A method and device for calibrating the working bandwidth and noise level of a large-size magnetic sensor

Abstract

The present invention discloses a method and device for calibrating the working bandwidth and noise level of a large-scale magnetic sensor, and belongs to the technical field of magnetic sensors. The method comprises selecting a test environment and a test device type, and laying a transmitting current coil as a calibration loop in the test environment; inputting an alternating current into the calibration loop to generate a magnetic field signal to first affect a standard magnetic sensor and a magnetic sensor to be tested, synchronously collecting voltage signals of the standard magnetic sensor and the magnetic sensor to be tested, and using the voltage signal to calibrate the working bandwidth of the magnetic sensor to be tested; inputting an alternating current into the calibration loop to generate a magnetic field signal to affect a homogeneous magnetic sensor and a magnetic sensor to be tested, synchronously collecting the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested and performing correlation calculation to obtain the noise level of the magnetic sensor to be tested. The present invention can be applied to the performance index testing and quantitative calibration of large-scale magnetic sensors in airborne electromagnetic detection systems or other equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic sensors, and in particular relates to a method and a device for calibrating the working bandwidth and noise level of a large-size magnetic sensor. Background Art

[0002] Geophysical electromagnetic detection systems usually use magnetic sensors to obtain the induced electromagnetic field signals of underground targets to be detected, and obtain information such as the morphology and distribution of underground media through relevant data processing, model inversion and other technical means, providing an analysis basis for geophysical detection results for geological structure surveys, groundwater resource exploration, mineral resource detection, etc.

[0003] In order to improve the data quality of the electromagnetic observation signal of the detection system, geophysical electromagnetic detection equipment usually uses large-size magnetic sensors to improve the sensitivity of the signal sensor. The precise working bandwidth and noise level indicators of the magnetic sensor are key indicators of the electromagnetic system, which have an important impact on the quality of electromagnetic data and subsequent inversion interpretation. Therefore, it is necessary to obtain the working bandwidth and noise level of the large-size magnetic sensor before the formal operation of the system to improve the quantitative accuracy of the observation signal and effectively evaluate the quality of the observation data. The precise testing and calibration of the magnetic sensor can, on the one hand, verify whether the technical indicators of the magnetic sensor meet the requirements of the electromagnetic detection system indicators, and on the other hand, obtain the precise quantitative response characteristics and data of the sensor, which can be used to obtain higher accuracy and higher reliability data processing and interpretation results in data processing.

[0004] The working bandwidth of the magnetic sensor is evaluated by its magnetic field conversion sensitivity curve, and is generally tested and calibrated using a "uniform magnetic field spiral tube coil" or "Hertz coil". An alternating current of known amplitude and frequency is input into the "uniform magnetic field spiral tube coil" or "Hertz coil" (called a calibration coil) to generate a certain magnetic field signal. The signal of the magnetic sensor placed inside the calibration coil is obtained, and the conversion coefficient of the magnetic sensor (usually a frequency-related curve, i.e., a magnetic field conversion sensitivity curve) is analyzed to obtain the working bandwidth of the magnetic sensor. However, the uniform magnetic field area of ​​the existing "uniform magnetic field spiral tube coil" or "Hertz coil" is relatively small, and most of the coil sizes are less than 2 meters. The uniform field space inside it that can be used for calibration is even smaller, so it is impossible to test and calibrate large-sized magnetic sensors with a diameter of more than several meters. At present, the quantitative test methods and technologies for the working bandwidth of large-sized magnetic sensors do not have high test accuracy.

[0005] In addition, the noise level test of magnetic sensors usually needs to be tested in a magnetic shielding space to eliminate the influence of interference electromagnetic fields in the environment on the noise test. The noise level test of small-sized magnetic sensors can be carried out in a magnetic shielding barrel or a magnetic shielding room, but for large-sized magnetic sensors with a diameter of more than several meters, there is no magnetic shielding room that can accommodate such large-sized magnetic sensors. The effective available space of the magnetic shielding room is usually less than 2 × 2 × 2 meters (length × width × height). Other super-large-sized shielding rooms are generally electromagnetic microwave darkrooms for high-frequency and radio frequency bands. For low-frequency magnetic shielding rooms, such shielding rooms are difficult to shield low-frequency environmental noise, so they cannot meet the high-precision noise level test requirements for low-frequency and low-noise magnetic sensors (such as large-sized low-frequency magnetic sensors that reach the femtosecond noise level). Therefore, the current sensor noise level test method technology under shielding room conditions is not suitable for the noise level test of large-sized and low-noise magnetic sensors in low-frequency electromagnetic detection systems. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method and device for calibrating the working bandwidth and noise level of a large-size magnetic sensor, and provides a detailed test method and calibration scheme, which can quantitatively test and calibrate the two important performance indicators of the working bandwidth and noise level of the magnetic sensor, thereby solving the problem that large-size, low-noise-level magnetic sensors cannot be quantitatively calibrated by conventional means. The method can be applied to the performance indicator testing and calibration of large-size magnetic field sensors in systems such as geophysical electromagnetic detection equipment.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A method for calibrating the working bandwidth and noise level of a large-size magnetic sensor, the method comprising:

[0009] Step 1, select a test environment and a test device type, and lay a transmitting current coil as a calibration loop in the test environment, and the test device type is used to place the calibration loop and the magnetic sensor to be tested;

[0010] Step 2: Inputting an alternating current into the calibration loop to generate a magnetic field signal to affect the standard magnetic sensor and the magnetic sensor to be tested, using a multi-channel receiver to synchronously collect voltage signals of the standard magnetic sensor and the magnetic sensor to be tested, and using the voltage signal to calibrate the working bandwidth of the magnetic sensor to be tested;

[0011] Step 3: Input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the magnetic sensor to be tested, use a multi-channel receiver to synchronously collect the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested, and perform correlation calculation to obtain the noise level of the magnetic sensor to be tested;

[0012] Wherein, the magnetic sensor to be tested is a large-size magnetic sensor, and the coil diameter of the large-size magnetic sensor is not less than 2 meters.

[0013] On the other hand, the present invention provides a device for calibrating the working bandwidth and noise level of a large-size magnetic sensor, comprising:

[0014] An equipment selection unit, used for selecting a test environment and a test device type, and laying a transmitting current coil as a calibration loop in the test environment, wherein the test device type is used for placing the calibration loop and the magnetic sensor to be tested;

[0015] a first signal acquisition unit, configured to input an alternating current into a calibration loop to generate a magnetic field signal to affect a standard magnetic sensor and a magnetic sensor to be tested, synchronously acquire voltage signals of the standard magnetic sensor and the magnetic sensor to be tested using a multi-channel receiver, and calibrate a working bandwidth of the magnetic sensor to be tested using the voltage signal;

[0016] The second signal acquisition unit is used to input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the magnetic sensor to be tested, and use a multi-channel receiver to synchronously acquire the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested and perform correlation calculation to obtain the noise level of the magnetic sensor to be tested; wherein the magnetic sensor to be tested is a large-size magnetic sensor, and the coil diameter of the large-size magnetic sensor is not less than 2 meters.

[0017] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned method for calibrating the working bandwidth and noise level of a large-size magnetic sensor.

[0018] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned method for calibrating the working bandwidth and noise level of a large-size magnetic sensor.

[0019] The beneficial effects of the present invention are:

[0020] The large-scale, high-precision magnetic sensor performance test and calibration method designed by the present invention can solve the calibration problem of the working bandwidth (including the conversion coefficient) of the large-scale magnetic sensor and the quantitative test problem of the noise level. It can provide a solution for the bandwidth calibration and quantitative test of the noise level of the large-scale magnetic sensor in the detection system such as airborne electromagnetic, and provide guidance for the optimization of the magnetic sensor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a flow chart of a method for calibrating the working bandwidth and noise level of a large-size magnetic sensor of the present invention;

[0022] Figure 2 It is a schematic diagram of the test scheme for the conversion coefficient of the concentric loop device;

[0023] Figure 3 It is a schematic diagram of the test scheme for the conversion coefficient of the dipole loop device;

[0024] Figure 4 This is a schematic diagram of the principle of noise level calibration for large-size magnetic sensors;

[0025] Figure 5 This is one of the conversion coefficient test results of the large-size magnetic sensor of the aeronautical magnetotelluric system in the embodiment of the present invention;

[0026] Figure 6 This is the second test result of the conversion coefficient of the large-size magnetic sensor of the aeronautical magnetotelluric system in the embodiment of the present invention;

[0027] Figure 7 This is a power spectrum density curve of the output voltage of the noise level test of the large-size magnetic sensor in the embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] Aiming at the problem that the high-precision performance indicators of large-size and low-noise-level magnetic sensors cannot be tested by traditional methods, the present invention proposes a method and device for calibrating the working bandwidth and noise level of large-size magnetic sensors. Figure 1 As shown, it is a flow chart of the method of the present invention. This scheme can quantitatively test and calibrate the two important performance indicators of the working bandwidth and noise level of the magnetic sensor, solving the problem that large-sized, low-noise-level magnetic sensors cannot be quantitatively calibrated by conventional means, and can be applied to the performance indicator test and calibration of large-sized magnetic field sensors in geophysical electromagnetic detection equipment and other systems. Based on the above settings, each step of the present invention is introduced as follows:

[0030] Step 1, select a test environment and a test device type, and lay a transmitting current coil as a calibration loop in the test environment, and the test device type is used to place the calibration loop and the magnetic sensor to be tested;

[0031] The working bandwidth index of the magnetic sensor is evaluated by testing the conversion coefficient curve characteristics of the external magnetic field amplitude into the voltage signal amplitude. The test scheme proposed by the present invention first requires two measurement conditions:

[0032] A standard small size magnetic sensor with known conversion coefficients Its working bandwidth basically covers the large-size magnetic sensor to be tested. , the magnetic sensor to be calibrated and measured is the large-size sensor. Small-size magnetic sensor The conversion coefficient can be obtained by using the current conventional test calibration method based on "uniform magnetic field spiral tube coil" or "Hertz coil". Here, as a distinction, the standard small size magnetic sensor Including coil-type magnetic sensors or magnetic rods, where the diameter of the coil-type magnetic sensor is less than 2 meters, and the large-size magnetic sensor Including magnetic sensors with coil diameter of 2 meters (inclusive) or more. A field environment with a large operating space and good electromagnetic environment to avoid the test work being affected by complex electromagnetic interference in the environment. The operating space of the field environment can meet the needs of laying a large-sized transmitting current coil on the ground (diameter is about 20-200 meters, different side lengths or diameters are selected according to the test frequency band). The transmitting current coil is called a calibration loop.

[0033] Step 2: Inputting an alternating current into the calibration loop to generate a magnetic field signal to affect the standard magnetic sensor and the magnetic sensor to be tested, using a multi-channel receiver to synchronously collect voltage signals of the standard magnetic sensor and the magnetic sensor to be tested, and using the voltage signal to calibrate the working bandwidth of the magnetic sensor to be tested;

[0034] The implementation plan for working bandwidth calibration is:

[0035] First, the large-size magnetic sensor to be calibrated Small size magnetic sensor with known conversion coefficient At the same time, place it in the center of the calibration loop (i.e. Figure 2 Schematic diagram of the concentric loop device shown in the figure) or placed at a farther position on one side of the calibration loop (i.e. Figure 3 ), the calibration loop is the transmitting current coil.

[0036] Secondly, an alternating current generator is used to pass alternating currents of different frequencies into the calibration loop to generate a magnetic field signal with a large amplitude in space to suppress the noise signals in the environment and the magnetic sensor itself, so that the small-sized magnetic sensor placed in the calibration loop and large size magnetic sensors A higher signal-to-noise ratio of the received signal can be obtained.

[0037] Then, a dual-channel signal receiver is used to synchronously collect the small-size magnetic sensor and large size magnetic sensors The voltage signal is a small-size magnetic sensor. and large size magnetic sensors It is obtained by converting the magnetic field signal of the environment through its own conversion coefficient.

[0038] for Figure 2 For concentric loop devices, it is advisable to use a calibration loop with a relatively large diameter to ensure that a uniform magnetic field signal is generated at the center of the loop. Figure 3 For dipole loop devices, a relatively large dipole distance (usually not less than 50 meters) is preferred to ensure that the calibration loop is within the range of the large-size magnetic sensor. The magnetic field at is uniform, Figure 3 One example is given, where the calibration loop is placed far away from the magnetic sensor to be tested (i.e., the large-size magnetic sensor to be calibrated). ) is greater than 50 meters. Thus, in the two test schemes, the large-size magnetic sensor and small size magnetic sensor The received magnetic field strength is equal.

[0039] ,

[0040] In the formula, Indicates the magnetic field strength ( , Magnetic sensor and Received magnetic field strength), The unit of magnetic field strength.

[0041] Use small size magnetic sensor The receiving response is used to calibrate large-size magnetic sensors response value to obtain a large-size magnetic sensor The conversion coefficient of the large-size magnetic sensor is then analyzed. working bandwidth.

[0042] For any frequency, large size magnetic sensor The received signal amplitude is , small size magnetic sensor The received signal amplitude is , small size magnetic sensor The conversion factor is The large-size magnetic sensor can be obtained by the following formula Conversion factor .

[0043] ,

[0044] ,

[0045] ,

[0046] Finally, by obtaining large-size magnetic sensors at different frequencies Conversion factor , the working bandwidth of the magnetic sensor can be determined according to its transfer function.

[0047] Step 3: Input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the large-size magnetic sensor to be calibrated. Use a multi-channel receiver to synchronously collect the output signals of the homogeneous magnetic sensor and the large-size magnetic sensor to be calibrated and perform correlation calculation to obtain the noise level of the large-size magnetic sensor to be calibrated.

[0048] The sensor noise test adopts a dual-sensor parallel noise test method and is tested based on a coherent noise power spectrum estimation algorithm.

[0049] The specific implementation steps of the noise level test are as follows:

[0050] First, select an environment away from strong interference and without near-field electromagnetic noise sources, use two large-size magnetic sensors of the same model, and use a parallel test method to test the noise level. The test principle is as follows: Figure 4 As shown. Place the large-sized magnetic sensor to be calibrated parallel to the ground. Homogeneous magnetic sensors . Homogeneous magnetic sensor Large magnetic sensor to be calibrated The hollow coil sensors are of the same model, same process and with high consistency. The magnetic sensor coils are placed parallel to each other and separated by a certain distance to eliminate mutual interference between the coils.

[0051] Secondly, the concentric loop device ( Figure 2 ) or dipole loop device ( Figure 3 ) Lay a large-sized calibration loop on the ground, and use an alternating current source to sequentially pass alternating currents of different frequencies through the calibration loop. The frequency value is selected based on the frequency band to be calibrated. Use a multi-channel synchronous signal receiver to collect homogeneous magnetic sensors Large-size magnetic sensor to be calibrated The output signal.

[0052] In theory, two coaxial or coplanar magnetic sensor coils placed close together in the same uniform magnetic field can receive magnetic field signals of the same intensity, synchronization, and coherence in the test environment. In addition to the environmental magnetic field signal, the output signal of the magnetic sensor coil also contains the noise signal of the magnetic sensor itself.

[0053] Two parallel magnetic sensor coils and Synchronous observation is performed. The measured signals include the environmental magnetic field signal and the noise signal of the magnetic sensor itself. Since the natural electromagnetic field is uniform within the measurement area, the measured magnetic field signal is fixed. The measured signal is expressed as follows:

[0054] ,

[0055] ,

[0056] in, Represents the environmental magnetic field signal, Represents parallel magnetic sensor coils and The noise signal itself.

[0057] The measured magnetic field signals are cross-correlated. For the same type of magnetic sensors, their noise level is not related to the external signal strength, and it is assumed that the noise signals of the two magnetic sensors themselves are and Not relevant:

[0058]

[0059]

[0060]

[0061] ,

[0062] and Magnetic sensor and The received signal, for and The cross-correlation function of Represents the environmental magnetic field signal, Indicates the magnetic sensor coil and The noise signal itself, Represents the autocorrelation function of the ambient magnetic field signal, Represents the ambient magnetic field signal and the magnetic sensor coil The cross-correlation function of the self-noise signal, Represents the ambient magnetic field signal and the magnetic sensor coil The cross-correlation function of the self-noise signal, Indicates the magnetic sensor coil and Cross-correlation function of the self-noise signal.

[0063] It can be seen that the actual measured signal contains noise The cross-correlation function is equal to the noise-free ambient magnetic field signal The autocorrelation function of .

[0064] Autocorrelation operation of the measured magnetic field signal:

[0065]

[0066]

[0067]

[0068] ,

[0069]

[0070]

[0071]

[0072] ,

[0073] Indicates magnetic sensor The autocorrelation function of the received signal, and Both represent the ambient magnetic field signal and the magnetic sensor coil The cross-correlation function of the self-noise signal, Indicates the magnetic sensor coil Autocorrelation function of the self-noise signal. Indicates magnetic sensor The autocorrelation function of the received signal, and Both represent the ambient magnetic field signal and the magnetic sensor coil The cross-correlation function of the self-noise signal, Indicates the magnetic sensor coil Autocorrelation function of the self-noise signal.

[0074] It can be seen that the autocorrelation function of the noisy magnetic field signal is equal to the sum of the autocorrelation function of the signal and the autocorrelation function of the random noise:

[0075] According to the above relationship, the random noise function of each magnetic sensor can be expressed by the difference between the autocorrelation function and the cross-correlation function of the measurement signal:

[0076] ,

[0077] ,

[0078] The homogeneous sensor and the large-size magnetic sensor to be calibrated are high-consistency coils that back up each other. , the noise level of the magnetic sensor can be obtained. By multiple measurements, some random coherent noise can be eliminated, and the measurement accuracy of the noise level can be further improved.

[0079] ,

[0080] In order to take into account the test plan and requirements of the noise level of the magnetic sensor, two magnetic sensors of the same type can be tested simultaneously when testing and calibrating the conversion coefficient and noise level of large-size magnetic sensors.

[0081] Preferably, the swept frequency alternating current source can be replaced by a pseudo-random signal generator and a power amplifier combination whose bandwidth meets the requirements;

[0082] The conversion coefficient used for calibration is known and the working bandwidth meets the requirements of small size magnetic sensor Commercial or independently developed standard magnetic sensors can be used instead, such as magnetic bars, small-sized magnetic sensor coils, etc.

[0083] The shape of the calibration loop in the concentric loop device and the dipole loop device is not limited to a rectangle or a circle, as long as the calibration loop generates a uniform magnetic field at the large-size magnetic sensor to be calibrated.

[0084] Example

[0085] The method of the present invention is used to test and calibrate the ultra-low noise level of the airborne magnetotelluric system and the working bandwidth and noise level of the ultra-large-size magnetic sensor. First, select a suitable test environment as required, and then measure and calibrate according to the above method. The working bandwidth test results of the magnetic sensor are as follows: Figure 5 and Figure 6 As shown in Table 1, the test results show that the sensor bandwidth is about 20 Hz-1000 Hz. The noise level test results of the magnetic sensor are shown in Table 1 and Figure 7 As shown, the test results show that the noise level of the sensor is about 7.6 fT / √Hz@75 Hz.

[0086] Table 1

[0087]

[0088] On the other hand, the present invention provides a device for calibrating the working bandwidth and noise level of a large-size magnetic sensor, wherein each module included in the device can implement each step of the aforementioned method, specifically including:

[0089] An equipment selection unit, used for selecting a test environment and a test device type, and laying a transmitting current coil as a calibration loop in the test environment, wherein the test device type is used for placing the calibration loop and the magnetic sensor to be tested;

[0090] a first signal acquisition unit, configured to input an alternating current into a calibration loop to generate a magnetic field signal to affect a standard magnetic sensor and a magnetic sensor to be tested, synchronously acquire voltage signals of the standard magnetic sensor and the magnetic sensor to be tested using a multi-channel receiver, and calibrate a working bandwidth of the magnetic sensor to be tested using the voltage signal;

[0091] The second signal acquisition unit is used to input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the magnetic sensor to be tested, and use a multi-channel receiver to synchronously acquire the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested and perform correlation calculation to obtain the noise level of the magnetic sensor to be tested; wherein the magnetic sensor to be tested is a large-size magnetic sensor, and the coil diameter of the large-size magnetic sensor is not less than 2 meters.

[0092] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned method for calibrating the working bandwidth and noise level of a large-size magnetic sensor.

[0093] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned method for calibrating the working bandwidth and noise level of a large-size magnetic sensor.

[0094] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for calibrating the working bandwidth and noise level of a large-size magnetic sensor, characterized in that: The method comprises: Step 1, select a test environment and a test device type, and lay a transmitting current coil as a calibration loop in the test environment, and the test device type is used to place the calibration loop and the magnetic sensor to be tested; Step 2: Inputting an alternating current into the calibration loop to generate a magnetic field signal to affect the standard magnetic sensor and the magnetic sensor to be tested, using a multi-channel receiver to synchronously collect voltage signals of the standard magnetic sensor and the magnetic sensor to be tested, and using the voltage signal to calibrate the working bandwidth of the magnetic sensor to be tested; Step 3: Input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the magnetic sensor to be tested, use a multi-channel receiver to synchronously collect the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested, and perform correlation calculation to obtain the noise level of the magnetic sensor to be tested; Wherein, the magnetic sensor to be tested is a large-size magnetic sensor, and the coil diameter of the large-size magnetic sensor is not less than 2 meters.

2. A method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 1, characterized in that: In the step 1, the test environment is an operating space that is large enough to lay a calibration loop, and the calibration loop is a transmitting current coil with a diameter of 20-200 meters.

3. The method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 1, characterized in that: The test device type in step 1 includes a concentric loop device or a dipole loop device.

4. The method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 1, characterized in that: The step 2 comprises: When the concentric loop device is selected, the magnetic sensor to be tested and the standard magnetic sensor are placed concentrically, coaxially and coplanarly, and the calibration loop is placed concentrically and coaxially with the magnetic sensor to be tested; when the dipole loop device is selected, the magnetic sensor to be tested and the standard magnetic sensor are placed concentrically, coaxially and coplanarly, and the calibration loop is placed at a position more than 50 meters away from the magnetic sensor to be tested; An alternating current generating device is used to input alternating currents of different frequencies into the calibration loop to generate a magnetic field signal in space; A dual-channel signal receiver is used to synchronously collect voltage signals of the standard magnetic sensor and the magnetic sensor to be tested; Using the voltage signal of the standard magnetic sensor to calibrate the response value of the magnetic sensor to be tested, and obtaining the conversion coefficient of the magnetic sensor to be tested; The conversion coefficient of the magnetic sensor to be tested at different frequencies is obtained, and the working bandwidth of the magnetic sensor to be tested is determined according to the conversion function.

5. A method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 4, characterized in that: The voltage signal is obtained by converting the magnetic field signal generated in the space by the standard magnetic sensor and the magnetic sensor to be tested through their own conversion coefficients.

6. A method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 4, characterized in that: The standard magnetic sensor is a magnetic sensor with a known conversion coefficient, and the working bandwidth of the standard magnetic sensor covers the magnetic sensor to be tested.

7. The method for calibrating the working bandwidth and noise level of a large-size magnetic sensor according to claim 1, characterized in that: The step 3 comprises: When the concentric loop device is selected, the calibration loop, the magnetic sensor to be tested, and the homogeneous magnetic sensor are placed concentrically and coaxially, wherein the magnetic sensor to be tested and the homogeneous magnetic sensor are placed parallel and not coplanar up and down; when the dipole loop device is selected, the magnetic sensor to be tested and the homogeneous magnetic sensor are placed parallel and not coplanar up and down, and the calibration loop is placed at a position more than 50 meters away from the magnetic sensor to be tested; An alternating current generating device is used to input alternating currents of different frequencies into the calibration loop to generate a magnetic field signal in space; A dual-channel signal receiver is used to synchronously collect output signals of a homogeneous magnetic sensor and a magnetic sensor to be tested, wherein the output signals include an ambient magnetic field signal and noise signals of the homogeneous magnetic sensor and the magnetic sensor to be tested; Cross-correlation operation and autocorrelation operation are performed on the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested, and a random noise function of the magnetic sensor to be tested is obtained based on the difference between the autocorrelation function and the cross-correlation function of the output signals.

8. A device for calibrating the working bandwidth and noise level of a large-size magnetic sensor, characterized in that: include: An equipment selection unit, used for selecting a test environment and a test device type, and laying a transmitting current coil as a calibration loop in the test environment, wherein the test device type is used for placing the calibration loop and the magnetic sensor to be tested; a first signal acquisition unit, configured to input an alternating current into a calibration loop to generate a magnetic field signal to affect a standard magnetic sensor and a magnetic sensor to be tested, synchronously acquire voltage signals of the standard magnetic sensor and the magnetic sensor to be tested using a multi-channel receiver, and calibrate a working bandwidth of the magnetic sensor to be tested using the voltage signal; The second signal acquisition unit is used to input an alternating current into the calibration loop to generate a magnetic field signal to affect the homogeneous magnetic sensor and the magnetic sensor to be tested, and use a multi-channel receiver to synchronously acquire the output signals of the homogeneous magnetic sensor and the magnetic sensor to be tested and perform correlation calculation to obtain the noise level of the magnetic sensor to be tested; wherein the magnetic sensor to be tested is a large-size magnetic sensor, and the coil diameter of the large-size magnetic sensor is not less than 2 meters.

9. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; When one or more programs are executed by the one or more processors, the one or more processors implement the method for calibrating the working bandwidth and noise level of a large-size magnetic sensor as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by the processor, the processor can implement the method for calibrating the working bandwidth and noise level of a large-size magnetic sensor as described in any one of claims 1-7.

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