration unit are run on the vehicle control system in the form of a script or application or any other compatible form to achieve self-calibration of the vehicle-mounted radar. This method can cover various types of vehicles and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Figure 1 The present invention is a flow chart of a vehicle-mounted radar self-calibration method.
[0048] Figure 2 The present invention is a schematic diagram of a vehicle-mounted radar collecting reference target information.
[0049] Figure 3 The figure is a schematic diagram of a vehicle-mounted radar self-calibration system of the present invention. DETAILED DESCRIPTION
[0050] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The drawings show preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.
[0051] Please refer to Figure 1 In a preferred embodiment, the present invention provides a vehicle-mounted radar self-calibration method, the method comprising:
[0052] S1: Obtain current vehicle driving information and determine whether the vehicle driving information satisfies a first calibration condition; if so, proceed to S2 to enter the vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program.
[0053] S2: Only when the vehicle driving information meets the second calibration condition, the vehicle-mounted radar is controlled to collect N reference target information, and the least square solution of the vehicle-mounted radar angle is calculated using the overdetermined equation group. , according to the least squares solution The final calibration angle is calculated, and the vehicle radar self-calibration is performed according to the final calibration angle, and N is a natural number greater than 2. In the specific implementation process, the vehicle driving information includes the driving speed, the yaw angular velocity, the wheel speed of each wheel, etc. From the parameters of the above various vehicle motion states, it is judged whether the vehicle is in the driving state and the vehicle speed is greater than the preset speed, and the vehicle yaw angular velocity is less than the preset angular velocity. This process is obtained by the first calibration unit embedded in the vehicle control system end, in which the thresholds of the relevant parameters are preset correspondingly, and the driving state of the vehicle is judged from whether each parameter reaches the corresponding threshold, and it is judged whether to enter the vehicle radar self-calibration program.
[0054] Among them, in this technical solution, only when the vehicle is in driving state and the speed is greater than the preset speed can the vehicle-mounted radar collect enough reference samples that are stationary relative to the environment, and the repetition rate between the stationary reference samples is reduced, so as to obtain multiple groups of different reference objects and ensure the accuracy of subsequent calibration data. After multiple tests, the preset speed set in this solution is preferably any speed value or speed range of 10-30m / h, but is not limited thereto, and can be set according to the vehicle model and specific needs.
[0055] In addition, in the present technical solution, the vehicle yaw rate is less than the preset angular velocity and can also be set according to different models and needs. During the driving state, the vehicle will adjust the steering wheel at any time according to different road sections and directions, but in most driving states it is in a straight driving mode. However, the straight driving described in the present invention is a relatively straight situation, that is, the vehicle yaw angle is within the preset range, and the vehicle driving direction is straight as a whole, which is regarded as a straight driving state. Only when the vehicle yaw angle exceeds the preset range, the vehicle is turning / turning around / changing lanes, etc., and the vehicle-mounted radar self-calibration program is not entered or paused at this time. Preferably, the preset angular velocity of the vehicle yaw rate is 5 degrees / second, and it can also be adjusted according to different measurement accuracies, which are not limited to this.
[0056] The reference target information collected by the vehicle-mounted radar is to select the reference object that is stationary relative to the radar on the road where the vehicle is traveling, and obtain the radial velocity of the reference object relative to the vehicle-mounted radar. This process is acquired by the acquisition unit embedded in the vehicle control system end, and the acquired reference target information will be sent to the second calibration unit for calculation, and the obtained results will be self-calibrated.
[0057] In this embodiment, S1 includes: setting the first calibration condition to a driving mode, and entering the vehicle radar self-calibration procedure only when the current vehicle driving information is in the driving mode.
[0058] During the specific implementation process, a first calibration condition is preset in the first calibration unit at the vehicle control system end. When the information obtained by the first calibration unit reaches the first calibration condition, it is determined that the vehicle is in driving mode, thereby entering the vehicle-mounted radar self-calibration program. It can be seen that the vehicle-mounted radar self-calibration program will automatically start after the vehicle starts driving, and the radar self-calibration algorithm is executed throughout the entire vehicle driving process, thereby ensuring the accuracy and efficiency of the vehicle radar calibration and making driving safer.
[0059] In this embodiment, please refer to Figure 2 , T is any reference target, the step S2 comprises: setting the second calibration condition to the vehicle speed When the vehicle reaches the second calibration condition, the vehicle radar collects information of reference targets within a preset range, and the reference target information includes at least the radial velocity of the reference object in the environment that is stationary relative to the vehicle radar. and angle The vehicle-mounted radar collects N reference target information each time it detects a frame of reference target.
[0060] In the above technical solution, the first calibration unit at the vehicle control system end presets the second calibration condition, which at least includes the yaw angular velocity. When the yaw angular velocity of the vehicle is less than a certain threshold, it is judged that the vehicle is in a straight-line driving state. At this time, the acquisition unit of the module at the vehicle control system end starts to collect reference target information within a preset range, wherein the preset range may be within the detection range of the vehicle-mounted radar itself, and can ensure the accuracy of the reference target information, which is generally 1.5 meters and can be set according to the performance of the vehicle-mounted radar itself, and the reference target may be trees, signboards, street lights or fences around the vehicle;
[0061] On the one hand, this process is different from the current method that relies on specific equipment or specific road sections and environmental targets. This method does not rely on specific equipment, road sections and environmental targets. It selects reference targets in real time according to the road where the vehicle is located, making the self-calibration of the vehicle-mounted radar more timely. On the other hand, collecting multiple reference target information for calculation further improves the accuracy of self-calibration.
[0062] In this embodiment, the step S2 further includes:
[0063] Please refer to Figure 2 , the radar angle calibration coordinates are constructed with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis, and the overdetermined equation group is calculated according to the N reference target information, and the formula is:
[0064] .
[0065] make , ;but .
[0066] make , , ,but ; where N=2,...,n. The least squares solution is : .
[0067] Vehicle radar calibration angle : .
[0068] In the above formula, is the vehicle driving speed; It is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; It is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y-axis; it is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction.
[0069] In the specific implementation process, the least squares method is used to perform curve fitting on N reference target information and calculate the approximate value of the complex function. This process can predict the change of radar angle during vehicle driving and improve the accuracy of self-calibration.
[0070] In this embodiment, the least squares solution The final calibration angle is calculated, and the method further includes: constructing a radar angle calibration coordinate with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis, and dividing the radar angle calibration coordinate into multiple groups of angle intervals according to the resolution; continuing to iterate the steps S1 and S2, and calibrating each vehicle-mounted radar according to the angle interval. After the preset time or the preset number of groupings is reached, the group with the largest number of groups is selected to obtain the average value to obtain the final calibration angle.
[0071] In the specific implementation process, the self-calibration angle space from -90° to 90° can be adjusted according to the resolution Arithmetic division into lengths of 180 Multiple groups of angle intervals are used to calibrate the angle of each vehicle-mounted radar according to the angle interval. Grouping, when the least squares solution of a single algorithm execution result When outputting, Add 1. After completing M times of algorithm execution, select the group with the largest number and take the average to obtain the final calibration angle. This process is a further screening of the reference target information, which further ensures the accuracy of the vehicle-mounted radar self-calibration.
[0072] It should be understood that the installation angle self-calibration applies to both forward radar and corner radar.
[0073] In this embodiment, the self-calibration of the vehicle-mounted radar according to the final calibration angle also includes: setting a tolerance range for the vehicle-mounted radar calibration angle, calculating the difference between the final calibration angle and the original calibration angle, and determining whether the difference is within the tolerance range; if the difference is within the tolerance range, correcting the difference so that the radar continues to work normally; otherwise, stopping the radar from working and reporting the risk.
[0074] During the specific implementation process, by setting the tolerance range of the vehicle-mounted radar calibration angle, the radar angle is checked and corrected under specific conditions, which enables the vehicle to continuously calibrate the installation angle during driving, saving manpower and material resources.
[0075] Please refer to Figure 3 As another preferred embodiment, the present invention further provides a calibration system using the above-mentioned vehicle-mounted radar self-calibration method, wherein the calibration system at least comprises:
[0076] The first calibration unit is used to obtain current vehicle driving information and determine whether the vehicle driving information meets a first calibration condition; if so, enter the vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program.
[0077] The acquisition unit is used to control the vehicle-mounted radar to acquire N reference target information and send it to the second calibration unit only when the vehicle driving information meets the second calibration condition.
[0078] The second calibration unit is used to calculate the least squares solution of the vehicle radar angle using an overdetermined equation set based on N reference targets , according to the least squares solution A final calibration angle is calculated, and the vehicle-mounted radar self-calibration is performed according to the final calibration angle, where N is a natural number greater than 2.
[0079] During the specific implementation process, the first calibration unit, the acquisition unit and the second calibration unit are run on the vehicle control system in the form of a script or application or any other compatible form. The first calibration unit, the acquisition unit and the second calibration unit communicate and interconnect with each other to realize self-calibration of the vehicle-mounted radar. This method can cover various types of vehicles and has wide applicability.
[0080] In this embodiment, it also includes:
[0081] The vehicle-mounted radar collects N reference target information each time it detects a frame of reference target.
[0082] The radar angle calibration coordinates are constructed with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis. The overdetermined equation group is calculated based on the N reference target information. The formula is:
[0083] .
[0084] make , ;but .
[0085] make , , ,but ; where N=2,...,n. The least squares solution is : .
[0086] Vehicle radar calibration angle : .
[0087] In the above formula, is the vehicle driving speed; It is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; It is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y axis; is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction.
[0088] Iteratively calculate the vehicle-mounted radar calibration angle After reaching the preset time or the preset number of groupings, the calibration angle of each vehicle radar is divided into angle intervals. The data are grouped and the group with the largest number is selected to take the average value to obtain the final calibration angle.
[0089] As another preferred embodiment, the present invention further provides a vehicle-mounted radar, which is used to collect reference target information, and a vehicle-mounted radar self-calibration method as described above is used through the reference target information to achieve calibration of the vehicle-mounted radar angle.
[0090] As another preferred embodiment, the present invention also provides a car, comprising a vehicle-mounted radar installed at any location of the car, and a computer-readable storage medium communicatively connected to the vehicle-mounted radar, wherein a computer program is stored on the computer-readable storage medium; the computer program is controlled and executed by one or more processors to implement a vehicle-mounted radar self-calibration method as described above.
[0091] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present invention thereto. Various changes and modifications may be made therein by one of ordinary skill in the art without departing from the scope and spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as required by the appended claims.
[0092] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.
[0093] The various system and method embodiments of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some modules according to embodiments of the present invention. The present invention can also be implemented as a device program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.
[0094] In the several embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative, for example, the division of functions is only a logical function division, and there may be other division methods in actual implementation, such as multiple tools or components can be combined or integrated into another system, or some features can be ignored or not executed.
[0095] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0096] Although the present invention is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes according to the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.
Claims
1. A vehicle-mounted radar self-calibration method, characterized in that: The method comprises: S1: Obtain current vehicle driving information and determine whether the vehicle driving information satisfies a first calibration condition; if so, proceed to S2 to enter the vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program; S2: Only when the vehicle driving information satisfies the second calibration condition, the vehicle-mounted radar is controlled to collect N reference target information, and then the least square solution D of the vehicle-mounted radar angle is calculated using an overdetermined equation group, and a final calibration angle is calculated according to the least square solution D, and the vehicle-mounted radar self-calibration is performed according to the final calibration angle, where N is a natural number greater than 2; Wherein, the step S2 further includes: constructing a radar angle calibration coordinate with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis, and performing an overdetermined equation group calculation according to the N reference target information, the formula is: V car *cos(α+β)=V d ; Let A = V car *cos(β), B = -V car *sin(β); then A cos(α) + B sin(α) = V d ; Let S = (V d1 , V d2 …V dn ) T , D = (A, B) T , then X·D=S; where N=1, 2, ..., n; Get the least squares solution D: D = X -1 ·S=(X T ·X) -1 ·X T ·S; Vehicle radar calibration angle β: In the above formula, V car is the vehicle driving speed; α is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; β is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y axis; V d is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction; The method of calculating the final calibration angle according to the least squares solution D also includes: dividing the radar angle calibration coordinates into multiple groups of angle intervals according to the resolution; continuing to iterate the steps S1 and S2, grouping each vehicle-mounted radar calibration angle β according to the angle interval, and after reaching a preset time or a preset number of groupings, selecting the group with the largest number of groups to take the average to obtain the final calibration angle.
2. A vehicle-mounted radar self-calibration method according to claim 1, characterized in that: The S1 includes: setting the first calibration condition to a driving mode, and entering the vehicle-mounted radar self-calibration program only when the current vehicle driving information is in the driving mode.
3. A vehicle-mounted radar self-calibration method according to claim 2, characterized in that: The step S2 includes: setting the second calibration condition to the vehicle speed V car If the vehicle yaw rate is less than the preset angular velocity, only when the vehicle reaches the second calibration condition, the vehicle-mounted radar collects reference target information within a preset range, and the reference target information at least includes the radial velocity V of the reference object in the environment that is stationary relative to the vehicle-mounted radar. d and angle α; the vehicle-mounted radar collects N reference target information each time it detects a frame of reference target.
4. A vehicle-mounted radar self-calibration method according to claim 3, characterized in that: The self-calibration of the vehicle-mounted radar according to the final calibration angle also includes: setting a tolerance range of the vehicle-mounted radar calibration angle, calculating the difference between the final calibration angle and the original calibration angle, and judging whether the difference is within the tolerance range; if the difference is within the tolerance range, correcting the difference so that the radar continues to work normally; otherwise, stopping the radar from working and reporting the risk.
5. A calibration system using a vehicle-mounted radar self-calibration method as described in any one of claims 1 to 4, characterized in that: The calibration system comprises at least: A first calibration unit, used to obtain current vehicle driving information and determine whether the vehicle driving information meets a first calibration condition; if so, enter a vehicle radar self-calibration program; otherwise, do not start the vehicle radar self-calibration program; A collection unit, used for controlling the vehicle-mounted radar to collect N reference target information and send it to the second calibration unit only when the vehicle driving information meets the second calibration condition; A second calibration unit is used to calculate a least square solution D of the vehicle-mounted radar angle according to N reference targets using an overdetermined equation group, calculate a final calibration angle according to the least square solution D, and perform vehicle-mounted radar self-calibration according to the final calibration angle, where N is a natural number greater than 2; Wherein, the vehicle-mounted radar collects N reference target information each time it detects a frame of reference target; The radar angle calibration coordinates are constructed with the current vehicle driving direction as the Y axis and the vehicle width direction as the X axis. The overdetermined equation group is calculated based on the N reference target information. The formula is: V car *cos(α+β)=V d ; Let A = V car *cos(β), B = -V car *sin(β); then A cos(α) + B sin(α) = V d ; Let S = (V d1 , V d2 …V dn ) T , D = (A, B) T , then X·D=S; where N=1, 2, ..., n; Get the least squares solution D: D = X -1 ·S=(X T ·T) -1 ·X T ·S; Vehicle radar calibration angle β: After the iterative calculation of the vehicle-mounted radar calibration angle β reaches a preset time or a preset number of groupings, each vehicle-mounted radar calibration angle β is grouped by dividing the angle interval, and the group with the largest number is selected to take the average to obtain the final calibration angle; In the above formula, V car is the vehicle driving speed; α is the angle between the position of the reference object in the environment that is stationary relative to the vehicle-mounted radar and the central axis of the detection range of the vehicle-mounted radar; β is the angle between the central axis of the detection range of the vehicle-mounted radar and the Y axis; V d is the radial velocity of the reference object relative to the vehicle-mounted radar in the driving direction.
6. A vehicle-mounted radar, characterized in that: The vehicle-mounted radar is used to collect reference target information, and the vehicle-mounted radar self-calibration method according to any one of claims 1 to 4 is used to calibrate the angle of the vehicle-mounted radar through the reference target information.
7. A car, characterized in that: It includes a vehicle-mounted radar installed at any place of a car, and a computer-readable storage medium communicatively connected to the vehicle-mounted radar, wherein a computer program is stored on the computer-readable storage medium; the computer program is controlled and executed by one or more processors to implement a vehicle-mounted radar self-calibration method as described in any one of claims 1 to 4.