An AR space true north calibration method, device, equipment and medium

Abstract

This invention relates to an AR spatial true north calibration method, apparatus, device, and medium. The method includes the following steps: acquiring fixed positioning data using an RTK device during movement; selecting a first positioning point and a second positioning point based on the fixed positioning data, calculating the coordinate azimuth between the two positioning points using Gaussian forward and inverse calculations, and calculating the meridian convergence angle at the first positioning point; calculating the angle between the line connecting the first and second positioning points and the true north direction based on the coordinate azimuth and the meridian convergence angle, obtaining the geographic true north direction angle; continuously monitoring the data from the gyroscopes of the RTK device and the AR operating device, and dynamically adjusting the true north direction angle in AR space using a dual-loop control structure based on the geographic true north direction angle to ensure that the AR space is consistent with the real geographic direction. Compared with the prior art, this invention improves the AR spatial direction accuracy from ±5° to ±0.1°, reaching the surveying and mapping grade standard.

Description

Technical Field

[0001] This invention relates to the field of augmented reality (AR) technology, and in particular to an AR spatial true north calibration method, apparatus, device and medium. Background Technology

[0002] Augmented Reality (AR) technology, as an interactive computing paradigm that overlays virtual information onto the physical world, has broad application prospects in fields such as industrial navigation, medical surgery, and education and training. However, a key challenge faced by AR devices in practical applications is the accurate calculation and correction of true north. Traditional AR devices typically rely on built-in gyroscopes and magnetometers to determine direction, but these sensors have inherent limitations: gyroscopes develop drift errors over long periods of use, and magnetometers are susceptible to interference from environmental magnetic fields, leading to inaccurate direction calculations.

[0003] In surveying, true north refers to the direction from a point on Earth towards the geographic North Pole, typically determined using a gyroscope or Polaris. AR spatial calculations, however, usually employ a Gaussian Cartesian coordinate system. In this system, the coordinate north direction and true north are separated by a meridian convergence angle. The meridian convergence angle is the angle between the vertical axis (grid north) and the tangent direction of the true meridian projection (true north) in the Gaussian Cartesian coordinate system. Its magnitude depends on the longitude and latitude difference of the point relative to the central meridian. In areas far from the central meridian, the meridian convergence angle can reach several degrees. Without correction, this will cause a deviation between the virtual information in AR space and the actual geographic direction, affecting the accuracy and reliability of AR applications.

[0004] Chinese patent CN119672264A discloses an AR positioning and orientation correction method, apparatus, device, and storage medium. This method obtains a first high-precision positioning point and a second high-precision positioning point, calculates the azimuth angles in the geographic coordinate system and the AR coordinate system respectively, and then uses the angle difference between these azimuth angles to determine the initial orientation when the device starts. Based on this initial orientation, the coordinate orientation of 3D scene elements in the AR scene can be rotated to complete the orientation correction. However, this method relies only on a single static orientation calibration at device startup and lacks a dynamic drift compensation mechanism during movement, causing the AR orientation accuracy to gradually decrease over time due to sensor drift. Summary of the Invention

[0005] The purpose of this invention is to provide an AR spatial true north calibration method, device, equipment, and medium. Through a dual-level dynamic calibration mechanism with inner and outer rings, the device continuously combines RTK absolute direction reference and gyroscope relative motion data during device movement, achieving real-time compensation for gyroscope drift. This enables long-term maintenance of consistency between AR space and real geographic direction, solving the problem of direction accuracy decaying over time after a single initial calibration.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to a first aspect of the present invention, an AR spatial true north calibration method is provided, the method comprising the following steps:

[0008] Utilize RTK equipment to acquire fixed-position data during movement;

[0009] Based on the fixed solution positioning data, the first positioning point and the second positioning point are selected. The coordinate azimuth angle between the two positioning points is calculated using Gaussian forward and inverse calculations, and the meridian convergence angle at the first positioning point is also calculated.

[0010] The angle between the line connecting the first and second positioning points and the true north direction is calculated based on the coordinate azimuth and the meridian convergence angle to obtain the geographic true north direction angle.

[0011] Continuously monitor the data from the gyroscopes on the RTK device and the AR operating device. Based on the true north direction, use a dual-loop control structure to dynamically adjust the true north direction in the AR space to ensure that the AR space is consistent with the real geographical direction.

[0012] The fixed location data includes geodetic latitude and longitude coordinates.

[0013] The method for selecting the first and second positioning points is as follows:

[0014] Continuous positioning point data is extracted from the fixed positioning data, and two positioning points with a distance greater than a preset value are selected and denoted as the first positioning point and the second positioning point. The first positioning point and the second positioning point satisfy all of the following conditions:

[0015] Both the fixed solution flags of the first and second positioning points are valid;

[0016] The time interval between the first positioning point and the second positioning point is within a preset time range;

[0017] The changes in the coordinates of the first and second positioning points in the vertical direction are less than the preset range.

[0018] The specific steps for calculating the coordinate azimuth angle between two positioning points using Gaussian forward and inverse calculations are as follows:

[0019] Based on the geodetic latitude and longitude coordinates of the first and second positioning points, the corresponding Gaussian plane coordinates are calculated using the forward calculation formula in Gaussian forward and inverse calculations:

[0020] X = F1(B, L);

[0021] Y = F2(B, L);

[0022] Where B is latitude, L is longitude, F1 and F2 are the forward calculation functions of Gaussian projection, and (X,Y) are the calculated Gaussian plane coordinates;

[0023] Calculate the coordinate azimuth angle based on the Gaussian plane coordinates of the first and second positioning points:

[0024] α=arctan((Y B -Y A ) / (X B -X A ));

[0025] Where α is the coordinate azimuth angle, (X A Y A (X) represents the Gaussian plane coordinates of the first positioning point. B Y B ) represents the Gaussian plane coordinates of the second positioning point.

[0026] The method for calculating the meridian convergence angle is as follows:

[0027] γ = Δλ·sinφ(φ);

[0028] Where γ is the meridian convergence angle, Δλ is the difference between the longitude of the first positioning point and the longitude of the central meridian, and φ is the latitude of the first positioning point.

[0029] The true north direction angle is the sum of the coordinate azimuth angle and the meridian convergence angle.

[0030] The method of dynamically adjusting the true north direction angle in AR space based on the geographic true north direction angle and using a dual-loop control structure specifically includes the following steps:

[0031] The geographic true north direction is transferred to the AR space as the initial true north direction.

[0032] Quaternion coordinate transformation and attitude alignment are performed in the inner loop of the dual-loop control structure:

[0033] Data from the gyroscopes of the RTK device and the AR running device are acquired, and the corresponding attitude quaternions are calculated respectively. The relative rotation between the two is calculated to obtain the rotation from the AR device coordinate system to the true north coordinate system. The coordinate system reference is aligned by fixing the rotation, and the attitude of the AR device relative to the geographic coordinate system is obtained by combining the rotations.

[0034] A preliminary true north direction is calculated based on the AR device's attitude relative to the geographic coordinate system and the geographic true north direction angle;

[0035] Gyroscope drift dynamic compensation is performed in the outer ring of the dual-loop control structure:

[0036] State equations are constructed based on Kalman filtering;

[0037] The difference between the geographic true north direction and the preliminary true north direction output by the inner loop is calculated to obtain the observation error;

[0038] The state estimate is corrected based on the observation error and the state equation, and the drift term in the state equation is updated.

[0039] The compensation amount is calculated based on the updated drift term, and the initial true north direction is compensated to output the corrected true north direction.

[0040] According to a second aspect of the present invention, an AR space true north calibration device is provided for implementing the method, the device comprising:

[0041] Geographic True North Angle Estimation Module: Utilizes RTK equipment to acquire fixed-location data during movement; based on the fixed-location data, selects a first and a second positioning point, calculates the coordinate azimuth angle between the two positioning points using Gaussian forward and inverse calculations, and calculates the meridian convergence angle at the first positioning point; based on the coordinate azimuth angle and the meridian convergence angle, calculates the angle between the line connecting the first and second positioning points and the true north direction to obtain the geographic true north angle;

[0042] AR Space True North Calibration Module: Continuously monitors the data from the gyroscopes on the RTK device and the AR operating device. Based on the geographic true north direction angle, it uses a dual-loop control structure to dynamically adjust the true north direction angle in AR space, ensuring that the AR space is consistent with the real geographic direction.

[0043] According to a third aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the method described thereon.

[0044] According to a fourth aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described thereon.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) This invention realizes the dynamic mapping of RTK positioning data and Gaussian plane coordinate system. By real-time coupling calculation of the coordinate azimuth angle between two points and the meridian convergence angle, it solves the problem of true north deviation caused by projection distortion in non-central meridian areas of traditional AR systems. Compared with the passive calibration method of magnetometer relying on the prior art, this invention actively introduces geographic projection parameter compensation, which improves the AR spatial orientation accuracy from ±5° to ±0.1°, reaching the surveying grade standard.

[0047] (2) This invention proposes a dual-loop correction architecture of gyroscope difference conversion and Kalman filtering: the inner loop achieves attitude alignment between RTK and AR devices through quaternion coordinate transformation (including 90° alignment of the X-axis), and the outer loop uses state equations to dynamically compensate for gyroscope drift. This spatiotemporal dual calibration mechanism effectively overcomes the cumulative error problem of traditional inertial navigation systems (INS), and improves the stability of orientation maintenance by more than 300% in continuous motion scenarios.

[0048] (3) This invention constructs a complete technical link from centimeter-level RTK positioning to pixel-level AR rendering: through key technologies such as data parsing, Gaussian forward and inverse calculation, and rotation matrix injection, an scalable AR geospatial benchmark framework is formed. This architecture has been verified to be applicable in complex scenarios such as power inspection and mine positioning, enabling AR applications to maintain an automatic compensation capability for convergence angle within 1.93° in areas with a longitude difference of 3°.

[0049] (4) This invention breaks through the limitations of traditional AR devices that rely on manual calibration and pioneers a self-calibration method based on motion trajectory: it automatically extracts the orientation reference through a 5-10 meter displacement segment and combines it with an RTK fixed solution state machine to ensure data reliability. This "calibration in motion" mode shortens the device initialization time from minutes to seconds, and is particularly suitable for time-sensitive scenarios such as emergency rescue and battlefield command. Attached Figure Description

[0050] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0052] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0053] Example 1

[0054] This invention combines high-precision RTK positioning technology with augmented reality spatial computing theory to achieve accurate calculation and correction of true north for AR devices in complex geographical environments. This method utilizes fixed-resolution positioning data acquired by the RTK device during movement, and through calculations of the coordinate azimuth between two points, meridian convergence angle, and gyroscope data difference conversion, effectively solves the true north error problem caused by the lack of meridian convergence angle correction in the edge regions of the Gaussian projection zone for traditional AR devices, thus improving the accuracy and reliability of AR spatial calculations.

[0055] This embodiment first provides an AR spatial true north calibration method based on RTK positioning data, such as... Figure 1 As shown, the method includes the following steps:

[0056] S1, using RTK equipment to acquire fixed positioning data during movement.

[0057] RTK positioning modules use high-precision RTK receivers to receive satellite signals from GPS, BeiDou, and other satellites, combined with base station data, to achieve centimeter-level positioning accuracy. The data output format of the RTK receiver is typically NMEA or RINEX, containing geodetic coordinate information such as longitude, latitude, and elevation.

[0058] In practical applications, the RTK receiver needs to maintain continuous movement and record positioning data at regular intervals (e.g., 1 second). When the RTK receiver obtains a fixed solution (i.e., integer ambiguity has been resolved), it indicates that the positioning data has high accuracy and can be used as a basis for calculating true north.

[0059] S2, based on the fixed solution positioning data, select the first positioning point A and the second positioning point B, use Gaussian forward and inverse calculations to calculate the coordinate azimuth between the two positioning points, and calculate the meridian convergence angle at the first positioning point.

[0060] S21, select the first positioning point A and the second positioning point B.

[0061] Continuous positioning point data are extracted from the fixed positioning data, and two positioning points A and B with a distance of more than 5-10 meters are selected. Positioning points A and B satisfy all of the following conditions:

[0062] Both location points A and B have valid fixed solution flags (e.g., fixstat=1 in RTKLib indicates a fixed solution).

[0063] The time interval between positioning point A and positioning point B is within a preset time range (usually 1-2 seconds) to ensure sufficient relative displacement between the two points;

[0064] The changes in the coordinates of positioning points A and B in the vertical direction are less than the preset range. That is, the changes in the coordinates of positioning points A and B should mainly be reflected in the horizontal direction, with smaller changes in the vertical direction.

[0065] S22, calculate the coordinate azimuth between two positioning points using Gaussian forward and inverse calculations.

[0066] Gaussian forward and inverse calculations are mathematical methods for transforming geodetic latitude and longitude coordinates to Gaussian projection plane coordinates. Based on the geodetic latitude and longitude coordinates of the first and second positioning points, the corresponding Gaussian plane coordinates are calculated using the forward calculation formula in Gaussian forward and inverse calculations, respectively.

[0067] X = F1(B, L);

[0068] Y = F2(B, L);

[0069] Where B is latitude, L is longitude, F1 and F2 are the forward calculation functions of Gaussian projection, and (X,Y) are the calculated Gaussian plane coordinates;

[0070] Calculate the coordinate azimuth angle based on the Gaussian plane coordinates of the first and second positioning points:

[0071] α=arctan((Y B -Y A ) / (X B -XA ));

[0072] Where α is the coordinate azimuth angle, (X A Y A Let (X) be the Gaussian plane coordinates of the location point A. B Y B () represents the Gaussian plane coordinates of the location point B.

[0073] S23, calculate the meridian convergence angle.

[0074] γ = Δλ·sinφ(φ);

[0075] Where γ is the meridian convergence angle, Δλ is the difference between the longitude of point A and the longitude of the central meridian, and φ is the latitude of point A.

[0076] In one embodiment, Δλ=L A -L0,L A Let L1 be the longitude of point A, and L0 be the longitude of the central meridian. The Gaussian projection is divided into 6-degree and 3-degree zones based on the projection area. The formula for calculating the longitude of the central meridian is:

[0077] For a 6-degree zone: L0 = 6 × N - 3, where N is the zone number;

[0078] For a 3-degree zone: L0 = 3 × n, where n is the zone number.

[0079] S3, based on the coordinate azimuth and meridian convergence angle, calculate the angle between the line connecting the first and second positioning points and the true north direction to obtain the geographic true north direction angle.

[0080] In this embodiment, the geographic true north direction angle = coordinate azimuth angle α + meridian convergence angle γ.

[0081] S4 continuously monitors the data from the gyroscopes on the RTK device and the AR operating device. Based on the true north direction, it uses a dual-loop control structure to dynamically adjust the true north direction in the AR space to ensure that the AR space is consistent with the real geographical direction.

[0082] Specifically, the following steps are included:

[0083] S41 transfers the geographic true north direction angle to AR space as the initial true north direction angle.

[0084] S42, quaternion coordinate transformation and attitude alignment are performed in the inner loop of the dual-loop control structure:

[0085] S421, acquire data from the gyroscopes of the RTK device and the AR running device, and calculate the corresponding attitude quaternions Q respectively. RTK and Q ARCalculate the relative rotation between the two to obtain the rotation Q from the AR device coordinate system to the true north coordinate system. RTK-AR The coordinate system is aligned by a fixed rotation, and the posture of the AR device relative to the geographic coordinate system is obtained by combining rotations.

[0086] AR devices typically use a right-handed coordinate system for their gyroscopes, while AR development platforms like Unity use a left-handed coordinate system, necessitating coordinate system transformation. In Unity, this can be achieved using the following function:

[0087] private static Quaternion ConvertQuaternion(Quaternion q) {

[0088] return new Quaternion(qx, qy, -qz, -qw);

[0089] }

[0090] Meanwhile, since AR devices are typically held vertically, while the gyroscope's reference orientation is horizontal, a 90° rotation around the X-axis is required to align the coordinate system.

[0091] transform.rotation = baseRotation * ConvertQuaternion(gyro.attitude);

[0092] Where baseRotation is Quaternion.Euler(90, 0, 0), it means rotating 90° around the X-axis.

[0093] S422, a preliminary true north direction is calculated based on the AR device's attitude relative to the geographic coordinate system and the geographic true north direction angle.

[0094] S43, perform gyroscope drift dynamic compensation in the outer loop of the dual-loop control structure:

[0095] S431, constructing state equations based on Kalman filtering;

[0096] θ k =θ k-1 +ωΔt+b k-1 Δt 2 ;

[0097] b k =b k-1 +v;

[0098] Where, θ kHere, ω is the true north direction angle after the k-th iteration correction, ω is the angular velocity measured by the gyroscope, Δt is the sampling time interval, and b is the true north direction angle after the k-th iteration correction. k denoted as gyroscope angular velocity deviation (i.e., drift rate), and v is the process noise.

[0099] S432, calculate the difference between the geographic true north angle and the preliminary true north direction output by the inner loop, and obtain the observation error e. k .

[0100] S433, based on observation error e k The state equation is used to correct the state estimate and update the drift term b in the state equation. k .

[0101] S434 calculates the compensation amount based on the updated drift term, compensates for the initial true north direction, and outputs the corrected true north direction.

[0102] This method can:

[0103] 1. Improve AR spatial orientation accuracy: By dynamically calculating the meridian convergence angle and correcting the gyroscope orientation of the AR device, the true north orientation error caused by the lack of correction of the meridian convergence angle in the edge region of the Gaussian projection zone of traditional AR devices is solved, and the orientation accuracy is improved to the centimeter level.

[0104] 2. Enhance the reliability of AR applications: Provide a stable and reliable geographic orientation reference in AR application scenarios such as industrial navigation, medical surgery, and education and training, ensuring that virtual information in AR space is accurately aligned with the real geographic environment.

[0105] 3. Reduce the difficulty of AR device calibration: Traditional AR devices require frequent calibration of gyroscopes and magnetometers, while this method automatically calculates the true north direction through RTK positioning data, reducing the need for manual calibration and improving the convenience of AR applications.

[0106] 4. Expanding the scope of AR applications: This method enables AR applications to accurately adapt to the projection characteristics of different geographical regions, especially in areas far from the central meridian, such as the area at 40° North latitude and a longitude difference of 3° where the convergence angle can reach 1.93°, providing a wider range of applicability for AR applications.

[0107] Example 2

[0108] This embodiment provides the implementation process of AR spatial rendering based on embodiment 1.

[0109] The AR spatial rendering module adjusts the rendering direction of virtual information based on the corrected true north direction to ensure that the virtual information in AR space is consistent with the real geographical direction.

[0110] In Unity, this can be achieved through the following steps:

[0111] 1. Obtain the corrected true north direction angle θ;

[0112] 2. Construct the rotation matrix R z(θ) θ represents a rotation about the Z-axis by an angle θ;

[0113] 3. Applying rotation matrices to virtual objects in AR space:

[0114] 31. Construct the rotation matrix: Quaternion rotation = Quaternion.Euler(0, 0, theta);

[0115] 32. Applying rotation matrices:

[0116] virtualObject.transform rotation = rotation * virtualObject.transform rotation;

[0117] In Unreal Engine, this can be achieved through the following steps:

[0118] 1. Obtain the corrected true north direction angle θ;

[0119] 2. Calculate the transformation matrix and apply the true north direction angle θ to the AR space;

[0120] 3. Update the rendering parameters in the AR space to ensure that the virtual information is consistent with the real geographical orientation.

[0121] Example 3

[0122] The above is an introduction to the method embodiments. The following describes the solution of the present invention further through device embodiments.

[0123] An AR spatial true north calibration device based on RTK positioning data is used to implement the method described in Embodiment 1. The device includes:

[0124] Geographic True North Angle Estimation Module: Utilizes RTK equipment to acquire fixed-location data during movement; based on the fixed-location data, selects a first and a second positioning point, calculates the coordinate azimuth angle between the two positioning points using Gaussian forward and inverse calculations, and calculates the meridian convergence angle at the first positioning point; based on the coordinate azimuth angle and the meridian convergence angle, calculates the angle between the line connecting the first and second positioning points and the true north direction to obtain the geographic true north angle;

[0125] AR Space True North Calibration Module: Continuously monitors the data from the gyroscopes on the RTK device and the AR operating device. Based on the geographic true north direction angle, it uses a dual-loop control structure to dynamically adjust the true north direction angle in AR space, ensuring that the AR space is consistent with the real geographic direction.

[0126] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the described module can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0127] Example 4

[0128] The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0129] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0130] The processing unit executes the various methods and processes described above, such as methods S1 to S4. For example, in some embodiments, methods S1 to S4 may be implemented as computer software programs tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of methods S1 to S4 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S4 by any other suitable means (e.g., by means of firmware).

[0131] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0132] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0133] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0134] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An AR spatial true north calibration method, characterized in that, The method includes the following steps: Utilize RTK equipment to acquire fixed-position data during movement; Based on the fixed solution positioning data, the first positioning point and the second positioning point are selected. The coordinate azimuth angle between the two positioning points is calculated using Gaussian forward and inverse calculations, and the meridian convergence angle at the first positioning point is also calculated. The angle between the line connecting the first and second positioning points and the true north direction is calculated based on the coordinate azimuth and the meridian convergence angle to obtain the geographic true north direction angle. Continuously monitor the data from the gyroscopes on the RTK device and the AR running device, and dynamically adjust the true north direction in the AR space based on the geographic true north direction using a dual-loop control structure to ensure that the AR space is consistent with the real geographic direction; The method for selecting the first and second positioning points is as follows: Continuous positioning point data is extracted from the fixed positioning data, and two positioning points with a distance greater than a preset value are selected and denoted as the first positioning point and the second positioning point. The first positioning point and the second positioning point satisfy all of the following conditions: Both the fixed solution flags of the first and second positioning points are valid; The time interval between the first positioning point and the second positioning point is within a preset time range; The vertical changes in the coordinates of the first and second positioning points are less than the preset range; The method of dynamically adjusting the true north direction angle in AR space based on the geographic true north direction angle and using a dual-loop control structure specifically includes the following steps: The geographic true north direction is transferred to the AR space as the initial true north direction. Quaternion coordinate transformation and attitude alignment are performed in the inner loop of the dual-loop control structure: Data from the gyroscopes of the RTK device and the AR running device are acquired, and the corresponding attitude quaternions are calculated respectively. The relative rotation between the two is calculated to obtain the rotation from the AR device coordinate system to the true north coordinate system. The coordinate system reference is aligned by fixing the rotation, and the attitude of the AR device relative to the geographic coordinate system is obtained by combining the rotations. A preliminary true north direction is calculated based on the AR device's attitude relative to the geographic coordinate system and the geographic true north direction angle; Gyroscope drift dynamic compensation is performed in the outer ring of the dual-loop control structure: State equations are constructed based on Kalman filtering; The difference between the geographic true north direction and the preliminary true north direction output by the inner loop is calculated to obtain the observation error; The state estimate is corrected based on the observation error and the state equation, and the drift term in the state equation is updated. The compensation amount is calculated based on the updated drift term, and the initial true north direction is compensated to output the corrected true north direction.

2. The AR spatial true north calibration method according to claim 1, characterized in that, The fixed location data includes geodetic latitude and longitude coordinates.

3. The AR spatial true north calibration method according to claim 1, characterized in that, The specific steps for calculating the coordinate azimuth angle between two positioning points using Gaussian forward and inverse calculations are as follows: Based on the geodetic latitude and longitude coordinates of the first and second positioning points, the corresponding Gaussian plane coordinates are calculated using the forward calculation formula in Gaussian forward and inverse calculations: X = F1(B, L); Y = F2(B, L); Where B is latitude, L is longitude, F1 and F2 are the forward calculation functions of Gaussian projection, and (X,Y) are the calculated Gaussian plane coordinates; Calculate the coordinate azimuth angle based on the Gaussian plane coordinates of the first and second positioning points: α=arctan((Y B -AND A ) / (X B -X A )); Where α is the coordinate azimuth angle, (X A Y A (X) represents the Gaussian plane coordinates of the first positioning point. B Y B ) represents the Gaussian plane coordinates of the second positioning point.

4. The AR spatial true north calibration method according to claim 1, characterized in that, The method for calculating the meridian convergence angle is as follows: γ = Δλ·sinφ(φ); Where γ is the meridian convergence angle, Δλ is the difference between the longitude of the first positioning point and the longitude of the central meridian, and φ is the latitude of the first positioning point.

5. The AR spatial true north calibration method according to claim 1, characterized in that, The true north direction angle is the sum of the coordinate azimuth angle and the meridian convergence angle.

6. An AR spatial true north calibration device, characterized in that, The apparatus for implementing the method as described in any one of claims 1 to 5 comprises: Geographic True North Angle Estimation Module: Utilizes RTK equipment to acquire fixed-location data during movement; based on the fixed-location data, selects a first and a second positioning point, calculates the coordinate azimuth angle between the two positioning points using Gaussian forward and inverse calculations, and calculates the meridian convergence angle at the first positioning point; based on the coordinate azimuth angle and the meridian convergence angle, calculates the angle between the line connecting the first and second positioning points and the true north direction to obtain the geographic true north angle; AR Space True North Calibration Module: Continuously monitors the data from the gyroscopes on the RTK device and the AR operating device. Based on the geographic true north direction angle, it uses a dual-loop control structure to dynamically adjust the true north direction angle in AR space, ensuring that the AR space is consistent with the real geographic direction.

7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 5.

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