Multi-sensor fusion inclination measurement coordinate correction method

Abstract

The invention relates to the technical field of inclination measurement coordinate correction, in particular to a multi-sensor fusion inclination measurement coordinate correction method. According to the inclination measurement coordinate correction method based on multi-sensor fusion, the forced constraint in the direction of the centering rod is eliminated fundamentally, so that a measurer can place the centering rod at will, tedious alignment operation is not needed, the operation difficulty is remarkably reduced, and the measurement efficiency and precision are improved; therefore, the correction method has better convenience and wider adaptability. Measurement data of the magnetometer and the gyroscope are calculated in a fusion mode through a Kalman filtering algorithm in the processing unit, the short-term high precision of the gyroscope and the long-term stability of the magnetometer are fully utilized, noise and instantaneous interference are effectively restrained, the high-precision true north azimuth angle is directly output, the limitation of a simple average method is avoided, and the real north azimuth angle is obtained. According to the correction method, the overall measurement precision and the system robustness are remarkably improved, so that the correction precision of the coordinates of the target point location is greatly improved.

Description

Technical Field

[0001] This application relates to the field of tilt measurement coordinate correction technology, and in particular to a tilt measurement coordinate correction method using multi-sensor fusion. Background Technology

[0002] In the field data acquisition process, traditional total station methods using prisms require rigorous leveling of the forward-looking prism to ensure accurate reception of reflected signals and precise angle measurements, thereby correctly obtaining the three-dimensional coordinates of the measured point. The leveling process involves precisely centering the prism's horizontal bubble and ensuring its base is stable, preventing any slight tilt that could cause signal reflection path deviation. Insufficient leveling can lead to reflected waves deviating from the expected path or increased angular deviation, resulting in measurement errors at the millimeter or even centimeter level. In severe cases, this can affect the reliability of coordinate data and the accuracy of subsequent engineering applications, such as causing positional deviations in road construction or building layout.

[0003] In traditional surveying techniques, if the leveling process is not strictly implemented, target eccentricity will occur, leading to reflected wave offset or angular deviation, which in turn causes measurement errors and affects the reliability of coordinate data. In addition, the setup, centering, and leveling of prisms are quite cumbersome, involving the adjustment of precision instruments. Even when using a centering rod instead of a tripod, it is difficult to keep the centering rod perfectly plumb under certain special working conditions. Or, uneven ground or human error may cause the centering rod to tilt slightly, and the tilt of the centering rod will introduce tilt angle error, resulting in millimeter or even centimeter-level deviations in the coordinates of the points measured by the total station. This not only reduces the efficiency of surveying operations, but also seriously affects the accuracy, reliability, and stability of the surveying system.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this application is to provide a tilt measurement coordinate correction method based on multi-sensor fusion, so as to solve or alleviate the problems existing in the prior art.

[0006] To achieve the above objectives, this application provides the following technical solution: A method for correcting tilt measurement coordinates through multi-sensor fusion. A measuring module is installed on the centering rod; The measurement module includes a tilt sensor, a magnetometer, a gyroscope, and a processing unit; The correction method includes the following steps: Step 1: Place the bottom end of the centering rod at the point to be measured. superior; Step 2: Establish an auxiliary coordinate system to align the center point of the prism at the top of the centering rod. At the test point The projection point on the horizontal plane is the origin of the coordinate system. '; passing through the origin of the coordinate system Furthermore, the three mutually perpendicular axes are the Z-axis, Y-axis, and X-axis; Step 3, the tilt sensor measures the centering rod at... Face and The tilt angles of the surface projection are respectively angles. with horns ; Step 4, the point to be measured The elevation was corrected. Step 5, the point to be measured Correction is performed using Gaussian coordinates; with the point to be measured Establish a Gaussian plane coordinate system with the origin as the reference point, and determine the location of the points to be measured. and the origin The connecting line is denoted as the offset vector. offset vector The length is the horizontal coordinate tilt offset distance ; The magnetometer combined with the processing unit obtains the offset vector. Estimate of true north azimuth ; The gyroscope measurement and processing unit calculates the current offset vector. True North Angle Prediction ; The processing unit uses a built-in algorithm to... and Perform fusion calculations to obtain the offset vector. azimuth of coordinates ; Known Coordinates in Gaussian coordinate system, combined with and To obtain the location of the point to be measured Gaussian coordinates.

[0007] The tilt measurement coordinate correction method based on multi-sensor fusion described above is preferably implemented in step 4, specifically, where the center point of the prism is known. Given the elevation H, determine the origin of the coordinate system in the auxiliary coordinate system. With the center point of the prism distance , center point of prism Elevation H minus distance That is, the location of the point to be measured is obtained. True elevation ; prism center point The elevation H is the actual measured offset elevation of the tilted centering rod. Add centering rod height ;in: Actual measured offset point elevation The calculation formula is as follows: ; In the formula: The actual measured elevation of the offset point; The length of the centering rod; The total station's own height; The elevation of the known point where the total station is located; The slope distance from the center point of the prism; The vertical angle is the center point of the prism; Test point True elevation The calculation formula is as follows: .

[0008] The tilt measurement coordinate correction method based on multi-sensor fusion described above is preferably implemented in an auxiliary coordinate system, where the position of the point to be measured is... The projection point on the X-axis is B, and the projection point on the Y-axis is A; passing through the center point of the prism. Make parallel to Auxiliary plane, point The projection of point A onto the auxiliary plane is C, and the projection of point A onto the auxiliary plane is... The projection of point B onto the auxiliary plane is ; thereby establishing A rectangular parallelepiped structure; Among the angles For angle ,and horn ; because It is a right triangle, and It is a right angle, and We can obtain: .

[0009] The tilt measurement coordinate correction method based on multi-sensor fusion described above is preferably implemented in an auxiliary coordinate system, where the position of the point to be measured is... To the center point of the prism The distance is the length of the centering rod. Origin of coordinates With the center point of the prism ' distance ; and The calculation formula is as follows: ; Solve We can obtain: ; Will Substitute the points to be measured True elevation From the calculation formula, we can obtain: .

[0010] The tilt measurement coordinate correction method based on multi-sensor fusion described above is preferably implemented in step 5, in the auxiliary coordinate system. In a cuboid structure, the horizontal coordinate tilt offset distance That is, a vector Length; In a right triangle From this, we can obtain: ; The distance is , The distance is That is, the horizontal coordinate tilt offset distance for: .

[0011] In the multi-sensor fusion tilt measurement coordinate correction method described above, preferably, in step 5, the magnetometer initially measures the offset vector. magnetic north azimuth By combining the magnetic declination δ of the local true north and magnetic north directions, the offset vector can be obtained. Estimate of true north azimuth The calculation formula is: ; The gyroscope measures the angular velocity of the centering rod. The angular velocity data is integrated and combined with the estimated true north azimuth from the previous moment. Calculate the current offset vector True North Angle Prediction .

[0012] In the multi-sensor fusion tilt measurement coordinate correction method described above, preferably, in step 5, the built-in algorithm set in the processing unit is the Kalman filter algorithm; Estimate the true north azimuth. Predicted value of true north azimuth The values ​​are input together into the Kalman filter algorithm, where the true north azimuth estimate is... As an observation to correct for the system's long-term drift; the predicted true north azimuth angle value The derivation process is integrated into the state prediction model; The Kalman filter algorithm then dynamically calculates the optimal weights based on a preset noise model to estimate the true north azimuth. Predicted value of true north azimuth The fusion calculation is performed to output an optimal estimate of the true north azimuth. .

[0013] The preferred method for tilt measurement coordinate correction using multi-sensor fusion, as described above, employs the following Kalman filter algorithm: First, we define the state vector: In the formula, Represents the state of the system at a certain moment. The true north azimuth angle to be estimated. b The gyroscope's angular velocity is zero bias; Secondly, state prediction is performed: ; ; In the formula: It is a prediction of the current state based on the previous moment, i.e., a prediction of the true north azimuth. ; The representative will control the input amount. The matrix that maps the influence of the system state onto the state vector; This is the state transition matrix; This is the control variable for the current state, i.e., the original angular velocity reading of the gyroscope; Predicted state covariance matrix; The process noise covariance matrix; express The transpose of the matrix; Finally, update the observations: ; In the formula: The observed value, i.e., the estimated true north azimuth angle calculated from magnetometer data. ; The optimal true north azimuth estimate for the state at time k. ; a matrix that maps the system state space to the observation space; where, For Kalman gain.

[0014] The tilt measurement coordinate correction method based on multi-sensor fusion described above, preferably, has a Kalman gain. The calculation formula is: ; In the formula: To observe the noise covariance matrix; The transpose of matrix H; ; The updated state covariance matrix provides the basis for the next iteration and is used to dynamically adjust the Kalman gain.

[0015] The tilt measurement coordinate correction method based on multi-sensor fusion described above, preferably, uses the offset vector in a Gaussian plane coordinate system. The formula for calculating the coordinate azimuth angle is: In the formula, The pre-stored meridional convergence angle in the processing unit; Given that the origin of the coordinate system has been measured by a total station Gaussian coordinates are The location of the point to be measured can be obtained. The actual coordinates are: .

[0016] Compared with the closest prior art, the technical solution of this application has the following beneficial effects: The tilt measurement coordinate correction method based on multi-sensor fusion fundamentally eliminates the forced constraint of the centering rod direction, allowing surveyors to place the centering rod at will without tedious alignment work, significantly reducing the difficulty of operation, improving measurement efficiency and accuracy, and making the correction method more convenient and adaptable.

[0017] Furthermore, by fusing the measurement data from the magnetometer and gyroscope using the Kalman filter algorithm in the processing unit, the high short-term accuracy of the gyroscope and the long-term stability of the magnetometer are fully utilized to effectively suppress noise and transient interference, and directly output a high-precision true north azimuth angle. This avoids the limitations of the simple averaging method, significantly improving the overall measurement accuracy and system robustness of the correction method, and greatly enhancing the accuracy of the target point coordinate correction. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 A flowchart of a correction method provided according to some embodiments of this application; Figure 2 This is a schematic diagram illustrating the principle of elevation measurement of the point to be measured after the centering rod is tilted, according to some embodiments of this application. Figure 3 This is a schematic diagram illustrating the spatial relationship between two tilt angles in an auxiliary coordinate system provided according to some embodiments of this application; Figure 4 This is a diagram showing the conversion relationship between magnetic north azimuth and true north azimuth according to some embodiments of this application; Figure 5 This is a schematic diagram illustrating the conversion between true north azimuth and coordinate azimuth according to some embodiments of this application. Detailed Implementation

[0019] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0020] In the following description, the terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0022] In the description of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] The present application will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0024] According to specific embodiments of this application, such as Figure 1-5 As shown, this application provides a tilt measurement coordinate correction method based on multi-sensor fusion. A measurement module is provided on the centering rod. The measurement module includes a tilt sensor. In this embodiment, the tilt sensor can be built into the centering rod, or the tilt sensor can be installed on the centering rod as an external component. It is necessary to ensure that the axis of the tilt sensor coincides with the axis of the centering rod, and to ensure that the installation of the tilt sensor does not affect the prism at the top of the centering rod.

[0025] The tilt sensor has two measuring units arranged perpendicularly to each other. These two units measure two tilt angles of the projection of the centering rod onto two mutually perpendicular vertical planes. In this embodiment, a prism is mounted on the top of the centering rod, and the two measuring units of the tilt sensor measure the tilt angles of the projection of the centering rod onto the two mutually perpendicular vertical planes. The tilt sensor can be a dual-axis tilt sensor. In other embodiments, the tilt sensor can also be a conventional sensor, in which case two tilt sensors are set on the centering rod, and the two tilt sensors are arranged perpendicularly to each other; similarly, it can measure the two tilt angles of the projection of the centering rod onto two mutually perpendicular vertical planes.

[0026] The measurement module also includes a magnetometer, a gyroscope, and a processing unit. The main axes of the magnetometer and gyroscope are aligned with the axis of the centering rod. The magnetometer is used to measure the magnetic azimuth of the centering rod, and the gyroscope is used to measure the angular velocity of the centering rod. The processing unit uses a built-in algorithm to fuse the measurement data from the magnetometer and gyroscope to obtain the true north azimuth of the centering rod. In this embodiment, the centering rod is a hollow rod, and both the magnetometer and gyroscope are set on the central axis of the centering rod, with their main axes coinciding with the central axis of the centering rod.

[0027] The correction method includes the following steps: Step 1: Place the bottom end of the centering rod at the point to be measured. superior.

[0028] Step 2: Establish an auxiliary coordinate system to align the center point of the prism at the top of the centering rod. At the point to be measured The projection point on the horizontal plane is the origin of the coordinate system. '; passing through the origin of the coordinate system And the vertical axis perpendicular to the horizontal plane is the Z-axis. At this point, since the origin of the coordinate system... 'It is the center point of the prism' '' projection, so The point must lie on the Z-axis; it must pass through the origin. 'And the horizontal axis perpendicular to the direction of a measurement unit arrangement is the Y-axis, passing through the origin of the coordinate system.' And the horizontal axis perpendicular to the Y-axis is the X-axis.

[0029] In this embodiment, the upward direction of the Z-axis is taken as the positive direction of the Z-axis, and the left-to-right direction of the X-axis is taken as the positive direction of the X-axis; on the Y-axis, the outside-to-inside direction is taken as the positive direction of the Y-axis.

[0030] Step 3, the tilt sensor measures the centering rod at Y. 'Z-plane and X-plane' The tilt angles of the Z-plane projection are respectively angles. with horns In this embodiment, the angle measured by one measuring unit in the tilt sensor is the angle measured by the tilt sensor to center the rod at X. The angle between the Z-plane projection and the Z-axis, i.e., angle ∠b; the angle measured by another measuring unit is the angle measured by the tilt sensor on the centering rod in the Y-axis. The angle between the Z-plane projection and the Z-axis, i.e., the angle ;when Incline direction is When the axis is in the positive direction ,on the contrary ;when Incline direction is When the axis is in the positive direction ,on the contrary .

[0031] Step 4, the point to be measured The elevation is corrected; specifically, the center point of the prism is known. Given the elevation H, determine the origin of the coordinate system in the auxiliary coordinate system. 'With the center point of the prism ' distance , center point of prism 'Elevation H minus distance That is, the location of the point to be measured is obtained. True elevation .

[0032] Step 5, the point to be measured The Gaussian coordinates are used for correction; specifically, the position of the point to be measured is determined in the auxiliary coordinate system. and the origin The distance ' is denoted as the horizontal coordinate tilt offset distance. .

[0033] With the point to be measured Establish a Gaussian plane coordinate system with the origin as the reference point, and determine the location of the points to be measured. and the origin The connecting line is denoted as the offset vector. .

[0034] The offset vector was measured using a magnetometer. magnetic north azimuth By combining the local magnetic declination δ pre-stored in the processing unit, the offset vector is obtained. Estimate of true north azimuth .

[0035] The gyroscope measures the angular velocity of the centering rod. The angular velocity data is integrated and combined with the estimated true north azimuth from the previous moment. Calculate the current offset vector True North Angle Prediction .

[0036] Then the processing unit uses a built-in algorithm to estimate the true north azimuth angle. Predicted value of true north azimuth Perform fusion calculations to obtain the offset vector. The optimal true north azimuth estimate .

[0037] In the Gaussian plane coordinate system, the optimal true north azimuth angle estimate is used. Combined with the meridional convergence angle pre-stored in the processing unit Calculate the offset vector azimuth of coordinates That is, the coordinates from north to the point to be measured. and the origin The clockwise angle of the connecting lines.

[0038] Given the origin of the coordinate system The horizontal coordinate tilt offset distance obtained from the above process in the Gaussian coordinate system. With azimuth The location of the point to be measured can be obtained. Gaussian coordinates in a Gaussian coordinate system.

[0039] In this correction method, a tilt sensor is installed on the centering rod. The tilt sensor measures two tilt angles of the centering rod projected onto two mutually perpendicular vertical planes. Based on this, the distance between the center point of the tilted prism and the origin of the coordinate system is solved in an auxiliary coordinate system. Subtract the distance to be solved from the known elevation of the prism center point. The location of the point to be measured can then be obtained. The true elevation.

[0040] Then, based on the two tilt angles measured by the tilt sensor, the Y-axis and offset vector are solved in the auxiliary coordinate system. The included angle and the horizontal coordinate tilt offset distance Then, the processing unit uses a built-in algorithm to fuse the magnetometer and gyroscope measurement data to calculate the true north azimuth of the centering rod, greatly simplifying the calculation process and increasing accuracy; this is combined with the horizontal coordinate tilt offset distance. Thus, the location of the point to be measured is obtained. Coordinates in a Gaussian coordinate system.

[0041] A preliminary estimate of the true north azimuth was obtained through magnetometer measurements. This step effectively suppresses random noise and provides a high-quality observation benchmark for subsequent fusion.

[0042] By measuring the angular velocity of the centering rod using a gyroscope and combining it with the estimated value from the previous moment, the predicted value of the true north azimuth angle is calculated. This path is unaffected by magnetic fields and has high accuracy in the short term.

[0043] Finally, the built-in algorithm in the processing unit fuses the measurement data from the magnetometer and gyroscope, making full use of the gyroscope's short-term high accuracy and the magnetometer's long-term stability to effectively suppress noise and transient interference, and directly output a high-precision true north azimuth angle. This avoids the limitations of the simple averaging method, significantly improving the overall measurement accuracy and system robustness of the correction method, and greatly enhancing the accuracy of the target point coordinate correction.

[0044] In this multi-sensor fusion tilt measurement coordinate correction method, it is only necessary to set up the centering rod at the point to be measured without adjusting the level of the centering rod. The centering rod can be kept at any tilt angle. By using a multi-sensor measurement unit that integrates tilt sensors, magnetometers and gyroscopes, the three-dimensional coordinate data of the point to be measured can be accurately compensated and corrected. This eliminates the influence of the tilt angle caused by the tilt of the centering rod on the accuracy of the three-dimensional coordinates of the point to be measured, solves the problem of three-dimensional coordinate distortion caused by the tilt of the centering rod in actual measurement, and realizes accurate position measurement of the point to be measured.

[0045] In other words, this correction method fundamentally eliminates the forced constraint on the direction of the centering rod, allowing surveyors to place the centering rod at will without having to perform tedious alignment work. This significantly reduces the difficulty of operation, improves measurement efficiency and accuracy, and makes the correction method more convenient and adaptable.

[0046] In step 4, the center point of the prism The elevation H is the actual measured offset elevation of the tilted centering rod. Add centering rod height ;in: Actual measured offset point elevation The calculation formula is as follows: ; In the formula: The actual measured elevation of the offset point; The length of the centering rod; The total station's own height; The elevation of the known point where the total station is located; The slope distance from the center point of the prism; The vertical angle is the center point of the prism.

[0047] Test point True elevation The calculation formula is as follows: .

[0048] In this embodiment, the measurement results after the center rod is tilted are as follows: Figure 2 As shown, the coordinates of the total station are known. The coordinates of the actual measured offset points corresponding to the centering rod after tilting are obtained by the total station. Due to the origin of the coordinate system If the offset point is on the same vertical axis, then the origin of the coordinate system... Gaussian coordinates are .

[0049] In the appendix Figure 2 , 3 In an ideal state, the centering rod is at position OP as shown in the diagram, where OP is vertical. In the actual state described in this application, the centering rod is... The tilted state of the prism. The center point of the prism. The elevation H is the height of the centering rod. Add the actual measured offset point elevation The actual measured coordinates of the offset point are: Z in the text is... ; Prism center point The elevation H is also the point to be measured. True elevation Add distance Therefore, it is only necessary to find the origin of the coordinate system. 'With the center point of the prism ' distance The location of the point to be measured can then be obtained. True elevation .

[0050] In the auxiliary coordinate system, the point to be measured The projection point on the X-axis is B, and the projection point on the Y-axis is A; passing through the center point of the prism. 'Make parallel to X The auxiliary plane of Y, point The projection of point A onto the auxiliary plane is C, and the projection of point A onto the auxiliary plane is... The projection of point B onto the auxiliary plane is ; thereby establishing It has a rectangular parallelepiped structure.

[0051] Among the angles For angle ,and horn .

[0052] because It is a right triangle, and It is a right angle, and We can obtain: .

[0053] In this embodiment, vector 'and 'For the inclined centering rod' Projected onto a plane With plane The tilt angles measured by the tilt sensor in the two directions are as follows. and That is, the centering rod at direction and The tilt angles in the direction are respectively angles. with horns .

[0054] when Incline direction is When the axis is in the positive direction ,on the contrary ;when Incline direction is When the axis is in the positive direction ,on the contrary .

[0055] exist In a cuboid structure, The distance is , Therefore, we can conclude that: ; ; because It is a right triangle, and Since the angle is right, by the Pythagorean theorem, we can obtain:

[0056]

[0057] In the auxiliary coordinate system, the point to be measured To the center point of the prism The distance is the length of the centering rod. Origin of coordinates 'With the center point of the prism ' distance ; and The calculation formula is as follows: ; Solve We can obtain: ; Will Substitute the points to be measured True elevation From the calculation formula, we can obtain: .

[0058] In this embodiment, In a cuboid structure, equal ; equal ,in for ' '; From this, we can obtain and The calculation relationship is used to correct the position of the point to be measured. True elevation .

[0059] In step 5, in the auxiliary coordinate system In a cuboid structure, the horizontal coordinate tilt offset distance That is, a vector The length of a right triangle; From this, we can obtain: ; The distance is , The distance is That is, the horizontal coordinate tilt offset distance for: .

[0060] In step 5, the magnetometer initially measures the offset vector. magnetic north azimuth By combining the magnetic declination δ of the local true north and magnetic north directions, the offset vector can be obtained. Estimate of true north azimuth The calculation formula is: .

[0061] In this embodiment, the magnetometer performs high-frequency sampling within a short period of time to obtain hundreds of consecutive raw magnetic azimuth angle data. After outlier removal from this dataset, an arithmetic mean is applied to obtain a stable and reliable offset vector. Preliminary magnetic north azimuth Magnetic declination is the angle of magnetic north relative to true north, with positive declination to the east and negative declination to the west; the specific angle depends on the location. Due to the long-term stability of the magnetometer, this step effectively suppresses random noise, providing a high-quality observational benchmark for subsequent data fusion.

[0062] In step 5, the processing unit's built-in algorithm is the Kalman filter algorithm; the true north azimuth estimate is... Predicted value of true north azimuth The values ​​are input together into the Kalman filter algorithm, where the true north azimuth estimate is... As an observation to correct for the system's long-term drift, it utilizes The high reliability characteristic after averaging improves the system's reliability; the predicted true north azimuth angle value... The derivation process is incorporated into the state prediction model, utilizing... The high frequency and high anti-interference characteristics provide continuous and smooth angle changes.

[0063] The Kalman filter algorithm then dynamically calculates the optimal weights based on a preset noise model to estimate the true north azimuth. Predicted value of true north azimuth The fusion calculation is performed to output an optimal estimate of the true north azimuth. .

[0064] The calculation process of the Kalman filter algorithm is as follows: First, we define the state vector: In the formula, Represents the state of the system at a certain moment. Let be the true north azimuth angle to be estimated, and b be the zero bias of the gyroscope angular velocity.

[0065] Secondly, state prediction is performed: ; ; In the formula: It is a prediction of the current state based on the previous moment, i.e., a prediction of the true north azimuth. ; The representative will control the input amount. The matrix that maps the influence of the system state onto the state vector; This is the state transition matrix; This is the control variable for the current state, i.e., the original angular velocity reading of the gyroscope; Predicted state covariance matrix; Q is the process noise covariance matrix, representing the uncertainty or error of the state prediction model itself; where, the larger Q is, the less reliable the prediction model is, and the Kalman filter algorithm tends to favor observed magnetometer data; express The transpose of .

[0066] Finally, update the observations: ; In the formula: The observed value, i.e., the estimated true north azimuth angle calculated from magnetometer data. ; The optimal true north azimuth estimate for the state at time k. ; a matrix that maps the system state space to the observation space; where, This refers to the Kalman gain.

[0067] Kalman gain The calculation formula is: ; In the formula: To observe the noise covariance matrix; The transpose of matrix H is represented by this matrix.

[0068] ; This is the updated state covariance matrix. In this embodiment, the prediction step at the next time step (k+1) begins with the current optimal estimate and uncertainty. For example, in P(k|k-1)=AP(k-1|k-1)A'+Q, P(k-1|k-1) is the updated P(k|k) from the previous iteration, which is the updated state covariance matrix. This provides a basis for the next iteration, used to dynamically adjust the Kalman gain.

[0069] In the Gaussian plane coordinate system, the offset vector The formula for calculating the coordinate azimuth angle is: .

[0070] In this embodiment, the meridional convergence angle The north direction is the deflection angle relative to true north. East deflection is positive and west deflection is negative. It can be calculated using Gaussian projection parameters or the local coordinate system, or it can be embedded in the processing unit for real-time querying via geographic location.

[0071] Offset vector azimuth of coordinates The true plane coordinates, relative to the measured coordinates, are rotated clockwise in the north direction. Degree, distance The location.

[0072] Given that the origin of the coordinate system has been measured by a total station 'The actual coordinates are The location of the point to be measured can be obtained. The actual coordinates are: .

[0073] In this embodiment, after obtaining the offset vector Horizontal coordinate tilt offset distance With azimuth In this case, according to the principle of trigonometric functions, the offset vector The northward offset in the Gaussian coordinate system is offset vector The eastward offset in the Gaussian coordinate system is Then Subtract the corresponding offset from the true coordinates in the north and east directions, and then combine this with the previous correction method to obtain the location of the point to be measured. True elevation That is, the location of the point to be measured is obtained. The actual coordinates.

[0074] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for correcting tilt measurement coordinates using multi-sensor fusion, characterized in that, A measuring module is installed on the centering rod; The measurement module includes a tilt sensor, a magnetometer, a gyroscope, and a processing unit; The correction method includes the following steps: Step 1: Place the bottom end of the centering rod at the point to be measured. superior; Step 2: Establish an auxiliary coordinate system to align the center point of the prism at the top of the centering rod. At the point to be measured The projection point on the horizontal plane is the origin of the coordinate system. '; passing through the origin of the coordinate system Furthermore, the three mutually perpendicular axes are the Z-axis, Y-axis, and X-axis; Step 3, the tilt sensor measures the centering rod at Y. 'Z-plane and X-plane' The tilt angles of the Z-plane projection are respectively angles. with horns ; Step 4, the point to be measured The elevation was corrected. Step 5, the point to be measured Correction is performed using Gaussian coordinates; with the point to be measured Establish a Gaussian plane coordinate system with the origin as the reference point, and determine the location of the points to be measured. and the origin The connecting line is denoted as the offset vector. offset vector The length is the horizontal coordinate tilt offset distance ; The magnetometer combined with the processing unit obtains the offset vector. Estimate of true north azimuth ; The gyroscope measurement and processing unit calculates the current offset vector. True North Angle Prediction ; The processing unit uses a built-in algorithm to... and Perform fusion calculations to obtain the offset vector. azimuth of coordinates ; Known 'Coordinates in Gaussian coordinate system, combined with and To obtain the location of the point to be measured Gaussian coordinates.

2. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 1, characterized in that, In step 4, specifically, the center point of the prism is known. Given the elevation H, determine the origin of the coordinate system in the auxiliary coordinate system. 'With the center point of the prism ' distance , center point of prism 'Elevation H minus distance That is, the location of the point to be measured is obtained. True elevation ; prism center point The elevation H is the actual measured offset elevation of the tilted centering rod. Add centering rod height ;in: Actual measured offset point elevation The calculation formula is as follows: ； In the formula: The actual measured elevation of the offset point; The length of the centering rod; The total station's own height; The elevation of the known point where the total station is located; The slope distance from the center point of the prism; The vertical angle is the center point of the prism; Test point True elevation The calculation formula is as follows: 。 3. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 2, characterized in that, In the auxiliary coordinate system, the point to be measured The projection point on the X-axis is B, and the projection point on the Y-axis is A; passing through the center point of the prism. 'Make parallel to X The auxiliary plane of Y, point The projection of point A onto the auxiliary plane is C, and the projection of point A onto the auxiliary plane is... The projection of point B onto the auxiliary plane is ; thereby establishing AB -C The rectangular structure of '; Among the angles For angle ,and horn ; because It is a right triangle, and It is a right angle, and We can obtain: .

4. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 3, characterized in that, In the auxiliary coordinate system, the point to be measured To the center point of the prism The distance is the length of the centering rod. ; Origin of coordinates 'With the center point of the prism ' distance ; and The calculation formula is as follows: ； Solve We can obtain: ； Will Substitute the points to be measured True elevation From the calculation formula, we can obtain: 。 5. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 4, characterized in that, In step 5, in the auxiliary coordinate system AB -C In the cuboid structure, the horizontal coordinate tilt offset distance That is, a vector Length; In a right triangle From this, we can obtain: ； The distance is , The distance is That is, the horizontal coordinate tilt offset distance for: 。 6. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 5, characterized in that, In step 5, the magnetometer initially measures the offset vector. magnetic north azimuth By combining the magnetic declination δ of the local true north and magnetic north directions, the offset vector can be obtained. Estimate of true north azimuth The calculation formula is: ； The gyroscope measures the angular velocity of the centering rod. The angular velocity data is integrated and combined with the estimated true north azimuth from the previous moment. Calculate the current offset vector True North Angle Prediction .

7. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 6, characterized in that, In step 5, the built-in algorithm set in the processing unit is the Kalman filter algorithm; Estimate the true north azimuth. Predicted value of true north azimuth The values ​​are input together into the Kalman filter algorithm, where the true north azimuth estimate is... As an observation to correct for the system's long-term drift; the predicted true north azimuth angle value The derivation process is incorporated into the state prediction model; The Kalman filter algorithm then dynamically calculates the optimal weights based on a preset noise model to estimate the true north azimuth. Predicted value of true north azimuth The fusion calculation is performed to output an optimal estimate of the true north azimuth. .

8. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 7, characterized in that, The calculation process of the Kalman filter algorithm is as follows: First, we define the state vector: In the formula, Represents the state of the system at a certain moment. Let be the true north azimuth angle to be estimated, and b be the zero bias of the gyroscope angular velocity; Secondly, state prediction is performed: ； ； In the formula: It is a prediction of the current state based on the previous moment, i.e., a prediction of the true north azimuth. ; The representative will control the input amount. The matrix that maps the influence of the system state onto the state vector; This is the state transition matrix; This is the control variable for the current state, i.e., the original angular velocity reading of the gyroscope; Predicted state covariance matrix; The process noise covariance matrix; express The transpose of the matrix; Finally, update the observations: ； In the formula: The observed value, i.e., the estimated true north azimuth angle calculated from magnetometer data. ; The optimal true north azimuth estimate for the state at time k. ; a matrix that maps the system state space to the observation space; where, This is the Kalman gain.

9. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 8, characterized in that, Kalman gain The calculation formula is: ； In the formula: To observe the noise covariance matrix; The transpose of matrix H; ； The updated state covariance matrix provides the basis for the next iteration and is used to dynamically adjust the Kalman gain.

10. The tilt measurement coordinate correction method based on multi-sensor fusion according to claim 9, characterized in that, In the Gaussian plane coordinate system, the offset vector The formula for calculating the coordinate azimuth angle is: In the formula, To process the pre-stored meridional convergence angle in the processing unit; Given that the origin of the coordinate system has been measured by a total station 'Gaussian coordinates are The location of the point to be measured can be obtained. The actual coordinates are: .

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