Laser installation deviation calibration method for inclination measurement system

Abstract

The invention discloses a laser installation deviation calibration method for an inclination measurement system, and relates to the technical field of inclination measurement systems, and the technical scheme is characterized in that the method comprises the following steps: preparing a laser level meter, and a first plane and a second plane which are perpendicular to each other in a space; the inclination measurement system and the laser level are respectively placed on the first plane, the laser level is vertically arranged on the first plane, and the laser level and the inclination measurement system respectively establish a laser level indication horizontal plane and an inclination measurement system laser with the second plane; wherein the tilt measurement system is adjustable to at least a first orientation and a second orientation; performing inclination measurement system laser and IMU (Inertial Measurement Unit) deviation pitch angle calibration based on the first orientation; and calibrating a deviation course angle between the laser of the inclination measurement system and the IMU based on the second orientation. The method has the advantages of simplicity, convenience and rapidness in operation, low equipment cost and site requirements and suitability for engineering application.

Description

Technical Field

[0001] The present invention relates to the technical field of tilt measurement systems, and more specifically, it relates to a calibration method for laser installation deviation of a tilt measurement system. Background Art

[0002] In a tilt measurement system, a centering rod, an inertial measurement unit (IMU), a laser rangefinder (for emitting the laser of the tilt measurement system), and a GNSS RTK work together to determine the coordinates of a measurement point. Among them, the IMU provides attitude data, the laser rangefinder is responsible for measuring the distance, and the GNSS RTK gives the position information of the top of the centering rod. These data are combined with the length of the centering rod to calculate the specific coordinates of the laser point. However, the installation deviation angle between the IMU and the laser rangefinder will significantly affect the measurement accuracy. In the prior art, there are many deficiencies in the calibration method of the installation deviation angle between the IMU and the laser rangefinder. Most methods rely on accurate RTK position information or the three-dimensional position information of the calibration points measured by a high-precision total station. This not only requires calibration in an outdoor open area, but also has complex operations and high equipment costs. For example, the method of patent number CN118426005A can calculate the installation deviation angle between the laser and the RTK, but it needs to obtain the three-dimensional position information of the calibration points, has high requirements for the measurement environment, and the operation is relatively complex.

[0003] Therefore, a new solution needs to be proposed to solve this problem. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a calibration method for laser installation deviation of a tilt measurement system, which has the advantages of simple and fast operation, low equipment cost and site requirements, and is suitable for engineering application.

[0005] The above technical object of the present invention is achieved through the following technical solutions: A calibration method for laser installation deviation of a tilt measurement system includes the following steps:

[0006] Prepare a laser level and a first plane and a second plane that are perpendicular to each other in space;

[0007] Place the tilt measurement system and the laser level on the first plane respectively, and the laser level is erected on the first plane. The laser level and the tilt measurement system respectively establish a laser level indicating the horizontal plane and the laser of the tilt measurement system with the second plane, where the tilt measurement system can be adjusted to at least a first azimuth and a second azimuth;

[0008] Based on the first azimuth, calibrate the pitch angle of the installation deviation between the laser of the tilt measurement system and the IMU;

[0009] Based on the second azimuth, calibrate the heading angle of the installation deviation between the laser of the tilt measurement system and the IMU.

[0010] In one embodiment, the laser level indicates the horizontal plane emitted from the laser emission point of the laser level. The laser of the tilt measurement system is emitted from the laser emission point of the tilt measurement system. The laser level indicates that the horizontal plane is perpendicular to the second plane. The laser of the tilt measurement system is perpendicular to the second plane and a laser spot is formed on the second plane.

[0011] In one embodiment, the first azimuth is the azimuth when the tilt measurement system is erected. The specific method for calibrating the pitch angle deviation between the laser of the tilt measurement system and the IMU installation based on the first azimuth includes the following steps:

[0012] Erect the tilt measurement system on the first plane so that the mapping surface of the tilt measurement system is parallel or substantially parallel to the second plane;

[0013] Measure the height from the laser emission point of the tilt measurement system to the first plane respectively and the height from the laser emission point of the laser level to the first plane

[0014] Measure the distance between the laser spot of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane

[0015] Read the distance between the laser emission point and its laser spot of the tilt measurement system from the tilt measurement system and obtain the three-axis data (a x , a y , a z ) of the accelerometer in the IMU at this moment;

[0016] From this, the pitch angle Δθ of the deviation between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula:

[0017]

[0018] where, arcsin is the arcsine function and arctan is the arctangent function.

[0019] In one embodiment, after measuring the distance between the laser spot of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane , it is agreed that when the laser spot of the tilt measurement system is lower than the horizontal plane indicated by the laser level the value of is taken as negative, and vice versa as positive.

[0020] In one embodiment, the second orientation is the orientation when the tilt measurement system rotates by ±90 degrees around the normal of the second plane. The specific method for calibrating the deviation course angle between the laser of the tilt measurement system and the IMU installation based on the second orientation includes the following steps:

[0021] Measure the height from the laser emission point of the tilt measurement system to the first plane respectively and the height from the laser emission point of the laser level to the first plane

[0022] Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane

[0023] Read the distance between the laser emission point and its laser point of the tilt measurement system from the tilt measurement system and obtain the three-axis data (a x , a y , a z ) of the accelerometer in the IMU at this moment;

[0024] Thus, the deviation course angle Δψ between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula:

[0025]

[0026] where arcsin is the arcsine function and arctan is the arctangent function.

[0027] In one embodiment, after measuring the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane it is agreed that when the laser point of the tilt measurement system is lower than the horizontal plane indicated by the laser level the value of is taken as negative, and vice versa as positive.

[0028] In one embodiment, the first plane includes but is not limited to a horizontal tabletop, and the second plane includes but is not limited to a vertical plane.

[0029] In one embodiment, both the first plane and the second plane are smooth planes.

[0030] In summary, the present invention has the following beneficial effects: Through the geometric constraints of the laser level and the first plane and the second plane, the present invention only needs to measure the height difference and the plane distance with a straight ruler and cooperate with the data of the IMU three-axis accelerometer to establish a geometric model, and complete the calibration of the pitch angle of the laser and IMU installation deviation of the tilt measurement system and the calibration of the heading angle of the laser and IMU installation deviation of the tilt measurement system. It does not need to rely on high-precision RTK, total station or complex three-dimensional coordinate calibration points, greatly reducing the equipment cost and site requirements, with simple operation and high calibration efficiency, and is suitable for engineering application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a flowchart of a method for calibrating the laser installation deviation of a tilt measurement system according to an embodiment of the present application;

[0032] Figure 2 is a schematic diagram of a method for calibrating the pitch angle of the laser and IMU installation deviation of a tilt measurement system based on the first azimuth in the method for calibrating the laser installation deviation of a tilt measurement system according to an embodiment of the present application;

[0033] Figure 3 is a schematic diagram of a method for calibrating the heading angle of the laser and IMU installation deviation of a tilt measurement system based on the second azimuth in the method for calibrating the laser installation deviation of a tilt measurement system according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] As Figure 1 , Figure 2 and Figure 3 shown, an embodiment of the present application provides a method for calibrating the laser installation deviation of a tilt measurement system, including the following steps:

[0036] S1. Prepare a laser level and a first plane and a second plane that are perpendicular to each other in space. The first plane includes but is not limited to a horizontal tabletop, specifically a horizontal tabletop, and the second plane includes but is not limited to a vertical plane, specifically a vertical wall surface. In order to reduce the interference of surface roughness on laser reflection, both the first plane and the second plane are smooth planes;

[0037] S2. Place the tilt measurement system and the laser level on the first plane respectively, with the laser level standing upright on the first plane. The laser level and the tilt measurement system are respectively used to establish the horizontal plane indicated by the laser level and the laser of the tilt measurement system with the second plane, where the tilt measurement system can be adjusted to at least a first azimuth and a second azimuth;

[0038] S3. Calibrate the pitch angle deviation between the laser of the tilt measurement system and the IMU installation based on the first azimuth;

[0039] S4. Calibrate the heading angle deviation between the laser of the tilt measurement system and the IMU installation based on the second azimuth.

[0040] It should be noted that there is no order of precedence between the above steps S3 and S4.

[0041] In the above method, through the geometric constraints of the laser level, the first plane and the second plane, only a ruler is needed to measure the height difference and the plane distance, and then a geometric model can be established in cooperation with the IMU triaxial accelerometer data, and the pitch angle deviation calibration between the laser of the tilt measurement system and the IMU installation and the heading angle deviation calibration between the laser of the tilt measurement system and the IMU installation can be completed. There is no need to rely on high-precision RTK, total station or complex three-dimensional coordinate calibration points, which greatly reduces the equipment cost and site requirements, is easy to operate, has high calibration efficiency, and is suitable for engineering applications.

[0042] In this embodiment, the horizontal plane indicated by the laser level is emitted from the laser emission point of the laser level, and the laser of the tilt measurement system is emitted from the laser emission point of the laser rangefinder of the tilt measurement system. The horizontal plane indicated by the laser level is perpendicular to the second plane, and the laser of the tilt measurement system is perpendicular to the second plane, and laser points are formed on the second plane.

[0043] In this embodiment, the first azimuth is the azimuth when the tilt measurement system stands upright. The specific method for calibrating the pitch angle deviation between the laser of the tilt measurement system and the IMU installation based on the first azimuth includes the following steps:

[0044] Place the tilt measurement system upright on the first plane so that the surveying and mapping surface of the tilt measurement system is parallel or approximately parallel to the second plane;

[0045] Measure the height from the laser emission point of the tilt measurement system to the first plane respectively and the height from the laser emission point of the laser level to the first plane

[0046] Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane

[0047] Read the distance between the laser emission point of the tilt measurement system and its laser point from the tilt measurement system And obtain the three-axis data of the accelerometer in the IMU at this moment (a x , a y , a z );

[0048] From this, the pitch angle Δθ of the deviation between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula:

[0049]

[0050] Where, arcsin is the arcsine function and arctan is the arctangent function.

[0051] In this embodiment, the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level is measured in the second plane After that, it is agreed that when the laser point of the tilt measurement system is lower than the horizontal plane indicated by the laser level the value is taken as negative, otherwise it is taken as positive.

[0052] In this embodiment, the second azimuth is the azimuth when the tilt measurement system rotates around the normal of the second plane to ±90 degrees. The specific method for calibrating the course angle of the deviation between the laser of the tilt measurement system and the IMU installation based on the second azimuth includes the following steps:

[0053] Measure the height from the laser emission point of the tilt measurement system to the first plane and the height from the laser emission point of the laser level to the first plane

[0054] Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane

[0055] Read the distance between the laser emission point and its laser point of the tilt measurement system from the tilt measurement system And obtain the three-axis data of the accelerometer in the IMU at this moment (a x , a y , a z );

[0056] From this, the course angle Δψ of the deviation between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula:

[0057]

[0058] Where, arcsin is the arcsine function and arctan is the arctangent function.

[0059] In this embodiment, the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level is measured in the second plane Afterwards, it is agreed that when the laser point of the tilt measurement system is lower than the horizontal plane indicated by the laser level, the value is taken as negative, and vice versa as positive.

[0060] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A calibration method for laser installation deviation of an inclination measurement system, characterized in that: It includes the following steps: Prepare a laser level and a first plane and a second plane that are perpendicular to each other in space; Place the tilt measurement system and the laser level on the first plane respectively, and the laser level stands upright on the first plane. The laser level and the tilt measurement system respectively establish a laser level indicating the horizontal plane and the laser of the tilt measurement system with the second plane, where the tilt measurement system can be adjusted to at least a first orientation and a second orientation; Calibrate the pitch angle deviation between the laser of the tilt measurement system and the IMU installation based on the first orientation; Calibrate the heading angle deviation between the laser of the tilt measurement system and the IMU installation based on the second orientation.

2. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 1, characterized in that: The laser level indicating the horizontal plane is emitted from the laser emission point of the laser level. The laser of the tilt measurement system is emitted from the laser emission point of the tilt measurement system. The laser level indicating the horizontal plane is perpendicular to the second plane. The laser of the tilt measurement system is perpendicular to the second plane and forms a laser point on the second plane.

3. The laser installation deviation calibration method for the tilt measurement system according to claim 2, wherein: The first orientation is the orientation when the tilt measurement system stands upright. The specific method for calibrating the pitch angle deviation between the laser of the tilt measurement system and the IMU installation based on the first orientation includes the following steps: Stand the tilt measurement system on the first plane so that the surveying and mapping surface of the tilt measurement system is parallel or approximately parallel to the second plane; Measure the height from the laser emission point of the tilt measurement system to the first plane respectively and the height from the laser emission point of the laser level to the first plane Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane Read the distance between the laser emission point and the laser point of the tilt measurement system from the tilt measurement system and obtain the three-axis data of the accelerometer in the IMU at this moment (a x , a y , a z ); Thus, the pitch angle deviation Δθ between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula: where arcsin is the arcsine function and arctan is the arctangent function.

4. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 3, characterized in that: Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane After that, it is agreed that when the laser point of the tilt measurement system is lower than the horizontal plane indicated by the laser level the value is taken as negative, and vice versa as positive.

5. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 2, wherein: The second orientation is the orientation when the tilt measurement system rotates around the normal of the second plane to ±90 degrees. The specific method for calibrating the heading angle deviation between the laser of the tilt measurement system and the IMU installation based on the second orientation includes the following steps: Measure the height from the laser emission point of the tilt measurement system to the first plane respectively and the height from the laser emission point of the laser level to the first plane Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane Read the distance between the laser emission point and the laser point of the tilt measurement system from the tilt measurement system And at this moment, obtain the three-axis data of the accelerometer in the IMU (a x , a y , a z ); Thus, the heading angle deviation Δψ between the laser of the tilt measurement system and the IMU installation can be calculated by the following formula: where arcsin is the arcsine function and arctan is the arctangent function.

6. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 5, characterized in that: Measure the distance between the laser point of the tilt measurement system and the horizontal plane indicated by the laser level in the second plane After that, it is agreed that when the laser point of the tilt measurement system is below the horizontal plane indicated by the laser level the value is taken as negative, and vice versa as positive.

7. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 1, characterized in that: The first plane includes but is not limited to a horizontal tabletop, and the second plane includes but is not limited to a vertical plane.

8. The method for calibrating the laser installation deviation of the tilt measurement system according to claim 7, wherein: Both the first plane and the second plane are smooth planes.

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