Clinometer multi-position calibration deviation angle correction method

Abstract

The invention discloses an inclinometer multi-position calibration deviation angle correction method. The method comprises the steps that a coordinate system output data set LHm * 3 of a three-axis magnetic sensor instrument is obtained; calculating to obtain a deviation angle range, wherein the deviation angle range comprises an x-direction deviation angle range, a y-direction deviation angle range and a z-direction deviation angle range; obtaining a plurality of x-direction deviation angles according to a set first interval value within the determined x-direction deviation angle range; obtaining a plurality of y-direction deviation angles according to a set first interval value within the determined y-direction deviation angle range; obtaining a plurality of z-direction deviation angles according to a set first interval value within the determined z-direction deviation angle range; obtaining a conversion matrix from an instrument coordinate system to an ENU coordinate system; calculating to obtain a three-axis magnetic sensor calibration coefficient; and traversing all deviation angles, and selecting the calibration coefficient of the three-axis magnetic sensor with the minimum error from all obtained calculation results as the calibration coefficient of the inclinometer.

Description

Technical Field

[0001] This invention belongs to the field of geophysical logging technology, specifically relating to a method for correcting the deviation angle of a multi-position calibration of an inclinometer. Background Technology

[0002] Inclinometers are primarily used to monitor the tilt angles and displacement changes of geological structures such as roadways and goafs. The accuracy of their measurement data is crucial for the timely detection of potential safety hazards and the optimization of mining plans. However, inclinometers are affected by various factors during use, such as temperature changes, mechanical vibrations, and electromagnetic interference. These factors can increase the instrument's measurement errors, thus affecting the reliability of the data. Therefore, precise calibration of inclinometers is a key step in ensuring the accuracy of their measurement data. The calibration process requires the inclinometer to be calibrated under strictly controlled experimental conditions using high-precision standard instruments to eliminate systematic and random errors, thereby improving the accuracy and repeatability of the measurement results.

[0003] Currently, in the multi-position calibration process of inclinometers, if a symmetric or upper triangular matrix is ​​used for the calibration coefficient matrix, an unknown triaxial angular deviation will exist between the calculated calibration coefficients and the actual calibration coefficients. One method to determine the deviation angle is to use the actual measured values ​​of fixed points for correction. This method calculates the deviation angle by selecting measurement data from four fixed points. However, using fixed points to calculate the deviation angle has certain limitations. For example, the selection of fixed points may not be representative, or the fixed points themselves may have measurement errors. These factors can lead to errors remaining in the corrected data. Furthermore, fixed-point correction usually assumes that the error is uniformly distributed within the measurement area, but in practical applications, errors often have spatial correlations, which may lead to insufficient correction. Therefore, although the fixed-point correction method can reduce deviation to some extent, it still cannot meet the needs of high-precision instrument measurement, and its accuracy and reliability still need to be further improved. Summary of the Invention

[0004] In view of the defects and deficiencies of the prior art, the present invention provides a method for correcting the deviation angle of a multi-position calibration of an inclinometer, so as to solve the technical problem that the deviation angle correction method of the fixed point in the prior art is not accurate and reliable.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for correcting the calibration deviation angle of an inclinometer at multiple positions includes the following steps: Step 1: Place the inclinometer to be calibrated onto a three-axis non-magnetic turntable. The inclinometer is equipped with a three-axis magnetic sensor. Step 2: Rotate the three-axis non-magnetic turntable to m predetermined reference angle positions, and obtain three coordinate system output data points for the three-axis magnetic sensor instrument at each reference angle position, thus obtaining the three-axis magnetic sensor instrument coordinate system output dataset LH. m×3 ; Step 3: Output dataset LH based on the obtained triaxial magnetic sensor instrument coordinate system. m×3 The deviation angle range is calculated, and the deviation angle range includes the deviation angle range in the x-direction, the deviation angle range in the y-direction, and the deviation angle range in the z-direction. Step 4: Within the determined range of x-direction deviation angles, take values ​​at a set first interval to obtain multiple x-direction deviation angles; within the determined range of y-direction deviation angles, take values ​​at a set first interval to obtain multiple y-direction deviation angles; within the determined range of z-direction deviation angles, take values ​​at a set first interval to obtain multiple z-direction deviation angles. Step 5: Substitute the obtained multiple x-direction deviation angles, multiple y-direction deviation angles, and multiple z-direction deviation angles into the three-dimensional coordinate rotation transformation formula to obtain the transformation matrix from the instrument coordinate system to the ENU coordinate system; Step 6: Output the triaxial magnetic sensor instrument coordinate system dataset LH obtained in Step 2. m×3 The ENU coordinate system transformation matrix obtained in step 5 is substituted into the least squares optimization coefficient equation of the error model to calculate the calibration coefficients of the triaxial magnetic sensor. Step 7: Repeat step 6 until all deviation angles are traversed. Select the triaxial magnetic sensor calibration coefficient with the smallest error from all the obtained triaxial magnetic sensor calibration coefficients as the inclinometer calibration coefficient.

[0006] The present invention also has the following technical features: Specifically, the range of the x-direction deviation angle is as follows:

[0007] In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the x-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0008] Furthermore, the range of the y-direction deviation angle is as follows:

[0009] In the formula, , For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the y-direction measured at that time. For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0010] Furthermore, the range of the z-direction deviation angle is as follows:

[0011] In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the y-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0012] Furthermore, the least squares optimization coefficient equation described in step 6 is as follows:

[0013] In the formula, C is the calibration coefficient of the triaxial magnetic sensor, and ; Output dataset for the coordinate system of a three-axis magnetic sensor instrument; R m×3 The transformation matrix for m sets of data; T This is a transpose.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) The method of the present invention can effectively improve the calibration accuracy of the inclinometer, thereby improving the trajectory measurement accuracy, thereby reducing repeated drilling, ensuring the gas control effect, and greatly improving the efficiency of gas and water hazard control and coal mining. Attached Figure Description

[0015] Figure 1 This is a comparison chart of the deviation angle correction effect obtained in Embodiment 1 of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0016] In the calibration system of this invention, the movement of the three-axis non-magnetic turntable is manually controlled to realize the position change of the inclinometer on the three-axis non-magnetic turntable. After the inclinometer moves to the set reference angle position, the three-axis magnetic sensor collects data. After the data collection is completed and saved, the three-axis non-magnetic turntable moves to the next reference angle position to collect data.

[0017] The inventive concept of this invention is as follows: The theoretical assumption of the ellipsoid fitting correction method introduces a deviation angle. During the calibration process, it is necessary to measure the deviation angle and correct it. However, the measured data has a certain measurement error, which will lead to incomplete correction of the deviation angle. This invention, by giving a range of deviation angles, traverses all angles within the deviation value range to find the optimal deviation angle correction value, obtains the optimal deviation angle correction parameter, and obtains the inclinometer calibration coefficient.

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, any other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0019] Example 1 Following the above technical solution, this embodiment discloses a method for correcting the deviation angle of a multi-position calibration of an inclinometer, including the following steps: Step 1: Place the inclinometer to be calibrated onto a three-axis non-magnetic turntable. The inclinometer is equipped with a three-axis magnetic sensor. Step 2: Rotate the three-axis non-magnetic turntable to m predetermined reference angle positions, and obtain three coordinate system output data points for the three-axis magnetic sensor instrument at each reference angle position, thus obtaining the three-axis magnetic sensor instrument coordinate system output dataset LH. m×3 ; Step 3: Output dataset LH based on the obtained triaxial magnetic sensor instrument coordinate system. m×3 The deviation angle range is calculated, and the deviation angle range includes the deviation angle range in the x-direction, the deviation angle range in the y-direction, and the deviation angle range in the z-direction. The range of the x-direction deviation angle is as follows:

[0020] In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the x-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0021] The range of the y-direction deviation angle is as follows:

[0022] In the formula, , For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the y-direction measured at that time. For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0023] The range of the z-direction deviation angle is as follows:

[0024] In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the y-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

[0025] In this embodiment, the determined range of the x-direction deviation angle is [-1°, 1°], the determined range of the y-direction deviation angle is [-1.2°, 1.2°], and the determined range of the z-direction deviation angle is [-1.1°, 1.1°].

[0026] Step 4: Within the determined range of x-direction deviation angles, take values ​​at a set first interval to obtain multiple x-direction deviation angles; within the determined range of y-direction deviation angles, take values ​​at a set first interval to obtain multiple y-direction deviation angles; within the determined range of z-direction deviation angles, take values ​​at a set first interval to obtain multiple z-direction deviation angles. In this embodiment, the first interval is 0.1°, resulting in 21 x-direction deviation angles, 25 y-direction deviation angles, and 23 z-direction deviation angles.

[0027] Step 5: Substitute the obtained 21 x-direction deviation angles, 25 y-direction deviation angles, and 23 z-direction deviation angles into the existing three-dimensional coordinate rotation transformation formula to obtain the transformation matrix from the instrument coordinate system to the ENU coordinate system; Step 6: Output the triaxial magnetic sensor instrument coordinate system dataset LH obtained in Step 2. m×3 The ENU coordinate system transformation matrix obtained in step 5 is substituted into the least squares optimization coefficient equation of the error model to calculate the calibration coefficients of the triaxial magnetic sensor. Step 7: Repeat step 6 until all deviation angles are traversed. Select the triaxial magnetic sensor calibration coefficient with the smallest error from all the obtained triaxial magnetic sensor calibration coefficients as the inclinometer calibration coefficient.

[0028] The error model is as follows:

[0029] In the formula: These are the calibrated vector values. , , They are respectively Components in the X, Y, and Z directions; The coefficients are to be determined, where The component value is the multiplier coefficient; Add coefficients as needed. This is the value of the coefficient component.

[0030] To obtain the optimal calibration coefficients, an overdetermined equation approach is used to find the optimal solution. The least squares optimization coefficient equation is as follows:

[0031] In the formula, C is the calibration coefficient of the triaxial magnetic sensor, and ; Output dataset for the coordinate system of a three-axis magnetic sensor instrument; R m×3 The transformation matrix for m sets of data; T This is a transpose.

[0032] In this embodiment, the final calibration coefficient C=[k,b] is: .

[0033] The effects of the example are as follows Figure 1 As shown, the azimuth correction error without using the deviation angle correction method of this embodiment is represented by a dashed line, with a maximum calibration error of approximately 1.2° across 120 calibration points; the azimuth correction error using the deviation angle correction method of this patent is represented by a solid line, with a maximum azimuth error of approximately 1.0° across 120 calibration points. Using the method of this patent reduces the maximum azimuth correction error by 0.2°.

[0034] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent variations made to the content described in the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for correcting the deviation angle of a multi-position calibration of an inclinometer, characterized in that, Includes the following steps: Step 1: Place the inclinometer to be calibrated onto a three-axis non-magnetic turntable. The inclinometer is equipped with a three-axis magnetic sensor. Step 2: Rotate the three-axis non-magnetic turntable to m predetermined reference angle positions, and obtain three coordinate system output data points for the three-axis magnetic sensor instrument at each reference angle position, thus obtaining the three-axis magnetic sensor instrument coordinate system output dataset LH. m×3 ; Step 3: Output dataset LH based on the obtained triaxial magnetic sensor instrument coordinate system. m×3 The deviation angle range is calculated, and the deviation angle range includes the deviation angle range in the x-direction, the deviation angle range in the y-direction, and the deviation angle range in the z-direction. Step 4: Within the determined range of x-direction deviation angles, take values ​​at a set first interval to obtain multiple x-direction deviation angles; within the determined range of y-direction deviation angles, take values ​​at a set first interval to obtain multiple y-direction deviation angles; within the determined range of z-direction deviation angles, take values ​​at a set first interval to obtain multiple z-direction deviation angles. Step 5: Substitute the obtained multiple x-direction deviation angles, multiple y-direction deviation angles, and multiple z-direction deviation angles into the three-dimensional coordinate rotation transformation formula to obtain the transformation matrix from the instrument coordinate system to the ENU coordinate system; Step 6: Output the triaxial magnetic sensor instrument coordinate system dataset LH obtained in Step 2. m×3 The ENU coordinate system transformation matrix obtained in step 5 is substituted into the least squares optimization coefficient equation of the error model to calculate the calibration coefficients of the triaxial magnetic sensor. Step 7: Repeat step 6 until all deviation angles are traversed. Select the triaxial magnetic sensor calibration coefficient with the smallest error from all the obtained triaxial magnetic sensor calibration coefficients as the inclinometer calibration coefficient.

2. The method for correcting the deviation angle of a multi-position calibration instrument as described in claim 1, characterized in that, The range of the x-direction deviation angle is as follows: In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the x-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

3. The method for correcting the deviation angle of a multi-position calibration instrument as described in claim 1, characterized in that... The range of the y-direction deviation angle is as follows: In the formula, , For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the y-direction measured at that time. For the triaxial magnetic sensor at the reference angle The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

4. The method for correcting the deviation angle of a multi-position calibration instrument as described in claim 1, characterized in that, The range of the z-direction deviation angle is as follows: In the formula, , For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the y-direction measured at that time. For a triaxial magnetic sensor at a reference angle of The instrument coordinate system output data in the z-direction measured at that time. This is the correction factor, with a value of 3.

5. The method for correcting the deviation angle of a multi-position calibration instrument as described in claim 1, characterized in that, The least squares optimization coefficient equation described in step 6 is as follows: In the formula, C is the calibration coefficient of the triaxial magnetic sensor, and ; Output dataset for the coordinate system of a three-axis magnetic sensor instrument; R m×3 The transformation matrix for m sets of data; T This is a transpose.

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