Spatial displacement gauge and hole displacement measurement method

Abstract

This invention discloses a spatial displacement gauge and a method for measuring the displacement of holes. It measures spatial displacement based on a sensor of the Earth's inherent physical vector field, using the initial attitude of the space in which the spatial displacement gauge is located as the reference attitude for displacement monitoring, and monitors spatial displacement at different elevations and cross-sections. Each measuring point forms its own system and is uniformly referenced to the north direction of the Earth's inherent physical vector field, thus possessing the advantages of equal precision and a unified coordinate system for observing the three-dimensional spatial displacement of measuring points at different elevations.

Description

Technical Field

[0001] This invention relates to the field of slope safety monitoring, and in particular to a spatial displacement meter and a method for measuring the displacement of holes. Background Technology

[0002] To understand the formation and occurrence mechanisms of landslides, slope safety monitoring focuses on monitoring surface and deep displacements. Deep displacement monitoring aims to clarify the deformation depth of the slope, the displacement within that depth, and the temporal development characteristics of potential shear displacements. Current manual methods for monitoring deep slope displacement include sliding inclinometers, while automatic methods include fixed and flexible inclinometers. However, the displacement directions measured by these methods and equipment are inaccurate, and observations cannot continue when encountering large shear displacements. Sliding inclinometers measure displacement directions based on the fixed direction of the inclinometer tube's grooved track. In reality, the direction of the grooved track changes, leading to distorted displacement data. When encountering excessive shear displacement, the inclinometer tube may break due to displacement misalignment, preventing further observation. Fixed and flexible inclinometers calculate displacement directions based on the initial direction given by the protective tube guide rail. Due to dynamic changes in displacement, the initial direction may not accurately reflect the deformation direction. Furthermore, when encountering excessive shear displacement, the connecting cables and rods between automatic observation instruments may break, preventing further observation. Therefore, the aforementioned deep slope displacement monitoring technology cannot be adapted to long-term monitoring of deep displacement, nor can it accurately reflect the changes in deep displacement.

[0003] The focus of slope safety monitoring is on monitoring surface and deep displacement. The main monitoring methods for deep displacement include sliding inclinometers, fixed inclinometers, and flexible inclinometers. However, inclinometers can only measure based on the fixed track direction of the inclinometer tube or protective tube inside the borehole. Since the track direction is actually variable, the observed displacement data cannot accurately reflect the direction of deep displacement. Furthermore, these methods can lead to the breakage of the inclinometer tube or equipment when the instrument encounters excessive shear displacement at a deep sliding zone, preventing continued observation. In recent years, addressing the issue of inclinometers not being able to measure the true direction of displacement in real time, a solution has been proposed: adding direction monitoring instruments to the inclinometer to solve the problem of deep displacement and its true direction. However, this requires the simultaneous use of two types of instruments—inclinometers for both tilt direction and tilt angle—for joint observation.

[0004] CN210105845U discloses an electronic inclinometer that can measure three-dimensional gravitational acceleration and the direction and intensity of a magnetic field. However, this patent does not explain how to use this electronic inclinometer to measure spatial displacement in order to more accurately and vividly reflect the displacement of the deep parts of the slope. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a spatial displacement meter and a hole displacement measurement method to address the shortcomings of the existing technology, so as to ensure that the observed displacement data can truly and accurately reflect the direction of deep displacement.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a spatial displacement meter, comprising:

[0007] Protective tube;

[0008] Multiple vector field sensors are arranged along the axial direction of the protective tube inside the protective tube;

[0009] The vector field sensor includes a Z-axis probe, an X-axis probe, and a Y-axis probe;

[0010] The Z-axis probe, X-axis probe, and Y-axis probe are all perpendicular to each other;

[0011] The Z-axis probe is parallel to the axis of the protective tube;

[0012] The Z-axis probes of two adjacent vector field sensors are connected to each other, the X-axis probes are connected to each other, and the Y-axis probes are connected to each other.

[0013] The spatial displacement meter of the present invention does not require the addition of a direction monitoring instrument to the inclinometer. Displacement monitoring can be achieved by using a vector field sensor. The structure is simple. The vector field sensor of the present invention includes a Z-axis probe, an X-axis probe and a Y-axis probe. Therefore, the observed displacement data can truly and accurately reflect the direction of deep displacement.

[0014] To further protect the spatial displacement gauge, the bottom end of the protective tube is mounted on the base. The displacement gauge of this invention uses an aluminum alloy protective tube, making it lighter and easier to install without the need for a fixed guide groove in the measuring hole.

[0015] In this invention, the base can be a rubber base.

[0016] Adjacent vector field sensors are electrically connected via connectors. This allows for easy expansion of the number of vector field sensors within the spatial displacement gauge.

[0017] Two adjacent vector field sensors are connected by a cable, and the cable length is greater than the distance between the two vector field sensors. This invention reserves cable length (greater than the distance between the two vector field sensors) for deformation requirements between measurement points; therefore, after installation, the instrument cable will not be broken due to deep displacement, thus affecting the observation results.

[0018] The protective tube is equipped with a cable connector at its top, which is connected to a connecting cable for easy connection to external equipment.

[0019] The present invention also provides a method for measuring the spatial displacement inside a hole using the above-mentioned spatial displacement gauge, comprising the following steps:

[0020] Insert at least one spatial displacement gauge into the hole, with each vector field sensor corresponding to one measuring point;

[0021] For each measuring point, the displacement Dx in the X direction, the displacement Dy in the Y direction, and the displacement Dz in the Z direction are calculated using the following formula:

[0022] Dx=L sinθ y *cosθ z -L sinθ y0 *cosθ z0 ;

[0023] Dy=L sinθ y *sinθ z -L sinθ y0 *sinθ z0 ;

[0024] Dz=-L cosθ y +L cosθ y0 ;

[0025] Where, θ z =tan -1 C21 / C11; θ z0 =tan -1 K21 / K11; C is the matrix representing the change from the Earth's inherent physical vector Q to the initial attitude of the space displacement meter; K is the matrix representing the change from the Earth's inherent physical vector Q to the current attitude of the space displacement meter; L is the gauge length of the space displacement meter, i.e., the length of the protective tube.

[0026] Traditional inclinometer displacement measurement uses inclinometers or accelerometers to measure angles. These sensors measure the tilt angle in space, and the displacement of the corresponding monitoring segment in the orthogonal direction is calculated using the projection angle of this tilt angle onto the orthogonal monitoring plane and the probe length. The direction of this displacement is determined by a fixed guide groove. However, due to deformation, the guide groove direction constantly changes, resulting in a distorted displacement data. This invention, on the other hand, measures displacement based on the Earth's inherent vector field. The displacement direction calculated from the measuring point is based on a unified north direction, providing a more accurate and realistic representation of the measuring point's attitude and displacement. This ensures that the observed displacement data accurately reflects the direction of deep displacement.

[0027] The method of the present invention further includes:

[0028] The overall displacement of the hole is calculated using the following formula:

[0029] Dx(n)=Dx(n-1)+L sinθ y *cosθ z -L sinθ y0 *cosθ z0 ;

[0030] Dy(n)=Dy(n-1)+L sinθ y *sinθ z -L sinθ y0 *sinθ z0 ;

[0031] Dz(n)=Dz(n-1)-L cosθ y +L cosθ y0 ;

[0032] Where n is the number of spatial displacement gauges; Dx(n) is the displacement in the X direction of the nth spatial displacement gauge; Dy(n) is the displacement in the Y direction of the nth spatial displacement gauge; Dz(n) is the displacement in the Z direction of the nth spatial displacement gauge; Dx(n-1) is the displacement in the X direction of the (n-1)th spatial displacement gauge; Dy(n-1) is the displacement in the Y direction of the (n-1)th spatial displacement gauge; and Dz(n-1) is the displacement in the Z direction of the (n-1)th spatial displacement gauge.

[0033] The nth spatial displacement meter is connected in series with the (n-1)th spatial displacement meter.

[0034] Traditional inclinometer displacement calculations suffer from inconsistencies because the displacement direction at each measuring point is not fixed, resulting in distorted cumulative displacements that are not uniformly oriented. In contrast, the overall displacement calculation of this invention involves the accumulation of displacements on a unified azimuth reference, ensuring consistent displacement directions at all measuring points and after accumulation. This provides a more accurate reflection of deep-seated deformation.

[0035] The expression for the change matrix C from the Earth's inherent physical vector Q to the initial attitude of the space displacement meter is:

[0036]

[0037] in, in This represents the projection of the Earth's inherent physical vector field onto the N-frame (which is the North-East-Sky coordinate system, i.e., the XYZ coordinate system). A (t) P represents the vector field sensor data obtained after the current filtering. (t-1)The covariance data obtained from the previous calculation (i.e., A) (t-1) The covariance is initially set to P. (0) =10; V is the observation noise, R is the process noise. This is the vector field sensor data obtained after the previous filtering. The data is obtained from measurements by a vector field sensor, and I is the identity matrix.

[0038] In this calculation process, the calculation steps for the transformation matrix C are streamlined, and the calculation speed is improved.

[0039] In this invention,

[0040] ;in, Let Q be the angle between vectors B and Q. in Let Q be the angle between vectors B and Q.

[0041] B (t) This is the vector field sensor data obtained after the current filtering. This is the vector field sensor data obtained after the previous filtering. I represents the data vector measured by the vector field sensor in the current attitude, and I is the identity matrix.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] 1. This invention also reserves cables for deformation requirements between instrument measuring points. Therefore, after installation, the instrument cables will not be broken due to deep displacement, thus affecting the observation effect and the service life of the displacement meter.

[0044] 2. This invention measures spatial displacement based on an Earth's inherent physical vector field sensor. The initial attitude of the space where the displacement meter is located is used as the reference attitude for displacement monitoring, enabling spatial displacement monitoring at different elevations (depths) and cross-sections. Each measuring point forms its own system and is uniformly referenced to the north direction of the Earth's inherent physical vector field. Therefore, it has the advantage of observing the three-dimensional spatial displacement of measuring points at different elevations (depths) with equal precision and a unified coordinate system.

[0045] 3. This invention, based on the integration of sensors with the Earth's inherent physical vector field, can accurately acquire the attitude data of the displacement gauge in space, thereby accurately calculating the spatial displacement of the measured location and providing more precise observation data. Simultaneously, the calculated attitude and displacement data are highly accurate, stable, and less susceptible to environmental interference. Furthermore, it eliminates the need to establish directional references at depth or borehole openings. Compared to current deep displacement monitoring methods, the monitoring process is simpler, and the monitoring results are more accurate. Attached Figure Description

[0046] Figure 1 This is a structural diagram of a spatial displacement meter according to an embodiment of the present invention;

[0047] Figure 2 This is a structural diagram of a vector field sensor according to an embodiment of the present invention.

[0048] Figure 3 This is a spatial displacement meter circuit according to an embodiment of the present invention.

[0049] Figure 4 This is a diagram illustrating the data acquisition process in an embodiment of the present invention.

[0050] Figure 5 This is a flowchart illustrating the spatial displacement direction and spatial displacement calculation process in an embodiment of the present invention.

[0051] Figure 6 This is a flowchart illustrating the displacement calculation process in an embodiment of the present invention. Detailed Implementation

[0052] like Figure 1 As shown, the spatial displacement gauge of this embodiment includes a protective tube 2, which is made of aluminum alloy. Multiple vector field sensors 1 are disposed inside the protective tube and arranged along its axial direction. Two adjacent vector field sensors 1 are connected by two cable segments 3, which are connected by a connector 6. Of course, the number of cable segments can be set according to actual usage requirements.

[0053] A rubber base 7 is provided at the bottom of the protective tube 2 (the end located deep in the hole during use) to prevent the bottom of the protective tube from being damaged when it is inserted into the hole. A cable connector 4 is provided at the top of the protective tube, which connects to an external connecting cable 5 to facilitate the use of multiple spatial displacement gauges in series.

[0054] In one implementation of the present invention, the structure of the vector field sensor 1 is as follows: Figure 2 As shown. The vertical (Z) direction Earth's inherent physical vector field sensor probe 8, the horizontal (X) direction Earth's inherent physical vector field sensor probe 9, and the horizontal (Y) direction Earth's inherent physical vector field sensor probe 10 are all perpendicular to each other. The Z-direction probe of the vector field sensor is parallel to the axis of the protective tube 2.

[0055] like Figure 3As shown, the spatial displacement meter circuit of this invention includes an MCU processor, a CAN bus communication module and interface, an analog-to-digital circuit for the Earth's intrinsic physical vector field, an XYZ three-dimensional Earth's intrinsic physical vector field sensor probe, a filtering circuit, and other modules. The MCU processor sends a data request and acquires the measured value of the Earth's intrinsic physical vector field read by the probe through the control circuit. The analog value of the Earth's intrinsic physical vector field is converted from analog to digital by the analog-to-digital converter and then transmitted to the MCU processor through the filtering circuit. The MCU processor calculates the current displacement using its embedded software, and the displacement data is transmitted to the host computer via the CAN communication module.

[0056] The embedded software functional modules mainly include MCU processor, Earth's inherent physical vector field data acquisition, data denoising, data processing, SPI communication, and CAN communication.

[0057] like Figure 4 As shown, in one implementation of the present invention, after the circuit is powered on, the MCU processor is started and configuration parameters are loaded. According to the configuration settings, probe data is read via the SPI communication protocol, and data processing is performed after data acquisition. Displacement data is obtained through comprehensive calculation of the data sets. The data is then sent to the host computer via the CAN protocol.

[0058] like Figure 5 As shown, in one implementation of the present invention, a three-axis sensor probe of the Earth's inherent physical vector field displacement meter (X, Y, Z axes) is used to observe the detected values ​​of the vector fields in each direction (X, Y, Z) and their angles with the north direction of the Earth's inherent physical vector field, using the Earth's inherent physical vector field as a reference. The spatial displacement direction and its changes are then calculated through spatial displacement calculation processing. The specific calculation process includes: first, measuring the initial values ​​(initial attitude) of the Earth's inherent physical vector field displacement meter sensor (i.e., the vector sensor) on the three axes; then, calculating the matrix parameters based on the relationship between the data collected by the Earth's inherent physical vector field sensor (current attitude) and the initial values ​​(data) and the Earth's inherent physical vector field; and finally, obtaining the rotation angles (Euler angles) around the X, Y, and Z axes from the matrix parameters, thus obtaining the current attitude of the displacement meter (i.e., the spatial displacement meter), and calculating the current tilt angle and the angle with the north direction (direction angle) of the displacement meter based on the rotation angle. Based on the current tilt angle, direction angle, initial attitude of the sensor, and gauge length, the three-dimensional (X, Y, Z) displacement of the sensor's location can be calculated.

[0059] In one implementation of this invention, to reduce the impact of interference noise on the accuracy of the data detected by the Earth's inherent physical vector field sensor, Kalman filtering is performed on the sensor measurements. The specific calculation method is as follows, taking the data filtering calculation process obtained from any one-axis sensor (any probe of the vector field sensor) as an example:

[0060] Let the observation noise be V (sensor noise), the process noise be R (transfer noise from the previous data to the current data), the Kalman gain be K, and the covariance be P (here, filtering is used for one-dimensional data on any axis, so the variable X...). * There is only one (covariance is variance), and the previous covariance is P. 上次 The intermediate calculated value is P 中间计算 The sensor measured data as X * (For any axis), the optimal value of the data filtering is Y, and the previous optimal value is Y. 上次 , where Y 上次 The initial value is set to the initial measurement value (i.e., the initial detection data of the geophysical vector field), P 上次 The initial value is 10 (this value will converge automatically and will not affect the actual effect).

[0061] The optimization process is as follows:

[0062] Additional process noise: P 中间计算 =P 上次 +V;

[0063] Calculate the Kalman gain: K = P 中间计算 / (P 中间计算 +R);

[0064] Estimate the optimal value: Y = Y 上次 +K*(XY 上次 );

[0065] Calculate the covariance (for univariate filtering, the covariance is the same as the variance when there is only one variable): P = (1-K)*P 中间计算 ;

[0066] Update covariance: P 上次 =P;

[0067] Update the optimal value: Y 上次 =Y;

[0068] Data from other axes and sensors are filtered using the same method. Therefore, when the sensor data is... At that time, the optimal filtered value of data A1 (i.e., the vector field sensor data A obtained after this (t-th) filtering) is... (t) )for:

[0069] The displacement calculation process of this invention embodiment is as follows: Figure 6 As shown.

[0070] Figure 6 The calculation formula and process are explained below:

[0071] Let the coordinate system N be North-East-Sky (XYZ). The initial attitude of the displacement gauge is in the Earth's inherent physical vector field. The X, Y, and Z axis sensor data (processed by filtering and noise reduction algorithm) is A. (t) The projection vector of the Earth's inherent physical vector field Q onto the N-system is: q x q y q z That is, the components of the Earth's magnetic field on the three axes (q) x q y q z For the calculation process, please refer to: Yang Mengyu et al. Calculation of the IGRF International Geomagnetic Reference Field Model. Electronic Measurement Technology. Vol. 40, No. 6. June 2017. Let the gauge length of each displacement gauge be L (2 - the length of the displacement sensor protection tube), and the number of displacement gauges be n.

[0072] The transformation matrix from Earth's inherent physical vector Q to the initial attitude of the displacement gauge The change matrix from Earth's inherent physical vector Q to the current attitude of the displacement gauge According to Euler's theorem, in three-dimensional space, any rotational transformation can be reduced to a combination of rotations along coordinate axes, with no more than three combinations, and two adjacent rotations must be along different coordinate axes. Therefore, a transformation can be represented by three rotation angles along the coordinate axes (Euler angles). Let α, β, and γ be the angles of rotation around the Z-axis in the XY plane, around the Y-axis in the XZ plane, and around the X-axis in the YZ plane, respectively. Then the matrix of rotations along the Z, Y, and X axes is:

[0073] matrix Similarly, matrix K represents the Euler rotation in three-dimensional space.

[0074] Therefore, the projection Q of the Earth's inherent physical vector field into the N-system is the current attitude data vector. The rotation matrix K satisfies the following equation:

[0075] K = BQ -1 ;

[0076] The initial attitude is similarly satisfied.

[0077] C = AQ -1 ;

[0078] The transformation matrix C and K can be obtained from the above principles and formulas:

[0079] The matrix calculation process, taking C as an example, is as follows: Let the angle between the two vectors be θ.

[0080] 1) Calculation of vector rotation angle, which can be obtained from the definition of dot product.

[0081] Therefore, the angle between the two vectors is

[0082] 2) Calculation of the vector rotation axis: According to the definition of the cross product, the rotation axis vector is...

[0083] 3) Convert the vector μ to a unit vector to obtain the vector. Take the antisymmetric matrix of ω as

[0084] 4) From Rodriguez's rotation formula, the corresponding rotation matrix can be determined.

[0085]

[0086] Where I is a 3x3 identity matrix;

[0087] 5) Similarly, the rotation matrix K can be obtained.

[0088]

[0089] in Let Q be the angle between vectors B and Q. It is obtained by unit vectorization of the rotation axis vectors μ1 = B * Q.

[0090] B (t) This is the vector field sensor data obtained after the current filtering. This is the vector field sensor data obtained after the previous filtering. I represents the data vector measured by the vector field sensor in the current attitude, and I is the identity matrix.

[0091] The current attitude angle can be derived from the trigonometric relationships in the transformation matrix C and K:

[0092] The direction angle of rotation of the XY plane of coordinate system N around the Z-axis is:

[0093] θ z =tan -1 C21 / C11;

[0094] The XZ plane of coordinate system N rotates about the Y-axis by a pitch (tilt) angle of degrees.

[0095]

[0096] The initial attitude angle is:

[0097] The direction angle of rotation of the XY plane of coordinate system N around the Z-axis is:

[0098] θ z0 =tan -1 K21 / K11;

[0099] The XZ plane of coordinate system N rotates about the Y-axis by a pitch (tilt) angle of degrees.

[0100]

[0101] Then, the horizontal projection length of the displacement gauge's vertex in the current tilted attitude is D = L sinθ. y The corresponding direction angle is θ z The initial horizontal projection length D0 = L sinθ y0 The corresponding direction angle is θ z0 Therefore, the current displacement of a single displacement gauge in the horizontal plane is the difference in the horizontal projection length of the displacement gauge in the N coordinate system before and after the attitude change:

[0102] The displacement in the X direction is: Dx = L sinθ y *cosθ z -L sinθ y0 *cosθ z0 ;

[0103] The displacement in the Y direction is: Dy = L sinθ y *sinθ z -L sinθ y0 *sinθ z0 ;

[0104] The displacement in the Z direction is: Dz = -L cosθ y +L cosθ y0 ;

[0105] Cumulative displacement of multiple displacement gauges (n represents the number of displacement gauges):

[0106] Dx(n)=Dx(n-1)+L sinθ y *cosθ z -L sinθ y0 *cosθ z0 ;

[0107] Dy(n)=Dy(n-1)+L sinθ y *sinθ z -L sinθ y0 *sinθ z0 ;

[0108] The displacement in the Z direction is: Dz(n) = Dz(n-1) - L cosθ y +L cosθ y0 .

[0109] This invention employs an instrument composed of orthogonal triaxial sensors. By comprehensively utilizing the detection data of the Earth's inherent physical vector field, it obtains the current attitude of the sensor (device), such as the tilt angle and tilt direction of the sensor (device). It also uses the obtained data to calculate the comprehensive displacement of a single sensor and multiple sensors in series in the three-dimensional (X, Y, Z) directions.

[0110] The method involves calculating the matrix parameters of the Earth's intrinsic physical vector field based on the relationship between the initial and current attitude data, obtaining the angles (Eulerian angles) of rotation around the X, Y, and Z axes, and thus determining the sensor's current attitude. Furthermore, the sensor's tilt angle and northward angle (azimuth angle) are calculated based on the rotation angles. Finally, the three-dimensional (X, Y, Z) displacement of the sensor's location is calculated using the sensor's gauge length, current tilt angle and azimuth angle, and initial attitude.

[0111] In geological landslide monitoring projects, large deformations can render general equipment unusable. For example, inclinometers cannot be used due to shear deformation in inclinometer holes. However, the spatial displacement meter in this embodiment of the invention has a cable allowance inside the sensor housing. When large shear deformation occurs, the cable allowance will be pulled out without damaging the spatial displacement meter, thus extending the service life of the equipment.

[0112] Because conventional inclinometers require dedicated displacement orientation equipment and devices to determine the displacement direction, such as inclinometer tubes with orientation grooves, the spatial displacement meter of this invention automatically detects and calculates displacement based on the north direction of the Earth's inherent physical vector field after deployment (i.e., independent detection), without the need for additional auxiliary orientation equipment and devices.

Claims

1. A method for measuring the spatial displacement inside a hole using a spatial displacement gauge, characterized in that, Includes the following steps: At least one spatial displacement gauge is inserted into the hole, with each vector field sensor corresponding to one measuring point; for each measuring point, the displacement Dx in the X direction, the displacement Dy in the Y direction, and the displacement Dz in the Z direction are calculated using the following formula: Dx=Lsinθ y *cosθ z -L sinθ y0 *cosθ z0 ; Dy=Lsinθ y *sinθ z -Lsinθ y0 *sinθ z0 ; Dz=-Lcosθ y +Lcosθ y0 ; Where, θ z =tan -1 C21 / C11; θ z0 tan -1 K21 / K11; C is the matrix representing the change from the Earth's inherent physical vector Q to the initial attitude of the space displacement meter; K is the matrix representing the change from the Earth's inherent physical vector Q to the current attitude of the space displacement meter; L is the gauge length of the space displacement meter, i.e., the length of the protective tube. The overall displacement of the hole is calculated using the following formula: Dx(n)=Dx(n-1)+Lsinθ y *cosθ z -L sinθ y0 *cosθ z0 ; Dy(n)=Dy(n-1)+Lsinθ y *sinθ z -L sinθ y0 *sinθ z0 4 Dz(n)=Dz(n-1)-Lcosθ y +Lcosθ y0 ; Where n is the number of spatial displacement gauges; Dx(n) is the displacement in the X direction of the nth spatial displacement gauge; Dy(n) is the displacement in the Y direction of the nth spatial displacement gauge; Dz(n) is the displacement in the Z direction of the nth spatial displacement gauge; Dx(n-1) is the displacement in the X direction of the (n-1)th spatial displacement gauge; Dy(n-1) is the displacement in the Y direction of the (n-1)th spatial displacement gauge; and Dz(n-1) is the displacement in the Z direction of the (n-1)th spatial displacement gauge. The nth spatial displacement meter is connected in series with the (n-1)th spatial displacement meter; The spatial displacement meter includes: Protective tube; Multiple vector field sensors are arranged along the axial direction of the protective tube inside the protective tube; The vector field sensor includes a Z-axis probe, an X-axis probe, and a Y-axis probe; The Z-axis probe, X-axis probe, and Y-axis probe are all perpendicular to each other; The Z-axis probe is parallel to the axis of the protective tube; The Z-axis probes of two adjacent vector field sensors are connected to each other, the X-axis probes are connected to each other, and the Y-axis probes are connected to each other.

2. The method according to claim 1, characterized in that, The expression for the change matrix C from the Earth's inherent physical vector Q to the initial attitude of the space displacement meter is: in, in This represents the projection of the Earth's inherent physical vector field onto the XYZ coordinate system. A (t) P represents the vector field sensor data obtained after the current filtering. (t-1) The vector field sensor data A obtained after the previous filtering. (t-1) The covariance data, with the initial value of the covariance data set to P. (0) =10; V is the observation noise, R is the process noise. This is the vector field sensor data obtained after the previous filtering. The data is obtained from measurements by a vector field sensor, and I is the identity matrix.

3. The method according to claim 1, characterized in that, in, in This represents the projection of the Earth's inherent physical vector field onto the XYZ coordinate system. Let Q be the angle between vectors B and Q. B (t) This is the vector field sensor data obtained after the current filtering. This is the vector field sensor data obtained after the previous filtering. I represents the data vector measured by the vector field sensor in the current attitude, and I is the identity matrix.

4. The method according to claim 1, characterized in that, The bottom end of the protective tube is mounted on the base.

5. The method according to claim 4, characterized in that, The base is a rubber base.

6. The method according to any one of claims 1, 4, and 5, characterized in that, Two adjacent vector field sensors are connected by a cable, and the length of the cable is greater than the distance between the two vector field sensors.

7. The method according to any one of claims 1, 4, and 5, characterized in that, The top of the protective tube is provided with a cable connector, which is connected to the connecting cable.

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