Vehicle course angle measuring method and device, vehicle and storage medium

Abstract

The invention relates to the technical field of vehicle-mounted navigation positioning, in particular to a vehicle course angle measuring method and device, a vehicle and a storage medium, and the method comprises the following steps: obtaining carrier phase data, wheel speed data and inertia measurement data of the vehicle; calculating a first track point of the vehicle according to the carrier phase data, and calculating a second track point and a local course angle of the vehicle according to the wheel speed data and the inertia measurement data; and calculating the rotation amount between the track points according to the first track point and the second track point, and stacking the rotation amount between the track points and the local course angle to obtain a final course angle of the vehicle. Therefore, the problem that the real-time performance, accuracy and continuity of the vehicle course data are poor due to the fact that a high-precision RTK positioning result is used for connecting the differential signals is solved.

Description

Technical Field

[0001] This application relates to the field of vehicle navigation and positioning technology, and in particular to a method, device, vehicle, and storage medium for measuring vehicle heading angle. Background Technology

[0002] In vehicle-mounted integrated navigation and positioning, accurate initial heading angle is fundamental to positioning. Related technologies, such as using GNSS (Global Navigation Satellite System) dual antennas, absolute velocity, or absolute position for calculation, require two GNSS boards, increasing cost. Using GNSS position for calculation necessitates connecting differential signals to obtain a fixed GNSS solution and requires the vehicle to travel a certain distance in a straight line. Similarly, using GNSS velocity for calculation also requires connecting differential signals to obtain a fixed GNSS solution and imposes limitations on the vehicle's minimum speed. Summary of the Invention

[0003] This application provides a method, device, vehicle, and storage medium for measuring vehicle heading angle, in order to solve the problems of poor real-time performance, accuracy, and continuity of vehicle heading data caused by connecting differential signals with high-precision RTK (Real-Time Kinematic) positioning results in related technologies.

[0004] The first aspect of this application provides a method for measuring the heading angle of a vehicle, comprising the following steps: acquiring carrier phase data, wheel speed data, and inertial measurement data of the vehicle; calculating a first trajectory point of the vehicle based on the carrier phase data; calculating a second trajectory point and a local heading angle of the vehicle based on the wheel speed data and the inertial measurement data; calculating the rotation between the trajectory points based on the first trajectory point and the second trajectory point; and superimposing the rotation between the trajectory points and the local heading angle to obtain the final heading angle of the vehicle.

[0005] Optionally, calculating the first trajectory point of the vehicle based on the carrier phase data includes: determining the carrier data of a reference frame from the carrier phase data; obtaining the carrier data of other frames in the carrier phase data; and performing inter-epoch differential calculation based on the carrier data of the reference frame and the carrier data of other frames to obtain the first trajectory point of the vehicle.

[0006] Optionally, the first trajectory point of the vehicle is obtained by performing inter-epoch difference calculation based on the carrier data of the reference frame and the carrier data of other frames, including: constructing a target equation based on the carrier data of the reference frame and the carrier data of other frames, wherein the unknown parameters of the target equation are the position error correction and the receiver clock offset; iteratively solving the target equation to obtain the position error correction and the receiver clock offset; and calculating the first trajectory point of the vehicle based on the position error correction, the receiver clock offset and the carrier data of the reference frame.

[0007] Optionally, before iteratively solving the objective equation to obtain the position error correction and receiver clock offset, the method further includes: performing a post-hoc residual check on the carrier phase data; removing data from the carrier phase data based on the check results; and iteratively solving the objective equation based on the removed carrier phase data to obtain the position error correction and receiver clock offset.

[0008] Optionally, before calculating the first trajectory point of the vehicle based on the carrier phase data, the method further includes: preprocessing the carrier phase data, wherein the preprocessing method includes at least one of ephemeris error correction, ionospheric delay correction, tropospheric delay correction and Earth rotation correction.

[0009] Optionally, calculating the rotation between the trajectory points based on the first trajectory point and the second trajectory point includes: performing trajectory point matching on the first trajectory point and the second trajectory point; and solving for the rotation between the trajectory points based on the trajectory point matching result.

[0010] Optionally, before obtaining the vehicle's final heading angle by stacking the rotation between trajectory points and the local heading angle, the method further includes: acquiring the wheel speed data and inertial measurement data at the current moment; and updating the local heading angle based on the wheel speed data and inertial measurement data at the current moment.

[0011] A second aspect of this application provides a vehicle heading angle measuring device, comprising: an acquisition module for acquiring carrier phase data, wheel speed data, and inertial measurement data of the vehicle; a calculation module for calculating a first trajectory point of the vehicle based on the carrier phase data, and calculating a second trajectory point and a local heading angle of the vehicle based on the wheel speed data and the inertial measurement data; and a superposition module for calculating the rotation between the trajectory points based on the first trajectory point and the second trajectory point, and superimposing the rotation between the trajectory points and the local heading angle to obtain the final heading angle of the vehicle.

[0012] Optionally, the calculation module is further configured to: calculate the first trajectory point of the vehicle based on the carrier phase data, including: determining the carrier data of the reference frame from the carrier phase data; obtaining the carrier data of other frames in the carrier phase data; and performing inter-epoch differential calculation based on the carrier data of the reference frame and the carrier data of other frames to obtain the first trajectory point of the vehicle.

[0013] Optionally, the calculation module is further configured to: perform inter-epoch difference calculations to obtain the first trajectory point of the vehicle based on the carrier data of the reference frame and the carrier data of other frames, including: constructing a target equation based on the carrier data of the reference frame and the carrier data of other frames, wherein the unknown parameters of the target equation are the position error correction and the receiver clock offset; iteratively solving the target equation to obtain the position error correction and the receiver clock offset; and calculating the first trajectory point of the vehicle based on the position error correction, the receiver clock offset, and the carrier data of the reference frame.

[0014] Optionally, the vehicle heading angle measuring device further includes: a verification module, used to perform a post-verification residual verification on the carrier phase data before iteratively solving the objective equation to obtain the position error correction and receiver clock offset; to remove data from the carrier phase data based on the verification results; and to iteratively solve the objective equation based on the removed carrier phase data to obtain the position error correction and receiver clock offset.

[0015] Optionally, the vehicle heading angle measuring device further includes a preprocessing module for preprocessing the carrier phase data before calculating the first trajectory point of the vehicle based on the carrier phase data. The preprocessing method includes at least one of ephemeris error correction, ionospheric delay correction, tropospheric delay correction, and Earth rotation correction.

[0016] Optionally, the overlay module is further configured to: calculate the rotation amount between the trajectory points based on the first trajectory point and the second trajectory point, including: performing trajectory point matching on the first trajectory point and the second trajectory point; and solving for the rotation amount between the trajectory points based on the trajectory point matching result.

[0017] Optionally, the vehicle heading angle measuring device further includes: an update module, used to acquire wheel speed data and inertial measurement data at the current moment before obtaining the final heading angle of the vehicle by superimposing the rotation amount between trajectory points and the local heading angle; and to update the local heading angle based on the wheel speed data and inertial measurement data at the current moment.

[0018] A third aspect of this application provides a vehicle, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the vehicle heading angle measurement method, apparatus, vehicle, and storage medium as described in the above embodiments.

[0019] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle heading angle measurement method, apparatus, vehicle, and storage medium as described in the above embodiments.

[0020] Therefore, this application has the following beneficial effects: This application's embodiments acquire vehicle carrier phase data, wheel speed data, and inertial measurement data. Using the carrier phase data from a single antenna, differential calculations are performed between epochs to obtain a relatively accurate first trajectory point. A second trajectory point is obtained using wheel speed / IMU (Inertial Measurement Unit) combined navigation. The relative heading angle between the two trajectory points is determined, and after transformation, the heading angle in the global coordinate system is obtained. This allows for real-time detection and correction of dynamic interference, adapting to dynamic motion scenarios where the vehicle enters areas with satellite signal obstruction. It reduces hardware costs and achieves high-precision convergence in computation, as well as accuracy and continuity in positioning under complex environments. Therefore, it solves the technical problems of non-real-time, inaccurate, and discontinuous vehicle heading data caused by connecting high-precision RTK positioning results with differential signals in related technologies.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a vehicle heading angle measurement method provided according to an embodiment of this application; Figure 2 This is a schematic diagram of a vehicle heading angle measurement method according to an embodiment of this application; Figure 3 This is an example diagram of a vehicle heading angle measuring device provided according to an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] The following description, with reference to the accompanying drawings, outlines a vehicle heading angle measurement method, apparatus, vehicle, and storage medium according to embodiments of this application. Addressing the issues of poor real-time performance, accuracy, and continuity of vehicle heading data caused by connecting high-precision RTK positioning results with differential signals, as mentioned in the background art, this application provides a vehicle heading angle measurement method. In this method, carrier phase data, wheel speed data, and inertial measurement data of the vehicle are acquired; a first trajectory point of the vehicle is calculated based on the carrier phase data; a second trajectory point and a local heading angle of the vehicle are calculated based on the wheel speed data and inertial measurement data; the rotation between the trajectory points is calculated based on the first and second trajectory points; and the rotation between the trajectory points and the local heading angle are superimposed to obtain the final heading angle of the vehicle. This solves the problems of poor real-time performance, accuracy, and continuity of vehicle heading data caused by connecting high-precision RTK positioning results with differential signals in related technologies.

[0025] Specifically, Figure 1 This is a flowchart of a vehicle heading angle measurement method according to an embodiment of this application.

[0026] like Figure 1 As shown, the method for measuring the vehicle's heading angle includes the following steps: In step S101, the vehicle's carrier phase data, wheel speed data, and inertial measurement data are acquired.

[0027] Among them, carrier phase data is the phase difference between the carrier signal transmitted by the satellite and the carrier signal received by the receiver; wheel speed data is quantitative data describing the rotational speed of wheels in wheeled moving vehicles such as vehicles, collected by dedicated sensors; wheel speed inertia is the signal measured by the wheel speed sensor, which, due to its physical characteristics and measurement principle, cannot reflect the real, instantaneous speed change of the wheel in an instant, and there is an extremely short lag or delay; measurement data is numerical or information obtained by measuring tools or sensors to describe the physical and chemical properties of the measured object.

[0028] Understandably, by collecting GNSS carrier phase data, wheel speed data, and inertial measurement data, the limitation of single GNSS carrier phase data being easily obstructed can be overcome, enabling high-precision, high-continuity, and high-reliability dynamic perception and positioning control in autonomous driving.

[0029] Specifically, GNSS carrier phase data offers millimeter-level phase measurement accuracy, enabling high-precision positioning such as the lateral positioning accuracy within 10cm required for autonomous driving and the coordinate accuracy within millimeters required for surveying. However, carrier phase data is susceptible to errors caused by ionospheric delay, tropospheric delay, and satellite clock bias. In such cases, measurement data such as temperature / humidity data from meteorological sensors and attitude data from IMU inertial measurement units can correct the errors in GNSS carrier phase data, ultimately improving the accuracy from meters to millimeters to centimeters for ordinary GNSS pseudorange, thus meeting the needs of precision scenarios such as axis layout in bridge construction and crustal deformation monitoring.

[0030] This application embodiment, by collecting GNSS carrier phase data, wheel speed data, and inertial measurement data, can overcome the limitation of single GNSS carrier phase data being easily obstructed, and achieve high-precision, high-continuity, and high-reliability dynamic perception and positioning control in autonomous driving.

[0031] In step S102, the first trajectory point of the vehicle is calculated based on the carrier phase data, and the second trajectory point and local heading angle of the vehicle are calculated based on the wheel speed data and inertial measurement data.

[0032] The first trajectory point is the absolute position of the vehicle in a globally unified coordinate system, calculated from GNSS carrier phase data; the second trajectory point is the relative position of the vehicle relative to the first trajectory point, calculated from wheel speed data and inertial measurement data; and the local heading angle is the driving direction angle of the vehicle in a local coordinate system, calculated from wheel speed data and inertial measurement data.

[0033] Understandably, carrier phase data can be used to determine the carrier data of the reference frame and obtain the carrier data of other frames. By iteratively solving the objective equation, the initial position deviation is corrected using the position error correction number, and the distance error caused by the time difference is eliminated by using the receiver clock offset calculation, thus obtaining the vehicle's first trajectory point. By using wheel speed data and inertial measurement data, the vehicle's second trajectory point and local heading angle are calculated. This allows for real-time detection and correction of dynamic interference, eliminating the error of the vehicle entering the satellite signal blockage area while driving. It can adapt to vehicle dynamic motion scenarios and achieves high-precision convergence of calculation and continuity of positioning in complex environments.

[0034] Specifically, GNSS carrier phase data is acquired, and preprocessing is performed on the carrier data, including ephemeris error correction, ionospheric delay correction, tropospheric delay correction, and Earth rotation correction, to obtain carrier observation data of good quality. The reference frame carrier data is used as the base station observation data, and the other frame data is used as the rover data. Based on the base station and rover data, a least squares equation is constructed with the unknown parameters being the position error correction and the receiver clock offset. The unknown parameters are solved, and the accurate position error correction is obtained using the iterative least squares method. The single-point solution coordinates of the first frame data are added, and a post-hoc residual test is performed to remove data with gross errors, resulting in a first trajectory point with an accurate relative position. Combined navigation using IMU and wheel speed is used to obtain a second trajectory point and the corresponding heading angle.

[0035] Furthermore, in an embodiment of this application, calculating the first trajectory point of the vehicle based on carrier phase data includes: determining the carrier data of a reference frame from the carrier phase data; obtaining the carrier data of other frames in the carrier phase data; and performing inter-epoch differential calculation based on the carrier data of the reference frame and the carrier data of other frames to obtain the first trajectory point of the vehicle.

[0036] The reference frame is a spatial coordinate system composed of three elements: origin, coordinate axis direction, and length unit, used to quantify the vehicle's position and attitude. Other frames are sets of carrier phase data collected at different time points relative to the reference frame for dynamic comparison. An epoch is a time sampling point in GNSS positioning. Between epochs refers to the time interval and data correlation between two adjacent epochs. Differential calculation is the process of subtracting the observation data from the base station and the rover station to eliminate common errors in GNSS positioning, thereby improving positioning accuracy.

[0037] It is understood that the embodiments of this application can determine the carrier data of the reference frame and obtain the carrier data of other frames through carrier phase data. By performing differential calculation between epochs using the carrier data of the reference frame and the carrier data of other frames, the first trajectory point of the vehicle can be obtained. This can detect and correct dynamic interference in real time, adapt to vehicle dynamic motion scenarios, and ensure the real-time performance, availability, and centimeter-level accuracy of the first trajectory point in scenarios such as sharp turns and emergency braking.

[0038] Specifically, carrier phase data has the potential for millimeter-level accuracy, but the raw observations contain a large number of errors such as receiver clock bias, short-term electromagnetic interference, and multipath effects. These errors are a bottleneck that cannot be overcome in single-epoch positioning, which uses data from a single point in time to calculate the position. By using a combination of reference frames, other frames, and inter-epoch differentials, these key errors can be eliminated in a targeted manner, ensuring high-precision positioning.

[0039] In urban environments with tall buildings and trees, satellite signals can be reflected by objects and received, resulting in multipath effects. Or, due to interference from mobile phone base stations and high-voltage lines, single-epoch carrier data may experience jump errors, directly affecting the accuracy of the location. By using inter-epoch difference, similar interference components in two frames can be canceled out, preserving the phase difference of the distance between the satellite and the receiver caused by the actual vehicle movement, making the positioning results more stable.

[0040] Further, in an embodiment of this application, the first trajectory point of the vehicle is obtained by performing inter-epoch difference calculation based on the carrier data of the reference frame and the carrier data of other frames, including: constructing a target equation based on the carrier data of the reference frame and the carrier data of other frames, wherein the unknown parameters of the target equation are the position error correction and the receiver clock offset; iteratively solving the target equation to obtain the position error correction and the receiver clock offset; and calculating the first trajectory point of the vehicle based on the position error correction, the receiver clock offset and the carrier data of the reference frame.

[0041] Among them, the objective equation is the equation that establishes the mathematical relationship between GNSS observation data and the positioning parameters to be determined; the error correction is the inverse value calculated for known or modelable errors in GNSS positioning, which can deduct the influence of errors from the original observation values, making the observation data closer to the true values; the receiver clock offset is the time deviation between the local clock of the GNSS receiver and the standard time of the GNSS system.

[0042] Understandably, by using carrier data from a reference frame and carrier data from other frames, a target equation is constructed with position error correction and receiver clock offset as position parameters. This target equation is then solved iteratively. The initial position deviation is corrected by using position error correction, and the distance error caused by time difference is eliminated by using receiver clock offset calculation. The position error correction and receiver clock offset are obtained and the first trajectory point of the vehicle is calculated. The residual error is eliminated, and high-precision convergence of the calculation is achieved. It is adapted to the dynamic motion scenario of the vehicle and ensures the real-time performance and stability of the first trajectory point.

[0043] Specifically, the reference frame carrier data is used as the base station observation data, and its precise coordinates are known. The other frame carrier data is the rover data, and its coordinates are to be determined. The reference frame carrier phase data with known precise coordinates and the original carrier phase data of other frames are input to construct a least squares objective equation containing two unknown parameters: position error correction and receiver clock offset. Substituting the original data, the first position error correction and the first receiver clock offset are initially solved. Since the base station coordinates are known, the theoretical observation value can be accurately calculated. The residuals generated by comparing with the actual observation values ​​of other frames are minimized by the least squares method. The position error correction for correcting the initial coordinates of the rover and the receiver clock offset for eliminating time synchronization errors are then solved, and finally the first trajectory point of the vehicle's precise position is obtained.

[0044] Furthermore, in the embodiments of this application, before iteratively solving the objective equation to obtain the position error correction and receiver clock offset, the method further includes: performing a post-hoc residual test on the carrier phase data; removing data from the carrier phase data based on the test results; and iteratively solving the objective equation based on the removed carrier phase data to obtain the position error correction and receiver clock offset.

[0045] Among them, residual testing is a quality control process that checks the rationality of the solution model, the normality of the observation data, and the accuracy of the solution of unknown parameters by analyzing the gap between the actual observation data and the theoretical data calculated by the model.

[0046] Understandably, by performing post-hoc residual verification on the carrier phase data, removing the data from the carrier phase data based on the verification results, and iteratively solving the objective equation to obtain the position error correction and receiver clock offset, abnormal data can be eliminated, erroneous data can be avoided from deviating from the positioning results, the solution model can be optimized, and the output first trajectory point can be ensured to have no hidden errors, thus meeting the requirements of high-precision applications.

[0047] Specifically, the calculation process for the post-hoc residual test of carrier phase observation data is as follows: (1) The formulas for calculating the position error correction and receiver clock error are as follows: L=HX Where L is the difference between carrier observations between epochs, H is the coefficient matrix, and X is the position error correction and receiver clock offset to be determined. (2) We can find the unknown parameter X using the least squares method; (3) Substitute X into the calculation formula to obtain the residual value V=HX-L; (4) Calculate the mean square error RMS of the residual V. If the RMS is greater than the set threshold, it is determined that the carrier observation data has cycle slips and gross errors, and the largest residual V_max is removed. (5) Construct the observation equation V=HX_s using the remaining residual values, iterate steps (2~4) until RMS is less than the threshold. At this time, the position error correction and receiver clock offset obtained are relatively accurate.

[0048] Furthermore, in the embodiments of this application, before calculating the first trajectory point of the vehicle based on the carrier phase data, the method further includes: preprocessing the carrier phase data, wherein the preprocessing method includes at least one of ephemeris error correction, ionospheric delay correction, tropospheric delay correction and Earth rotation correction.

[0049] Among them, ephemeris error is the deviation between the satellite position given by the broadcast ephemeris and the satellite's actual position in space; ephemeris error correction is the method to correct the deviation between the satellite position given by the broadcast ephemeris and the satellite's actual position in space; ionospheric delay is the change in the propagation speed and path of the satellite signal when it passes through the ionosphere, resulting in a longer signal propagation time and a longer measured distance than the actual distance; ionospheric delay correction is the method to correct for the change in the propagation speed and path of the satellite signal when it passes through the ionosphere, resulting in a longer signal propagation time and a longer measured distance; tropospheric delay is the satellite's... When a signal passes through the troposphere, it is affected by the dry air and water vapor in the neutral atmosphere, resulting in slower propagation speed and path curvature. Tropospheric delay correction is a method to correct for the slowed propagation speed and path curvature caused by the dry air and water vapor in the neutral atmosphere when the satellite signal passes through the troposphere. Earth rotation correction rotates the satellite coordinates at the time of signal transmission to the Earth-fixed coordinate system at the time of signal reception, thereby ensuring that the coordinates of the satellite and receiver are calculated in the same unified, non-rotating reference frame, eliminating the correction method for geometric distance deviations introduced by the Earth's rotation.

[0050] It is understood that the embodiments of this application can preprocess carrier phase data by using methods such as ephemeris error correction, ionospheric delay correction, tropospheric delay correction and Earth rotation correction, which can eliminate systematic errors in satellite navigation, improve positioning accuracy, and ensure data reliability and result stability.

[0051] Specifically, ephemeris error correction corrects the deviation between broadcast ephemeris and the actual satellite orbital parameters. This can be achieved by introducing a precise ephemeris to replace the less accurate broadcast ephemeris, thus directly eliminating orbital parameter deviations. For example, a precise ephemeris with centimeter-level accuracy can be generated 1-3 days after observation, or a near-real-time precise ephemeris with decimeter-level accuracy can be generated 15-30 minutes later. The satellite coordinates in the precise ephemeris can be read by positioning software and combined with satellite clock error correction to directly obtain the actual satellite position.

[0052] Ionospheric delay is caused by the slower propagation speed and longer path of L-band signals through the ionosphere. Correction requires selecting a method based on single-frequency / dual-frequency observations. One approach utilizes the inverse relationship between ionospheric delay and the square of the frequency of the two frequencies broadcast by GPS / BeiDou satellites to directly eliminate the delay. For example, to observe the delay difference between dual-frequency signals, a receiver can simultaneously receive pseudorange or carrier phase observations of L1 and L2 signals, and solve simultaneous equations to eliminate the delay in the pseudorange observations, thus eliminating ionospheric delay. Alternatively, a single-frequency receiver can read information such as solar activity index, observation time, and user latitude / longitude from the navigation messages broadcast by the satellite, estimate the ionospheric delay, and subtract the estimated value from the single-frequency pseudorange / phase observation to offset the ionospheric delay.

[0053] This application embodiment can determine the carrier data of the reference frame and obtain the carrier data of other frames through carrier phase data. By iteratively solving the objective equation, the initial position deviation is corrected using the position error correction number, and the distance error caused by the time difference is eliminated by the receiver clock offset calculation, thus obtaining the first trajectory point of the vehicle. By using wheel speed data and inertial measurement data, the second trajectory point and local heading angle of the vehicle are calculated. It can detect and correct dynamic interference in real time, eliminate the error of the vehicle entering the satellite signal blockage area while driving, adapt to the dynamic motion scenario of the vehicle, and achieve high-precision convergence of calculation and continuity of positioning in complex environments.

[0054] In step S103, the rotation between the trajectory points is calculated based on the first trajectory point and the second trajectory point. The rotation between the trajectory points and the local heading angle are then superimposed to obtain the final heading angle of the vehicle.

[0055] Among them, rotation amount is a physical quantity that describes the magnitude and direction of the turning action of a vehicle around a certain axis within a specific time period; final heading angle is the final angular deviation of the vehicle's current driving direction relative to the reference direction.

[0056] Understandably, by calculating the rotation between the first and second trajectory points and then stacking it with the local heading angles, the final heading angle of the vehicle is obtained. The high-precision direction reference of the first trajectory point is used to correct the cumulative error of the local heading angle of the second trajectory point, thus completely eliminating the cumulative drift error of the local heading angle and ensuring the accuracy of the direction and the consistency of the overall trajectory positioning of the vehicle.

[0057] For example, the local heading angle depends on the wheel speed and the autonomous calculation of the IMU. The rotation amount is the quantified value of the directional deviation between the first trajectory point and the second trajectory point. For example, if the true heading angle of the first trajectory point is 30°, the local heading angle is 27°, and the rotation amount is +3°, after superposition, the final heading angle is 27° + 3° = 30°, which directly eliminates the 3° drift error accumulated by the IMU and improves the directional accuracy from the angle corresponding to the meter-level deviation to the angle corresponding to the centimeter-level deviation.

[0058] Furthermore, in an embodiment of this application, calculating the rotation amount between trajectory points based on the first trajectory point and the second trajectory point includes: performing trajectory point matching on the first trajectory point and the second trajectory point; and solving for the rotation amount between trajectory points based on the trajectory point matching result.

[0059] Trajectory point matching is a technical process in fields such as vehicle positioning, autonomous driving, and traffic data analysis that unifies discrete trajectory points from different sources, with different precision, or in different states into the same reference system by associating them with preset rules, algorithms, and features.

[0060] Understandably, by matching the first and second trajectory points and calculating the rotation between them, the error of the second trajectory point can be corrected, eliminating the positioning interruption caused by signal blockage in GNSS scenarios such as tunnels, underground parking garages, and densely populated high-rise buildings. This adapts to dynamic vehicle movement scenarios and achieves high-precision convergence of calculations and continuity of positioning in complex environments.

[0061] Specifically, the calculation steps of the ICP method include: (1) Data preparation: Prepare source point cloud and target point cloud, and ensure that the two point cloud data have been error-removed; (2) Initialization: Set the identity matrix as the initial transformation matrix, and define the convergence threshold and the maximum number of iterations; (3) Corresponding point matching: For each point in the source point cloud, find the nearest neighbor point in the target point cloud using the nearest point search method; (4) Error removal: Remove point pairs that are too far apart.

[0062] (5) Calculate the transformation matrix: Calculate the rotation matrix and translation vector using the least squares method.

[0063] (6) Transformation application: Apply the calculated transformation matrix to the source point cloud to update the position of the source point cloud; (7) Determine convergence: Check whether the change in the matrix and the change in the distance between corresponding points are less than the threshold; (8) Iteration loop: If it does not converge, return to step 3 and continue iterating until the convergence condition is met or the maximum number of iterations is reached; (9) Output results: Returns the final transformation matrix and the registered point cloud data.

[0064] For example, the first and second trajectory points are matched and solved using the ICP method to obtain the rotation between the two trajectory points. First, valid matching pairs are extracted from the trajectory point matching results. Each matching pair includes a high-precision reference trajectory point and a trajectory point to be corrected. A continuous set of 10-50 high-precision, anomaly-free points from the first trajectory points is selected, with the coordinates of each point being two-dimensional (x_p, y_p) / three-dimensional (x_p, y_p, z_p). A continuous set of points from the second trajectory points that are in the same time period as the target point set is selected, ensuring that the number of points is consistent with P, with coordinates of (x_q, y_q). Second, for each point q_i in the source point set Q_k after the k-th iteration of the source point set, the point p_j with the smallest Euclidean distance in the target point set P is found, forming a corresponding point pair (q_i, p_j). Based on all corresponding point pairs (q_i, p_j), the rotation between the two trajectory points is calculated. The algorithm calculates the optimal rotation matrix and translation vector that minimizes the sum of squared distances between the source and target points after the transformation. Then, it updates the source point set with the new rotation matrix and translation vector, calculates the error index of the current iteration, and determines whether the iteration has converged. After the iteration converges, the final rotation matrix reflects the optimal rotation relationship between the two trajectory point sets.

[0065] Furthermore, in the embodiments of this application, before obtaining the final heading angle of the vehicle by superimposing the rotation amount between trajectory points and the local heading angle, the method further includes: acquiring the wheel speed data and inertial measurement data at the current moment; and updating the local heading angle based on the wheel speed data and inertial measurement data at the current moment.

[0066] Understandably, by acquiring the wheel speed data and inertial measurement data at the current moment to update the local heading angle, an autonomous orientation reference that does not rely on GNSS can be built for the vehicle. This can be adapted to the dynamic motion scenario of the vehicle, achieving high-precision convergence of the calculation and continuity of positioning in complex environments.

[0067] Specifically, wheel speed data is collected by wheel speed meters. The raw output is mostly pulse signals, which are then processed and converted into quantitative parameters for direct calculation. These parameters include pulse-type parameters for calculating wheel speed / distance, speed and distance-type parameters for direct positioning estimation, and left and right wheel difference parameters to assist in verifying steering / slippage. Inertial measurement data can reflect the vehicle's motion attitude, including gyroscope angular rate data reflecting steering actions, accelerometer data to assist in judging slippage / acceleration, and data to ensure data synchronization / calibration.

[0068] The vehicle's driving state is verified and the original steering angle increment is calculated by using the pulse difference parameters of the wheel speed data at the current moment, the derived speed parameters, the state verification parameters, the steering core parameters, auxiliary verification parameters, and the data validity parameters of the measurement data. The steering angle increment is then corrected using the wheel speed data to obtain the updated local heading angle.

[0069] This application embodiment calculates the rotation between the first trajectory point and the second trajectory point, and then superimposes the local heading angles to obtain the vehicle's final heading angle. The high-precision direction reference of the first trajectory point is used to correct the cumulative error of the local heading angle of the second trajectory point, thus completely eliminating the cumulative drift error of the local heading angle and ensuring the accuracy of the direction and the consistency of the overall vehicle trajectory positioning.

[0070] To better understand the solution of this application, the vehicle heading angle measurement method of this application is described below through a specific embodiment, such as... Figure 2 As shown: In step S201, single-antenna carrier data: Collect GNSS carrier phase data.

[0071] In step S202, data preprocessing: The carrier data is preprocessed, including ephemeris error correction, ionospheric delay correction, tropospheric delay correction, and Earth rotation correction, to obtain carrier observation data of better quality.

[0072] In step S203, the inter-epoch difference calculation is performed: The first frame of carrier data is used as the base station observation data, and the other frames are used as rover data. Based on the base station and rover data, a least squares equation is constructed with the unknown parameters being the position error correction and the receiver clock offset, and the unknown parameters are obtained.

[0073] In step S204, GNSS trajectory points: After verification, residual tests are performed to remove data with gross errors. The iterative least squares method is used to obtain accurate position error corrections. These corrections are then added to the single-point coordinates of the first frame of data to obtain a trajectory point A with an accurate relative position.

[0074] In step S205, the fusion calculation is performed: By combining IMU and wheel speed for navigation, a trajectory point B and its corresponding heading angle are obtained.

[0075] In step S206, ICP matching is used to calculate the rotation amount: Trajectory point matching involves matching trajectory points A and B using the ICP method to obtain the rotation amount between the two trajectory points.

[0076] In step S207, the actual heading angle is: The true heading angle is obtained by superimposing the heading angle obtained from the latest IMU / wheel speed combined navigation and the rotation amount obtained from trajectory matching.

[0077] In summary, the vehicle heading angle measurement method proposed in this application acquires the vehicle's carrier phase data, wheel speed data, and inertial measurement data. Using the carrier phase data from a single antenna, it performs differential calculations between epochs to obtain a relatively accurate first trajectory point. A second trajectory point is obtained using wheel speed / IMU combined navigation. The relative heading angle between the two trajectory points is obtained using ICP matching. After transformation, the heading angle in the global coordinate system is obtained. This method can detect and correct dynamic interference in real time, adapting to dynamic motion scenarios where vehicles enter areas where satellite signals are blocked. It reduces hardware costs and achieves high-precision convergence of calculations and continuous positioning in complex environments.

[0078] Next, the vehicle heading angle measuring device according to the embodiments of this application is described with reference to the accompanying drawings.

[0079] Figure 3 This is a block diagram of a vehicle heading angle measuring device according to an embodiment of this application.

[0080] like Figure 3 As shown, the vehicle heading angle measuring device 300 includes: an acquisition module 301, a calculation module 302, and an overlay module 303.

[0081] The acquisition module 301 is used to acquire the vehicle's carrier phase data, wheel speed data, and inertial measurement data; the calculation module 302 is used to calculate the vehicle's first trajectory point based on the carrier phase data, and to calculate the vehicle's second trajectory point and local heading angle based on the wheel speed data and inertial measurement data; the superposition module 303 is used to calculate the rotation between the trajectory points based on the first trajectory point and the second trajectory point, and to superimpose the rotation between the trajectory points and the local heading angle to obtain the vehicle's final heading angle.

[0082] Furthermore, in this embodiment of the application, the calculation module 302 is further configured to: calculate the first trajectory point of the vehicle based on the carrier phase data, including: determining the carrier data of the reference frame from the carrier phase data; obtaining the carrier data of other frames in the carrier phase data; and performing inter-epoch differential calculation based on the carrier data of the reference frame and the carrier data of other frames to obtain the first trajectory point of the vehicle.

[0083] Furthermore, in this embodiment, the calculation module 302 is further configured to: perform inter-epoch difference calculation to obtain the first trajectory point of the vehicle based on the carrier data of the reference frame and the carrier data of other frames, including: constructing a target equation based on the carrier data of the reference frame and the carrier data of other frames, wherein the unknown parameters of the target equation are the position error correction and the receiver clock offset; iteratively solving the target equation to obtain the position error correction and the receiver clock offset; and calculating the first trajectory point of the vehicle based on the position error correction, the receiver clock offset and the carrier data of the reference frame.

[0084] Furthermore, in this embodiment of the application, the vehicle heading angle measuring device 300 further includes: a preprocessing module, used to preprocess the carrier phase data before calculating the first trajectory point of the vehicle based on the carrier phase data, the preprocessing method including at least one of ephemeris error correction, ionospheric delay correction, tropospheric delay correction and Earth rotation correction.

[0085] Furthermore, in this embodiment, the overlay module 303 is further configured to: calculate the rotation amount between the trajectory points based on the first trajectory point and the second trajectory point, including: performing trajectory point matching on the first trajectory point and the second trajectory point; and solving for the rotation amount between the trajectory points based on the trajectory point matching result.

[0086] Furthermore, in this embodiment of the application, the vehicle heading angle measuring device 300 further includes: an update module, used to acquire wheel speed data and inertial measurement data at the current moment before obtaining the final heading angle of the vehicle by superimposing the rotation amount between trajectory points and the local heading angle; and to update the local heading angle based on the wheel speed data and inertial measurement data at the current moment.

[0087] It should be noted that the foregoing explanation of the vehicle heading angle measurement method embodiment also applies to the vehicle heading angle measurement device of this embodiment, and will not be repeated here.

[0088] In summary, the vehicle heading angle measurement device proposed in this application acquires the vehicle's carrier phase data, wheel speed data, and inertial measurement data. It uses the carrier phase data from a single antenna to perform differential calculations between epochs, obtaining a relatively accurate first trajectory point. A second trajectory point is obtained using wheel speed / IMU combined navigation. The relative heading angle between the two trajectory points is obtained using ICP matching. After transformation, the heading angle in the global coordinate system is obtained. This device can detect and correct dynamic interference in real time, adapting to dynamic motion scenarios where vehicles enter areas where satellite signals are blocked. It reduces hardware costs and achieves high-precision convergence of calculations and continuous positioning in complex environments.

[0089] Figure 4 This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application. The vehicle 400 may include: The memory 401, the processor 402, and the computer program stored on the memory 401 and capable of running on the processor 402.

[0090] When the processor 402 executes the program, it implements the vehicle heading angle measurement method provided in the above embodiments.

[0091] Furthermore, vehicle 400 also includes: Communication interface 403 is used for communication between memory 401 and processor 402.

[0092] The memory 401 is used to store computer programs that can run on the processor 402.

[0093] The memory 401 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0094] If the memory 401, processor 402, and communication interface 403 are implemented independently, then the communication interface 403, memory 401, and processor 402 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0095] Optionally, in a specific implementation, if the memory 401, processor 402, and communication interface 403 are integrated on a single chip, then the memory 401, processor 402, and communication interface 403 can communicate with each other through an internal interface.

[0096] Processor 402 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0097] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the vehicle heading angle measurement method described above.

[0098] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0100] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0101] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0102] Those skilled in the art will understand that all or part of the steps of the methods implementing the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0103] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for measuring the heading angle of a vehicle, characterized in that, Includes the following steps: Acquire vehicle carrier phase data, wheel speed data, and inertial measurement data; The first trajectory point of the vehicle is calculated based on the carrier phase data, and the second trajectory point and local heading angle of the vehicle are calculated based on the wheel speed data and the inertial measurement data. The rotation between the trajectory points is calculated based on the first trajectory point and the second trajectory point. The final heading angle of the vehicle is obtained by superimposing the rotation between the trajectory points and the local heading angle.

2. The vehicle heading angle measurement method according to claim 1, characterized in that, The step of calculating the first trajectory point of the vehicle based on the carrier phase data includes: The carrier data of the reference frame is determined from the carrier phase data; The carrier data of other frames in the carrier phase data are obtained, and the first trajectory point of the vehicle is obtained by performing interepoch difference calculation based on the carrier data of the reference frame and the carrier data of other frames.

3. The vehicle heading angle measurement method according to claim 2, characterized in that, The step of obtaining the first trajectory point of the vehicle by performing inter-epoch difference calculation based on the carrier data of the reference frame and the carrier data of other frames includes: A target equation is constructed based on the carrier data of the reference frame and the carrier data of other frames. The unknown parameters of the target equation are the position error correction and the receiver clock offset. The position error correction and receiver clock offset are obtained by iteratively solving the objective equation. Based on the position error correction, the receiver clock offset, and the carrier data of the reference frame, the first trajectory point of the vehicle is calculated.

4. The vehicle heading angle measurement method according to claim 3, characterized in that, Before iteratively solving the objective equation to obtain the position error correction and receiver clock offset, the following steps are also included: Perform a post-hoc residual test on the carrier phase data; Data in the carrier phase data will be removed based on the test results; The objective equation is solved iteratively based on the removed carrier phase data to obtain the position error correction and receiver clock offset.

5. The method for measuring the heading angle of a vehicle according to any one of claims 1-4, characterized in that, Before calculating the first trajectory point of the vehicle based on the carrier phase data, the method further includes: The carrier phase data is preprocessed, and the preprocessing method includes at least one of ephemeris error correction, ionospheric delay correction, tropospheric delay correction and Earth rotation correction.

6. The vehicle heading angle measurement method according to claim 1, characterized in that, The step of calculating the rotation between the trajectory points based on the first trajectory point and the second trajectory point includes: Perform trajectory point matching between the first trajectory point and the second trajectory point; The rotation between the trajectory points is calculated based on the trajectory point matching results.

7. The vehicle heading angle measurement method according to claim 1, characterized in that, Before stacking the rotation between the trajectory points and the local heading angle to obtain the vehicle's final heading angle, the method further includes: Obtain the wheel speed data and inertial measurement data at the current moment; The local heading angle is updated based on the current wheel speed data and inertial measurement data.

8. A vehicle heading angle measuring device, characterized in that, include: The acquisition module is used to acquire the vehicle's carrier phase data, wheel speed data, and inertial measurement data; The calculation module is used to calculate the first trajectory point of the vehicle based on the carrier phase data, and to calculate the second trajectory point and local heading angle of the vehicle based on the wheel speed data inertia and the measurement data; The overlay module is used to calculate the rotation between the trajectory points based on the first trajectory point and the second trajectory point, and to overlay the rotation between the trajectory points and the local heading angle to obtain the final heading angle of the vehicle.

9. A vehicle, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the vehicle heading angle measurement method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they implement the vehicle heading angle measurement method according to any one of claims 1-7.

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