Millimeter wave radar dynamic calibration method and device based on high-precision positioning

Abstract

The application discloses a kind of millimeter wave radar dynamic calibration method and device based on high-precision positioning, the method includes: by millimeter wave radar, the original measurement data including distance, azimuth and speed are acquired, and screening with preset condition;Based on the type of road boundary under high-precision positioning and line point, the road boundary curve equation is fitted;The point-line correlation is carried out to the screened millimeter wave radar measurement data and road boundary curve equation, to associate the measurement value of millimeter wave radar with the road boundary under high-precision map;Based on the above association, the azimuth in the original measurement data is corrected by the azimuth calculated by road boundary curve equation;According to the installation parameters of millimeter wave radar and the corrected azimuth, the misalignment angle of millimeter wave radar is calculated.The application calibrates millimeter wave radar using high-precision positioning, uses the road boundary of structured road as the true value of millimeter wave radar, and can effectively improve the calibration precision of millimeter wave radar.

Description

Technical Field

[0001] This invention relates to the field of millimeter-wave radar calibration technology, and in particular to a dynamic calibration method and apparatus for millimeter-wave radar based on high-precision positioning. Background Technology

[0002] Millimeter-wave radar is widely used in autonomous driving due to its low susceptibility to lighting and weather conditions and its long monitoring range. Current autonomous driving perception systems typically rely on multi-sensor coupling, including millimeter-wave radar, cameras, and lidar, to obtain data from various sensors, thereby improving the accuracy of target localization and recognition, and ultimately enhancing the safety redundancy and stability of the autonomous driving system. During vehicle operation, vibrations due to road conditions can cause the millimeter-wave radar to tilt at its installation angle, necessitating dynamic calibration.

[0003] Existing dynamic calibration and misalignment detection for millimeter-wave radars are based on estimating the installation angle deviation from the current angle measurement results. Since the angle measurement accuracy of millimeter-wave radars is not high and true values ​​are lacking, the calibration accuracy of millimeter-wave radars is low, which in turn leads to the deterioration of angle measurement. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a dynamic calibration method and apparatus for millimeter-wave radar based on high-precision positioning. The method uses high-precision positioning to calibrate millimeter-wave radar and takes the road boundary of structured roads as the true value of millimeter-wave radar, which can effectively improve the calibration accuracy of millimeter-wave radar.

[0005] To achieve the above objectives, embodiments of the present invention provide a dynamic calibration method for millimeter-wave radar based on high-precision positioning, comprising:

[0006] Raw measurement data, including distance, azimuth, and velocity, are acquired using millimeter-wave radar and then filtered according to preset conditions.

[0007] Based on the type and points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting.

[0008] The filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map.

[0009] Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation.

[0010] The misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle.

[0011] As an improvement to the above solution, before acquiring the raw measurement data including range, azimuth, and velocity via millimeter-wave radar, the following steps are also included:

[0012] The millimeter-wave radar is synchronized with the high-precision positioning module in time.

[0013] As an improvement to the above solution, before acquiring the raw measurement data including range, azimuth, and velocity via millimeter-wave radar, the following steps are also included:

[0014] The vehicle speed and body attitude parameters are acquired, and it is determined whether the preset dynamic calibration conditions are met based on the vehicle speed and body attitude parameters; wherein, the body attitude parameters include acceleration, steering wheel angle, yaw rate and pitch rate.

[0015] As an improvement to the above solution, the preset condition is:

[0016] The original measurement data is static, non-multipath, and has a confidence level greater than a preset threshold.

[0017] As an improvement to the above scheme, the method of fitting the road boundary curve equation based on the type and line points of the road boundary under high-precision positioning specifically includes:

[0018] High-precision positioning results are obtained in real time through a high-precision positioning module;

[0019] The high-precision positioning result is matched with a high-precision map to convert the real-world position into a position relative to the high-precision map.

[0020] The type and line points of the road boundary based on the current location are obtained from the high-precision map broadcast, and the road boundary curve equation is obtained by fitting with the vehicle center as the origin.

[0021] As an improvement to the above solution, the step of calculating the misalignment angle of the millimeter-wave radar based on its installation parameters and the corrected azimuth angle specifically includes:

[0022] Based on the installation parameters of the millimeter-wave radar, the corrected azimuth angle, and the velocity of the measurement point, a set of equations is established:

[0023]

[0024]

[0025] ...

[0026]

[0027] Among them, v v Represents the velocity of the measurement point; θ′n θ represents the corrected azimuth angle; θ0 represents the azimuth angle at installation; θ Δ Indicates the azimuth angle to be calibrated; This represents the pitch angle in the original measurement data; Indicates the pitch angle during installation; Indicates the pitch angle to be calibrated;

[0028] The misalignment angle of the millimeter-wave radar is obtained by solving the system of equations using an estimation method.

[0029] As an improvement to the above solution, the method further includes:

[0030] The vehicle attitude angle at time m is calculated as follows:

[0031]

[0032]

[0033] Among them, YawAngle m PitchAngle m Let be the vehicle attitude angles at time m, yawRate and pitchRate be the yaw rate and pitch rate respectively, and Δt be the update period for the vehicle attitude angles.

[0034] According to the formula:

[0035]

[0036]

[0037] The misalignment angle of the millimeter-wave radar is filtered.

[0038] in, These are the filtered angles, and N is the number of accumulated frames. YawAngle is the misalignment angle calculated for the i-th frame. i PitchAngle i , where are the vehicle attitude angles at time i.

[0039] As an improvement to the above solution, the method further includes:

[0040] Calculate t i Time and t j The difference in vehicle attitude angle at each moment is:

[0041]

[0042]

[0043] Among them, ΔYawAngle i-j For t i Time and t j The difference in yaw angle at any given moment, ΔPitchAngle i-j For t i Time and t j The difference in pitch angle at any given moment, YawRate and PitchRate are the yaw rate and pitch rate, respectively;

[0044] A filtering algorithm is used to filter the misalignment angle of the millimeter-wave radar.

[0045] This invention also provides a millimeter-wave radar dynamic calibration device based on high-precision positioning, including a millimeter-wave radar and a data processing device, wherein the millimeter-wave radar and the data processing device are connected by communication.

[0046] The millimeter-wave radar transmits the raw measurement data, including distance, azimuth, and velocity, to the data processing device.

[0047] The data processing device is equipped with a calibration algorithm module, which performs the following processing during operation:

[0048] The original measurement data is filtered according to preset conditions; based on the type and line points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting.

[0049] The filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map.

[0050] Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation.

[0051] The misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle.

[0052] As an improvement to the above solution, the data processing device is also equipped with a high-precision positioning module and a high-precision map. The high-precision positioning module is used to acquire high-precision positioning results in real time.

[0053] As an improvement to the above scheme, the data processing device acts as a time synchronization master, sending a synchronization message, and the millimeter-wave radar acts as a time synchronization slave, responding to the synchronization message to synchronize the time axis of the millimeter-wave radar with the time of the data processing device.

[0054] This invention also provides a millimeter-wave radar dynamic calibration device based on high-precision positioning, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the millimeter-wave radar dynamic calibration method based on high-precision positioning described above.

[0055] Compared to existing technologies, the beneficial effects of the millimeter-wave radar dynamic calibration method and apparatus based on high-precision positioning provided in this invention are as follows: Raw measurement data, including distance, azimuth, and velocity, are acquired using millimeter-wave radar and filtered according to preset conditions; a road boundary curve equation is obtained by fitting the road boundary type and line points under high-precision positioning; the filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to associate the millimeter-wave radar measurement values ​​with the road boundaries under the high-precision map; based on the above correlation, the azimuth angle in the raw measurement data is corrected using the azimuth angle calculated from the road boundary curve equation; and the misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle. This invention obtains the road boundary curve equation by fitting the road boundary type and line points under high-precision positioning, and uses the road boundary of the structured road as the true value for millimeter-wave radar calibration, effectively improving the calibration accuracy of the millimeter-wave radar. Attached Figure Description

[0056] Figure 1 This is a flowchart illustrating a preferred embodiment of a millimeter-wave radar dynamic calibration method based on high-precision positioning provided by the present invention.

[0057] Figure 2 This is a schematic diagram of a preferred embodiment of a millimeter-wave radar dynamic calibration device based on high-precision positioning provided by the present invention;

[0058] Figure 3 This is a schematic diagram of another preferred embodiment of a millimeter-wave radar dynamic calibration device based on high-precision positioning provided by the present invention. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Please see Figure 1 , Figure 1This is a flowchart illustrating a preferred embodiment of a millimeter-wave radar dynamic calibration method based on high-precision positioning provided by the present invention. The millimeter-wave radar dynamic calibration method based on high-precision positioning includes:

[0061] S1 acquires raw measurement data including distance, azimuth, and velocity through millimeter-wave radar and filters them according to preset conditions;

[0062] S2, based on the type and line points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting;

[0063] S3, perform point-to-line correlation between the filtered millimeter-wave radar measurement data and the road boundary curve equation to correlate the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map;

[0064] S4. Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation.

[0065] S5. Based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle, the misalignment angle of the millimeter-wave radar is calculated.

[0066] Specifically, this embodiment acquires raw measurement data, including distance, azimuth, and velocity, using millimeter-wave radar and filters it according to preset conditions. Based on the type of road boundary and the points along the road under high-precision positioning, the road boundary curve is fitted to obtain the road boundary curve equation. Then, the filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurements with the road boundary under the high-precision map. Based on this correlation, the azimuth angle calculated using the road boundary curve equation is used to correct the azimuth angle in the raw measurement data. Finally, based on the millimeter-wave radar's installation parameters and the corrected azimuth angle, the misalignment angle of the millimeter-wave radar is calculated.

[0067] It should be noted that since the raw measurement data of millimeter-wave radar can be incorporated into the domain controller for processing, and the domain controller has a high-precision positioning module and a high-precision map, the embodiments of the present invention obtain the road boundary curve equation by fitting the type of road boundary and line points under high-precision positioning. The road boundary of the structured road is used as the true value of the millimeter-wave radar to calibrate the millimeter-wave radar, which can effectively improve the calibration accuracy of the millimeter-wave radar.

[0068] In another preferred embodiment, before acquiring raw measurement data including range, azimuth, and velocity via millimeter-wave radar in step S1, the method further includes:

[0069] The millimeter-wave radar is synchronized with the high-precision positioning module in time.

[0070] Specifically, in this embodiment, before acquiring the raw measurement data including distance, azimuth, and velocity via millimeter-wave radar, the high-precision positioning module in the domain controller is first synchronized with the millimeter-wave radar in time. The autonomous driving domain controller, acting as the time synchronization master, sends a synchronization message, and the millimeter-wave radar, acting as the slave, responds to the synchronization request and aligns its own timeline with the domain controller. After the high-precision positioning module and the millimeter-wave radar are synchronized, the millimeter-wave radar adds a synchronized timestamp to the acquired raw measurement data including distance, azimuth, and velocity and transmits it to the domain controller. It should be noted that some millimeter-wave radars do not have pitch angle measurement capabilities and therefore do not output pitch angle.

[0071] This embodiment uses CAN time synchronization based on autoSar. When the connection is Ethernet, gTPT time synchronization is used.

[0072] In another preferred embodiment, before acquiring the raw measurement data including range, azimuth, and velocity via millimeter-wave radar in step S1, the method further includes:

[0073] The vehicle speed and body attitude parameters are acquired, and it is determined whether the preset dynamic calibration conditions are met based on the vehicle speed and body attitude parameters; wherein, the body attitude parameters include acceleration, steering wheel angle, yaw rate and pitch rate.

[0074] Specifically, before acquiring raw measurement data including distance, azimuth, and speed via millimeter-wave radar, this embodiment also acquires vehicle speed and body attitude parameters, and determines whether preset dynamic calibration conditions are met based on these parameters. These dynamic calibration conditions can be set according to actual conditions. For example, the vehicle speed can be set to operate within a certain range, such as (10, 150) kph; the yaw rate to be less than a certain value, such as 60° / s; the pitch rate to be less than a certain value, such as 10° / s; the absolute value of acceleration to be less than a certain value, such as 2 m / s²; and the absolute value of steering wheel angle to be less than a certain value, such as 90°.

[0075] As a preferred embodiment, the preset conditions are:

[0076] The original measurement data is static, non-multipath, and has a confidence level greater than a preset threshold.

[0077] Specifically, in this embodiment, the preset conditions are as follows: the original measurement data is stationary, non-multipath, and the confidence level is greater than a preset threshold. Here, non-multipath refers to echoes that are not radar waves due to multiple reflections. A normal radar echo is a single reflection. In this embodiment, after acquiring the original measurement data from the millimeter-wave radar, points with high confidence (or high signal-to-noise ratio), stationary, and non-multipath are selected based on the attributes of the millimeter-wave point cloud.

[0078] In another preferred embodiment, step S2, based on the type and points of the road boundary under high-precision positioning, fits the road boundary curve equation, specifically including:

[0079] S201, high-precision positioning results are obtained in real time through the high-precision positioning module;

[0080] S202, Match the high-precision positioning result with the high-precision map to convert the real-world position into a position relative to the high-precision map;

[0081] S203, obtain the type and line point of the road boundary based on the current location matching of the high-precision map broadcast, and fit the road boundary curve equation with the vehicle center as the origin.

[0082] Specifically, this embodiment uses a high-precision positioning module to acquire in real time satellite positioning signals from GNSS, RTK service signals, vehicle speed signals, visually perceived lane lines and ground marking signals, triaxial acceleration and triaxial angular rate signals provided by a high-precision IMU, and road elements provided by an HD map, to obtain a fused centimeter-level high-precision positioning result. The high-precision positioning result is matched with a high-precision map using a built-in deflection plugin to convert the real-world position into a position relative to the high-precision map. The type and points of the road boundaries matched based on the current positioning are obtained from the high-precision map broadcast. With the vehicle center as the origin, a cubic curve equation is fitted based on the type and points of the road boundaries to obtain the road boundary curve equation:

[0083] y = C0 + C1x + C2x 2 +C3x 3

[0084] Where x represents the longitudinal distance in the vehicle's rectangular coordinate system, y represents the lateral distance in the vehicle's rectangular coordinate system, and C0, C1, C2, and C3 are all constants.

[0085] Transforming the raw measurement data from the millimeter-wave radar and the equation of the road boundary curve into the same vehicle coordinate system yields:

[0086] y = C0 + C1(x - x0) + C2(x - x0) 2 +C3(x-x0) 3 +y0

[0087] Where x0 is the longitudinal deviation between the two road boundaries, and y0 is the lateral deviation between the two road boundaries. The original measurements in the polar coordinate system... The original millimeter-wave radar measurement data is transformed into the same coordinate system as the road boundary curve equation, and a preset threshold is used to correlate the filtered original millimeter-wave radar measurement data with the road boundary curve equation, retaining the measurement data that can be correlated with the curve equation. The size of the threshold is usually positively correlated with the accuracy of the original measurement data. For points that have already been correlated, due to the more precise radar distance measurement, the distance measurement value (Range) of the original measurement data is then used. n Substituting the equation of the road boundary curve, the corrected azimuth angle θ′ is calculated. n .

[0088] In another preferred embodiment, step S5, based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle, calculates the misalignment angle of the millimeter-wave radar, specifically including:

[0089] S501, establish a set of equations based on the installation parameters of the millimeter-wave radar, the corrected azimuth angle, and the velocity of the measurement point:

[0090]

[0091]

[0092] ...

[0093]

[0094] Among them, v v Represents the velocity of the measurement point; θ′ n θ represents the corrected azimuth angle; θ0 represents the azimuth angle at installation; θ Δ Indicates the azimuth angle to be calibrated; This represents the pitch angle in the original measurement data; Indicates the pitch angle during installation; Indicates the pitch angle to be calibrated;

[0095] S502, the equations are solved using an estimation method to obtain the misalignment angle of the millimeter-wave radar.

[0096] Specifically, this embodiment is based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle θ′. n And establish a system of equations for the Doppler velocity at the measurement point:

[0097]

[0098]

[0099] ...

[0100]

[0101] Among them, v v Represents the velocity of the measurement point; θ′ n θ represents the corrected azimuth angle; θ0 represents the azimuth angle at installation; θ Δ Indicates the azimuth angle to be calibrated; This represents the pitch angle in the original measurement data; Indicates the pitch angle during installation; Indicates the pitch angle to be calibrated;

[0102] The above equations are solved using estimation methods, such as the least squares method, to obtain the misalignment angle of the millimeter-wave radar.

[0103] It should be noted that for millimeter-wave radars that do not measure elevation, only θ is calculated. Δ That's it. Also, it's important to note that the result obtained here... It incorporates the deflection angle caused by the non-linear motion of the vehicle body itself.

[0104] In yet another preferred embodiment, the method further includes:

[0105] The vehicle attitude angle at time m is calculated as follows:

[0106]

[0107]

[0108] Among them, YawAngle m PitchAngle m Let be the vehicle attitude angles at time m, yawRate and pitchRate be the yaw rate and pitch rate respectively, and Δt be the update period for the vehicle attitude angles.

[0109] According to the formula:

[0110]

[0111]

[0112] The misalignment angle of the millimeter-wave radar is filtered.

[0113] in, These are the filtered angles, and N is the number of accumulated frames. YawAngle is the misalignment angle calculated for the i-th frame. i PitchAngle i , where are the vehicle attitude angles at time i.

[0114] Specifically, in this embodiment, the vehicle attitude angle is calculated by integrating the angular rate output by the IMU. Zero-point correction of the vehicle's angular rate monitors the steering wheel angle to within a certain value, and the offset is obtained by averaging the angular rates. This embodiment assumes the angular rate is unbiased.

[0115] The vehicle attitude angle at time m (referring to the m-th cycle of the angular velocity change from non-zero) is calculated as follows:

[0116]

[0117]

[0118] Among them, YawAngle m PitchAngle m Let be the vehicle attitude angles at time m, and let YawRate and PitchRate be the yaw rate and pitch rate, respectively. Let Δt be the update period for the vehicle attitude angles.

[0119] Since the calculation frequency of the misalignment angle of millimeter-wave radar is lower than the attitude change frequency, for the i-th calculated value, YawAngle can be taken as the nearest value. i and PitchAngle i According to the formula:

[0120]

[0121]

[0122] Perform multi-frame smoothing filtering.

[0123] in, These are the filtered angles, and N is the number of accumulated frames. YawAngle is the misalignment angle calculated for the i-th frame. i PitchAngle i , where are the vehicle attitude angles at time i.

[0124] It should be noted that N can be determined by the required accuracy or time. A smaller N can be used for sudden misalignment detection, while a larger N can be used for dynamic calibration. Multi-frame smoothing filtering can also be accomplished by Kalman filtering or other filtering methods.

[0125] In yet another preferred embodiment, the method further includes:

[0126] Calculate t i Time and t j The difference in vehicle attitude angle at each moment is:

[0127]

[0128]

[0129] Among them, ΔYawAngle i-j For t i Time and t j The difference in yaw angle at any given moment, ΔPitchAngle i-j For t i Time and t j The difference in pitch angle at any given moment, YawRate and PitchRate are the yaw rate and pitch rate, respectively;

[0130] A filtering algorithm is used to filter the misalignment angle of the millimeter-wave radar.

[0131] Specifically, in this embodiment, compensating for the vehicle body attitude angle can also be achieved using state transition, i.e., calculating t i Time and t j The differences in vehicle attitude angles at each moment, ΔYawAngle and ΔPitchAngle:

[0132]

[0133]

[0134] This facilitates the use of Kalman filtering or other filtering algorithms for multi-frame filtering.

[0135] The millimeter-wave radar dynamic calibration method based on high-precision positioning provided in this invention improves the robustness of millimeter-wave radar calibration algorithms. Traditional calibration algorithms often fail to operate in real-time or lead to calculation errors due to incorrect point selection in tunnels or multi-level traffic conditions. The millimeter-wave radar dynamic calibration method based on high-precision positioning provided in this invention avoids these issues by incorporating a matching process with road boundaries.

[0136] On the other hand, as shown in Table 1, the millimeter-wave radar dynamic calibration method based on high-precision positioning provided in this embodiment of the invention improves the accuracy of the calibration algorithm. This embodiment of the invention uses the corrected measurement quantity θ′. n Replace the original measurement θ n .

[0137]

[0138] Where, ΔR map HD map mapping accuracy typically reaches the centimeter level, ΔR position To achieve centimeter-level accuracy in high-precision fusion positioning, ΔR mes Millimeter-wave radar measurement accuracy can reach 0.1m-0.3m.

[0139] Table 1

[0140]

[0141]

[0142] Accordingly, the present invention also provides a millimeter-wave radar dynamic calibration device based on high-precision positioning, which can realize all the processes of the millimeter-wave radar dynamic calibration method based on high-precision positioning in the above embodiments.

[0143] Please see Figure 2 , Figure 2 This is a schematic diagram of a preferred embodiment of a millimeter-wave radar dynamic calibration device based on high-precision positioning provided by the present invention. The millimeter-wave radar dynamic calibration device based on high-precision positioning includes a millimeter-wave radar and a data processing device, and the millimeter-wave radar and the data processing device are communicatively connected.

[0144] The millimeter-wave radar transmits the raw measurement data, including distance, azimuth, and velocity, to the data processing device.

[0145] The data processing device is equipped with a calibration algorithm module, which performs the following processing during operation:

[0146] The original measurement data is filtered according to preset conditions; based on the type and line points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting.

[0147] The filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map.

[0148] Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation.

[0149] The misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle.

[0150] Preferably, the data processing device is further provided with a high-precision positioning module and a high-precision map, wherein the high-precision positioning module is used to acquire high-precision positioning results in real time.

[0151] Preferably, the data processing device acts as a time synchronization master, sending a synchronization message, and the millimeter-wave radar acts as a time synchronization slave, responding to the synchronization message to synchronize the time axis of the millimeter-wave radar with the time of the data processing device.

[0152] Preferably, before acquiring raw measurement data including range, azimuth, and velocity via millimeter-wave radar, the following steps are also performed:

[0153] The vehicle speed and body attitude parameters are acquired, and it is determined whether the preset dynamic calibration conditions are met based on the vehicle speed and body attitude parameters; wherein, the body attitude parameters include acceleration, steering wheel angle, yaw rate and pitch rate.

[0154] Preferably, the preset condition is:

[0155] The original measurement data is static, non-multipath, and has a confidence level greater than a preset threshold.

[0156] Preferably, the process of fitting the road boundary curve equation based on the type and line points of the road boundary under high-precision positioning specifically includes:

[0157] High-precision positioning results are obtained in real time through a high-precision positioning module;

[0158] The high-precision positioning result is matched with a high-precision map to convert the real-world position into a position relative to the high-precision map.

[0159] The type and line points of the road boundary based on the current location are obtained from the high-precision map broadcast, and the road boundary curve equation is obtained by fitting with the vehicle center as the origin.

[0160] Preferably, the step of calculating the misalignment angle of the millimeter-wave radar based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle specifically includes:

[0161] Based on the installation parameters of the millimeter-wave radar, the corrected azimuth angle, and the velocity of the measurement point, a set of equations is established:

[0162]

[0163]

[0164] ...

[0165]

[0166] Among them, v v Represents the velocity of the measurement point; θ′ n θ represents the corrected azimuth angle; θ0 represents the azimuth angle at installation; θ Δ Indicates the azimuth angle to be calibrated; This represents the pitch angle in the original measurement data; Indicates the pitch angle during installation; Indicates the pitch angle to be calibrated;

[0167] The misalignment angle of the millimeter-wave radar is obtained by solving the system of equations using an estimation method.

[0168] Preferably, the calibration algorithm module further performs:

[0169] The vehicle attitude angle at time m is calculated as follows:

[0170]

[0171]

[0172] Among them, YawAngle m PitchAngle m Let be the vehicle attitude angles at time m, yawRate and pitchRate be the yaw rate and pitch rate respectively, and Δt be the update period for the vehicle attitude angles.

[0173] According to the formula:

[0174]

[0175]

[0176] The misalignment angle of the millimeter-wave radar is filtered.

[0177] in, These are the filtered angles, and N is the number of accumulated frames. YawAngle is the misalignment angle calculated for the i-th frame. i PitchAngle i , where are the vehicle attitude angles at time i.

[0178] Preferably, the calibration algorithm module further performs:

[0179] Calculate t i Time and t j The difference in vehicle attitude angle at each moment is:

[0180]

[0181]

[0182] Among them, ΔYawAngle i-j For t i Time and t j The difference in yaw angle at any given moment, ΔPitchAngle i-j For t i Time and t jThe difference in pitch angle at any given moment, YawRate and PitchRate are the yaw rate and pitch rate, respectively;

[0183] A filtering algorithm is used to filter the misalignment angle of the millimeter-wave radar.

[0184] In specific implementation, the working principle, control process and technical effects of the millimeter-wave radar dynamic calibration device based on high-precision positioning provided in this embodiment of the invention are the same as those of the millimeter-wave radar dynamic calibration method based on high-precision positioning in the above embodiments, and will not be repeated here.

[0185] Please see Figure 3 , Figure 3 This is a schematic diagram of another preferred embodiment of a millimeter-wave radar dynamic calibration device based on high-precision positioning provided by the present invention. The millimeter-wave radar dynamic calibration device based on high-precision positioning includes a processor 301, a memory 302, and a computer program stored in the memory 302 and configured to be executed by the processor 301. When the processor 301 executes the computer program, it implements the millimeter-wave radar dynamic calibration method based on high-precision positioning described in any of the above embodiments.

[0186] Preferably, the computer program can be divided into one or more modules / units (such as computer program 1, computer program 2, ...), and the one or more modules / units are stored in the memory 302 and executed by the processor 301 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the millimeter-wave radar dynamic calibration device based on high-precision positioning.

[0187] The processor 301 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 301 can be any conventional processor. The processor 301 is the control center of the millimeter-wave radar dynamic calibration device based on high-precision positioning, and connects the various parts of the millimeter-wave radar dynamic calibration device based on high-precision positioning using various interfaces and lines.

[0188] The memory 302 mainly includes a program storage area and a data storage area. The program storage area can store the operating system, applications required for at least one function, etc., while the data storage area can store related data, etc. Furthermore, the memory 302 can be a high-speed random access memory, or a non-volatile memory, such as a plug-in hard disk, a smart media card (SMC), a secure digital card (SD), and a flash card, or it can be other volatile solid-state storage devices.

[0189] It should be noted that the aforementioned millimeter-wave radar dynamic calibration device based on high-precision positioning may include, but is not limited to, processors and memory, as will be understood by those skilled in the art. Figure 3 The structural diagram is merely an example of the above-mentioned millimeter-wave radar dynamic calibration device based on high-precision positioning, and does not constitute a limitation on the above-mentioned millimeter-wave radar dynamic calibration device based on high-precision positioning. It may include more or fewer components than shown in the diagram, or combine certain components, or use different components.

[0190] This invention provides a method and apparatus for dynamic calibration of millimeter-wave radar based on high-precision positioning. The method involves acquiring raw measurement data including distance, azimuth, and velocity using millimeter-wave radar and filtering it according to preset conditions. Based on the type and points of the road boundary under high-precision positioning, a road boundary curve equation is fitted. The filtered millimeter-wave radar measurement data is then correlated with the road boundary curve equation to associate the millimeter-wave radar measurements with the road boundary under a high-precision map. Based on this correlation, the azimuth angle in the raw measurement data is corrected using the azimuth angle calculated from the road boundary curve equation. Finally, the misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle. This invention, by fitting the road boundary curve equation to the type and points of the road boundary under high-precision positioning, uses the road boundary of the structured road as the true value for millimeter-wave radar calibration, effectively improving the calibration accuracy of the millimeter-wave radar.

[0191] It should be noted that the system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the system embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0192] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A dynamic calibration method for millimeter-wave radar based on high-precision positioning, characterized in that, include: Raw measurement data, including distance, azimuth, and velocity, are acquired using millimeter-wave radar and then filtered according to preset conditions. Based on the type and points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting, including: High-precision positioning results are obtained in real time through a high-precision positioning module; The high-precision positioning result is matched with a high-precision map to convert the real-world position into a position relative to the high-precision map. The type and line points of the road boundary matched based on the current location are obtained from the high-precision map broadcast. With the vehicle center as the origin, the road boundary curve equation is fitted. The filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map. Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation. Based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle, the misalignment angle of the millimeter-wave radar is calculated, including: Based on the installation parameters of the millimeter-wave radar, the corrected azimuth angle, and the velocity of the measurement point, a set of equations is established: in, Indicates the velocity at the measurement point; Indicates the corrected azimuth angle; Indicates the azimuth angle during installation; Indicates the azimuth angle to be calibrated; This represents the pitch angle in the original measurement data; Indicates the pitch angle during installation; Indicates the pitch angle to be calibrated; The misalignment angle of the millimeter-wave radar is obtained by solving the system of equations using an estimation method. , ).

2. The millimeter-wave radar dynamic calibration method based on high-precision positioning as described in claim 1, characterized in that, Before acquiring raw measurement data including range, azimuth, and velocity via millimeter-wave radar, the process also includes: The millimeter-wave radar is synchronized with the high-precision positioning module in time.

3. The millimeter-wave radar dynamic calibration method based on high-precision positioning as described in claim 2, characterized in that, Before acquiring raw measurement data including range, azimuth, and velocity via millimeter-wave radar, the process also includes: The vehicle speed and body attitude parameters are acquired, and it is determined whether the preset dynamic calibration conditions are met based on the vehicle speed and body attitude parameters; wherein, the body attitude parameters include acceleration, steering wheel angle, yaw rate and pitch rate.

4. The millimeter-wave radar dynamic calibration method based on high-precision positioning as described in claim 1, characterized in that, The preset conditions are: The original measurement data is static, non-multipath, and has a confidence level greater than a preset threshold.

5. The millimeter-wave radar dynamic calibration method based on high-precision positioning as described in claim 1, characterized in that, The method further includes: The vehicle attitude angle at time m is calculated as follows: in, Let be the vehicle attitude angle at time m, and let YawRate and PitchRate be the yaw rate and pitch rate, respectively. The update cycle for the vehicle body attitude angle; According to the formula: The misalignment angle of the millimeter-wave radar is filtered. in,( ) represent the filtered angles, and N represents the accumulated frame count. ) are the misalignment angles calculated for the i-th frame, , where are the vehicle attitude angles at time i.

6. The millimeter-wave radar dynamic calibration method based on high-precision positioning as described in claim 1, characterized in that, The method further includes: calculate Time and The difference in vehicle attitude angle at each moment is: in, for Time and The difference in yaw angle at any given moment, for Time and The difference in pitch angle at any given moment, YawRate and PitchRate are the yaw rate and pitch rate, respectively; A filtering algorithm is used to filter the misalignment angle of the millimeter-wave radar.

7. A dynamic calibration device for millimeter-wave radar based on high-precision positioning, characterized in that, It includes a millimeter-wave radar and a data processing device, wherein the millimeter-wave radar and the data processing device are connected in communication. The millimeter-wave radar transmits the raw measurement data, including distance, azimuth, and velocity, to the data processing device. The data processing device is equipped with a calibration algorithm module, which performs the following processing during operation: The original measurement data is filtered according to preset conditions; based on the type and line points of the road boundary under high-precision positioning, the equation of the road boundary curve is obtained by fitting. The filtered millimeter-wave radar measurement data is correlated with the road boundary curve equation to link the millimeter-wave radar measurement values ​​with the road boundary under the high-precision map. Based on the above correlation, the azimuth angle in the original measurement data is corrected using the azimuth angle calculated from the road boundary curve equation. The misalignment angle of the millimeter-wave radar is calculated based on the installation parameters of the millimeter-wave radar and the corrected azimuth angle.

8. The millimeter-wave radar dynamic calibration device based on high-precision positioning as described in claim 7, characterized in that, The data processing device is also equipped with a high-precision positioning module and a high-precision map. The high-precision positioning module is used to acquire high-precision positioning results in real time.

9. The millimeter-wave radar dynamic calibration device based on high-precision positioning as described in claim 8, characterized in that, The data processing device acts as a time synchronization master, sending a synchronization message. The millimeter-wave radar acts as a time synchronization slave, responding to the synchronization message to synchronize the time axis of the millimeter-wave radar with the time of the data processing device.

10. A dynamic calibration device for millimeter-wave radar based on high-precision positioning, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the millimeter-wave radar dynamic calibration method based on high-precision positioning as described in any one of claims 1 to 6.

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