Method and device for calibrating external parameters of millimeter wave radar-imu, equipment and storage medium

Abstract

The application relates to a millimeter wave radar-IMU external parameter calibration method and device, equipment and a storage medium, wherein the method comprises the following steps: acquiring global positioning coordinates of at least one corner reflector, global positioning coordinates of a motion carrier and a plurality of initial point cloud coordinates of each corner reflector; determining target point cloud coordinates of each corner reflector from the plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the motion carrier; converting the global positioning coordinates of each corner reflector to an IMU coordinate system to obtain IMU coordinates of each corner reflector; performing coordinate correlation on the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector; and obtaining the external parameters of the millimeter wave radar-IMU based on an iterative least square method. Thus, the problem of insufficient precision and robustness of millimeter wave radar-IMU calibration in a complex environment is solved, and the calibration precision and system robustness in a dynamic environment are greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of external parameter calibration, and in particular to a method, device, equipment and storage medium for extrinsic parameter calibration of a millimeter-wave radar-IMU. Background Art

[0002] With the growing demand for high-precision positioning, navigation, and perception in fields such as autonomous driving, drones, and robotics, millimeter-wave radar and IMUs (Inertial Measurement Units) have become essential sensors for achieving high-precision spatial perception and dynamic positioning. Accurate calibration of millimeter-wave radar and IMUs is a key step in achieving high-precision pose and velocity estimation for combined millimeter-wave radar-IMU systems. This calibration process not only provides the necessary coordinate system transformation for converting target positions detected by the millimeter-wave radar into the navigation coordinate system, but also lays the foundation for further sensor fusion.

[0003] Related technologies propose an odometer-based method for millimeter-wave radar-IMU external parameter calibration, which estimates the vehicle's own posture using millimeter-wave radar and IMU respectively, and correlates the posture information of the two to solve the external parameters.

[0004] However, in practical applications, the accuracy of millimeter-wave radar-IMU calibration is limited by multiple factors. First, millimeter-wave radars often use corner reflectors (hereinafter referred to as corner reflectors) as targets, but the limited number of corner reflectors leads to insufficient observation data, making the calibration results dependent on limited observations, which in turn limits the accuracy. Second, the point cloud generated by millimeter-wave radar is sparse and sensitive to the reflection intensity of different materials, making it difficult to extract features from specific areas of interest. Due to the scarcity of valid observations, it is difficult for millimeter-wave radars to achieve high-precision pose estimation through methods such as SLAM, and the IMU's pose calculation through integration has the problem of error accumulation, further affecting the calibration accuracy. In addition, in dynamic environments such as shipborne systems, the installation positions of millimeter-wave radars and IMUs will be affected by external interference such as water waves as the carrier moves, causing the observations to be interfered with by noise such as background objects and multipath signals, affecting the stability and reliability of the calibration. Summary of the Invention

[0005] The present application provides a millimeter-wave radar-IMU external parameter calibration method, device, equipment and storage medium to solve the problem of insufficient accuracy and robustness in the calibration of millimeter-wave radar-IMU in complex environments, and greatly improves the calibration accuracy and system robustness in dynamic environments.

[0006] The first embodiment of the present application provides a millimeter wave radar-IMU external parameter calibration method, comprising the following steps:

[0007] Acquire the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector;

[0008] Determine the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving vehicle;

[0009] The global positioning coordinates of each corner reflector are converted to the IMU coordinate system to obtain the IMU coordinates of each corner reflector, the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector are coordinate-associated, and the external parameters of the millimeter-wave radar-IMU are obtained based on the iterative least squares method.

[0010] Optionally, in some embodiments, determining the point cloud coordinates of each corner reflector from a plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier comprises:

[0011] Determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier;

[0012] The target point cloud coordinates of each corner reflector are determined from the multiple initial point cloud coordinates of each corner reflector according to the reference distance.

[0013] Optionally, in some embodiments, determining the reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier includes:

[0014] Based on a preset distance calculation formula, a reference distance between each corner reflector and the moving carrier is determined according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, wherein the preset distance calculation formula is:

[0015]

[0016] Among them, D IR,k is the reference distance, is the global positioning coordinate of the i-th reflector, is the global positioning coordinates of the moving carrier.

[0017] Optionally, in some embodiments, converting the global positioning coordinates of each corner reflector into an IMU coordinate system to obtain the IMU coordinates of each corner reflector includes:

[0018] Obtain the IMU pose sequence based on the preset GNSS / INS combination algorithm;

[0019] Converting the global positioning coordinates of each corner reflector into a navigation coordinate system to obtain the navigation coordinate system coordinates of each corner reflector;

[0020] The IMU coordinates of each corner reflector are obtained according to the IMU posture sequence and the navigation coordinate system coordinates of each corner reflector.

[0021] A second embodiment of the present application provides an external parameter calibration device for a millimeter-wave radar-IMU, including:

[0022] an acquisition module, configured to acquire the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector;

[0023] A determination module, configured to determine a target point cloud coordinate of each corner reflector from a plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier;

[0024] The association module is used to convert the global positioning coordinates of each corner reflector into the IMU coordinate system to obtain the IMU coordinates of each corner reflector, coordinately associate the target point cloud coordinates of each corner reflector with the IMU coordinates of each corner reflector, and obtain the external parameters of the millimeter wave radar-IMU based on the iterative least squares method.

[0025] Optionally, in some embodiments, the determining module includes:

[0026] A first determining unit is configured to determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier;

[0027] The second determining unit is configured to determine the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector according to the reference distance.

[0028] Optionally, in some embodiments, the first determining unit includes:

[0029] a calculation subunit, configured to determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier based on a preset distance calculation formula, wherein the preset distance calculation formula is:

[0030]

[0031] Among them, DIR,k is a reference distance, is a global positioning coordinate of the i-th reflector, is a global positioning coordinate of the moving carrier.

[0032] Optionally, in some embodiments, the association module comprises:

[0033] The first generating unit is configured to obtain the pose sequence of the IMU based on a preset GNSS / INS combination algorithm.

[0034] The switching unit is configured to convert the global positioning coordinate of each corner reflector to a navigation coordinate system to obtain a navigation coordinate system coordinate of each corner reflector.

[0035] The second generating unit is configured to obtain the IMU coordinate of each corner reflector according to the pose sequence of the IMU and the navigation coordinate system coordinate of each corner reflector.

[0036] The third aspect of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for calibrating the external parameters of the millimeter wave radar-IMU as described in the above embodiments.

[0037] The fourth aspect of the present application provides a computer readable storage medium having a computer program stored thereon, wherein the program is executed by a processor to implement the method for calibrating the external parameters of the millimeter wave radar-IMU as described in the above embodiments.

[0038] Therefore, the present application has at least the following beneficial effects:

[0039] (1) The present application uses a moving carrier to observe the corner reflector, and the plurality of corner reflector sequences obtained can compensate for the limited calibration accuracy caused by the insufficient number of corner reflectors.

[0040] (2) The present application uses GNSS to screen the point cloud coordinates of the corner reflector, which effectively suppresses the influence of noise and gross errors in the initial stage.

[0041] (3) The present application introduces GNSS assistance, and the IMU pose calculated by GNSS / INS combination can accurately calculate the pose of the IMU in the GNSS coordinate system, thereby converting the corner reflector to the IMU coordinate system.

[0042] In summary, the present application not only solves the limitations of traditional calibration methods in complex environments, but also greatly improves the calibration accuracy and robustness of the system in dynamic environments. BRIEF DESCRIPTION OF DRAWINGS

[0043] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0044] Figure 1 A flowchart of a method for calibrating external parameters of a millimeter wave radar-IMU according to an embodiment of the present application;

[0045] Figure 2 A schematic diagram of an experiment for calibrating external parameters of a shipborne millimeter wave radar-IMU according to an embodiment of the present application;

[0046] Figure 3 A schematic diagram of external parameters of a millimeter wave radar-IMU according to an embodiment of the present application;

[0047] Figure 4 A schematic diagram of a result of alignment of an angle after conversion of external parameters according to an embodiment of the present application, wherein the angle is aligned in a millimeter wave radar coordinate system and an IMU coordinate system, Figure 4 (a) is a schematic diagram of a result of alignment using external parameters calculated in the first iteration, Figure 4 (b) is a schematic diagram of a result of alignment using external parameters calculated in the 20th iteration;

[0048] Figure 5 A flowchart of a method for calibrating a millimeter wave radar-IMU according to an embodiment of the present application;

[0049] Figure 6 A block schematic diagram of a device for calibrating external parameters of a millimeter wave radar-IMU according to an embodiment of the present application;

[0050] Figure 7 A schematic diagram of a structure of an apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0051] Embodiments of the present application are described in detail below with reference to the attached drawings, which are meant to be exemplary and not limiting.

[0052] The following describes the extrinsic parameter calibration method, device, equipment and storage medium of the millimeter wave radar-IMU of the embodiment of the present application with reference to the accompanying drawings. In response to the problem of insufficient accuracy and robustness of the calibration of the millimeter wave radar-IMU in a complex environment mentioned in the above background technology, the present application provides an extrinsic parameter calibration method of the millimeter wave radar-IMU, in which, first, according to the GNSS coordinate sequence of the carrier and the GNSS coordinates of the inverse angle, the distance from the inverse angle to the IMU at different times is calculated, and the inverse angle point cloud coordinates are pre-selected based on this; then, the IMU pose is calculated by the GNSS / INS combined algorithm, and the inverse angle GNSS coordinates are converted accordingly to obtain the inverse angle IMU system coordinates; finally, by associating the inverse angle point cloud coordinates and the IMU system coordinates, the millimeter wave radar-IMU extrinsic parameters are estimated, and the iterative least squares form is used in the calculation to gradually eliminate gross errors from the pre-selected inverse angle coordinates, thereby improving the accuracy of the extrinsic parameter solution.

[0053] Specifically, Figure 1 A flow chart of an extrinsic parameter calibration method for a millimeter-wave radar-IMU provided in an embodiment of the present application.

[0054] like Figure 1 As shown, the millimeter wave radar-IMU external parameter calibration method includes the following steps:

[0055] In step S101 , the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector are acquired.

[0056] Among them, the global positioning coordinates are measured by the GNSS RTK method, and the initial point cloud coordinates are measured by millimeter wave radar.

[0057] Specifically, combined Figure 2 As shown, in this embodiment of the application, three corner reflectors are placed stationary on shore and the GNSS RTK method is used to accurately measure the GNSS coordinates of the corner reflectors, with RTK measurement accuracy reaching the centimeter level. While the ship is in motion, the millimeter-wave radar, IMU, and GNSS are activated. The millimeter-wave radar detects the corner reflectors to obtain an initial point cloud sequence; the IMU and GNSS are used to estimate the IMU's accurate position and pose.

[0058] In step S102 , based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, the target point cloud coordinates of each corner reflector are determined from a plurality of initial point cloud coordinates of each corner reflector.

[0059] Further, in some embodiments, based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the motion carrier, the point cloud coordinates of each corner reflector are determined from multiple initial point cloud coordinates of each corner reflector, including: determining a reference distance between each corner reflector and the motion carrier based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the motion carrier; and determining the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector based on the reference distance.

[0060] It should be noted that, in the embodiments of this application, Figure 3 As shown, let the millimeter wave radar coordinate system be M, the IMU coordinate system be I, the earth coordinate system be G, and the external reference be Indicates the transformation parameters from the IMU coordinate system to the millimeter wave radar coordinate system, for example, the external parameters in represents the rotation from the I system to the M system, Represents the translation from I system to M system.

[0061] Specifically, in the earth coordinate system G, the angular inverse coordinate measured by GNSS RTK is They represent longitude, latitude, and elevation respectively. Under stationary conditions, the coordinate values ​​do not change with time.

[0062] In the M coordinate system, the homogeneous coordinate form of the angle inverse is Where i represents the angle number and k represents the time. The IMU coordinates are calculated using the GNSS / INS combination method. k represents the time.

[0063] In the embodiment of the present application, after obtaining the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and multiple initial point cloud coordinates of each corner reflector, the radar point cloud can be pre-selected.

[0064] The sampling rate of the millimeter wave radar is 20Hz, and the point cloud measured at each moment can be converted into multiple distances. These points are affected by noise and clutter, making it difficult to accurately screen the corner inversion points without other observation assistance. The embodiment of the present application can first convert the point cloud at the kth moment into a distance, that is:

[0065]

[0066] Then pass and Calculate the distance from the inverse angle to the IMU:

[0067]

[0068] In the case of long distance, if the distances from the millimeter wave radar and the IMU are approximately equal, the reference distance DIR,k To D i,k Perform pre-screening to obtain the pre-selected corner inverse point cloud sequence

[0069] In step S103, the global positioning coordinates of each corner reflector are converted to the IMU coordinate system to obtain the IMU coordinates of each corner reflector, the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector are coordinate-associated, and the external parameters of the millimeter-wave radar-IMU are obtained based on the iterative least squares method.

[0070] Furthermore, in some embodiments, the global positioning coordinates of each corner reflector are converted to an IMU coordinate system to obtain the IMU coordinates of each corner reflector, including: obtaining the IMU posture sequence based on a preset GNSS / INS combination algorithm; converting the global positioning coordinates of each corner reflector to a navigation coordinate system to obtain the navigation coordinate system coordinates of each corner reflector; and obtaining the IMU coordinates of each corner reflector based on the IMU posture sequence and the navigation coordinate system coordinates of each corner reflector.

[0071] Specifically, when determining the target point cloud coordinates of each corner reflector, the embodiment of the present application can convert the target point cloud coordinates of the corner reflector into the IMU coordinate system.

[0072] Specifically, according to the inverse angular coordinates IMU coordinates First, convert both to the navigation coordinate system (east-north-up, enu), and get

[0073] Specifically, all longitude and latitude heights [BLH] T All converted into Cartesian coordinates [xyz] T In the form of selecting an origin [x0y0z0] T Finally, the navigation coordinates of a point are calculated as follows:

[0074]

[0075] Where [ΔxΔyΔz] T =[xyz] T -[x0y0z0] T .

[0076] The IMU attitude obtained by the GNSS / INS combination algorithm is relative to the navigation coordinate system, so the IMU position (navigation system coordinates) and attitude can form a pose sequence. You can Convert to IMU coordinate system I and get the inverse I coordinate system

[0077]

[0078] After preselection and conversion, the coordinates of the two coordinate systems at time k are associated and

[0079]

[0080]

[0081] The weight of each equation is Where exp(·) represents the exponential function and F is the scaling factor. The above formula can be simplified as Then the K moments can be combined to obtain the following equations:

[0082]

[0083] External Reference Solve via weighted least squares:

[0084]

[0085] When solving, multiple iterations are performed and the residual is eliminated in each iteration Larger items to increase The estimation accuracy of .

[0086] In actual implementation, the present embodiment first selects synchronized moments for the three angle-inverted point cloud sequences during data processing. The results are then evaluated by aligning the angle-inverted coordinates in the IMU and millimeter-wave radar coordinate systems using estimated extrinsic parameters to assess the alignment. Twenty rounds of iterative calculations are performed, and observations with large residuals are removed during the iterations. Figure 4 (a) and Figure 4 (b) shows the results of the angular reverse coordinate alignment after the 1st and 20th iterations, respectively. It can be seen that with the increase of iterations, better alignment effects can be achieved, and outliers can be eliminated by limiting the residual.

[0087] Table 1 shows the extrinsic parameter results, extrinsic parameter statistics, and alignment reprojection error for the calibrated millimeter-wave radar-IMU. The results show that the estimated millimeter-wave radar-IMU heading deviation angle error is 0.07 degrees, and the translation difference is 0.1 meter, demonstrating the high calibration accuracy of this embodiment. The reprojection error is 0.2 meters, which is consistent with the ranging accuracy of millimeter-wave radar.

[0088] Among them, Table 1 is the statistical analysis table of millimeter wave radar-IMU external parameters.

[0089] Table 1

[0090]

[0091] In summary, combined Figure 5 As shown, the embodiment of the present application proposes a method for calibrating the external parameters of a moving carrier millimeter-wave radar-IMU based on angle reflection under the assistance of GNSS. In this method, three corner reflectors obtain high-precision GNSS coordinates through GNSS RTK, and the millimeter-wave radar, IMU, and GNSS are synchronously turned on during the movement of the carrier. The distance from the corner reflector to the carrier is dynamically calculated through the GNSS coordinate sequence of the carrier and the GNSS coordinates of the corner reflector, thereby selecting the angle reflection point cloud coordinates; then, the high-precision posture of the IMU is calculated through the GNSS / INS combined navigation algorithm, and the GNSS coordinates of the corner reflector are converted to the IMU coordinate system to obtain the position of the angle reflection in the IMU coordinate system; finally, the point cloud coordinates of the angle reflection are associated with the coordinates in the IMU coordinate system, and the external parameters of the millimeter-wave radar-IMU are solved by the iterative least squares method, and the gross error data are gradually eliminated during the calculation process to improve the accuracy. As a result, the limitations of the traditional calibration method in complex environments are solved, and the calibration accuracy and system robustness in dynamic environments are greatly improved. The embodiments of the present application provide a new calibration solution for the efficient fusion of millimeter-wave radar and IMU, which is suitable for various practical application scenarios, including autonomous driving, drone navigation, robotics, positioning and perception of unmanned ships, etc. At the same time, this technology can effectively improve the positioning accuracy of the sensor fusion system and provide solid support for the technological development of related fields.

[0092] According to the extrinsic parameter calibration method of the millimeter-wave radar-IMU proposed in the embodiment of the present application, by obtaining the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and multiple initial point cloud coordinates of each corner reflector, and based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, the target point cloud coordinates of each corner reflector are determined from the multiple initial point cloud coordinates of each corner reflector, and the global positioning coordinates of each corner reflector are converted to the IMU coordinate system to obtain the IMU coordinates of each corner reflector, the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector are coordinate-correlated, and the extrinsic parameters of the millimeter-wave radar-IMU are obtained based on the iterative least squares method. In this way, the problem of insufficient accuracy and robustness of millimeter-wave radar-IMU calibration in complex environments is solved, and the calibration accuracy and system robustness in dynamic environments are greatly improved.

[0093] Next, the extrinsic parameter calibration device of the millimeter-wave radar-IMU proposed in accordance with an embodiment of the present application will be described with reference to the accompanying drawings.

[0094] Figure 6 It is a block diagram of the external parameter calibration device of the millimeter wave radar-IMU embodiment of the present application.

[0095] like Figure 6 As shown, the millimeter wave radar-IMU external parameter calibration device 10 includes: an acquisition module 100, a determination module 200 and an association module 300.

[0096] The acquisition module 100 is configured to acquire the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector.

[0097] The determination module 200 is configured to determine the target point cloud coordinates of each corner reflector from a plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier.

[0098] The association module 300 is used to convert the global positioning coordinates of each corner reflector into the IMU coordinate system to obtain the IMU coordinates of each corner reflector, coordinately associate the target point cloud coordinates of each corner reflector with the IMU coordinates of each corner reflector, and obtain the external parameters of the millimeter wave radar-IMU based on the iterative least squares method.

[0099] Optionally, in some embodiments, the determination module 200 includes: a first determination unit and a second determination unit.

[0100] The first determining unit is configured to determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier.

[0101] The second determining unit is configured to determine the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector according to the reference distance.

[0102] Optionally, in some embodiments, the first determining unit includes: a calculating subunit.

[0103] The calculation subunit is configured to determine a reference distance between each corner reflector and the moving carrier based on a preset distance calculation formula according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, wherein the preset distance calculation formula is:

[0104]

[0105] Among them, D IR,k is the reference distance, is the global positioning coordinate of the i-th reflector, is the global positioning coordinates of the moving carrier.

[0106] Optionally, in some embodiments, the association module 300 includes: a first generation unit, a switching unit, and a second generation unit.

[0107] The first generation unit is used to obtain the IMU pose sequence based on a preset GNSS / INS combination algorithm.

[0108] The switching unit is used to convert the global positioning coordinates of each corner reflector into a navigation coordinate system to obtain the navigation coordinate system coordinates of each corner reflector.

[0109] The second generating unit is used to obtain the IMU coordinates of each corner reflector according to the IMU posture sequence and the navigation coordinate system coordinates of each corner reflector.

[0110] It should be noted that the above explanation of the embodiment of the millimeter-wave radar-IMU external parameter calibration method is also applicable to the external parameter calibration device of the millimeter-wave radar-IMU of this embodiment, and will not be repeated here.

[0111] According to the external parameter calibration device of the millimeter-wave radar-IMU proposed in the embodiment of the present application, by obtaining the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and multiple initial point cloud coordinates of each corner reflector, and based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, the target point cloud coordinates of each corner reflector are determined from the multiple initial point cloud coordinates of each corner reflector, and the global positioning coordinates of each corner reflector are converted to the IMU coordinate system to obtain the IMU coordinates of each corner reflector, the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector are coordinate-correlated, and the external parameters of the millimeter-wave radar-IMU are obtained based on the iterative least squares method. In this way, the problem of insufficient accuracy and robustness of millimeter-wave radar-IMU calibration in complex environments is solved, and the calibration accuracy and system robustness in dynamic environments are greatly improved.

[0112] Figure 7 This is a schematic diagram of the structure of the device provided in the embodiment of the present application. The device may include:

[0113] Memory 701 , processor 702 , and computer programs stored in the memory 701 and executable on the processor 702 .

[0114] When the processor 702 executes the program, the millimeter wave radar-IMU external parameter calibration method provided in the above embodiment is implemented.

[0115] Furthermore, the device also includes:

[0116] The communication interface 703 is used for communication between the memory 701 and the processor 702 .

[0117] The memory 701 is used to store computer programs that can be run on the processor 702 .

[0118] The memory 701 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0119] If the memory 701, processor 702, and communication interface 703 are implemented independently, the communication interface 703, memory 701, and processor 702 can be connected to each other via a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0120] Optionally, in a specific implementation, if the memory 701, the processor 702 and the communication interface 703 are integrated on a chip, the memory 701, the processor 702 and the communication interface 703 can communicate with each other through an internal interface.

[0121] The processor 702 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0122] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned millimeter-wave radar-IMU external parameter calibration method.

[0123] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0124] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0125] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0126] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0127] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0128] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A millimeter wave radar-IMU external parameter calibration method, characterized in that: The following steps are involved: Acquire the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector; Determine the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving vehicle; The global positioning coordinates of each corner reflector are converted to the IMU coordinate system to obtain the IMU coordinates of each corner reflector, the target point cloud coordinates of each corner reflector and the IMU coordinates of each corner reflector are coordinate-associated, and the external parameters of the millimeter-wave radar-IMU are obtained based on the iterative least squares method.

2. The method according to claim 1, characterized in that The step of determining the point cloud coordinates of each corner reflector from a plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier comprises: Determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier; The target point cloud coordinates of each corner reflector are determined from the multiple initial point cloud coordinates of each corner reflector according to the reference distance.

3. The method according to claim 2, characterized in that The determining of a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier comprises: Based on a preset distance calculation formula, a reference distance between each corner reflector and the moving carrier is determined according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier, wherein the preset distance calculation formula is: Among them, D IR,k is the reference distance, is the global positioning coordinate of the i-th reflector, is the global positioning coordinates of the moving carrier.

4. The method according to claim 1, wherein The converting the global positioning coordinates of each corner reflector into the IMU coordinate system to obtain the IMU coordinates of each corner reflector includes: Obtain the IMU pose sequence based on the preset GNSS / INS combination algorithm; Converting the global positioning coordinates of each corner reflector into a navigation coordinate system to obtain the navigation coordinate system coordinates of each corner reflector; The IMU coordinates of each corner reflector are obtained according to the IMU posture sequence and the navigation coordinate system coordinates of each corner reflector.

5. A millimeter wave radar-IMU external parameter calibration device, characterized in that: include: an acquisition module, configured to acquire the global positioning coordinates of at least one corner reflector, the global positioning coordinates of the moving carrier, and a plurality of initial point cloud coordinates of each corner reflector; A determination module, configured to determine a target point cloud coordinate of each corner reflector from a plurality of initial point cloud coordinates of each corner reflector based on the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier; The association module is used to convert the global positioning coordinates of each corner reflector into the IMU coordinate system to obtain the IMU coordinates of each corner reflector, coordinately associate the target point cloud coordinates of each corner reflector with the IMU coordinates of each corner reflector, and obtain the external parameters of the millimeter wave radar-IMU based on the iterative least squares method.

6. The device according to claim 5, characterized in that The determining module includes: A first determining unit is configured to determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier; The second determining unit is configured to determine the target point cloud coordinates of each corner reflector from the multiple initial point cloud coordinates of each corner reflector according to the reference distance.

7. The device according to claim 6, characterized in that The first determining unit includes: a calculation subunit, configured to determine a reference distance between each corner reflector and the moving carrier according to the global positioning coordinates of each corner reflector and the global positioning coordinates of the moving carrier based on a preset distance calculation formula, wherein the preset distance calculation formula is: Among them, D IR,k is the reference distance, is the global positioning coordinate of the i-th reflector, is the global positioning coordinates of the moving carrier.

8. The device according to claim 5, characterized in that The association module includes: A first generating unit is used to obtain an IMU pose sequence based on a preset GNSS / INS combination algorithm; A switching unit, configured to convert the global positioning coordinates of each corner reflector into a navigation coordinate system to obtain the navigation coordinate system coordinates of each corner reflector; The second generating unit is used to obtain the IMU coordinates of each corner reflector according to the posture sequence of the IMU and the navigation coordinate system coordinates of each corner reflector.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the extrinsic parameter calibration method of the millimeter-wave radar-IMU according to any one of claims 1 to 4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the millimeter-wave radar-IMU external parameter calibration method as described in any one of claims 1 to 4.

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