Fluxgate magnetometer coefficient calibration method, device and equipment

Abstract

The present invention provides a coefficient calibration method, device and equipment for a fluxgate magnetometer, which can be applied to the field of magnetic measurement technology. The method includes: performing phase point scanning on the induction signal in the probe of the fluxgate magnetometer to determine the optimal phase point; for each target axis of the probe, by adjusting the input signal of the digital-to-analog converter on the target axis, according to the sampled output value of the induction signal output by the analog-to-digital converter on the target axis at the optimal phase point, determining the numerical boundary of the induction signal corresponding to the target axis; when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located, by traversing the input signal of the digital-to-analog converter on the target axis, based on the numerical boundary of the induction signal, collecting the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal; based on the data set corresponding to each target axis, performing coefficient calibration on each target axis to obtain the target coefficient corresponding to each target axis.

Description

Technical Field

[0001] The present invention relates to the field of magnetic measurement technology, and in particular to a coefficient calibration method, device and equipment for a fluxgate magnetometer. Background Art

[0002] The fluxgate magnetometer is an instrument used to measure slowly varying magnetic fields. It has the characteristics of high resolution, wide measurement range, reliability and durability. It is widely used in the fields of space magnetic measurement, geomagnetic research, geological exploration, etc. Therefore, it is important to accurately calibrate the fluxgate magnetometer coefficients.

[0003] The traditional coefficient calibration of a digital fluxgate magnetometer is usually carried out in a laboratory environment by controlling the current flowing through the Helmholtz coil to generate a variable magnetic field. A high-precision magnetometer can be used to determine the linear relationship between the current flowing through the Helmholtz coil and the magnetic field generated in its main direction, so that during the coefficient calibration of the magnetometer, the current value is converted into the provided magnetic field value based on the linear relationship. However, due to problems such as the linearity of the current source and the voltage source, the reference magnetic field generated by the Helmholtz coil is derived from the theoretical current value, which is not a completely linear relationship, thereby affecting the accuracy of the magnetometer coefficient calibration.

[0004] Therefore, how to quickly and accurately achieve coefficient calibration of the fluxgate magnetometer is a technical problem that needs to be solved in the related art. Summary of the invention

[0005] In view of the above problems, the present invention provides a method, device and equipment for improving coefficient calibration of a fluxgate magnetometer.

[0006] According to a first aspect of the present invention, a coefficient calibration method for a fluxgate magnetometer is provided, comprising:

[0007] Performing phase point scanning on the induced signal in the probe of the fluxgate magnetometer to determine the best phase point;

[0008] For each target axis of the probe, by adjusting the input signal of the digital-to-analog converter on the target axis, according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point, the sensing signal value boundary corresponding to the target axis is determined, wherein the sensing signal corresponds to the input signal, and the sensing signal is the input signal of the analog-to-digital converter;

[0009] In a case where the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located, sampling output values ​​of the analog-to-digital converter on the target axis corresponding to the input signal are collected based on the numerical boundary of the induced signal by traversing the input signal of the digital-to-analog converter on the target axis; and

[0010] Based on the data set corresponding to each of the above-mentioned target axes, the coefficients of each of the above-mentioned target axes are calibrated to obtain the target coefficients corresponding to each of the above-mentioned target axes, wherein the above-mentioned data set includes multiple groups of sampling data, and each group of the above-mentioned sampling data includes an input signal and a sampling output value corresponding to the input signal.

[0011] According to an embodiment of the present invention, the above-mentioned phase point scanning of the induced signal in the probe of the fluxgate magnetometer to determine the optimal phase point includes repeatedly performing the following operations until the first cycle round satisfies the first preset condition:

[0012] If the first cycle does not satisfy the first preset condition,

[0013] For the nth phase point in the sensing signal, a first sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the nth phase point is collected, wherein the sensing signal is divided into 4N phase points of equal duration, n is an integer greater than or equal to 1 and less than or equal to N, N is an integer greater than or equal to 1, the sensing signal is obtained by processing the initial sensing signal using a second harmonic method, and the sensing signal is non-saturated;

[0014] Collecting a second sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the N+nth phase point;

[0015] Collecting a third sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the 2N+nth phase point;

[0016] Collecting a fourth sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the 3N+nth phase point;

[0017] Calculating a value corresponding to the nth phase point according to the first sampled output value, the second sampled output value, the third sampled output value and the fourth sampled output value;

[0018] When the number of acquisitions for the nth phase point meets the preset number, n is incremented;

[0019] Determine the maximum value among the multiple values ​​obtained when the first cycle round satisfies the first preset condition as the target value;

[0020] The phase point corresponding to the target value is determined as the optimal phase point. According to an embodiment of the present invention, the target axis includes two digital-to-analog converters, the probe includes three target axes, and when the probe is in a magnetic shielding state, the coefficient calibration method of the fluxgate magnetometer further includes:

[0021] For the mth digital-to-analog converter on the ith target axis, when the remaining digital-to-analog converters on the three target axes are turned off, the input signal of the mth digital-to-analog converter on the ith target axis is traversed to collect the sampled output value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the jth target axis at the optimal phase point, wherein i is an integer ranging from 1 to 3, m is an integer ranging from 1 to 2, j is an integer ranging from 1 to 3, and i and j are different;

[0022] According to the plurality of sets of input signals and sampled output values, an initial non-orthogonality coefficient corresponding to the j-th target axis is calculated; and

[0023] The non-orthogonality coefficient corresponding to the j-th target axis is determined based on the target coefficient corresponding to the j-th target axis and the initial orthogonality coefficient.

[0024] According to an embodiment of the present invention, the method of adjusting the input signal of the digital-to-analog converter on the target axis and determining the value boundary of the sensing signal corresponding to the target axis according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point includes:

[0025] When the waveform of the first sensing signal corresponding to the first input signal of the digital-to-analog converter satisfies a second preset condition, determining a first critical value according to a fifth sampled output value of the first sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point;

[0026] determining a second critical value according to a sixth sampled output value of the second sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point when the waveform of the second sensing signal corresponding to the second input signal of the digital-to-analog converter satisfies a third preset condition, wherein the first input signal and the second input signal are different; and

[0027] The numerical boundary of the sensing signal is determined according to the first critical value and the second critical value.

[0028] According to an embodiment of the present invention, the above-mentioned traversing the input signal of the digital-to-analog converter on the target axis and collecting the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal based on the numerical boundary of the sensing signal includes repeatedly performing the following operations until the second cycle round satisfies the fourth preset condition:

[0029] If the second cycle does not satisfy the fourth preset condition,

[0030] Collecting a seventh sampled output value corresponding to the input signal output by the analog-to-digital converter on the target axis;

[0031] When the seventh sampling output value is not within the range of the sensing signal value boundary and the input signal of the digital-to-analog converter does not exceed the critical range, the input signal of the digital-to-analog converter is increased by a preset step length.

[0032] According to an embodiment of the present invention, the coefficient calibration of each of the target axes is performed based on the data set corresponding to each of the target axes to obtain the target coefficient corresponding to each of the target axes, including:

[0033] For each of the above target axes, a multi-equation system is determined by randomly taking three groups of sampling data from the above data set;

[0034] Eliminate the equation groups that meet the screening conditions from the multiple equation groups to obtain multiple target equation groups;

[0035] Solving the above multiple target equation groups to obtain coefficients corresponding to each of the above target equation groups;

[0036] Performing histogram processing on the coefficients corresponding to each of the above target equation groups to determine histogram data; and

[0037] Gaussian fitting is performed on the above histogram data to obtain the target coefficient corresponding to the above target axis.

[0038] According to an embodiment of the present invention, when the probe is in a magnetic shielding state, the coefficient calibration method of the fluxgate magnetometer further includes:

[0039] When the output signal of the digital-to-analog converter on each target axis of the probe is set to zero,

[0040] Collecting the eighth sampled output value of the analog-to-digital converter on each of the target axes;

[0041] When the probe is rotated by a predetermined angle, a ninth sampled output value of the analog-to-digital converter on each of the target axes is collected;

[0042] For each of the target axes, the magnetometer zero drift corresponding to the target axis is calculated based on the eighth sampled output value, the ninth sampled output value and the target coefficient corresponding to the target axis.

[0043] According to an embodiment of the present invention, the coefficient calibration method of the fluxgate magnetometer further includes:

[0044] According to the target coefficient corresponding to the target axis, the non-orthogonality coefficient and the magnetometer zero drift, an output magnetic field expression corresponding to the target axis is determined.

[0045] A second aspect of the present invention provides a coefficient calibration device for a fluxgate magnetometer, comprising: a first determination module, a second determination module, a first acquisition module and a calibration module.

[0046] The first determination module is used to perform phase point scanning on the induction signal in the probe of the fluxgate magnetometer to determine the optimal phase point;

[0047] A second determination module is used for determining, for each target axis of the probe, a numerical boundary of the sensing signal corresponding to the target axis according to a sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point by adjusting the input signal of the digital-to-analog converter on the target axis, wherein the sensing signal corresponds to the input signal and is the input signal of the analog-to-digital converter;

[0048] A first acquisition module is used for acquiring a sampled output value corresponding to the input signal of the analog-to-digital converter on the target axis based on the numerical boundary of the induced signal by traversing the input signal of the digital-to-analog converter on the target axis when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located; and

[0049] A calibration module is used to calibrate the coefficients of each of the above-mentioned target axes based on the data set corresponding to each of the above-mentioned target axes to obtain the target coefficients corresponding to each of the above-mentioned target axes, wherein the above-mentioned data set includes multiple groups of sampling data, and each group of the above-mentioned sampling data includes an input signal and a sampling output value corresponding to the input signal.

[0050] A third aspect of the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the above method.

[0051] The fourth aspect of the present invention further provides a computer-readable storage medium on which a computer program or instruction is stored, and the steps of the above method are implemented when the above computer program or instruction is executed by a processor.

[0052] The fifth aspect of the present invention also provides a computer program product, including a computer program or instructions, which implement the steps of the above method when executed by a processor.

[0053] According to the coefficient calibration method, device and equipment of the fluxgate magnetometer provided by the present invention, the present invention is different from the traditional method of simultaneously changing the external magnetic field and the feedback parameter to calibrate the fluxgate magnetometer coefficient. The fixed external magnetic field is selected to remain unchanged and the feedback parameter (the input signal of the digital-to-analog converter) is automatically traversed and adjusted. On this basis, the coefficient of the target axis is calibrated based on the collected data set to obtain the corresponding target coefficient. Since only a fixed external magnetic field is required, there is no need to adjust the external magnetic field value multiple times, and there is no need to consider the linearity problem of the current source and the voltage source. At the same time, the time waiting for the magnetic field to stabilize during the coefficient calibration process can be effectively shortened; and compared with the traditional coefficient calibration method, the present invention has lower requirements for the noise level index of the magnetic field source (such as the current source) and is easier to implement; the feedback parameters of DACC and DACF are automatically traversed by code without manual setting through instructions, which can effectively improve the calibration efficiency. Therefore, under the same magnetic field source, the coefficient calibration is more accurate and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0055] Figure 1 An application scenario diagram of a coefficient calibration method for a fluxgate magnetometer according to an embodiment of the present invention is shown;

[0056] Figure 2 A flow chart of a coefficient calibration method of a fluxgate magnetometer according to an embodiment of the present invention is shown;

[0057] Figure 3 A flow chart of determining an optimal phase point according to an embodiment of the present invention is shown;

[0058] Figure 4 The waveform diagram actually measured by collecting the best phase point according to an embodiment of the present invention is shown;

[0059] Figure 5 A flow chart of determining non-orthogonal coefficients according to an embodiment of the present invention is shown;

[0060] Figure 6 A measured fitting diagram of a non-orthogonality coefficient according to an embodiment of the present invention is shown;

[0061] Figure 7 A flow chart of collecting the output of an analog-to-digital converter on a target axis according to an embodiment of the present invention is shown;

[0062] Figure 8 A schematic diagram of a target coefficient histogram and a Gaussian fitting curve under a certain data set according to an embodiment of the present invention is shown;

[0063] Fig. 9A schematic diagram showing the influence of the k coefficient on the output magnetic field according to an embodiment of the present invention is shown;

[0064] Fig.10 A structural block diagram of a coefficient calibration device for a fluxgate magnetometer according to an embodiment of the present invention is shown;

[0065] Fig.11 A block diagram of an electronic device suitable for implementing a coefficient calibration method for a fluxgate magnetometer according to an embodiment of the present invention is shown.

[0066] The reference numerals are as follows:

[0067] 1-Magnetic shielding tube

[0068] 2-Helmholtz coil fixed frame

[0069] 3-Helmholtz coil

[0070] 4-Probe of fluxgate magnetometer

[0071] 5-Non-magnetic fixed base

[0072] 6- Current source

[0073] 7- Fluxgate electronics DETAILED DESCRIPTION

[0074] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0075] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0076] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0077] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0078] In the technical solution of the present invention, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0079] In the scenario of using personal information for automated decision-making, the methods, devices, and systems provided by the embodiments of the present invention provide users with corresponding operation portals for users to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered. The expression "automated decision-making" here refers to the activity of automatically analyzing and evaluating an individual's behavioral habits, interests and hobbies, or economic, health, credit status, etc. through computer programs, and making decisions. The expression "expert decision-making" here refers to the activity of making decisions by people who specialize in a certain field, have specialized experience, knowledge and skills, and have reached a certain level of professionalism.

[0080] In the process of implementing the present invention, it is found that the fluxgate of the magnetometer uses Faraday's law of electromagnetic induction to modulate the magnetic field information to be measured into the output induced electromotive force, and the magnetic field information can be further restored by extracting the required harmonic components in the output electromotive force.

[0081] The core of the digital fluxgate magnetometer includes a sampling ADC (Analog-to-Digital Converter) and two feedback DACs (Digital-to-Analog Converters). The two feedback DACs are the fine adjustment DAC (DACF) and the coarse adjustment DAC (DACC), which have different adjustment capabilities for the feedback magnetic field. In addition, due to the non-orthogonality of the three-axis structure of the fluxgate probe, the magnetic field on one axis will also be affected by the feedback magnetic field of other axes. Therefore, taking the x-axis as an example, the magnetic field to be measured on it can be finally expressed by express.

[0082] in, , , Represents the coefficients of ADC, DACF and DACC on the x-axis, Indicates the system zero drift of the x-axis, , , , Represents the non-orthogonality influence coefficients of the fine DAC (DACF) and coarse DAC (DACC) of the y-axis and z-axis on the x-axis respectively.

[0083] The traditional coefficient calibration steps include:

[0084] 1. Adjust the feedback DACC and DACF outputs to 0, change the value of the magnetic field to be measured within the non-saturation range of the ADC, and obtain the relationship between the ADC value and the magnetic field to be measured. Sure ;

[0085] 2. Keep the feedback output of DACC at 0, change DACF and the external field to be measured, and adjust the output voltage according to the ADC’s ​​non-saturation range. Sure ;

[0086] 3. Same as step 2, change the values ​​of DACC and DACF and the external field to be measured, according to Sure ;

[0087] 4. Use the sensor flip test to estimate the internal offset of the prototype and finally determine the overall bias magnetic field B of the system;

[0088] 5. Finally, the non-orthogonality coefficients are calibrated.

[0089] In a laboratory environment, a variable magnetic field is generated by controlling the current flowing through the Helmholtz coil. However, due to problems such as the linearity of the current source and the voltage source, the reference magnetic field generated by the Helmholtz coil is derived from the theoretical current value, which is not a completely linear relationship, thus affecting the accuracy of the magnetometer coefficient calibration. Therefore, how to quickly and accurately calibrate the coefficients of the fluxgate magnetometer is a technical problem that needs to be solved in the related art. To this end, an embodiment of the present invention provides a fluxgate magnetometer coefficient calibration method.

[0090] Figure 1 An application scenario diagram of a coefficient calibration method for a fluxgate magnetometer according to an embodiment of the present invention is shown.

[0091] like Figure 1As shown, the application scenario 100 according to this embodiment may include a computer 101, a network 102 and a server 103. The network 102 is used to provide a medium for a communication link between the computer 101 and the server 103. The network 102 may include various connection types, such as wired, wireless communication links or optical fiber cables, etc.

[0092] The fluxgate magnetometer electronics box 7 is used to collect the signals output by the fluxgate magnetometer probe 4, and can also package the collected signals and send them to the computer 101. The user can use the computer 101 to interact with the server 103 through the network 102 to receive or send messages.

[0093] The server 105 may be a server that provides various services, such as a background management server (only as an example) that provides support for websites browsed by users using the computer 101. The background management server may analyze and process received data such as user requests, and feed back processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal device.

[0094] For example, the server 105 can perform phase point scanning on the induction signal in the probe of the fluxgate magnetometer to determine the optimal phase point, and for each target axis of the probe, by adjusting the input signal of the digital-to-analog converter on the target axis, according to the sampled output value of the induction signal output by the analog-to-digital converter on the target axis at the optimal phase point, determine the numerical boundary of the induction signal corresponding to the target axis, so that when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located, by traversing the input signal of the digital-to-analog converter on the target axis, based on the numerical boundary of the induction signal, the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal is collected, thereby performing coefficient calibration on each target axis based on the data set corresponding to each target axis to obtain the target coefficient corresponding to each target axis, wherein the data set includes multiple groups of sampling data, and each group of sampling data includes an input signal and a sampled output value corresponding to the input signal.

[0095] It should be noted that the coefficient calibration method of the fluxgate magnetometer provided in the embodiment of the present invention can generally be performed by the server 105. Accordingly, the coefficient calibration device of the fluxgate magnetometer provided in the embodiment of the present invention can generally be set in the server 105. The coefficient calibration method of the fluxgate magnetometer provided in the embodiment of the present invention can also be performed by a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105. Correspondingly, the coefficient calibration device of the fluxgate magnetometer provided in the embodiment of the present invention can also be set in a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105.

[0096] It should be understood that Figure 1 The number of terminal devices, networks and servers in the embodiment is only for illustration. Any number of terminal devices, networks and servers may be provided according to the implementation requirements.

[0097] The following will be based on Figure 1 The scene described by Figure 2~Figure 8 The coefficient calibration method of the fluxgate magnetometer according to the embodiment of the present invention is described in detail.

[0098] Figure 2 A flow chart of a coefficient calibration method for a fluxgate magnetometer according to an embodiment of the present invention is shown.

[0099] like Figure 2 As shown, the method 200 includes operations S210 to S240.

[0100] In operation S210, a phase point scan is performed on an induction signal in a probe of a fluxgate magnetometer to determine an optimal phase point.

[0101] According to an embodiment of the present invention, in the process of measuring an external magnetic field using a fluxgate magnetometer, an excitation signal can be input into the probe of the fluxgate magnetometer, wherein the excitation signal is a fixed signal. The input of the excitation signal is conducive to the fluxgate magnetometer's effective detection of the external magnetic field and ensuring the accuracy of the measurement.

[0102] According to an embodiment of the present invention, when an excitation signal is input into a probe of a fluxgate magnetometer, an initial induction signal can be generated in the probe, and the initial induction signal is processed using a second harmonic method to obtain an induction signal. In order to ensure the accuracy and precision of the fluxgate magnetometer measurement, the induction signal can be phase-point scanned to determine the optimal phase point, so that the subsequent fluxgate magnetometer can achieve the best measurement effect at the optimal phase point, improve the accuracy and stability of the measurement, and thus improve the accuracy of the coefficient calibration.

[0103] In operation S220, for each target axis of the probe, the input signal of the digital-to-analog converter on the target axis is adjusted, and the sensing signal value boundary corresponding to the target axis is determined according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point.

[0104] The sensing signal corresponds to the input signal, and the sensing signal is the input signal of the analog-to-digital converter.

[0105] According to an embodiment of the present invention, the probe of the fluxgate magnetometer is a three-axis structure, that is, the probe of the fluxgate magnetometer may include three target axes, which may be an x-axis, a y-axis and a z-axis, respectively, wherein each target axis includes two digital-to-analog converters and one analog-to-digital converter, the two digital-to-analog converters are DACF and DACC, and the analog-to-digital converter is ADC.

[0106] According to an embodiment of the present invention, in the subsequent coefficient calibration process of the fluxgate magnetometer, it is necessary to collect the output of the ADC, and the ADC sampling in the magnetometer is the process of converting analog signals into digital signals. The non-saturation interval of the ADC can ensure that the signal is accurately converted within this interval to avoid measurement errors or saturation caused by excessively strong or weak signals, thereby ensuring the reliability of the measurement results. Therefore, it is necessary to determine the numerical boundary of the induced signal for the ADC.

[0107] According to an embodiment of the present invention, with respect to the target axis: the x-axis, the input signal of the digital-to-analog converter on the x-axis is continuously adjusted, that is, the input signals of DACF and DACC are adjusted, and the sensing signal input to the analog-to-digital converter on the x-axis also changes with the input signal, so that the numerical boundary of the sensing signal corresponding to the x-axis, that is, the numerical boundary of the sensing signal corresponding to the ADC on the x-axis, can be determined based on the sampled output value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the x-axis at the optimal phase point.

[0108] The induction signal is a signal obtained by processing the initial induction signal using the second harmonic method.

[0109] In operation S230, when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located, the input signal of the digital-to-analog converter on the target axis is traversed and based on the numerical boundary of the induced signal, the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal is collected.

[0110] According to an embodiment of the present invention, since the output of the acquired analog-to-digital converter on the target axis is needed in the subsequent process of coefficient calibration of the target axis, in order to improve the accuracy and sensitivity of the magnetometer measurement, that is, to improve the accuracy of the output of the analog-to-digital converter, the direction of the target axis to be measured can be kept consistent with the main direction of the fixed external magnetic field, so that the response of the magnetometer is the strongest and most stable, so that the magnetometer can more accurately measure the magnetic field strength of the external magnetic field.

[0111] According to an embodiment of the present invention, Figure 1 In the application scenario 100 shown in FIG. 1 , a large fixed external magnetic field can be generated by a current source 2 (or a voltage source, a resistor with a heat sink, or a multimeter) and a Helmholtz coil 3. The selection of the current source can be based on the random noise on the current source. , the smaller the random noise, the better.

[0112] According to an embodiment of the present invention, a probe of a fluxgate magnetometer is placed in a Helmholtz coil 3, and the direction of the target axis to be measured of the fluxgate probe is roughly adjusted to be consistent with the main direction of the fixed external magnetic field; the digital-to-analog converters on other target axes are turned off, and the input signal of the digital-to-analog converter on the target axis to be measured is set so that the input signal of the ADC on the target axis to be measured, that is, the induction signal, is in a non-saturated region; the position of the probe is fine-tuned to drive the ADC on the target axis to be measured to perform sampling at an optimal phase point, and when the target axis to be measured is consistent with the main direction of the fixed external magnetic field, the absolute value of the data collected by the ADC is the largest, that is, when the absolute value of the data collected by the ADC is the largest, it can be determined that the direction of the target axis to be measured is consistent with the main direction of the fixed external magnetic field.

[0113] According to an embodiment of the present invention, the input signal of the digital-to-analog converter on the target axis also has a corresponding range interval. Within the range interval, the input signal of the digital-to-analog converter on the target axis can be traversed to obtain the sensing signals corresponding to different input signals, and based on the numerical boundary of the sensing signal, the sampled output value output by the analog-to-digital converter on the target axis corresponding to the input signal within the numerical boundary of the sensing signal is collected.

[0114] In operation S240 , coefficient calibration is performed on each target axis based on the data set corresponding to each target axis to obtain a target coefficient corresponding to each target axis.

[0115] The data set may include multiple groups of sampling data, and each group of sampling data may include an input signal and a sampling output value corresponding to the input signal.

[0116] According to an embodiment of the present invention, the input signal in the collected data may include an input value of DACF and an input value of DACC. For each target axis, the target axis may be coefficient-calibrated based on multiple groups of sampled data in a data set corresponding to the target axis to obtain a corresponding target coefficient.

[0117] According to the embodiment of the present invention, the present invention is different from the traditional method of simultaneously changing the external magnetic field and the feedback parameter to calibrate the fluxgate magnetometer coefficient. The fixed external magnetic field is selected to remain unchanged and the feedback parameter (the input signal of the digital-to-analog converter) is automatically traversed and adjusted. On this basis, the coefficient of the target axis is calibrated based on the collected data set to obtain the corresponding target coefficient. Since only a fixed external magnetic field is required, there is no need to adjust the external magnetic field value multiple times, and there is no need to consider the linearity problem of the current source and the voltage source. At the same time, the time waiting for the magnetic field to stabilize during the coefficient calibration process can be effectively shortened; and compared with the traditional coefficient calibration method, the present invention has lower requirements for the noise level index of the magnetic field source (such as the current source) and is easier to implement; the feedback parameters of DACC and DACF are automatically traversed by code without manual setting through instructions, which can effectively improve the calibration efficiency. Therefore, under the same magnetic field source, the coefficient calibration is more accurate and efficient.

[0118] Figure 3 A flow chart for determining an optimal phase point according to an embodiment of the present invention is shown.

[0119] like Figure 3 As shown, the method 300 includes operations S310 to S390.

[0120] In operation S310 , for an nth phase point in the sensing signal, a first sampled output value of the sensing signal output by an analog-to-digital converter in the probe at the nth phase point is collected.

[0121] The induction signal is divided into 4N phase points of equal duration, n is an integer greater than or equal to 1 and less than or equal to N, N is an integer greater than or equal to 1, and the induction signal is obtained by processing the initial induction signal using the second harmonic method, and the induction signal is non-saturated.

[0122] According to an embodiment of the present invention, when collecting the nth phase point in the sensing signal, the first sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the nth phase point is first collected. .

[0123] In operation S320, a second sampled output value of a sensing signal output by an analog-to-digital converter in the probe at an N+nth phase point is collected.

[0124] According to an embodiment of the present invention, the second sampling output value of the sensing signal output by the analog-to-digital converter at the N+n phase point is collected by offsetting N phase points from the nth phase point in the sensing signal. .

[0125] In operation S330, a third sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the 2N+nth phase point is collected.

[0126] According to an embodiment of the present invention, the sensing signal output by the analog-to-digital converter is offset by 2N phase points from the nth phase point in the sensing signal to collect the third sampling output value at the 2N+n phase point. .

[0127] In operation S340, a fourth sampled output value of the sensing signal output by the analog-to-digital converter in the probe at the 3N+nth phase point is collected.

[0128] According to an embodiment of the present invention, the fourth sampling output value of the sensing signal output by the analog-to-digital converter at the 3N+n phase point is collected by offsetting the nth phase point in the sensing signal by 3N phase points. .

[0129] In operation S350, a value corresponding to the nth phase point is calculated based on the first sampled output value, the second sampled output value, the third sampled output value, and the fourth sampled output value.

[0130] According to an embodiment of the present invention, based on the first sampled output value, the second sampled output value, the third sampled output value and the fourth sampled output value, a value corresponding to the nth phase point is calculated. , the value corresponding to the nth phase point is the data collected by ADC.

[0131] In operation S360, it is determined whether the number of acquisitions for the nth phase point meets a preset number.

[0132] According to an embodiment of the present invention, when the number of acquisitions for the nth phase point does not meet the preset number, the above operations S310 to S350 are performed; when the number of acquisitions for the nth phase point meets the preset number, operation S370 is performed.

[0133] According to an embodiment of the present invention, the preset number of times may be the preset number of times of repeatedly collecting data for the same phase point. When collecting data for a phase point, there may be some noise, so the influence of the noise may be reduced by repeatedly collecting data for the same phase point for the preset number of times.

[0134] In operation S370, n is incremented to determine whether the first cycle round satisfies a first preset condition.

[0135] According to an embodiment of the present invention, when the first cycle round does not satisfy the first preset condition, the above operations S310 to S360 are performed; when the first cycle round satisfies the first preset condition, operations S380 and S390 are performed.

[0136] According to an embodiment of the present invention, the first preset condition may indicate whether the first cycle is N. For example, when n is 10, n is incremented, and when the 11th cycle does not meet the first preset condition, the 11th phase point is collected.

[0137] The induced signal is a signal processed by the second harmonic method. Due to the symmetry of the second harmonic, it is sufficient to scan N consecutive phase points.

[0138] In operation S380, a maximum value among a plurality of values ​​obtained when the first cycle round satisfies the first preset condition is determined as a target value.

[0139] According to an embodiment of the present invention, multiple values ​​obtained in the cycle can be The maximum value among them is determined as the target value.

[0140] In operation S390, a phase point corresponding to the target value is determined as an optimal phase point.

[0141] According to an embodiment of the present invention, the phase point corresponding to the target value may be determined as the optimal phase point.

[0142] Figure 4 A waveform diagram actually measured by collecting the best phase point according to an embodiment of the present invention is shown.

[0143] like Figure 4 As shown in the figure, when N is 75, the horizontal axis (phase counter) can represent the phase point, and the vertical axis (data) can represent the value corresponding to the phase point. Therefore, from Figure 4 In the test, it can be determined that the best phase point (Best Phase Test) is the 40th phase point.

[0144] According to an embodiment of the present invention, for the same phase point, the sampling output value corresponding to the phase point, the sampling output value corresponding to the phase point offset by N phase points, the sampling output value corresponding to the phase point offset by 2N phase points, and the sampling output value corresponding to the phase point offset by 3N phase points are collected in sequence, and the numerical value corresponding to the phase point is calculated based on the four sampling output values. Since measurements are performed at multiple phase points, the influence of random errors and systematic errors can be reduced, the reliability of the measurement results can be improved, and the accuracy of the determined optimal phase point can be improved.

[0145] According to an embodiment of the present invention, when the probe is in a magnetic shielding state, the coefficient calibration method of the above-mentioned fluxgate magnetometer also includes: for the mth digital-to-analog converter on the ith target axis, when the remaining digital-to-analog converters on the three target axes are turned off, by traversing the input signal of the mth digital-to-analog converter on the ith target axis, collecting the sampled output value of the induction signal corresponding to the input signal output by the analog-to-digital converter on the jth target axis at the optimal phase point; according to multiple groups of input signals and the sampled output values, calculating the initial non-orthogonality coefficient corresponding to the jth target axis; and determining the non-orthogonality coefficient corresponding to the jth target axis according to the target coefficient corresponding to the jth target axis and the initial orthogonality coefficient.

[0146] The target axis may include two digital-to-analog converters, and the probe includes three target axes, wherein i is an integer ranging from 1 to 3, m is an integer ranging from 1 to 2, and j is an integer ranging from 1 to 3, and i and j are different.

[0147] According to an embodiment of the present invention, Figure 1 As shown, the probe 4 of the fluxgate magnetometer can be placed in the magnetic shielding cylinder 1 so that the probe is in a magnetic shielding state.

[0148] Figure 5 A flow chart for determining non-orthogonal coefficients according to an embodiment of the present invention is shown.

[0149] like Figure 5 As shown, the method 500 includes operations S510 to S570.

[0150] In operation S510, the mth DAC starts with a value.

[0151] In operation S520 , the ADC collects data for the first time.

[0152] According to an embodiment of the present invention, in a case where the input signal of the mth DAC is a starting value, operation S520 is first started to be performed.

[0153] According to an embodiment of the present invention, taking the i-th target axis as the y-axis, the j-th target axis as the x-axis, and the m-th digital-to-analog converter as the DACF as an example, the non-orthogonality effect of the DACF on the y-axis on the x-axis is explained. The remaining digital-to-analog converters on the three target axes can be turned off, that is, the DACC on the y-axis, the DACF and DACC on the x-axis, and the DACF and DACC on the z-axis are turned off.

[0154] According to an embodiment of the present invention, the sampled output value of the sensing signal output by the DACF on the y-axis corresponding to the input signal at the optimal phase point is collected. , collect the sampling output value of the sensing signal output by the analog-to-digital converter on the y-axis at the point where the optimal phase point is offset by N phase points , collect the sampling output value of the sensing signal output by the analog-to-digital converter on the y-axis at the optimal phase point offset by 2N phase points , collect the sampling output value of the sensing signal output by the analog-to-digital converter on the y-axis at the optimal phase point offset by 3N phase points , and calculate The value of ADC at the optimal phase point, that is, the data acquisition result of ADC, can be obtained by performing operations similar to the above operations S310 to S350.

[0155] In operation S530, it is determined whether the data collection result is within the range of the sensing signal value boundary.

[0156] According to an embodiment of the present invention, when the data acquisition result is within the range of the sensing signal value boundary, operations S540 and S550 are performed; when the data acquisition result is not within the range of the sensing signal value boundary, operation S550 is performed.

[0157] In operation S540 , the ADC continues to collect data for a specified number of times.

[0158] In operation S550 , it is determined whether the input signal of the m th DAC exceeds a critical range.

[0159] According to an embodiment of the present invention, when the input signal of the mth DAC exceeds the critical range, operation S570 is performed; when the input signal of the mth DAC does not exceed the critical range, operation S560 is performed.

[0160] In operation S560, the input signal of the mth DAC increases by a designated step size.

[0161] In operation S570, the acquisition is ended.

[0162] According to an embodiment of the present invention, the main control chip in the magnetometer can automatically traverse the input signal of the mth digital-to-analog converter on the i-th target axis, that is, traverse the input signal of the DACF on the y-axis, and obtain the corresponding data acquisition result under each input signal, that is, execute the above-mentioned operations S510 to S570.

[0163] Among them, the ADC value at the optimal phase point , which can be recorded as , the corresponding input signal can be recorded as .

[0164] According to an embodiment of the present invention, the relationship between the non-orthogonality of the DACF input signal and the ADC value can be expressed as the following formula (1).

[0165] (1)

[0166] in, It can be expressed as the initial non-orthogonality coefficient of DACF on the y-axis to the x-axis.

[0167] According to an embodiment of the present invention, based on the above formula (1), according to the input signals of multiple groups of DACF and ADC values, the initial non-orthogonality coefficient corresponding to the x-axis can be determined: .

[0168] According to an embodiment of the present invention, the target coefficient corresponding to the x-axis may include , , , , , Represent the coefficients of ADC, DACF and DACC on the x-axis respectively. Since the ADC value on the x-axis is used, the initial non-orthogonality coefficient corresponding to the x-axis is and the non-orthogonality coefficient The relationship between Therefore, the non-orthogonality coefficient corresponding to the x-axis can be determined based on the target coefficient corresponding to the x-axis and the initial non-orthogonality coefficient.

[0169] Figure 6 A measured fitting diagram of a certain non-orthogonality coefficient according to an embodiment of the present invention is shown.

[0170] like Figure 6 As shown in the figure, the horizontal axis (DAC value) represents the input signal of different digital-to-analog converters, and the vertical axis can be represented as the ADC value. By performing nonorthogonality fitting on multiple real testing points, a fitting curve can be obtained. Among them, the horizontal and vertical coordinates of the real testing points are the input signal and the corresponding ADC value respectively.

[0171] According to an embodiment of the present invention, when the probe is in a magnetic shielding state, the three-axis non-orthogonality of the magnetometer probe can be calibrated to determine the non-orthogonality effect of a certain digital-to-analog converter on a certain target axis on another target axis. Therefore, the determination of the non-orthogonality coefficient can reduce the measurement error caused by the axial inconsistency of the magnetometer, thereby improving the accuracy and consistency of the measurement data.

[0172] According to an embodiment of the present invention, by adjusting the input signal of the digital-to-analog converter on the target axis, according to the sampled output value of the sampled signal output by the analog-to-digital converter on the target axis at the optimal phase point, the numerical boundary of the sensing signal corresponding to the target axis is determined, including: when the waveform of the first sensing signal corresponding to the first input signal of the digital-to-analog converter meets the second preset condition, according to the fifth sampled output value of the first sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point, determining the first critical value; when the waveform of the second sensing signal corresponding to the second input signal of the digital-to-analog converter meets the third preset condition, according to the sixth sampled output value of the second sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point, determining the second critical value, wherein the first input signal and the second input signal are different; determining the numerical boundary of the sensing signal according to the first critical value and the second critical value.

[0173] According to an embodiment of the present invention, for each target axis, the numerical boundary of the sensing signal corresponding to the target axis can be determined by continuously adjusting the input signal of the digital-to-analog converter on the target axis. Taking the determination of the numerical boundary of the sensing signal corresponding to the x-axis as an example, the input signal of the digital-to-analog converter on the x-axis is adjusted, and the waveform of the sensing signal on the x-axis is observed through an oscilloscope, that is, the input of the analog-to-digital converter on the x-axis is observed.

[0174] According to an embodiment of the present invention, the second preset condition can represent that the waveform of the first sensing signal tends to be positively saturated. When the waveform of the first sensing signal satisfies the second preset condition, that is, by continuously adjusting the input signal of the digital-to-analog converter on the x-axis, the value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the x-axis is is positive and maximum, then two-thirds of this value can be determined as the first critical value The fifth sampling output value of the first sensing signal output by the analog-to-digital converter on the x-axis at the optimal phase point is recorded as , the sampled output values ​​at the phase points offset by N, 2N, and 3N in sequence from the optimal phase point are .

[0175] According to an embodiment of the present invention, the third preset condition may indicate that the waveform of the second sensing signal tends to be reverse saturated. When the waveform of the second sensing signal satisfies the third preset condition, that is, by continuously adjusting the input signal of the digital-to-analog converter on the x-axis, the value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the x-axis is is negative and minimum, then two-thirds of this value can be determined as the second critical value The sixth sampling output value of the second sensing signal output by the analog-to-digital converter on the x-axis at the optimal phase point is recorded as , the sampled output values ​​at the phase points offset by N, 2N, and 3N in sequence from the optimal phase point are .

[0176] According to an embodiment of the present invention, based on the first critical value and the second critical value , the numerical boundary of the sensing signal can be determined, that is, the first critical value is the right boundary value of the numerical boundary of the sensing signal, and the second critical value is the left boundary value of the numerical boundary of the sensing signal.

[0177] According to an embodiment of the present invention, the determined numerical boundary of the sensing signal can be used for subsequent screening of the collected data to ensure that the ADC can accurately convert the signal within the range, avoid measurement errors or saturation caused by excessively strong or weak signals, and ensure the accuracy of the ADC measurement results.

[0178] According to an embodiment of the present invention, by traversing the input signal of the digital-to-analog converter on the target axis, based on the numerical boundary of the sensing signal, the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal is collected, including repeating the following operations until the second loop round satisfies the fourth preset condition: when the second loop round does not meet the fourth preset condition, the seventh sampled output value corresponding to the input signal output by the analog-to-digital converter on the target axis is collected; when the seventh sampled output value is not within the numerical boundary of the sensing signal and the input signal of the digital-to-analog converter does not exceed the critical range, the input signal of the digital-to-analog converter is increased by a preset step size.

[0179] According to an embodiment of the present invention, the input signals of the two digital-to-analog converters DACF and DACC on the target axis have a critical range, such as [0, 100]. The fourth preset condition may indicate that the input signals of the DACF and DACC on the target axis both exceed the corresponding critical range.

[0180] Figure 7 A flow chart of acquiring the output of an analog-to-digital converter on a target axis according to an embodiment of the present invention is shown.

[0181] like Figure 7 As shown, the method 700 includes operations S710 to S790.

[0182] In operation S710, an initial input signal of DACF is a first starting value, and an initial input signal of DACC is a second starting value.

[0183] In operation S720 , the ADC collects data for the first time.

[0184] According to an embodiment of the present invention, when the input signal of DACF is the first starting value and the input signal of DACC is the second starting value, operation S720 is first started.

[0185] According to an embodiment of the present invention, the first data acquisition result of the ADC is the seventh sampling output value, which is the ADC value at the optimal phase point, that is, .

[0186] In operation S730, it is determined whether the data collection result is within the range of the sensing signal value boundary.

[0187] According to an embodiment of the present invention, when the data acquisition result is within the range of the sensing signal value boundary, operations S740 and S750 are performed; when the data acquisition result is not within the range of the sensing signal value boundary, operation S750 is performed.

[0188] In operation S740 , the ADC continues to collect data for a specified number of times.

[0189] In operation S750, it is determined whether the input signal of the DACF exceeds a first critical range.

[0190] According to an embodiment of the present invention, when the input signal of the DACF exceeds the first critical range, operation S770 is performed; when the input signal of the DACF does not exceed the first critical range, operation S760 is performed.

[0191] In operation S760, the input signal of the DACF increases by a first preset step size.

[0192] In operation S770, it is determined whether the input signal of the DACC exceeds a second critical range.

[0193] According to an embodiment of the present invention, when the input signal of the DACC exceeds the second critical range, operation S790 is performed; when the input signal of the DACC does not exceed the second critical range, operation S780 is performed.

[0194] In operation S780, the input signal of DACC increases by a second preset step size, and the input signal of DACF returns to the first starting value.

[0195] In operation S790, the acquisition is ended.

[0196] According to an embodiment of the present invention, when the seventh sampling output value is within the numerical boundary of the sensing signal, the seventh sampling output value may be repeatedly collected for a specified number of times, and when the seventh sampling output value is repeatedly collected for a specified number of times, it is determined whether the input signal of the DACF exceeds the first critical range. When the seventh sampling output value is not within the numerical boundary of the sensing signal, it is directly determined whether the input signal of the DACF exceeds the first critical range.

[0197] According to an embodiment of the present invention, when the input signal of DACF does not exceed the first critical range, the input signal of DACF increases by the first preset step size corresponding to DACF; when the input signal of DACF exceeds the first critical range, it is determined whether the input signal of DACC exceeds the second critical range, and when the input signal of DACC exceeds the second critical range, the acquisition is terminated.

[0198] According to an embodiment of the present invention, when the input signal of DACC does not exceed the second critical range, the input signal of DACC increases by a corresponding second preset step size, and the input signal of DACF returns to the first starting value.

[0199] According to an embodiment of the present invention, through the above-mentioned operations S710 to S790, the input signals of DACF and DACC are traversed within the first critical range and the second critical range, so that a maximum of seventh sampling output values ​​can be collected, and based on the limitation of the numerical boundary of the sensing signal, the collected data is more accurate, which is convenient for subsequent coefficient calibration based on the collected data.

[0200] According to an embodiment of the present invention, based on a data set corresponding to each target axis, coefficients of each target axis are calibrated to obtain target coefficients corresponding to each target axis, including: for each target axis, multiple equation groups are determined based on arbitrarily taking out three groups of sampling data from the data set; equation groups that meet screening conditions in the multiple equation groups are screened out to obtain multiple target equation groups; the multiple target equation groups are solved to obtain coefficients corresponding to each target equation group; histogram processing is performed on the coefficients corresponding to each target equation group to determine histogram data; Gaussian fitting is performed on the histogram data to obtain target coefficients corresponding to the target axis.

[0201] According to an embodiment of the present invention, based on the above operations, a corresponding data set can be collected for each target axis, and the data set includes multiple groups of sampling data, and each group of sampling data includes the input signal of DACF, the input signal of DACC and the corresponding ADC value on the target axis.

[0202] According to an embodiment of the present invention, three groups of sampled data can be randomly taken out from the data set to obtain multiple equation groups. For example, if the data set includes four groups of sampled data A, B, C and D, data of four situations of A, B and C, A, B and D, B, C and D, and A, C and D can be taken out to form four three-variable linear equation groups.

[0203] According to an embodiment of the present invention, when the target axis is the x-axis, the set of equations corresponding to the x-axis can be expressed as the following formula (2).

[0204]

[0205] in, It can represent the number of equations in the system of equations. It can be expressed as the center value of the magnetic field in the main direction after the fixed external magnetic field is stabilized. When the output signal of the digital-to-analog converter on each target axis is set to zero, the ADC value of the analog-to-digital converter on each target axis at the optimal phase point is collected. .

[0206] According to an embodiment of the present invention, the screening condition may include that the input signals of DACC or DACF of the three equations in the equation group are the same, that is, or ; The input signals of DACC and DACF in the three equations in the equation group are in a certain proportional relationship, that is,

[0207] .

[0208] According to an embodiment of the present invention, the equation group that meets the above screening conditions is recorded as an invalid equation group, and the equation group that meets the above screening conditions can be screened out from the multiple equation groups to obtain multiple target equation groups, so that the multiple target equation groups can be solved to obtain coefficients corresponding to each equation group, such as the coefficient corresponding to the x-axis. , .

[0209] According to an embodiment of the present invention, each set of equations can be solved to obtain three coefficients. For each coefficient, the coefficient obtained by solving multiple sets of equations can be processed by histogram to obtain a histogram corresponding to the coefficient, so that the histogram data can be determined based on the histogram. The histogram data may include the nbin width of the histogram, the center value of each bin BinCenter, and the number of data on the bin HisCount.

[0210] Among them, the nbins width selection in the histogram processing of the three coefficients can be respectively , , .

[0211] According to an embodiment of the present invention, BinCenter and HisCount can be Gaussian fitting, where the initial peak value a of the Gaussian fitting is set to the maximum value of HistCount; the initial peak position b is set to the BinCenter value corresponding to the maximum value of HistCount; the initial half width c is set equal to the width of nbins during histogram processing, that is, , The initial half-width settings are , , ; The initial bias d is set to 0. Finally, the target coefficients are obtained according to the fitting results.

[0212] According to an embodiment of the present invention, based on the data set collected for each target axis, the accuracy of the target coefficient obtained by fitting can be improved by solving unknown parameters and determining the corresponding target coefficient through histogram processing and Gaussian fitting.

[0213] According to an embodiment of the present invention, when the probe is in a magnetic shielding state, the coefficient calibration method of the above-mentioned fluxgate magnetometer also includes: when the output signal of the digital-to-analog converter on each target axis of the probe is set to zero, the eighth sampling output value of the analog-to-digital converter on each target axis is collected; when the probe is rotated by a predetermined angle, the ninth sampling output value of the analog-to-digital converter on each target axis is collected; for each target axis, based on the eighth sampling output value, the ninth sampling output value and the target coefficient corresponding to the target axis, the magnetometer zero drift corresponding to the target axis is calculated.

[0214] According to an embodiment of the present invention, the input signals of the digital-to-analog converters on the three target axes are adjusted so that the output signals of the digital-to-analog converters on the target axes are zero. When the output signal of the digital-to-analog converter on each target axis is set to zero, the eighth sampled output value of the analog-to-digital converter on each target axis is collected. Taking the x-axis as the target axis, the eighth sampling output value of the analog-to-digital converter on the x-axis can be recorded as .

[0215] According to an embodiment of the present invention, the eighth sampling output value corresponding to the target axis is proportional to the sum of the zero drift of the magnetometer and the residual magnetism of the magnetic shielding device corresponding to the target axis, that is, Among them, the magnetic shielding tube 1 can be a magnetic shielding device.

[0216] According to an embodiment of the present invention, the preset angle may be 180 degrees, that is, while keeping the output signal of the digital-to-analog converter on the target axis at zero, the probe is rotated 180 degrees, and the ninth sampled output value of the analog-to-digital converter on each target axis is collected. Taking the x-axis as the target axis, the ninth sample output value of the analog-to-digital converter on the x-axis can be recorded as .

[0217] According to an embodiment of the present invention, the ninth sampling output value corresponding to the target axis is proportional to the difference between the zero drift of the magnetometer corresponding to the target axis and the residual magnetism of the magnetic shielding device, that is, .

[0218] According to an embodiment of the present invention, when the target axis is the x-axis, the zero drift of the magnetometer corresponding to the x-axis can be obtained by the following formula (3).

[0219] (3)

[0220] According to an embodiment of the present invention, the residual magnetism of the magnetic shielding device corresponding to the x-axis can be obtained by the following formula (4).

[0221] (4)

[0222] According to the embodiment of the present invention, when the target coefficient has been determined, the zero drift of the magnetometer and the residual magnetism of the magnetic shielding device can be determined based on the above formulas (3) and (4), thereby realizing the sensor flip test. In addition, the determination of the zero drift of the magnetometer is conducive to the determination of the subsequent output magnetic field expression.

[0223] According to an embodiment of the present invention, the coefficient calibration method of the fluxgate magnetometer further comprises: determining an output magnetic field expression corresponding to the target axis according to the target coefficient corresponding to the target axis, the non-orthogonality coefficient and the magnetometer zero drift.

[0224] According to an embodiment of the present invention, when the target axis is the x-axis, the output magnetic field expression corresponding to the x-axis can be expressed as the following formula (5).

[0225]

[0226] in, is the ADC value on the x-axis, is the input signal of the DACF on the x-axis, is the input signal of DACC on the x-axis, It can be expressed as the initial non-orthogonality coefficient of DACF on the y-axis to the x-axis, It can be expressed as the initial non-orthogonality coefficient of DACC on the y-axis to the x-axis, It can be expressed as the initial non-orthogonality coefficient of DACF on the z-axis to the x-axis, It can be expressed as the initial non-orthogonality coefficient of DACC on the z-axis to the x-axis.

[0227] in, , , , .

[0228] According to an embodiment of the present invention, based on the target coefficients, non-orthogonal coefficients and magnetometer zero drift obtained by the above operations, the output magnetic field expression corresponding to the target axis can be determined, that is, there is no need to consider the linearity of the current source and the voltage source.

[0229] The present invention can also be further described in detail through specific simulation tests, in which the residual magnetism of the magnetic shielding device and the zero drift and non-orthogonality effects of the fluxgate magnetometer are not considered:

[0230] ① Dataset design: initial setup , , , where the initial setting , , It is determined based on past experience. , , In known cases, The following traverses the input signals of DACC and DACF and automatically obtains the corresponding ADC values, where , is a random noise with a peak value of 10nT. Both DACC and DACF are set to 16-bit bipolar DAC. In this implementation, the DACC traversal step size is 2048, the DACF traversal step size is 1024, and the ADC effective data range is -360000~360000.

[0231] ②In , , In the case of unknowns, the linsolve function is used to solve the three-variable linear equations for the obtained multiple sets of data, and invalid equations are screened out.

[0232] ③ Perform histogram processing on the large number of k coefficients obtained in step ②. After testing, the nbins width selection in the histogram processing is , , is better (corresponding to , , The width of nbins in histogram processing).

[0233] ④ Obtain the relevant information of the histogram after step ③, including the center value BinCenter of each Bin and the number of data in the Bin HistCount, and perform Gaussian fitting. The initial peak value a of the Gaussian fitting is set to the maximum value of HistCount; the initial peak position b is set to the BinCenter value corresponding to the maximum value of HistCount; the initial half width c is set equal to the width of nbins during histogram processing, that is, , , The initial half-width settings are , , ; The initial bias d is set to 0. Finally, the k coefficients are obtained based on the fitting results.

[0234] ⑤ Under this data set, the k coefficient obtained by fitting is , , , the deviation between the fitted coefficient and the true coefficient is , , The corresponding data histogram and Gaussian fitting image are shown in the attached figure. Figure 8 As shown in the figure, the true coefficient is the coefficient initially set in step ①.

[0235] Figure 8 A schematic diagram of a target coefficient histogram and a Gaussian fitting curve under a certain data set according to an embodiment of the present invention is shown.

[0236] like Figure 8 As shown, Figure 8 The three figures on the left are for the three coefficients , , The histogram of Figure 8 The three pictures on the right are the Gaussian fitting curve (fitted curve) and the original histogram data (original hist) corresponding to the histogram.

[0237] ⑥Simulate the normal working mode of the fluxgate magnetometer and examine the influence of the fitted k coefficient on the output magnetic field. The normal working mode of the fluxgate magnetometer is set as follows: when the value of DACF exceeds the limit range, adjust DACC and DACF through the values ​​of ADC and DACF; when only the value of ADC exceeds the limit range, only adjust DACF.

[0238] Fig. 9 A schematic diagram showing the influence of the k coefficient on the output magnetic field according to an embodiment of the present invention is shown.

[0239] like Fig. 9 As shown, the vertical axes of the three figures are all magnetic field (Magnetic Field), and the horizontal axes are all changes with time. The first figure is the step change of the real magnetic field (MF real) with time. The second figure is the fitted magnetic field (MF fit) obtained based on the k coefficient obtained by fitting as the real magnetic field in the first figure changes in normal working mode. The third figure is the deviation between the fitted magnetic field in the second figure and the real magnetic field in the first figure (MF fit- MF real).

[0240] According to an embodiment of the present invention, simulation shows that, under the condition of a step-like changing external field with an initial value of -55000nT, a step size of 1000nT and a final value of 55000nT, the influence of the k coefficient obtained by fitting the data set on the output magnetic field of the magnetometer is such that the deviation between it and the real magnetic field is less than 2nT.

[0241] Based on the above-mentioned fluxgate magnetometer coefficient calibration method, the present invention also provides a fluxgate magnetometer coefficient calibration device. Fig.10 The device is described in detail.

[0242] Fig.10 A structural block diagram of a coefficient calibration device for a fluxgate magnetometer according to an embodiment of the present invention is shown.

[0243] like Fig.10 As shown, the coefficient calibration device 1000 of the fluxgate magnetometer of this embodiment includes a first determination module 1010 , a second determination module 1020 , a first acquisition module 1030 and a calibration module 1040 .

[0244] The first determination module 1010 is used to perform phase point scanning on the induced signal in the probe of the fluxgate magnetometer to determine the best phase point. In one embodiment, the first determination module 1010 can be used to perform the operation S210 described above, which will not be described in detail here.

[0245] The second determination module 1020 is used to determine the sensing signal value boundary corresponding to each target axis of the probe by adjusting the input signal of the digital-to-analog converter on the target axis and according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point. In one embodiment, the second determination module 1020 can be used to perform the operation S220 described above, which will not be repeated here.

[0246] The first acquisition module 1030 is used to acquire the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal by traversing the input signal of the analog-to-digital converter on the target axis based on the numerical boundary of the induced signal when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located. In one embodiment, the first acquisition module 1030 can be used to perform the operation S230 described above, which will not be repeated here.

[0247] The calibration module 1040 is used to calibrate the coefficients of each target axis based on the data set corresponding to each target axis to obtain the target coefficients corresponding to each target axis. In one embodiment, the calibration module 1040 can be used to perform the operation S240 described above, which will not be described in detail here.

[0248] According to an embodiment of the present invention, the first determining module 1010 includes a first collecting unit, a second collecting unit, a third collecting unit, a fourth collecting unit, a calculating unit, an increasing unit, a first determining unit and a second determining unit.

[0249] The first acquisition unit is used for acquiring, for the nth phase point in the sensing signal, a first sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the nth phase point when the first preset condition is not satisfied in the first cycle, wherein the sensing signal is divided into 4N phase points of equal duration, n is an integer greater than or equal to 1 and less than or equal to N, N is an integer greater than or equal to 1, the sensing signal is obtained by processing the initial sensing signal by using the second harmonic method, and the sensing signal is non-saturated.

[0250] The second acquisition unit is used to acquire a second sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the N+nth phase point.

[0251] The third acquisition unit is used to acquire a third sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 2N+nth phase point.

[0252] The fourth acquisition unit is used to acquire a fourth sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 3N+nth phase point.

[0253] The calculation unit is used to calculate a value corresponding to the nth phase point according to the first sampled output value, the second sampled output value, the third sampled output value and the fourth sampled output value.

[0254] The incrementing unit is used to increment n when the number of acquisition times for the nth phase point meets the preset number.

[0255] The first determining unit is used to determine the maximum value among multiple values ​​obtained when the first preset condition is satisfied in the first cycle as the target value.

[0256] The second determining unit is used to determine the phase point corresponding to the target value as the optimal phase point.

[0257] According to an embodiment of the present invention, the coefficient calibration device 1000 of a fluxgate magnetometer further includes a second acquisition module, a first calculation module and a third determination module.

[0258] The second acquisition module is used for acquiring the sampled output value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the jth target axis at the optimal phase point by traversing the input signal of the mth digital-to-analog converter on the i-th target axis while turning off the other digital-to-analog converters on the three target axes, wherein i is an integer ranging from 1 to 3, m is an integer ranging from 1 to 2, j is an integer ranging from 1 to 3, and i and j are different.

[0259] The first calculation module is used to calculate the initial non-orthogonality coefficient corresponding to the j-th target axis according to multiple groups of input signals and sampled output values.

[0260] The third determination module is used to determine the non-orthogonality coefficient corresponding to the j-th target axis according to the target coefficient corresponding to the j-th target axis and the initial orthogonality coefficient.

[0261] According to an embodiment of the present invention, the second determining module 1020 includes a third determining unit, a fourth determining unit and a fifth determining unit.

[0262] The third determination unit is used to determine the first critical value according to the fifth sampled output value of the first sensing signal output by the analog-to-digital converter at the optimal phase point on the target axis when the waveform of the first sensing signal corresponding to the first input signal of the digital-to-analog converter meets the second preset condition.

[0263] The fourth determination unit is used to determine the second critical value according to the sixth sampled output value of the second sensing signal output by the analog-to-digital converter at the optimal phase point on the target axis when the waveform of the second sensing signal corresponding to the second input signal of the digital-to-analog converter satisfies the third preset condition, wherein the first input signal and the second input signal are different.

[0264] The fifth determining unit is used to determine a value boundary of the sensing signal according to the first critical value and the second critical value.

[0265] According to an embodiment of the present invention, the first acquisition module 1030 includes a fifth acquisition unit and an increasing unit.

[0266] The fifth acquisition unit is used to acquire a seventh sampling output value corresponding to the input signal output by the analog-to-digital converter on the target axis when the fourth preset condition is not satisfied in the second cycle round.

[0267] The increasing unit is used to increase the input signal of the digital-to-analog converter by a preset step length when the seventh sampling output value is not within the range of the sensing signal value boundary and the input signal of the digital-to-analog converter does not exceed the critical range.

[0268] According to an embodiment of the present invention, the calibration module 1040 includes a sixth determination unit, a screening unit, a solving unit, a seventh determination unit and an obtaining unit.

[0269] The sixth determination unit is used to determine the multi-equation group for each target axis according to three groups of sampling data randomly selected from the data set.

[0270] The screening unit is used to screen out the equation groups that meet the screening conditions from the multiple equation groups to obtain multiple target equation groups.

[0271] The solving unit is used to solve multiple target equation groups to obtain coefficients corresponding to each target equation group.

[0272] The seventh determination unit is used to perform histogram processing on the coefficients corresponding to each target equation group to determine the histogram data.

[0273] The obtaining unit is used to perform Gaussian fitting on the histogram data to obtain the target coefficient corresponding to the target axis.

[0274] According to an embodiment of the present invention, the coefficient calibration device 1000 of the fluxgate magnetometer further includes a third acquisition module, a fourth acquisition module and a second calculation module.

[0275] The third acquisition module is used to acquire the eighth sampling output value of the analog-to-digital converter on each target axis of the probe when the output signal of the digital-to-analog converter on each target axis is set to zero.

[0276] The fourth acquisition module is used to acquire the ninth sampling output value of the analog-to-digital converter on each target axis when the probe is rotated by a predetermined angle.

[0277] The second calculation module is used to calculate the magnetometer zero drift corresponding to each target axis according to the eighth sampling output value, the ninth sampling output value and the target coefficient corresponding to the target axis.

[0278] According to an embodiment of the present invention, the coefficient calibration device 1000 for a fluxgate magnetometer further includes a fourth determination module.

[0279] The fourth determination module is used to determine the output magnetic field expression corresponding to the target axis according to the target coefficient, the non-orthogonality coefficient and the magnetometer zero drift corresponding to the target axis.

[0280] According to an embodiment of the present invention, any multiple modules of the first determination module 1010, the second determination module 1020, the first acquisition module 1030 and the calibration module 1040 can be combined into one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present invention, at least one of the first determination module 1010, the second determination module 1020, the first acquisition module 1030 and the calibration module 1040 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware and firmware or in a suitable combination of any of them. Alternatively, at least one of the first determination module 1010, the second determination module 1020, the first acquisition module 1030 and the calibration module 1040 may be at least partially implemented as a computer program module, and when the computer program module is executed, a corresponding function may be executed.

[0281] Fig.11 A block diagram of an electronic device suitable for implementing a coefficient calibration method for a fluxgate magnetometer according to an embodiment of the present invention is shown.

[0282] like Fig.11 As shown, the electronic device 1100 according to an embodiment of the present invention includes a processor 1101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1102 or a program loaded from a storage part 1108 to a random access memory (RAM) 1103. The processor 1101 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 1101 may also include an onboard memory for caching purposes. The processor 1101 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0283] In RAM 1103, various programs and data required for the operation of electronic device 1100 are stored. Processor 1101, ROM 1102 and RAM 1103 are connected to each other via bus 1104. Processor 1101 performs various operations of the method flow according to the embodiment of the present invention by executing the program in ROM 1102 and / or RAM 1103. It should be noted that the program can also be stored in one or more memories other than ROM 1102 and RAM 1103. Processor 1101 can also perform various operations of the method flow according to the embodiment of the present invention by executing the program stored in the one or more memories.

[0284] According to an embodiment of the present invention, the electronic device 1100 may further include an input / output (I / O) interface 1105, which is also connected to the bus 1104. The electronic device 1100 may further include one or more of the following components connected to the input / output (I / O) interface 1105: an input portion 1106 including a keyboard, a mouse, etc.; an output portion 1107 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 1108 including a hard disk, etc.; and a communication portion 1109 including a network interface card such as a LAN card, a modem, etc. The communication portion 1109 performs communication processing via a network such as the Internet. A drive 1110 is also connected to the input / output (I / O) interface 1105 as needed. A removable medium 1111, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1110 as needed, so that a computer program read therefrom is installed into the storage portion 1108 as needed.

[0285] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiment; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present invention is implemented.

[0286] According to an embodiment of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device. For example, according to an embodiment of the present invention, the computer-readable storage medium may include the ROM 1102 and / or RAM 1103 described above and / or one or more memories other than ROM 1102 and RAM 1103.

[0287] The embodiment of the present invention also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the coefficient calibration method of the fluxgate magnetometer provided in the embodiment of the present invention.

[0288] The computer program executes the above functions defined in the system / device of the embodiment of the present invention when it is executed by the processor 1101. According to the embodiment of the present invention, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0289] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 1109, and / or installed from a removable medium 1111. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0290] In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1109, and / or installed from the removable medium 1111. When the computer program is executed by the processor 1101, the above functions defined in the system of the embodiment of the present invention are performed. According to the embodiment of the present invention, the system, device, means, module, unit, etc. described above can be implemented by a computer program module.

[0291] According to an embodiment of the present invention, the program code for executing the computer program provided by the embodiment of the present invention can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0292] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0293] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present invention may be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features described in the various embodiments of the present invention may be combined and / or combined in various ways. All of these combinations and / or combinations fall within the scope of the present invention.

[0294] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination advantageously. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A coefficient calibration method for a fluxgate magnetometer, characterized in that: include: Performing phase point scanning on the induced signal in the probe of the fluxgate magnetometer to determine the optimal phase point includes repeatedly performing the following operations until the first cycle round satisfies the first preset condition: If the first cycle does not satisfy the first preset condition, For the nth phase point in the sensing signal, a first sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the nth phase point is collected, wherein the sensing signal is divided into 4N phase points of equal duration, n is an integer greater than or equal to 1 and less than or equal to N, N is an integer greater than or equal to 1, the sensing signal is obtained by processing the initial sensing signal using the second harmonic method, and the sensing signal is non-saturated; a second sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the N+nth phase point is collected; a second sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 2N+nth phase point is collected. The third sampling output value at the site; the fourth sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 3N+n phase point is collected; according to the first sampling output value, the second sampling output value, the third sampling output value and the fourth sampling output value, a value corresponding to the nth phase point is calculated; when the number of collection times for the nth phase point meets the preset number, n is incremented; the maximum value among the multiple values ​​obtained when the first cycle round meets the first preset condition is determined as the target value; the phase point corresponding to the target value is determined as the optimal phase point; For each target axis of the probe, by adjusting the input signal of the digital-to-analog converter on the target axis, according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point, the sensing signal value boundary corresponding to the target axis is determined, wherein the sensing signal corresponds to the input signal and the sensing signal is the input signal of the analog-to-digital converter; In a case where the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located, sampling output values ​​of the analog-to-digital converter on the target axis corresponding to the input signal are collected based on the numerical boundary of the induced signal by traversing the input signal of the digital-to-analog converter on the target axis; and Based on a data set corresponding to each of the target axes, coefficient calibration is performed on each of the target axes to obtain a target coefficient corresponding to each of the target axes, wherein the data set includes multiple groups of sampling data, and each group of the sampling data includes an input signal and a sampling output value corresponding to the input signal; Wherein, obtaining the target coefficient corresponding to each of the target axes includes: For each of the target axes, a plurality of equation groups are determined by randomly taking out three groups of sampling data from the data set; the equation groups that meet the screening conditions in the plurality of equation groups are screened out to obtain a plurality of target equation groups; the plurality of target equation groups are solved to obtain coefficients corresponding to each of the target equation groups; the coefficients corresponding to each of the target equation groups are processed by histogram to determine histogram data; the histogram data are Gaussian fitted to obtain target coefficients corresponding to the target axis.

2. The method according to claim 1, characterized in that The target axis includes two digital-to-analog converters, the probe includes three target axes, and when the probe is in a magnetic shielding state, the method further includes: For the mth digital-to-analog converter on the ith target axis, when the remaining digital-to-analog converters on the three target axes are turned off, the input signal of the mth digital-to-analog converter on the ith target axis is traversed to collect the sampled output value of the sensing signal corresponding to the input signal output by the analog-to-digital converter on the jth target axis at the optimal phase point, wherein i is an integer ranging from 1 to 3, m is an integer ranging from 1 to 2, j is an integer ranging from 1 to 3, and i and j are different; Calculating an initial non-orthogonality coefficient corresponding to the j-th target axis according to the multiple groups of input signals and sampled output values; and The non-orthogonality coefficient corresponding to the j-th target axis is determined based on the target coefficient corresponding to the j-th target axis and the initial non-orthogonality coefficient.

3. The method according to claim 1, characterized in that The step of adjusting the input signal of the digital-to-analog converter on the target axis and determining the value boundary of the sensing signal corresponding to the target axis according to the sampled output value of the sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point comprises: When the waveform of the first sensing signal corresponding to the first input signal of the digital-to-analog converter satisfies a second preset condition, determining a first critical value according to a fifth sampled output value of the first sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point; determining a second critical value according to a sixth sampled output value of the second sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point when a waveform of the second sensing signal corresponding to the second input signal of the digital-to-analog converter satisfies a third preset condition, wherein the first input signal and the second input signal are different; and The value boundary of the sensing signal is determined according to the first critical value and the second critical value.

4. The method according to claim 1, characterized in that The step of traversing the input signal of the digital-to-analog converter on the target axis and collecting the sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal based on the numerical boundary of the sensing signal includes repeatedly performing the following operations until the second cycle round satisfies a fourth preset condition: If the second cycle does not satisfy the fourth preset condition, Collecting a seventh sampled output value corresponding to the input signal output by the analog-to-digital converter on the target axis; When the seventh sampling output value is not within the range of the sensing signal value boundary and the input signal of the digital-to-analog converter does not exceed a critical range, the input signal of the digital-to-analog converter is increased by a preset step length.

5. The method according to claim 2, characterized in that: When the probe is in a magnetic shielding state, the method further includes: When the output signal of the digital-to-analog converter on each target axis of the probe is set to zero, Acquiring an eighth sampled output value of the analog-to-digital converter on each of the target axes; When the probe is rotated by a predetermined angle, collecting a ninth sampled output value of the analog-to-digital converter on each of the target axes; For each of the target axes, the magnetometer zero drift corresponding to the target axis is calculated according to the eighth sampled output value, the ninth sampled output value and the target coefficient corresponding to the target axis.

6. The method according to claim 5, characterized in that The method further comprises: An output magnetic field expression corresponding to the target axis is determined according to the target coefficient corresponding to the target axis, the non-orthogonality coefficient and the magnetometer zero drift.

7. A coefficient calibration device for a fluxgate magnetometer, characterized in that: include: A first determination module is used to perform phase point scanning on the induction signal in the probe of the fluxgate magnetometer to determine the optimal phase point; The first determining module includes repeatedly performing the following operations until the first cycle round satisfies the first preset condition: If the first cycle does not satisfy the first preset condition, For the nth phase point in the sensing signal, a first sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the nth phase point is collected, wherein the sensing signal is divided into 4N phase points of equal duration, n is an integer greater than or equal to 1 and less than or equal to N, N is an integer greater than or equal to 1, the sensing signal is obtained by processing the initial sensing signal using the second harmonic method, and the sensing signal is non-saturated; a second sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the N+nth phase point is collected; a second sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 2N+nth phase point is collected. The third sampling output value at the site; the fourth sampling output value of the sensing signal output by the analog-to-digital converter in the probe at the 3N+n phase point is collected; according to the first sampling output value, the second sampling output value, the third sampling output value and the fourth sampling output value, a value corresponding to the nth phase point is calculated; when the number of collection times for the nth phase point meets the preset number, n is incremented; the maximum value among the multiple values ​​obtained when the first cycle round meets the first preset condition is determined as the target value; the phase point corresponding to the target value is determined as the optimal phase point; A second determination module is used to determine, for each target axis of the probe, a numerical boundary of a sensing signal corresponding to the target axis by adjusting an input signal of a digital-to-analog converter on the target axis and according to a sampled output value of a sensing signal output by the analog-to-digital converter on the target axis at the optimal phase point, wherein the sensing signal corresponds to the input signal and is the input signal of the analog-to-digital converter; A first acquisition module is used for acquiring a sampled output value of the analog-to-digital converter on the target axis corresponding to the input signal based on a numerical boundary of the induced signal by traversing the input signal of the digital-to-analog converter on the target axis when the direction of the target axis is consistent with the main direction of the fixed external magnetic field where the fluxgate magnetometer is located; and A calibration module, configured to perform coefficient calibration on each target axis based on a data set corresponding to each target axis to obtain a target coefficient corresponding to each target axis, wherein the data set includes multiple groups of sampled data, and each group of sampled data includes an input signal and a sampled output value corresponding to the input signal; Wherein, obtaining the target coefficient corresponding to each of the target axes includes: For each of the target axes, a plurality of equation groups are determined by randomly taking out three groups of sampling data from the data set; the equation groups that meet the screening conditions in the plurality of equation groups are screened out to obtain a plurality of target equation groups; the plurality of target equation groups are solved to obtain coefficients corresponding to each of the target equation groups; the coefficients corresponding to each of the target equation groups are processed by histogram to determine histogram data; the histogram data are Gaussian fitted to obtain target coefficients corresponding to the target axis.

8. An electronic device, comprising: one or more processors; a memory for storing one or more computer programs, It is characterized in that the one or more processors execute the one or more computer programs to implement the steps of the method according to any one of claims 1 to 6.

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