A method and system for azimuth correction of magnetic field distortion curve

Abstract

The invention discloses a method and system for correcting the azimuth angle of a magnetic field distortion curve. The method comprises: constructing a curvature model and correcting the curvature model; sampling three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of a target to be corrected; performing coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected in turn to obtain a real-time magnetic field intensity value after the curvature changes; inputting the real-time magnetic field intensity value after the curvature changes into the corrected curvature model to retrieve the azimuth angle corresponding to the target to be corrected.

Description

Technical Field

[0001] The invention relates to the field of seismic instrument manufacturing, and in particular to a method and system for correcting the azimuth angle of a magnetic field distortion curve. Background Art

[0002] The magnetic field curve will be distorted when it is disturbed by the magnetic field. The existing methods for correcting the azimuth angle of the magnetic field distortion curve are:

[0003] (1) Azimuth correction is achieved based on an ideal ellipse model. This azimuth correction method is suitable for a region where a relatively wide magnetic field interference causes a distortion of the magnetic field curve. Its application scenario must be a relatively large magnetic field interference, and it can only be applied to a relatively small magnetic field curvature rate. It is not suitable for large magnetic field distortions caused by certain circuit interferences. Most of the magnetic field distortions involved in the field of seismic instrument manufacturing are due to the local strong magnetic field distortion caused by the seismic acquisition circuit on the magnetometer. Therefore, this azimuth correction method is not applicable in this scenario.

[0004] (2) Perform 360° full-angle correction sampling on the three coordinate axes, so as to collect the magnetic field values ​​of each coordinate axis and each azimuth point, and then perform fitting and correction based on the collected magnetic field strength. However, in the field of seismic instrument manufacturing, some specific instruments do not support 360° full-angle correction collection. For example, some instruments cannot be inverted after assembly due to their own sensors or weight and volume, and can only be rotated horizontally. Therefore, only horizontal rotation correction can be performed. In this scenario, this correction method cannot be implemented.

[0005] (3) For the curve of magnetic field distortion, curve fitting is performed to simplify the distorted magnetic field into a graphic model, and then the model is stretched and expanded to become an approximate prototype. However, the actual magnetic field interference cannot be simplified into a simple graphic model, so this correction method has the disadvantage of insufficient accuracy in this scenario.

[0006] Therefore, how to design an efficient and feasible azimuth correction method for the magnetic field distortion curve against local strong magnetic field interference is still a technical problem to be solved in this field. Summary of the invention

[0007] In view of this, the present invention proposes a method and system for correcting the azimuth of a magnetic field distortion curve, which can correct the azimuth of a magnetic field distortion curve under local strong magnetic field interference, and can only perform horizontal correction of 180°, thereby meeting the usage restrictions of seismic acquisition instruments on azimuth correction and improving the accuracy of azimuth correction.

[0008] The first aspect of the present invention provides an azimuth correction method for a magnetic field distortion curve, the method comprising: constructing a curvature model and correcting the curvature model; sampling three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of a target to be corrected; performing coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected in turn to obtain a real-time magnetic field intensity value after the curvature changes; inputting the real-time magnetic field intensity value after the curvature changes into the corrected curvature model to retrieve the azimuth corresponding to the target to be corrected.

[0009] Furthermore, the method for constructing the curvature model includes: setting the rotation angular velocity and the sampling frequency, sampling the target to be corrected according to the set sampling rate to set the three-dimensional first acceleration data and the three-dimensional first magnetic field intensity data of the rotation plane of the rotation angular velocity; performing coordinate system normalization processing on the three-dimensional first acceleration data and the three-dimensional first magnetic field intensity data; using the normalized three-dimensional first acceleration data to perform a dimensionality reduction transformation on the three-dimensional first magnetic field intensity data to obtain a two-dimensional first magnetic field intensity value; based on the two-dimensional first magnetic field intensity value, calculating the first plane stretching correction coefficient; using the first plane stretching correction coefficient and the two-dimensional first magnetic field intensity value, calculate the first magnetic field intensity value after the curvature changes, the first azimuth, the first absolute radius of the curve and the first variable sampling rate value, and construct a curvature model.

[0010] Furthermore, the calculation method of the first plane stretching correction coefficient is: traversally calculate the maximum and minimum values ​​of the two-dimensional first magnetic field intensity value to obtain the maximum and minimum values ​​of the two-dimensional coordinate axis; calculate the first plane stretching correction coefficient according to the maximum, minimum and intermediate variables of the two-dimensional coordinate axis.

[0011] Furthermore, the step of calculating the first magnetic field intensity value, the first azimuth, the first absolute radius of the curve and the first variable sampling rate value after the curvature changes, and constructing a curvature model includes: using the first plane stretching correction coefficient to perform plane stretching on the two-dimensional first magnetic field intensity value to obtain the first magnetic field intensity value after the curvature changes; calculating the first absolute radius of the curve formed by the first magnetic field intensity value after the curvature changes; solving discrete differences on the sample points on the curve formed by the first magnetic field intensity value after the curvature changes to obtain the rate of change of the first absolute radius of the curve, multiplying the set sampling rate by the rate of change of the first absolute radius of the curve to obtain the first variable sampling rate value; calculating the first azimuth corresponding to the magnetic field intensity value after the curvature changes; and constructing a curvature model based on the first magnetic field intensity value, the first azimuth, the first absolute radius of the curve and the first variable sampling rate value after the curvature changes.

[0012] Furthermore, the correction method of the curvature model includes: resampling the three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data of the target to be corrected according to the calculated first variable sampling rate to set the rotation angular velocity plane rotation; performing coordinate system normalization processing on the resampled three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data; using the normalized three-dimensional second acceleration data to perform a dimensionality reduction transformation on the three-dimensional second magnetic field intensity data to obtain a two-dimensional second magnetic field intensity value; based on the two-dimensional second magnetic field intensity value, calculating the second plane stretching correction coefficient; using the second plane stretching correction coefficient and the two-dimensional second magnetic field intensity value, calculate the second magnetic field intensity value after the curvature change, the second azimuth, the second absolute radius of the curve and the second variable sampling rate value, and construct a corrected curvature model.

[0013] Furthermore, the steps of performing coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and the three-dimensional real-time magnetic field intensity data of the target to be corrected in turn to obtain the real-time magnetic field intensity value after the curvature changes include: performing coordinate system normalization processing on the three-dimensional real-time acceleration data and the three-dimensional real-time magnetic field intensity data; performing dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data using the normalized three-dimensional real-time acceleration data to obtain a two-dimensional real-time magnetic field intensity value; and performing plane stretching on the two-dimensional real-time magnetic field intensity value using a first plane stretching correction coefficient to obtain the real-time magnetic field intensity value after the curvature changes.

[0014] Furthermore, the step of using the normalized three-dimensional real-time acceleration data to perform a dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data includes: calculating the synthetic acceleration based on the three-dimensional real-time acceleration data; using the synthetic acceleration to respectively calculate the pitch angle and the roll angle; and performing a dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data based on the pitch angle and the roll angle to obtain a two-dimensional real-time magnetic field intensity value.

[0015] Furthermore, the first plane stretching correction coefficient includes a stretching coefficient and a displacement coefficient. The method of using the first plane stretching correction coefficient to perform plane stretching on the two-dimensional real-time magnetic field intensity value to obtain the real-time magnetic field intensity value after the curvature changes is: multiplying the stretching system by the corresponding real-time magnetic field intensity value and summing the corresponding displacement coefficients to obtain the real-time magnetic field intensity value after the curvature changes.

[0016] A second aspect of the present invention provides an azimuth correction system for a magnetic field distortion curve, the system comprising: a memory for storing a computer program; a processor for implementing the steps of the azimuth correction method for a magnetic field distortion curve as described above when executing the computer program.

[0017] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of azimuth correction of the magnetic field distortion curve as described above are implemented.

[0018] The azimuth correction method and system of the magnetic field distortion curve mentioned above can solve the problem of azimuth distortion caused by magnetic flux distortion caused by local strong magnetic fields, and also have good compensation and correction effect for magnetic field distortion greater than 90°. The magnetic field intensity value after the curvature change is calculated, and this is introduced as a parameter into the method of correcting the curvature model, and the compensation accuracy is adjusted in real time according to the curvature model. Different compensation accuracies are used according to the curvature in the same model, which greatly improves the accuracy of model correction. Using the azimuth correction method provided in this embodiment, the target to be corrected is rotated in a plane, and due to the compensation effect of the acceleration sensor, it does not need to make too many restrictions on the horizontal tilt disturbance caused by the plane rotation when rotating in a plane. Therefore, for a target body with a relatively large mass volume, the difficulty of implementation is greatly increased, and it has great practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] For purposes of illustration and not limitation, the present invention will now be described in terms of preferred embodiments thereof, with particular reference to the accompanying drawings, in which:

[0020] Figure 1 It is a flow chart of a method for azimuth correction of a magnetic field distortion curve provided by an embodiment of the present invention.

[0021] Figure 2 It is a flow chart of a correction method for a curvature model provided in one embodiment of the present invention.

[0022] Figure 3 It is a schematic diagram of three-dimensional coordinates.

[0023] Figure 4 It is a schematic diagram of the curvature change.

[0024] Figure 5 It is a flow chart of another method for azimuth correction of a magnetic field distortion curve provided by an embodiment of the present invention.

[0025] Figure 6 It is a structural schematic diagram of an azimuth correction system for a magnetic field distortion curve provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. The embodiments described are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] Figure 1 This is a flow chart of an azimuth correction method for a magnetic field distortion curve provided by an embodiment of the present invention. The azimuth correction method for a magnetic field distortion curve first adopts a constant speed and constant sampling rate to sample the three-dimensional acceleration data and magnetic field strength data of the target to be corrected to establish a curvature model, and adopts a constant speed and variable sampling rate to sample the three-dimensional acceleration data and magnetic field strength data of the target to be corrected to correct the curvature model; after obtaining the curvature model, the three-dimensional acceleration data and magnetic field strength data of the target to be corrected are sampled in real time, and the three-dimensional real-time acceleration data and real-time magnetic field strength data of the target to be corrected are respectively normalized by the coordinate system, dimension reduction transformation and plane stretching to obtain the real-time magnetic field strength value after the curvature change, and the real-time magnetic field strength value after the curvature change is input into the curvature model, and a table search is performed to retrieve the real-time corresponding azimuth of the target to be corrected.

[0030] See also Figure 1 The azimuth correction method of the magnetic field distortion curve comprises the following steps:

[0031] S100, constructing a curvature model and correcting the curvature model.

[0032] Figure 2 FIG. 1 is a flow chart of a method for correcting a curvature model provided by an embodiment of the present invention. Figure 2 The specific implementation of step S100 is as follows:

[0033] S101, sampling three-dimensional first acceleration data and three-dimensional first magnetic field intensity data of a target to be calibrated at a constant speed and a constant sampling rate.

[0034] The magnetic field distortion curve is taken as the target to be corrected, the target to be corrected is rotated in a plane with a constant angular velocity, and three-dimensional first acceleration data and first magnetic field intensity data are sampled at a set fixed sampling rate through three acceleration sensors and a magnetic flux sensor.

[0035] Figure 3It is a schematic diagram of three-dimensional coordinates. Based on the right-hand coordinate system, it consists of three mutually perpendicular coordinate axes: X, Y, and Z. The X, Y, and Z directions of the three-dimensional accelerometer and the three-dimensional magnetometer coincide with these three dimensions. The three-dimensional accelerometer and the three-dimensional magnetometer are used to sample the acceleration data and magnetic field strength data of the three dimensions of X, Y, and Z.

[0036] Among them, the fixed sampling rate fSPS is related to the calibration accuracy coefficient AcuPar and the base sampling rate BaseSPS, and the relationship is:

[0037] fSPS=AcuPar*BaseGapAng / AdjT (1)

[0038] Among them, the base segmentation interval BaseGapAng is 360, the calibration accuracy coefficient AcuPar is 1°, and the fixed sampling rate fSPS is 36.

[0039] Among them, the relationship between the calibration time AdjT (in seconds) and the calibration autorotation angular velocity AdjAV (in degrees / second) is:

[0040] AdjT=360 / AdjAV (2)

[0041] That is, it is the time for the target plane to be corrected to rotate one circle, and the calibrated autorotation angular velocity AdjAV is 36° / second.

[0042] After setting various variable values ​​such as the fixed sampling rate fSPS, the calibrated autorotation angular velocity AdjAV, and the calibration time AdjT, this embodiment uses a processor to rotate the target to be calibrated at the calibrated autorotation angular velocity AdjAV plane, and at the same time samples acceleration data and magnetic field intensity data at the fixed sampling rate fSPS. After the calibration time AdjT, the target to be calibrated stops moving, and the processor stops sampling data and stores the collected data in the memory.

[0043] S102, performing coordinate system normalization processing on the three-dimensional first acceleration data and the three-dimensional first magnetic field intensity data.

[0044] After obtaining the first acceleration data and the first magnetic field strength data of the X, Y, and Z three dimensions, if the coordinate system applied at this time is a left-handed system, the first acceleration data and the first magnetic field strength data of the Z component collected at this time need to be transformed, and the transformation rule is:

[0045] VarZ=-VarZOrg (3)

[0046] Among them, VarZ is the acceleration data and magnetic field intensity data of the Z component after transformation, and VarZOrg is the acceleration data and magnetic field intensity data of the original Z component of the left-handed system before transformation.

[0047] S103, performing a dimensionality reduction transformation on the three-dimensional first magnetic field intensity data using the normalized three-dimensional first acceleration data to obtain a two-dimensional first magnetic field intensity value.

[0048] After the X, Y, Z three-dimensional first acceleration data and the first magnetic field strength data are normalized by the coordinate system, the X, Y, Z three-dimensional first magnetic field strength data needs to be reduced in dimension according to the corresponding three-dimensional first acceleration data, and the three-dimensional first magnetic field strength data needs to be converted into a two-dimensional first magnetic field strength value. The method of reducing the dimension of the X, Y, Z three-dimensional magnetic field strength data according to the corresponding three-dimensional acceleration data is:

[0049] S103-1, calculate the corresponding pitch angle θ and roll angle φ according to the acceleration data of X, Y, and Z. At this time, the accelerations of X, Y, and Z are s_X, s_Y, and s_Z respectively, and the calculation method of the pitch angle θ and the roll angle φ is:

[0050] (1) Calculate the composite acceleration based on the X, Y, and Z three-dimensional acceleration data.

[0051] In this embodiment, the calculation method of the synthetic acceleration is:

[0052] sg=s_X2+s_Y2+s_Z2 (4)

[0053] Where sg is the resultant acceleration.

[0054] (2) Using the resultant acceleration, calculate the pitch angle and roll angle respectively.

[0055] Among them, the calculation method of the pitch angle θ is:

[0056] θ=asin(s_x / sg)(5)

[0057] In the formula, asin represents the inverse transform of sine.

[0058] The calculation method of the roll angle φ is:

[0059] φ=asin(s_y / (sg*cos(f_Cmp_Theta)))(6)

[0060] S103-2, according to the obtained pitch angle θ and roll angle φ, the collected X, Y, Z three-dimensional magnetic field intensity values ​​f_Hx, f_Hy, f_Hz are transformed into a dimensionality reduction mode to obtain the two-dimensional first magnetic field intensity values ​​f_CHx, f_CHy. The transformation method is:

[0061] f_CHx=f_Hx*cos(f_Theta)+f_Hy*sin(f_Theta)*sin(f_Gamma)-f_Hz*sin(f_Theta)*cos(f_Gamma) (7)

[0062] f_CHy=f_Hy*cos(f_Gamma)+f_Hz*sin(f_Gamma) (8)

[0063] Among them, f_CHx and f_Chy are the two-dimensional magnetic field intensity values ​​after transformation.

[0064] S104, calculating a first plane stretching correction coefficient based on the two-dimensional first magnetic field intensity value.

[0065] Since the two-dimensional curve formed by the two-dimensional magnetic field intensity value after the dimensionality reduction transformation has a relatively large range of magnetic field distortion, it is necessary to perform plane stretching on the plane. The first plane stretching correction coefficient calculated at this time includes Xsf, Ysf, Xoff, and Yoff, and the four variables represent the stretching coefficient and displacement coefficient of the X-axis and the Y-axis respectively. Among them, the calculation method of the plane stretching correction coefficients Xsf, Ysf, Xoff, and Yoff is:

[0066] S104-1, traverse and calculate the maximum and minimum values ​​of the two-dimensional magnetic field intensity values ​​f_CHx and f_Chy, and calculate the maximum and minimum values ​​of the two-dimensional coordinate axes as maHy, miHy, maHx, miHx respectively.

[0067] S104-2, calculate the plane stretch correction coefficient according to the maximum and minimum values ​​of the two-dimensional coordinate axis. The plane stretch correction coefficients Xsf, Ysf, Xoff, Yoff are calculated as follows:

[0068] f_Ydis=maHy-miHy(9)

[0069] f_Xdis=maHx-miHx(10)

[0070] f_Temp=f_Ydis / f_Xdis(11)

[0071] Xsf=(1>f_Temp)? 1:f_Temp(12)

[0072] f_Temp=f_Xdis / f_Ydis(13)

[0073] Ysf=(1>f_Temp)? 1:f_Temp(14)

[0074] Xoff=(f_Xdis / 2-maHx)*Xsf(15)

[0075] Yoff=(f_Ydis / 2-maHy)*Ysf(16)

[0076] Where, f_Ydis, f_Xdis are the differences between the maximum and minimum values ​​of the Y-axis and the X-axis, and f_Temp is the intermediate variable of the calculation. Where, Xsf = (1>f_Temp)? 1:f_Temp means: if f_Temp is less than 1, then Xsf is equal to 1, otherwise, Xsf is equal to f_Temp.

[0077] S105, using the first plane stretching correction coefficient and the first two-dimensional magnetic field intensity value, calculate the first magnetic field intensity value after the curvature changes, the first azimuth angle, the first absolute radius of the curve and the first variable sampling rate value, and construct a curvature model.

[0078] According to the first plane stretching correction coefficient obtained above, the transformed two-dimensional first magnetic field intensity values ​​f_CHx and f_Chy are plane stretched, and then a curvature model is established under this model after stretching. After obtaining the plane stretching correction coefficient and the two-dimensional magnetic field intensity value, the curvature model is established as follows:

[0079] S105-1, using the plane stretching correction coefficient to perform plane stretching on the two-dimensional magnetic field intensity values ​​f_CHx and f_Chy to obtain the magnetic field intensity value after the curvature changes. The calculation method of the magnetic field intensity value after the curvature changes is:

[0080] C_CHx=Xsf*f_CHx+Xoff (17)

[0081] C_CHy=Ysf*f_CHy+Yoff (18)

[0082] Wherein, C_CHx and C_Chy are the magnetic field intensity values ​​after the curvature changes.

[0083] S105-2, calculating the absolute radius of the curve formed by the magnetic field intensity value after the curvature change.

[0084] This embodiment calculates the absolute radius C_R of the curve formed by the two plane coordinates C_CHx and C_Chy. The absolute radius C_R of the curve is:

[0085]

[0086] S105-3, calculate the rate of change of the absolute radius of the curve.

[0087] This embodiment calculates the rate of change C_RR of C_R, that is, to solve the discrete difference for each sample point corresponding to C_CHx and C_Chy, and symmetrically disperse the obtained C_RR into the range of 1 to F_Rat. F_Rat is the curvature refinement coefficient, and the value range is an integer greater than 2, wherein the larger the value, the higher the degree of refinement.

[0088] S105-4, multiplying the set fixed sampling rate by the change rate of the absolute radius of the curve to obtain a real-time sampling rate value of the variable sampling rate.

[0089] Figure 4 is a schematic diagram of the curvature change. Figure 4 As shown, at this time, the set fixed sampling rate fSPS is multiplied by the change rate of the absolute radius of the curve C_RR, that is, the real-time sampling rate value f_RSPS of the variable sampling rate at this time is obtained. This value is the variable sampling rate obtained on the basis of the fixed sampling rate. If the curve composed of C_CHx and C_Chy is close to the circumference, the obtained C_R conversion rate is close to 0, and when it is dispersed from 1 to F_Rat, its value is close to 1, so the sampling rate is the original reference sampling rate; if the curve composed of C_CHx and C_Chy is distorted, the obtained C_R conversion rate will increase sharply, so when it is dispersed from 1 to F_Rat, its value is close to F_Rat, and the required real-time sampling rate will increase accordingly, and it can also most accurately estimate the fitting requirements at this time.

[0090] S105-5, calculating the azimuth angle ψ corresponding to the magnetic field intensity value after the curvature changes. The azimuth angle ψ is calculated as follows:

[0091] ψ=atan(f_CHy / f_CHx) (20)

[0092] This embodiment calculates the corresponding azimuth angle ψ according to the magnetic field intensity values ​​C_CHx and C_Chy after the curvature changes.

[0093] S105-6, constructing a curvature model based on the magnetic field intensity value after the curvature changes, the azimuth angle, the absolute radius of the curve, and the real-time sampling rate value of the variable sampling rate.

[0094] In this embodiment, a curvature model is formed by the magnetic field intensity values ​​C_CHx and C_Chy after the curvature changes, the azimuth angle ψ, the absolute radius of the curve C_R and the real-time sampling rate value f_RSPS of the variable sampling rate, and the established curvature model is stored in a matrix array format, which is respectively formed by the magnetic field intensity values ​​C_CHx and C_Chy, the azimuth angle ψ, the absolute radius of the curve C_R and the real-time sampling rate value f_RSPS of the variable sampling rate.

[0095] S106 , resampling the three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data of the target to be calibrated at a constant speed and variable sampling rate according to the established curvature model.

[0096] The first real-time sampling rate value of the variable sampling rate obtained in step S105 is resampled with the set base sampling rate BaseSPS as the variable sampling interval, that is, with 1 / BaseSPS as the variable sampling time interval, to correct the curvature model. During the resampling period, the curvature model moves at a constant speed, and during the movement, data is resampled according to the curvature model established in step S105.

[0097] S107, establishing a new curvature model according to the resampled three-dimensional second acceleration data and second magnetic field intensity data, thereby correcting the curvature model.

[0098] In this embodiment, coordinate system normalization, dimensionality reduction transformation and plane stretching are performed on the three-dimensional second acceleration data and second magnetic field intensity data resampled in step S106, and a new curvature model is established.

[0099] Specifically, the specific implementation of step S107 is as follows:

[0100] S107 - 1 , performing coordinate system normalization processing on the resampled three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data.

[0101] The method of normalizing the coordinate system in step 107 - 1 is similar to the method of normalizing the coordinate system in step S02 , and will not be described in detail in this embodiment.

[0102] S107-2, using the normalized three-dimensional second acceleration data to perform a dimensionality reduction transformation on the three-dimensional second magnetic field intensity data to obtain a two-dimensional second magnetic field intensity value.

[0103] The corresponding pitch angle and roll angle are calculated according to the three-dimensional second acceleration data, and the collected three-dimensional second magnetic field intensity value is transformed into a dimension reduction according to the obtained pitch angle and roll angle values ​​to obtain a two-dimensional second magnetic field intensity value.

[0104] S107-3, calculating a second plane stretching correction coefficient based on the two-dimensional second magnetic field intensity value.

[0105] By traversing and calculating the maximum and minimum values ​​of the second magnetic field intensity values ​​in two dimensions, the maximum and minimum values ​​of the two-dimensional coordinate axis are calculated respectively. According to the maximum and minimum values ​​and intermediate variables of the two-dimensional coordinate axis, the second plane stretch correction coefficient is calculated.

[0106] S107-4, performing plane stretching on the two-dimensional second magnetic field intensity value using the second plane stretching correction coefficient to establish a new curvature model, thereby obtaining a corrected curvature model.

[0107] In this embodiment, the second plane stretch correction coefficient and the two-dimensional second magnetic field intensity value are used to calculate the second magnetic field intensity value after the curvature changes, the second azimuth angle, the second absolute radius of the curve, and the second variable sampling rate value to construct a new curvature model, which is the corrected curvature model. The new curvature model includes the second magnetic field intensity value after the curvature changes, the second azimuth angle, the second absolute radius of the curve, and the second variable sampling rate value.

[0108] S108, storing the new curvature model and the first plane stretching correction coefficient calculated in step S104.

[0109] The above-mentioned azimuth correction method of the magnetic field distortion curve first adopts a constant speed and a constant sampling rate to sample the three-dimensional acceleration data and the magnetic field strength data of the target to be corrected to establish a curvature model, and adopts a constant speed and a variable sampling rate to sample the three-dimensional acceleration data and the magnetic field strength data of the target to be corrected to correct the curvature model, which can solve the problem of azimuth distortion caused by the magnetic flux distortion caused by the local strong magnetic field.

[0110] The traditional azimuth correction algorithm is only aimed at the magnetic field distortion caused by a large-scale magnetic field interference. Its rule is to assume that the magnetic field distortion is a circular distortion based on a circle, and it is powerless for the situation where the magnetic field distortion angle is greater than 90°. The azimuth correction method of the magnetic field distortion curve of this embodiment can solve the magnetic field distortion caused by a large-scale magnetic field interference, and can solve the large-angle distortion of the magnetic field intensity caused by a local strong magnetic field, and it also has a good compensation and correction effect for the magnetic field distortion greater than 90°.

[0111] S200, sampling three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected.

[0112] In this embodiment, the three-dimensional acceleration data and the three-dimensional magnetic field intensity data of the target to be calibrated are sampled in real time by a three-dimensional accelerometer and a three-dimensional magnetometer.

[0113] S300, coordinate system normalization, dimension reduction transformation and plane stretching are performed on the three-dimensional real-time acceleration data and the three-dimensional real-time magnetic field intensity data of the target to be corrected in sequence to obtain the real-time magnetic field intensity value after the curvature changes.

[0114] Figure 5 FIG. 1 is a flow chart of another method for correcting the azimuth angle of a magnetic field distortion curve provided by an embodiment of the present invention. Figure 5The specific implementation method of normalizing the coordinate system, reducing the dimension and stretching the plane of the three-dimensional real-time acceleration data and the real-time magnetic field intensity data of the target to be corrected is as follows:

[0115] S301, coordinate system normalization processing is performed on three-dimensional real-time acceleration data and real-time magnetic field intensity data.

[0116] The method of normalizing the coordinate system in step S301 is similar to the method of normalizing the coordinate system in step S02, and will not be described in detail in this embodiment.

[0117] S302, using the normalized three-dimensional real-time acceleration data to perform a dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data to obtain a two-dimensional real-time magnetic field intensity value.

[0118] The corresponding pitch angle and roll angle are calculated according to the three-dimensional real-time acceleration data. According to the obtained pitch angle and roll angle values, the collected three-dimensional real-time magnetic field intensity values ​​are transformed into a dimensionality reduction mode to obtain a two-dimensional real-time magnetic field intensity value.

[0119] S303, performing plane stretching on the two-dimensional real-time magnetic field intensity value using the first plane stretching correction coefficient to obtain the real-time magnetic field intensity value after the curvature is changed.

[0120] The stretching systems of the two axes in the first plane stretching correction coefficient are multiplied by the corresponding real-time magnetic field intensity values ​​and the corresponding displacement coefficients are summed to obtain the real-time magnetic field intensity value after the curvature changes.

[0121] S400, inputting the real-time magnetic field intensity value after the curvature change into the corrected curvature model, and retrieving the azimuth angle corresponding to the target to be corrected in real time.

[0122] The above-mentioned azimuth correction method of the magnetic field distortion curve, after obtaining the curvature model, samples the three-dimensional acceleration data and magnetic field intensity data of the target to be corrected in real time, and respectively normalizes the coordinate system, reduces the dimension and stretches the three-dimensional real-time acceleration data and real-time magnetic field intensity data of the target to be corrected, obtains the real-time magnetic field intensity value after the curvature changes, inputs the real-time magnetic field intensity value after the curvature changes into the curvature model, performs a table search, and obtains the azimuth corresponding to the target to be corrected in real time with high accuracy.

[0123] The traditional correction algorithm is based on a circular or elliptical compensation algorithm, and its compensation accuracy is fixed. For the same object to be corrected, its compensation accuracy is not adjustable. For the same target, since the compensation accuracy of each angle is the same, its correction resolution is obviously insufficient for the strong distortion area. The azimuth correction method of the magnetic field distortion curve of this embodiment calculates the magnetic field distortion rate, introduces it as a parameter into the curvature model, adjusts the compensation accuracy in real time according to the curvature model, and adopts different compensation accuracies according to the curvature in the same model, which greatly improves the accuracy of model correction.

[0124] By using the above-mentioned azimuth correction method of the magnetic field distortion curve, the target to be corrected only needs to make a planar motion, and does not need a 360° stereo rotation. In addition, non-horizontal disturbances are automatically compensated in the planar motion, which greatly expands the scope of application.

[0125] In the traditional algorithm, since three parts of magnetic flux data need to be collected, the target body needs to be rotated 360° in an all-round stereoscopic manner to ensure that the three parts of magnetic flux data are evenly collected, so as to construct a three-part elliptical model. However, in fact, in specific application fields, especially seismic application fields, the target to be corrected is often relatively large, and it is not feasible to perform a 360° all-round stereoscopic rotation on the target to be corrected, which greatly limits the implementation of such correction algorithms. The azimuth correction method of the magnetic field distortion curve of this embodiment adopts an acceleration sensor and a magnetic flux sensor to simultaneously sample three-dimensional acceleration data and magnetic field intensity data, which removes the restriction on the 360° stereoscopic rotation of the target to be corrected. The target to be corrected only needs to perform a plane rotation, and due to the compensation effect of the acceleration data, it does not need to make too many restrictions on the horizontal inclination disturbance caused by the plane rotation when performing the plane rotation. Therefore, for a target body with a relatively large mass volume, the difficulty of implementation is greatly increased, and it has great practical value.

[0126] Corresponding to the above method embodiment, see Figure 6 , Figure 6 This is a schematic structural diagram of a magnetic field distortion curve azimuth correction system provided by another embodiment of the present invention. The system 100 may include:

[0127] Memory 101, used for storing computer programs;

[0128] The processor 102, when used to execute the computer program stored in the memory 101, can implement the following steps:

[0129] Construct a curvature model and correct the curvature model; sample three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected; perform coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected in turn to obtain the real-time magnetic field intensity value after the curvature changes; input the real-time magnetic field intensity value after the curvature changes into the corrected curvature model, and retrieve the azimuth corresponding to the target to be corrected.

[0130] For an introduction to the device provided by the present invention, please refer to the above method embodiment, and the present invention will not be elaborated here.

[0131] Corresponding to the above method embodiment, the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps can be implemented:

[0132] Construct a curvature model and correct the curvature model; sample three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected; perform coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected in turn to obtain the real-time magnetic field intensity value after the curvature changes; input the real-time magnetic field intensity value after the curvature changes into the corrected curvature model, and retrieve the azimuth corresponding to the target to be corrected.

[0133] The computer-readable storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0134] For an introduction to the computer-readable storage medium provided by the present invention, please refer to the above method embodiment, and the present invention will not be elaborated here.

[0135] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for azimuth correction of a magnetic field distortion curve, characterized in that: include: constructing a curvature model, and correcting the curvature model; The method for constructing the curvature model includes: Setting the rotation angular velocity and the sampling frequency, sampling the target to be calibrated according to the set sampling rate to set the three-dimensional first acceleration data of the rotation angular velocity plane and the three-dimensional first magnetic field intensity data; Performing coordinate system normalization processing on the three-dimensional first acceleration data and the three-dimensional first magnetic field intensity data; Performing a dimensionality reduction transformation on the three-dimensional first magnetic field intensity data using the normalized three-dimensional first acceleration data to obtain a two-dimensional first magnetic field intensity value; Calculating a first plane stretch correction coefficient based on the two-dimensional first magnetic field intensity value; The calculation method of the first plane stretch correction coefficient is: The maximum and minimum values ​​of the first magnetic field strength values ​​in the two-dimensional space are calculated to obtain the maximum and minimum values ​​of the two-dimensional coordinate axis. Calculate the first plane stretch correction coefficient according to the maximum value, minimum value and intermediate variable of the two-dimensional coordinate axis; Using the first plane stretch correction coefficient and the first two-dimensional magnetic field intensity value, calculate the first magnetic field intensity value after the curvature changes, the first azimuth angle, the first absolute radius of the curve, and the first variable sampling rate value, and construct a curvature model; The step of calculating the first magnetic field intensity value, the first azimuth angle, the first absolute radius of the curve and the first variable sampling rate value after the curvature changes, and constructing the curvature model comprises: Performing plane stretching on the two-dimensional first magnetic field intensity value using the first plane stretching correction coefficient to obtain the first magnetic field intensity value after the curvature is changed; Calculating a first absolute radius of a curve formed by first magnetic field intensity values ​​after the curvature changes; Solving discrete differences on sample points on a curve formed by the first magnetic field intensity value after the curvature changes to obtain a rate of change of a first absolute radius of the curve, and multiplying a set sampling rate by the rate of change of the first absolute radius of the curve to obtain a first variable sampling rate value; Calculate the first azimuth angle corresponding to the magnetic field intensity value after the curvature changes; Constructing a curvature model based on the first magnetic field intensity value after the curvature changes, the first azimuth, the first absolute radius of the curve, and the first variable sampling rate value; The correction method of the curvature model includes: Re-sampling the target to be calibrated according to the calculated first variable sampling rate to set the three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data of the rotation angular velocity plane; Performing coordinate system normalization processing on the resampled three-dimensional second acceleration data and the three-dimensional second magnetic field intensity data; Performing a dimensionality reduction transformation on the three-dimensional second magnetic field intensity data using the normalized three-dimensional second acceleration data to obtain a two-dimensional second magnetic field intensity value; Calculating a second plane stretch correction coefficient based on the two-dimensional second magnetic field intensity value; Using the second plane stretch correction coefficient and the two-dimensional second magnetic field intensity value, calculate the second magnetic field intensity value after the curvature changes, the second azimuth angle, the second absolute radius of the curve and the second variable sampling rate value, and construct a corrected curvature model; Sampling three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data of the target to be corrected; The three-dimensional real-time acceleration data and the three-dimensional real-time magnetic field intensity data of the target to be corrected are sequentially subjected to coordinate system normalization, dimension reduction transformation and plane stretching to obtain the real-time magnetic field intensity value after the curvature changes; The real-time magnetic field intensity value after the curvature change is input into the corrected curvature model, and the azimuth angle corresponding to the target to be corrected is retrieved.

2. The azimuth correction method of the magnetic field distortion curve according to claim 1, characterized in that: The step of performing coordinate system normalization, dimensionality reduction transformation and plane stretching on the three-dimensional real-time acceleration data and the three-dimensional real-time magnetic field intensity data of the target to be corrected in sequence to obtain the real-time magnetic field intensity value after the curvature changes includes: Performing coordinate system normalization processing on three-dimensional real-time acceleration data and three-dimensional real-time magnetic field intensity data; Using the normalized three-dimensional real-time acceleration data to perform dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data, to obtain a two-dimensional real-time magnetic field intensity value; The two-dimensional real-time magnetic field intensity value is plane stretched using the first plane stretching correction coefficient to obtain the real-time magnetic field intensity value after the curvature is changed.

3. The azimuth correction method of the magnetic field distortion curve according to claim 2, characterized in that: The step of performing dimensionality reduction transformation on the three-dimensional real-time magnetic field intensity data using the normalized three-dimensional real-time acceleration data comprises: Calculate synthetic acceleration based on three-dimensional real-time acceleration data; Using the resultant acceleration, the pitch angle and roll angle are calculated respectively; According to the pitch angle and the roll angle, the three-dimensional real-time magnetic field intensity data is transformed into a dimensionality reduction to obtain a two-dimensional real-time magnetic field intensity value.

4. The azimuth correction method of the magnetic field distortion curve according to claim 2, characterized in that: The first plane stretching correction coefficient includes a stretching coefficient and a displacement coefficient. The method of plane stretching the two-dimensional real-time magnetic field intensity value using the first plane stretching correction coefficient to obtain the real-time magnetic field intensity value after the curvature changes is: The real-time magnetic field intensity value after the curvature change is obtained by multiplying the stretching system with the corresponding real-time magnetic field intensity value and summing the corresponding displacement coefficients.

5. A magnetic field distortion curve azimuth correction system, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the method for azimuth correction of a magnetic field distortion curve as claimed in any one of claims 1 to 4 when executing the computer program.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the step of azimuth correction of the magnetic field distortion curve according to any one of claims 1 to 4 is implemented.

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