Radar automatic calibration methods, devices, equipment and storage media

Abstract

This invention discloses an automatic radar calibration method, apparatus, device, and storage medium, belonging to the field of radar calibration technology. The invention transmits a calibration signal to a calibration antenna and collects the feedback signal from the antenna based on the calibration signal; performs external calibration on the laser radar array to be calibrated according to the feedback signal; acquires radar data and preprocesses the radar data to obtain processed radar data; constructs an array covariance matrix based on the processed radar data; obtains eigenvectors based on the array covariance matrix and calculates calibration values ​​based on the eigenvectors; and performs amplitude and phase error calibration on the radar using the calibration values ​​to achieve automatic radar calibration. By performing external calibration on the laser radar array to be calibrated and performing amplitude and phase error calibration on the radar, the calibration accuracy of the radar is improved.

Description

Technical Field

[0001] This invention relates to the field of radar calibration technology, and in particular to an automatic radar calibration method, apparatus, equipment, and storage medium. Background Technology

[0002] LiDAR (Light Detection and Ranging) is a device that uses optical methods to accurately measure distances. It can be applied to obstacle detection, geological modeling, and location acquisition. The distance to a target is calculated by measuring the flight time of the emitted beam as it travels from the target to the lidar. Before use, lidar requires calibration to ensure accurate distance calculations.

[0003] Current radar calibration methods involve measurements taken in an anechoic chamber before the radar leaves the factory. After the radar is delivered and put into use, it cannot be completely placed in an anechoic chamber for measurement and calibration, resulting in low calibration accuracy. Summary of the Invention

[0004] The main objective of this invention is to provide an automatic radar calibration method, apparatus, device, and storage medium, aiming to solve the technical problem of low radar calibration accuracy in the prior art.

[0005] To achieve the above objectives, the present invention provides an automatic radar calibration method, the method comprising the following steps:

[0006] Transmit a calibration signal to the calibration antenna and collect the feedback signal from the calibration antenna based on the calibration signal;

[0007] The laser radar array to be calibrated is externally calibrated based on the feedback signal;

[0008] Acquire radar data and preprocess the radar data to obtain processed radar data;

[0009] Construct the array covariance matrix based on the processed radar data;

[0010] The eigenvectors are obtained based on the array covariance matrix, and the calibration values ​​are calculated based on the eigenvectors.

[0011] The radar amplitude and phase error are calibrated using the calibration values ​​to achieve automatic radar calibration.

[0012] Optionally, the step of calibrating the radar amplitude and phase error using the calibration value includes:

[0013] The correlation coefficient between the calibration values ​​is calculated using the calibration values.

[0014] Calculate and discard calibration values ​​whose correlation coefficient is greater than a preset calibration coefficient threshold.

[0015] The target calibration value is obtained by removing the discarded calibration value from the calibration value.

[0016] The radar amplitude and phase error are calibrated using the target calibration value.

[0017] Optionally, obtaining the eigenvector based on the array covariance matrix and calculating the calibration value based on the eigenvector includes:

[0018] The array covariance matrix is ​​subjected to eigenvalue decomposition to obtain the eigenvector corresponding to the largest eigenvalue;

[0019] Obtain the first relationship between the feature vectors and the guide vectors of the spatial array;

[0020] The first calibration value constant is obtained through the first relationship and the feature vector;

[0021] Obtain the guidance vector of the spatial array;

[0022] The second calibration constant is obtained through the guide vector of the spatial array;

[0023] The calibration value is calculated using the first calibration constant and the second calibration constant.

[0024] Optionally, constructing the array covariance matrix based on the processed radar data includes:

[0025] Radar array information is obtained based on the processed radar data;

[0026] The received array signal value is calculated using the radar array information;

[0027] Construct the array covariance matrix based on the received array signal values.

[0028] Optionally, calculating the received array signal value using the radar array information includes:

[0029] The radar array information is used to obtain the radar array, array quantity, number of snapshots, spatial signal vector, and noise data vector.

[0030] The amplitude error and phase error of the array elements are obtained by using the radar array and the number of array elements.

[0031] The amplitude and phase errors of the array elements are obtained by measuring the amplitude error and the phase error of the array elements.

[0032] The amplitude and phase errors of the array elements are summarized to obtain the array amplitude and phase error diagonal matrix;

[0033] Calculate the steering vector of the spatial array;

[0034] The received array signal value is calculated using the guide vector of the spatial array, the number of snapshots, the spatial signal vector, the noise data vector, and the array amplitude and phase error diagonal array.

[0035] Optionally, the guiding vector of the computational space array includes:

[0036] The array element coordinates and the target object's orientation angle are obtained based on the radar array information.

[0037] The path difference is calculated using the array element coordinates and the target object's orientation angle.

[0038] Obtain the signal wavelength;

[0039] The steering vector of the spatial array is calculated using the path difference and the signal wavelength.

[0040] Optionally, the step of acquiring radar data and preprocessing the radar data to obtain processed radar data includes:

[0041] Acquire the first set of radar data and the second set of radar data;

[0042] Perform a first Fourier transform on the first set of radar data and the second set of radar data to obtain range information;

[0043] Perform a second Fourier transform on the distance information to obtain the Doppler information of the target object;

[0044] The effective range of target object signal relative to radar distance and radial velocity is obtained based on the Doppler information of the target object;

[0045] The average value of the target object signal relative to the radar distance and the radial velocity range is calculated to obtain processed radar data.

[0046] Furthermore, to achieve the above objectives, the present invention also proposes an automatic radar calibration device, the automatic radar calibration device comprising:

[0047] The transmitting module is used to transmit a calibration signal to the calibration antenna and to acquire the feedback signal from the calibration antenna based on the calibration signal;

[0048] The calibration module is used to perform external calibration of the lidar array to be calibrated based on the feedback signal.

[0049] An acquisition module is used to acquire radar data and preprocess the radar data to obtain processed radar data.

[0050] The building module is used to construct the array covariance matrix based on the processed radar data;

[0051] The acquisition module is further configured to obtain an eigenvector based on the array covariance matrix and calculate a calibration value based on the eigenvector;

[0052] The calibration module is also used to calibrate the amplitude and phase error of the radar using the calibration value, so as to realize automatic radar calibration.

[0053] Furthermore, to achieve the above objectives, the present invention also proposes an automatic radar calibration device, which includes: a memory, a processor, and an automatic radar calibration program stored in the memory and executable on the processor, wherein the automatic radar calibration program is configured to implement the steps of the automatic radar calibration method described above.

[0054] In addition, to achieve the above objectives, the present invention also proposes a storage medium storing a radar automatic calibration program, which, when executed by a processor, implements the steps of the radar automatic calibration method as described above.

[0055] This invention achieves automatic radar calibration by transmitting a calibration signal to a calibration antenna and collecting feedback signals from the antenna based on the calibration signal; performing external calibration on the lidar array to be calibrated according to the feedback signals; acquiring radar data and preprocessing the radar data to obtain processed radar data; constructing an array covariance matrix based on the processed radar data; obtaining eigenvectors based on the array covariance matrix and calculating calibration values ​​based on the eigenvectors; and performing amplitude and phase error calibration on the radar using the calibration values. By performing external calibration on the lidar array to be calibrated and performing amplitude and phase error calibration on the radar, the calibration accuracy of the radar is improved. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of the radar automatic calibration device in the hardware operating environment involved in the embodiments of the present invention;

[0057] Figure 2 This is a flowchart illustrating the first embodiment of the radar automatic calibration method of the present invention;

[0058] Figure 3 This is a schematic diagram of the basic components of external calibration in one embodiment of the radar automatic calibration method of the present invention;

[0059] Figure 4 This is a flowchart illustrating the second embodiment of the radar automatic calibration method of the present invention;

[0060] Figure 5 This is a flowchart illustrating the third embodiment of the radar automatic calibration method of the present invention;

[0061] Figure 6This is a flowchart illustrating the fourth embodiment of the radar automatic calibration method of the present invention;

[0062] Figure 7 This is a structural block diagram of the first embodiment of the radar automatic calibration device of the present invention.

[0063] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0064] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0065] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of an automatic radar calibration device in the hardware operating environment of an embodiment of the present invention.

[0066] like Figure 1 As shown, the radar automatic calibration device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wireless-Fidelity (Wi-Fi) interface). The memory 1005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0067] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the radar automatic calibration equipment and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0068] like Figure 1 As shown, the memory 1005, which serves as a storage medium, may include an operating system, a network communication module, a user interface module, and a radar automatic calibration program.

[0069] exist Figure 1In the radar automatic calibration device shown, the network interface 1004 is mainly used for data communication with the network server; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the radar automatic calibration device of the present invention can be set in the radar automatic calibration device. The radar automatic calibration device calls the radar automatic calibration program stored in the memory 1005 through the processor 1001 and executes the radar automatic calibration method provided in the embodiment of the present invention.

[0070] This invention provides an automatic radar calibration method, referring to... Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of the radar automatic calibration method of the present invention.

[0071] In this embodiment, the automatic radar calibration method includes the following steps:

[0072] Step S10: Transmit a calibration signal to the calibration antenna and collect the feedback signal from the calibration antenna based on the calibration signal.

[0073] It should be noted that the execution subject of this embodiment is a radar automatic calibration device, but it can also be other devices or apparatuses that can achieve the same or similar functions. This embodiment does not limit this, and this embodiment uses a radar automatic calibration device as an example for explanation.

[0074] It should be noted that when the radar needs to be calibrated, an excitation signal can be emitted to form a calibration signal, which is then sent to the calibration antenna. After receiving the calibration signal, the calibration antenna will generate a feedback signal. The feedback signal generated by the calibration antenna based on the calibration signal can be sampled within the calibration channel.

[0075] Step S20: Perform external calibration on the laser radar array to be calibrated based on the feedback signal.

[0076] In practical implementation, after the feedback signal is collected, the lidar array to be calibrated can be externally calibrated using the feedback signal. For example... Figure 3 As shown, Figure 3This is a basic schematic diagram of the external calibration process. When performing external calibration of the transmitted signal, the control computer generates an excitation signal. This excitation signal is converted from D / A and up-converted to enter the transceiver network. It then passes through the "T channel" in the T / R component to each array element, forming a calibration signal. This signal is then transmitted through space to the calibration antenna, which receives and collects feedback signals through the calibration channel. These feedback signals are then processed by the control computer to achieve external calibration of the transmitted signal. When performing external calibration of the received signal, the control computer converts the excitation signal from D / A and up-converts it to enter the calibration channel. The signal is then fed to the calibration antenna through the "T channel" in the calibration component and transmitted through the calibration antenna. It is received by each array element in the array to be calibrated and enters the control computer through the sampling port of the receiving channel for external calibration.

[0077] Step S30: Acquire radar data and preprocess the radar data to obtain processed radar data.

[0078] It should be noted that after external calibration of the lidar array to be calibrated, radar data can be acquired, and the radar amplitude and phase errors can be calibrated using this data. After obtaining the radar data, due to the presence of interference data, preprocessing is necessary to improve the accuracy of the acquired radar data. Specifically, the preprocessing steps include: acquiring a first set of radar data and a second set of radar data; performing a first Fourier transform on the first and second sets of radar data to obtain range information; performing a second Fourier transform on the range information to obtain Doppler information of the target object; obtaining the effective range and radial velocity range of the target object signal relative to the radar based on the Doppler information of the target object; and calculating the average of the range and radial velocity range of the target object signal relative to the radar to obtain the processed radar data.

[0079] It should be understood that the first and second sets of radar data are collected by different radars. To synchronize these two sets of data, a first Fourier transform can be performed to obtain range information. A second Fourier transform is then performed on the range information to obtain the Doppler information of the target object. Based on this Doppler information, the effective range and radial velocity range of the target object signal relative to the radar can be determined. Finally, the range and radial velocity range of the target object signal relative to the radar are averaged, thereby synchronizing the first and second sets of radar data to obtain processed radar data.

[0080] Step S40: Construct the array covariance matrix based on the processed radar data.

[0081] It should be noted that after obtaining the processed radar data, the received array signal can be calculated based on the processed radar data, and thus the array covariance matrix can be constructed based on the received array signal.

[0082] Step S50: Obtain the eigenvector based on the array covariance matrix, and calculate the calibration value based on the eigenvector.

[0083] In practice, after constructing the array covariance matrix, eigenvalue decomposition can be performed on the array covariance matrix to obtain eigenvectors, and the radar calibration value can be calculated through the eigenvectors.

[0084] Step S60: Perform amplitude and phase error calibration on the radar using the calibration value to achieve automatic radar calibration.

[0085] It should be understood that once the radar calibration value is calculated, the radar amplitude and phase error can be calibrated using the calibration value, thereby improving the accuracy of radar calibration.

[0086] This embodiment transmits a calibration signal to a calibration antenna and collects the feedback signal from the calibration antenna based on the calibration signal; performs external calibration on the lidar array to be calibrated according to the feedback signal; acquires radar data and preprocesses the radar data to obtain processed radar data; constructs an array covariance matrix based on the processed radar data; obtains eigenvectors based on the array covariance matrix and calculates calibration values ​​based on the eigenvectors; and performs amplitude and phase error calibration on the radar using the calibration values ​​to achieve automatic radar calibration. By performing external calibration on the lidar array to be calibrated and performing amplitude and phase error calibration on the radar, the calibration accuracy of the radar is improved.

[0087] refer to Figure 4 , Figure 4 This is a flowchart illustrating the second embodiment of the radar automatic calibration method of the present invention.

[0088] Based on the first embodiment described above, step S60 of the radar automatic calibration method in this embodiment specifically includes:

[0089] Step S601: Calculate the correlation coefficient between the calibration values ​​using the calibration values.

[0090] It should be noted that after the calibration values ​​are calculated, they can be further processed to remove erroneous calibration values. Therefore, the correlation coefficients between the calibration values ​​can be calculated. For each calibration value γv (v = 1, 2, 3, ..., V), the correlation coefficients between it and the other calibration values ​​are calculated as follows: Equation 1:

[0091]

[0092] In Equation 1, j = 1, 2, 3, ..., V, and j ≠ i, E is the expected value, and P... ij The correlation coefficient.

[0093] Step S602: Calculate and discard calibration values ​​whose correlation coefficient is greater than the preset calibration coefficient threshold.

[0094] It should be noted that the preset calibration coefficient threshold can be set according to the requirements, such as 0.8, 0.9, 0.95, etc. This embodiment does not limit this. This embodiment takes 0.95 as an example for explanation. By comparing the correlation coefficient with the preset calibration coefficient threshold, the calibration value corresponding to the correlation coefficient greater than the preset calibration coefficient threshold is used as the calibration value to be removed.

[0095] Step S603: Remove the discarded calibration value from the calibration value to obtain the target calibration value.

[0096] The statistically obtained calibration values ​​are removed from the calibration values ​​to eliminate a large number of erroneous calibration values. The removed calibration values ​​are then used as the target calibration values.

[0097] Step S604: Perform amplitude and phase error calibration on the radar using the target calibration value.

[0098] It should be understood that once the target calibration value is obtained, the radar amplitude and phase error can be calibrated using the target calibration value, thereby improving the accuracy of the calibration.

[0099] This embodiment calculates the correlation coefficient between the calibration values; counts the calibration values ​​whose correlation coefficient is greater than a preset calibration coefficient threshold and discards them; removes the discarded calibration values ​​from the calibration values ​​to obtain the target calibration value; and performs amplitude and phase error calibration on the radar using the target calibration value. By removing erroneous values ​​from the calibration values ​​through the correlation coefficient, the correct calibration value is obtained, thereby improving the accuracy and effectiveness of the calibration.

[0100] refer to Figure 5 , Figure 5 This is a flowchart illustrating the third embodiment of the radar automatic calibration method of the present invention.

[0101] Based on the first embodiment described above, step S50 of the radar automatic calibration method in this embodiment specifically includes:

[0102] Step S501: Perform eigenvalue decomposition on the array covariance matrix to obtain the eigenvector corresponding to the largest eigenvalue.

[0103] It should be understood that eigenvalue decomposition of the array covariance matrix can be performed using principal component decomposition, singular value decomposition, etc. This embodiment does not limit this to any particular method. By performing eigenvalue decomposition on the array covariance matrix, the eigenvector e1 = [e1 = ...] corresponding to the largest eigenvalue is obtained.11 e 12 e 13 , ..., e 1M ] T .

[0104] Step S502: Obtain the first relationship between the feature vector and the guide vector of the spatial array.

[0105] The first relationship between the eigenvectors and the steering vectors of the spatial array is as follows: Equation 2:

[0106] T v α(θ v )=qe1 (Equation 2)

[0107] In Equation 2, T v Let e1 be the eigenvector, and α(θ) be the diagonal matrix representing the amplitude and phase errors of the array. v ) is the guidance vector of the spatial array, and q is the first calibration constant.

[0108] Step S503: Obtain the first calibration value constant through the first relationship and the feature vector.

[0109] It should be understood that once the first relation and eigenvector are obtained, the first calibration constant can be calculated using Equation 2 above.

[0110] Step S504: Obtain the guide vector of the spatial array.

[0111] The guiding vector of the spatial array is α(θ) v ), α(θ) v It also satisfies the following equation 3:

[0112] T v α(θ v )=[1,T2β2,T3β3,...,T M β M ] T (Equation 3)

[0113] In Equation 3, T v For the array amplitude and phase error diagonal matrix, α(θ) v ) is the guiding vector of the spatial array, β M This is the second calibration constant.

[0114] Step S505: Obtain the second calibration constant through the guide vector of the spatial array.

[0115] In practical implementation, after obtaining the guidance vector of the spatial array, the second calibration constant β can be obtained through Equation 3 above. M .

[0116] Step S506: Calculate the calibration value using the first calibration value constant and the second calibration value constant.

[0117] In practical implementation, after obtaining the first calibration constant and the second calibration constant, it can be determined from Equations 2 and 3 above that q = 1 / e 11 The calibration value γ can be calculated using the first calibration constant and the second calibration constant. v =[1,qe 11 / β2,qe 13 / β3,qe 1M / β M ].

[0118] This embodiment obtains the eigenvector corresponding to the largest eigenvalue by performing eigenvalue decomposition on the array covariance matrix; obtains a first relationship between the eigenvector and the steering vector of the spatial array; obtains a first calibration constant through the first relationship and the eigenvector; obtains the steering vector of the spatial array; obtains a second calibration constant through the steering vector of the spatial array; and calculates the calibration value through the first calibration constant and the second calibration constant. This allows for rapid calculation of the calibration value based on the first relationship between the eigenvector and the steering vector of the spatial array, thereby enabling automatic radar calibration and improving the calibration effect.

[0119] refer to Figure 6 , Figure 6 This is a flowchart illustrating the fourth embodiment of the radar automatic calibration method of the present invention.

[0120] Based on the first embodiment described above, step S40 of the radar automatic calibration method in this embodiment specifically includes:

[0121] Step S401: Obtain radar array information based on the processed radar data.

[0122] It should be noted that after obtaining the processed radar data, radar array information can be obtained from the processed radar data. The radar array information includes information such as radar array, array quantity, number of snapshots, and noise data vector.

[0123] Step S402: Calculate the received array signal value using the radar array information.

[0124] In specific implementation, the received array signal value can be calculated using the radar array, array quantity, number of snapshots, noise data vector, etc., from the radar array information. The specific steps are as follows: obtain the radar array, array quantity, number of snapshots, spatial signal vector, and noise data vector from the radar array information; obtain the amplitude error and phase error of the array elements from the radar array and the array quantity; obtain the amplitude and phase errors of the array elements from the amplitude and phase errors of the array elements; summarize the amplitude and phase errors of the array elements to obtain the array amplitude and phase error diagonal array; and calculate the steering vector of the spatial array.

[0125] It should be understood that the amplitude error and phase error of the array elements can be obtained from the radar array and array quantity information. The amplitude error of the array element is g. m The phase error of the array element is

[0126] In practical implementation, after obtaining the amplitude error and phase error of the array element, the amplitude error and phase error of the array element can be calculated to obtain the amplitude-phase error of the array element, as shown in Equation 4 below:

[0127]

[0128] In Equation 4, T m Let g be the amplitude and phase error of the m-th element. m Let m be the amplitude error of the m-th array element. Let T be the phase error of the m-th array element. T is obtained through calculation. m The amplitude and phase errors of the array elements are then summarized to obtain the array amplitude and phase error diagonal matrix T. v =diag[T1, T2, T3,...,T M ] represents the amplitude and phase error diagonal matrix of an M*M dimensional array.

[0129] Specifically, the steering vector of the spatial array is an M*1 dimensional steering vector of the spatial array. The specific steps for calculating the steering vector of the spatial array are as follows: obtain the array element coordinates and the target object direction angle based on the radar array information; calculate the path difference using the array element coordinates and the target object direction angle; obtain the signal wavelength; and calculate the steering vector of the spatial array using the path difference and the signal wavelength.

[0130] It should be noted that the radar array information contains element coordinates (x... m y m and the target object's orientation angle θ v It can be determined by the direction and angle θ of the target object. v The path difference is calculated using the array element coordinates, as shown in Equation 5:

[0131] dm =x m cosθ v +y m sinθ v (Equation 5)

[0132] In Equation 5, d m For path difference, x m y m Let θ be the coordinates of the array element. v The direction and angle of the target object.

[0133] In practical implementation, after calculating the path difference, the steering vector of the spatial array can be calculated using the path difference and the acquired signal wavelength, as shown in Equation 6:

[0134]

[0135] In Equation 6, α(θ) v ) is the steering vector of the spatial array, λ is the signal wavelength, and d M The path difference is used to calculate the steering vector of the space array using Equation 6 above, thus obtaining the steering vector of the space array.

[0136] In specific implementation, the received array signal value can be calculated using the guide vector of the spatial array, the number of snapshots, the spatial signal vector, the noise data vector, and the array amplitude and phase error diagonal array.

[0137] The specific calculation is as follows: (Formula 7)

[0138] X(t)=Tvα(θv)Sv(t)+N(t),t=1,2,...,L

[0139] (Equation 7)

[0140] In Equation 7, X(t) is the value of the receiving array signal, and α(θ) is the value of the receiving array signal. v T is the guiding vector of the spatial array. v S is a diagonal array for amplitude and phase error. v N(t) is the spatial signal vector, N(t) is the noise data vector, and L is the number of snapshots.

[0141] Step S403: Construct the array covariance matrix based on the received array signal values.

[0142] In practical implementation, after calculating the received array signal values, the array covariance matrix R can be constructed using the received array signal values. v The array covariance matrix (t) can be expressed as follows: Equation 8:

[0143]

[0144] In Equation 8, Rv (t) is the array covariance matrix, and E() is the expected value. The array covariance matrix can be constructed using Equation 8 above.

[0145] This embodiment obtains radar array information based on processed radar data; calculates the received array signal value using the radar array information; and constructs an array covariance matrix based on the received array signal value, which can quickly construct the array covariance matrix based on the processed radar data.

[0146] Reference Figure 7 , Figure 7 This is a structural block diagram of the first embodiment of the radar automatic calibration device of the present invention.

[0147] like Figure 7 As shown, the radar automatic calibration device proposed in this embodiment of the invention includes:

[0148] The transmitting module 10 is used to transmit a calibration signal to the calibration antenna and to collect the feedback signal from the calibration antenna based on the calibration signal.

[0149] The calibration module 20 is used to perform external calibration on the laser radar array to be calibrated based on the feedback signal.

[0150] The acquisition module 30 is used to acquire radar data and preprocess the radar data to obtain processed radar data.

[0151] Module 40 is used to construct the array covariance matrix based on the processed radar data.

[0152] The acquisition module 30 is further configured to obtain an eigenvector based on the array covariance matrix and calculate a calibration value based on the eigenvector.

[0153] The calibration module 20 is also used to perform amplitude and phase error calibration on the radar using the calibration value, so as to realize automatic radar calibration.

[0154] This embodiment transmits a calibration signal to a calibration antenna and collects the feedback signal from the calibration antenna based on the calibration signal; performs external calibration on the lidar array to be calibrated according to the feedback signal; acquires radar data and preprocesses the radar data to obtain processed radar data; constructs an array covariance matrix based on the processed radar data; obtains eigenvectors based on the array covariance matrix and calculates calibration values ​​based on the eigenvectors; and performs amplitude and phase error calibration on the radar using the calibration values ​​to achieve automatic radar calibration. By performing external calibration on the lidar array to be calibrated and performing amplitude and phase error calibration on the radar, the calibration accuracy of the radar is improved.

[0155] In one embodiment, the calibration module 20 is further configured to calculate the correlation coefficient between the calibration values ​​using the calibration values; count the calibration values ​​whose correlation coefficient is greater than a preset calibration coefficient threshold and discard them; remove the discarded calibration values ​​from the calibration values ​​to obtain the target calibration value; and perform amplitude and phase error calibration on the radar using the target calibration value.

[0156] In one embodiment, the acquisition module 30 is further configured to perform eigenvalue decomposition on the array covariance matrix to obtain the eigenvector corresponding to the largest eigenvalue; acquire a first relationship between the eigenvector and the steering vector of the spatial array; obtain a first calibration constant through the first relationship and the eigenvector; acquire the steering vector of the spatial array; obtain a second calibration constant through the steering vector of the spatial array; and calculate a calibration value through the first calibration constant and the second calibration constant.

[0157] In one embodiment, the construction module 40 is further configured to obtain radar array information based on the processed radar data; calculate the received array signal value using the radar array information; and construct an array covariance matrix based on the received array signal value.

[0158] In one embodiment, the construction module 40 is further configured to obtain the radar array, array quantity, number of snapshots, spatial signal vector, and noise data vector through the radar array information; obtain the amplitude error and phase error of the array elements through the radar array and the number of array elements; obtain the amplitude-phase error of the array elements through the amplitude error and phase error of the array elements; summarize the amplitude-phase errors of the array elements to obtain an array amplitude-phase error diagonal matrix; calculate the steering vector of the spatial array; and calculate the received array signal value through the steering vector of the spatial array, the number of snapshots, the spatial signal vector, the noise data vector, and the array amplitude-phase error diagonal matrix.

[0159] In one embodiment, the construction module 40 is further configured to obtain the array element coordinates and the target object direction angle based on the radar array information; calculate the path difference using the array element coordinates and the target object direction angle; obtain the signal wavelength; and calculate the steering vector of the spatial array using the path difference and the signal wavelength.

[0160] In one embodiment, the acquisition module 30 is further configured to acquire a first set of radar data and a second set of radar data; perform a first Fourier transform on the first set of radar data and the second set of radar data to obtain range information; perform a second Fourier transform on the range information to obtain Doppler information of the target object; obtain the effective range and radial velocity range of the target object signal relative to the radar based on the Doppler information of the target object; and calculate the mean of the range and radial velocity range of the target object signal relative to the radar to obtain processed radar data.

[0161] Furthermore, to achieve the above objectives, the present invention also proposes an automatic radar calibration device, which includes: a memory, a processor, and an automatic radar calibration program stored in the memory and executable on the processor, wherein the automatic radar calibration program is configured to implement the steps of the automatic radar calibration method described above.

[0162] Since this radar automatic calibration device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0163] Furthermore, this embodiment of the invention also proposes a storage medium storing a radar automatic calibration program, which, when executed by a processor, implements the steps of the radar automatic calibration method described above.

[0164] Since this storage medium adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0165] It should be understood that the above are merely illustrative examples and do not constitute any limitation on the technical solutions of the present invention. In specific applications, those skilled in the art can make settings as needed, and the present invention does not impose any restrictions on this.

[0166] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of the workflow to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here.

[0167] In addition, for technical details not described in detail in this embodiment, please refer to the radar automatic calibration method provided in any embodiment of the present invention, which will not be repeated here.

[0168] Furthermore, it should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0169] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0170] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0171] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. An automatic radar calibration method, characterized in that, The automatic radar calibration method includes: Transmit a calibration signal to the calibration antenna and collect the feedback signal from the calibration antenna based on the calibration signal; The laser radar array to be calibrated is externally calibrated based on the feedback signal; Acquire radar data and preprocess the radar data to obtain processed radar data; Construct the array covariance matrix based on the processed radar data; The eigenvectors are obtained based on the array covariance matrix, and the calibration values ​​are calculated based on the eigenvectors. The radar amplitude and phase error are calibrated using the calibration values ​​to achieve automatic radar calibration. The step of obtaining the eigenvector based on the array covariance matrix and calculating the calibration value based on the eigenvector includes: The array covariance matrix is ​​subjected to eigenvalue decomposition to obtain the eigenvector corresponding to the largest eigenvalue; Obtain the first relationship between the feature vectors and the guide vectors of the spatial array; The first calibration value constant is obtained through the first relationship and the feature vector; Obtain the guidance vector of the spatial array; The second calibration constant is obtained through the guide vector of the spatial array; The calibration value is calculated using the first calibration constant and the second calibration constant.

2. The radar automatic calibration method as described in claim 1, characterized in that, The step of calibrating the radar amplitude and phase error using the calibration value includes: The correlation coefficient between the calibration values ​​is calculated using the calibration values. Calculate and discard calibration values ​​whose correlation coefficient is greater than a preset calibration coefficient threshold. The target calibration value is obtained by removing the discarded calibration value from the calibration value. The radar amplitude and phase error are calibrated using the target calibration value.

3. The radar automatic calibration method as described in claim 1, characterized in that, The construction of the array covariance matrix based on the processed radar data includes: Radar array information is obtained based on the processed radar data; The received array signal value is calculated using the radar array information; Construct the array covariance matrix based on the received array signal values.

4. The radar automatic calibration method as described in claim 3, characterized in that, The calculation of the received array signal value using the radar array information includes: The radar array information is used to obtain the radar array, array quantity, number of snapshots, spatial signal vector, and noise data vector. The amplitude error and phase error of the array elements are obtained by using the radar array and the number of array elements. The amplitude and phase errors of the array elements are obtained by measuring the amplitude error and the phase error of the array elements. The amplitude and phase errors of the array elements are summarized to obtain the array amplitude and phase error diagonal matrix; Calculate the steering vector of the spatial array; The received array signal value is calculated using the guide vector of the spatial array, the number of snapshots, the spatial signal vector, the noise data vector, and the array amplitude and phase error diagonal array.

5. The radar automatic calibration method as described in claim 4, characterized in that, The guiding vector of the computational space array includes: The array element coordinates and the target object's orientation angle are obtained based on the radar array information. The path difference is calculated using the array element coordinates and the target object's orientation angle. Obtain the signal wavelength; The steering vector of the spatial array is calculated using the path difference and the signal wavelength.

6. The radar automatic calibration method according to any one of claims 1 to 5, characterized in that, The process of acquiring radar data and preprocessing the radar data to obtain processed radar data includes: Acquire the first set of radar data and the second set of radar data; Perform a first Fourier transform on the first set of radar data and the second set of radar data to obtain range information; Perform a second Fourier transform on the distance information to obtain the Doppler information of the target object; The effective range of target object signal relative to radar distance and radial velocity is obtained based on the Doppler information of the target object; The average value of the target object signal relative to the radar distance and the radial velocity range is calculated to obtain processed radar data.

7. An automatic radar calibration device, characterized in that, The automatic radar calibration device includes: The transmitting module is used to transmit a calibration signal to the calibration antenna and to acquire the feedback signal from the calibration antenna based on the calibration signal; The calibration module is used to perform external calibration of the lidar array to be calibrated based on the feedback signal. An acquisition module is used to acquire radar data and preprocess the radar data to obtain processed radar data. The building module is used to construct the array covariance matrix based on the processed radar data; The acquisition module is further configured to obtain eigenvectors based on the array covariance matrix and calculate calibration values ​​based on the eigenvectors. Specifically, the acquisition module is configured to: perform eigenvalue decomposition on the array covariance matrix to obtain the eigenvector corresponding to the largest eigenvalue; acquire a first relationship between the eigenvectors and the steering vector of the spatial array; obtain a first calibration constant through the first relationship and the eigenvectors; acquire the steering vector of the spatial array; obtain a second calibration constant through the steering vector of the spatial array; and calculate a calibration value through the first calibration constant and the second calibration constant. The calibration module is also used to calibrate the amplitude and phase error of the radar using the calibration value, so as to realize automatic radar calibration.

8. An automatic radar calibration device, characterized in that, The radar automatic calibration device includes: a memory, a processor, and a radar automatic calibration program stored in the memory and executable on the processor, the radar automatic calibration program being configured to implement the radar automatic calibration method as described in any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium stores an automatic radar calibration program, which, when executed by a processor, implements the automatic radar calibration method as described in any one of claims 1 to 6.

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