CPT magnetometer-based magnetometric measurement method, system, and media

Abstract

The application provides a method and system for measuring weak magnetic field based on CPT magnetometer and a medium, and relates to the field of magnetic field measurement. The method is applied to a CPT magnetometer system, which comprises a CPT magnetometer and a three-axis coil. The method comprises: generating laser by the CPT magnetometer, modulating the laser, and applying an external magnetic field to be measured to obtain a plurality of CPT transmission signals; generating an auxiliary magnetic field by the three-axis coil; compensating the magnetic field to be measured by the auxiliary magnetic field to adjust the magnetic field to be measured to an ideal working area of the CPT magnetometer, and calculating the magnetic field to be measured according to the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, wherein the magnetic field to be measured adjusted to the ideal working area of the CPT magnetometer represents that two adjacent CPT transmission signals are completely separated.

Description

Technical Field

[0001] This application relates to the field of magnetic field metrology, and in particular to a weak magnetic field measurement method, system and medium based on a CPT magnetometer. Background Technology

[0002] The Coherent Population Trapping (CPT) effect is a quantum coherence effect. Utilizing the CPT and Zeeman effects, absolute measurements of external magnetic fields can be achieved. A CPT magnetometer is essentially an absolute magnetometer. The magnitude of the magnetic field is calculated based on the frequency difference between two adjacent CPT transmission peaks. For example, when the magnetic field direction is parallel to the optical field direction, scanning a microwave frequency yields three CPT transmission peaks. Assuming the frequency difference between two adjacent transmission peaks is... The measured magnetic field value is Normally, when the magnetic field is greater than 1000 nT, adjacent transmission peaks can be completely separated, allowing for accurate measurement of the magnetic field strength. However, when the magnetic field is small, such as 100 nT, the frequency difference between two adjacent peaks is 700 Hz. Since the CPT signal linewidth is typically between hundreds of Hz and thousands of Hz, the two CPT signals overlap, making it difficult to distinguish the frequencies corresponding to their peak values. This frequency difference introduces a significant error, ultimately leading to inaccurate magnetic field measurements. Figure 1 As shown, Figure 1 (a) in the image represents the CPT signal when the magnetic field is 1200 nT. Figure 1 (b) in the figure represents the CPT signal at a magnetic field of 120 nT. The frequency corresponding to the peak value of the CPT signal at 120 nT is difficult to distinguish. Existing solutions typically involve narrowing the CPT signal linewidth by adjusting parameters such as the atomic gas cell temperature, beam diameter, and optical power to achieve measurement.

[0003] However, the method of narrowing the CPT signal linewidth by adjusting parameters such as atomic gas cell temperature, beam diameter, and optical power to achieve weak magnetic field measurement has certain limitations, because the CPT linewidth cannot be narrowed indefinitely, so there is always a certain dead zone for weak magnetic field measurement. Summary of the Invention

[0004] In view of this, this application provides a weak magnetic field measurement method, system and medium based on a CPT magnetometer, which solves the problem of the dead zone in weak magnetic field measurement in related technologies.

[0005] In a first aspect, embodiments of this application provide a weak magnetic field measurement method based on a CPT magnetometer, applied to a CPT magnetometer system, the CPT magnetometer system including a CPT magnetometer and a triaxial coil, the method comprising: The CPT magnetometer generates laser light, modulates the laser light, and applies an external magnetic field to obtain multiple CPT transmission signals. An auxiliary magnetic field is generated by the triaxial coil; The auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. The magnetic field to be measured is calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer. The adjustment of the magnetic field to be measured to the ideal working area indicates that two adjacent CPT transmission signals are completely separated.

[0006] The method described in the embodiments of this application may also have the following additional technical features: In the above technical solution, optionally, the auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area, and the magnetic field to be measured is calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: Using the auxiliary magnetic field, compensation is applied to the magnetic field to be measured in multiple directions to adjust it to the ideal working area. In each direction, based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the magnetic field to be measured in that direction and the angle between the magnetic field to be measured and that direction are calculated. The angle range is... ; The final magnitude of the magnetic field to be measured is determined based on the magnitudes of the magnetic field measured in multiple directions.

[0007] In any of the above technical solutions, optionally, the multiple directions include the x-axis direction, the y-axis direction, and the z-axis direction.

[0008] In any of the above technical solutions, optionally, for the x-axis direction, the auxiliary magnetic field is used to compensate the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area, and the magnitude of the magnetic field to be measured in the direction and the angle between the magnetic field to be measured and the direction are calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: The first x-axis auxiliary magnetic field generated by the x-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the first total magnetic field. The second x-axis auxiliary magnetic field generated by the x-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the second total magnetic field. Based on the first x-axis auxiliary magnetic field, the first total magnetic field, the second x-axis auxiliary magnetic field, and the second total magnetic field, calculate the magnitude of the magnetic field to be measured in the x-axis direction and the angle between the magnetic field to be measured and the x-axis direction.

[0009] In any of the above technical solutions, optionally, for the y-axis direction, the auxiliary magnetic field is used to compensate the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area, and the magnitude of the magnetic field to be measured in the direction of the auxiliary magnetic field and the angle between the magnetic field to be measured and the direction are calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: The first y-axis auxiliary magnetic field generated by the y-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the third total magnetic field. The second y-axis auxiliary magnetic field generated by the triaxial coil in the y-axis direction is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the fourth total magnetic field. Based on the first y-axis auxiliary magnetic field, the third total magnetic field, the second y-axis auxiliary magnetic field, and the fourth total magnetic field, calculate the magnitude of the magnetic field to be measured in the y-axis direction and the angle between the magnetic field to be measured and the y-axis direction.

[0010] In any of the above technical solutions, optionally, for the z-axis direction, the auxiliary magnetic field is used to compensate the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area, and the magnitude of the magnetic field to be measured in the direction and the angle between the magnetic field to be measured and the direction are calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: The first z-axis auxiliary magnetic field generated by the z-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the fifth total magnetic field. The second z-axis auxiliary magnetic field generated by the z-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the sixth total magnetic field. Based on the first z-axis auxiliary magnetic field, the fifth total magnetic field, the second z-axis auxiliary magnetic field, and the sixth total magnetic field, calculate the magnitude of the magnetic field to be measured in the z-axis direction and the angle between the magnetic field to be measured and the z-axis direction.

[0011] In any of the above technical solutions, optionally, the final magnitude of the magnetic field to be measured is determined based on the magnitudes of the auxiliary measurements of the magnetic field to be measured in multiple directions, including: The final magnitude of the magnetic field to be measured is one of the three auxiliary measurements in the three directions, or the average of two or three of the auxiliary measurements in the three directions is taken as the final magnitude of the magnetic field to be measured.

[0012] Secondly, embodiments of this application provide a CPT magnetometer system that implements the steps of the method described in the first aspect.

[0013] Optionally, in the above technical solution, the CPT magnetometer system includes a CPT magnetometer and a triaxial coil, wherein the triaxial coil is disposed on the outer periphery of the oven of the CPT magnetometer.

[0014] Thirdly, embodiments of this application provide a readable storage medium having a program or instructions stored thereon, characterized in that the program or instructions, when executed by a processor, implement the steps of the method as described in the first aspect.

[0015] The magnetic field weakening measurement method, CPT magnetometer system, and readable storage medium based on the embodiments of this application can solve the problem of two CPT signals not being completely distinguishable, reduce frequency difference errors, and improve the accuracy of magnetic field measurement values. Furthermore, this application does not use a method of narrowing the CPT signal linewidth by adjusting parameters such as atomic gas cell temperature, beam diameter, and optical power to achieve magnetic field weakening measurement, thus avoiding the problem of a certain dead zone in magnetic field weakening measurement caused by the inability to infinitely narrow the CPT linewidth.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram of CPT signals under a magnetic field of 1200 nT and a magnetic field of 120 nT is shown; Figure 2 A schematic diagram of the structure of the CPT magnetometer system according to an embodiment of this application is shown; Figure 3 A flowchart illustrating a weak magnetic field measurement method based on a CPT magnetometer according to an embodiment of this application is shown. Figure 4 A schematic diagram of weak magnetic field-assisted measurement according to an embodiment of this application is shown. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0019] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] To address the measurement dead zone issue of CPT magnetometers in weak magnetic regions, this application adjusts the CPT magnetometer to its ideal operating region, ensuring complete separation and no overlap between adjacent CPT transmission peaks. This is achieved by adding a bias magnetic field to the system.

[0021] The following description, in conjunction with the accompanying drawings, details the weak magnetic field measurement method, CPT magnetometer system, and readable storage medium based on the CPT magnetometer provided in this application through specific embodiments and application scenarios. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] This application provides a weak magnetic field measurement method based on a CPT magnetometer, applied to a CPT magnetometer system, such as... Figure 2 As shown, the CPT magnetometer system includes a CPT magnetometer and a triaxial coil 111. The CPT magnetometer includes a VCSEL controller 101, an RF-DC combiner 102, an RF signal generator 103, a triangular wave signal generator 104, a data acquisition device 105, a polarizer 106, a photoelectric detection amplifier 107, a gas chamber 108, an oven 109, and a laser 110.

[0023] like Figure 3 As shown in the embodiments of this application, the weak magnetic field measurement method based on a CPT magnetometer includes: Step 301: A laser is generated using a CPT magnetometer, and the laser is modulated and an external magnetic field to be measured is applied to obtain multiple CPT transmission signals.

[0024] The CPT magnetometer utilizes the interference effect between atomic energy levels for rubidium-87 ( 87 To obtain Rb atoms, it is necessary to generate multicolor light that satisfies the hyperfine energy level frequency difference. In this step, laser 110 emits laser light with a wavelength of 794.978 nm. A 3.417 GHz microwave signal generated by radio frequency signal generator 103 is used to half-wave modulate the laser frequency, resulting in a frequency difference of 6.834 GHz between the two bands, which roughly satisfies the hyperfine energy level difference. Then, the signal from triangular wave signal generator 104 is modulated onto radio frequency signal generator 103 for secondary modulation to achieve scanning of the multicolor light field. When the laser passes through a region containing Rb atoms... 87 The gas chamber 108 of Rb atoms can generate the CPT phenomenon due to the Zeeman effect. The absolute value of the magnetic field can be obtained by comparing the frequency difference between adjacent signal peaks of CPT.

[0025] It should be noted that the magnetic field to be measured is applied to a surface containing... 87 The space environment in which the Rb atom's gas chamber 108 is located.

[0026] It is worth noting that when a magnetic field is applied, for 87 Rb atom, magnetic quantum number m F The frequency differences of the Zeeman sublevels at ±1, ±2, and ±3 change with the magnetic field, resulting in a frequency shift. The CPT signal generated is a magnetic susceptibility signal, while m F The frequency difference between Zeeman sublevels with a value of 0 remains constant, always equal to the frequency difference between the hyperfine sublevels. The resulting CPT signal is a magnetically insensitive signal, so the magnitude of the magnetic field can be calculated from the frequency difference between the magnetically sensitive and magnetically insensitive signals. However, when the magnetic field is sufficiently small, such as 100 nT, the CPT signal has a certain linewidth due to its Lorentz shape, causing two CPT signals to overlap and become indistinguishable.

[0027] Step 302: An auxiliary magnetic field is generated by a triaxial coil.

[0028] In this step, to address the issue of the two CPT signals not being fully distinguishable, a triaxial coil is set up in the CPT magnetometer system for subsequent auxiliary measurements. The triaxial coil is used to generate an auxiliary magnetic field.

[0029] Step 303: Compensate the magnetic field to be measured using an auxiliary magnetic field to adjust the magnetic field to be measured to the ideal working area, and calculate the magnetic field to be measured based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer. The adjustment of the magnetic field to be measured to the ideal working area indicates that the two adjacent CPT transmission signals are completely separated.

[0030] In this embodiment, a triaxial coil is used for magnetic field compensation to bring the magnetic field to be measured into the ideal working region, that is, to completely separate two adjacent CPT transmission peaks without overlap. Then, based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude and direction of the weak magnetic field to be measured are calculated.

[0031] This application's embodiments can solve the problem of two CPT signals not being completely distinguishable, reduce frequency difference errors, and improve the accuracy of magnetic field measurements. Furthermore, this application does not use a method of narrowing the CPT signal linewidth by adjusting parameters such as atomic gas cell temperature, beam diameter, and optical power to achieve weak magnetic field measurement, thus avoiding the problem of a certain dead zone in weak magnetic field measurement caused by the inability to infinitely narrow the CPT linewidth.

[0032] To ensure the accuracy of the measured magnetic field, the effectiveness of this method was theoretically analyzed. In a CPT magnetometer system, the CPT signal has only one peak when there is no external magnetic field, but multiple transmission peaks exist when an external magnetic field is present. The magnitude of the external magnetic field can be calculated based on the frequency difference between the peaks. When the external magnetic field is small, such as 100 nT, the spacing between the peaks is small and difficult to distinguish due to the influence of the CPT signal linewidth, making the measurement quite difficult.

[0033] Therefore, by using an external triaxial coil to generate an auxiliary magnetic field, the magnetometer can be brought into the ideal working region to compensate for the magnetic field to be measured. Subsequently, the magnitude and direction of the magnetic field can be measured using the cosine theorem. This method can also be applied to other magnetometers that measure absolute magnetic fields, and has high extensibility and practical value.

[0034] In one embodiment of this application, step 303 involves compensating for the magnetic field to be measured using an auxiliary magnetic field to adjust it to the ideal operating range, and calculating the magnetic field to be measured based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: Step 3031: Using an auxiliary magnetic field, compensate for the magnetic field to be measured in multiple directions to adjust it to the ideal working area. In each direction, based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, calculate the magnitude of the auxiliary measurement of the magnetic field to be measured in the target direction and the angle between the magnetic field to be measured and the target direction. The angle range is... .

[0035] Among them, multiple directions include the x-axis direction, the y-axis direction, and the z-axis direction.

[0036] In one embodiment, an auxiliary magnetic field is used to compensate for the magnetic field under test, adjusting it to the ideal working area. Based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the auxiliary measurement of the magnetic field under test in the target direction and the angle between the magnetic field under test and the target direction are calculated. This includes: using a first auxiliary magnetic field generated by the triaxial coil in the target direction to perform a first compensation on the magnetic field under test, adjusting it to the ideal working area, and recording the total magnetic field measured by the CPT magnetometer; using a second auxiliary magnetic field generated by the triaxial coil in the target direction to perform a second compensation on the magnetic field under test, adjusting it to the ideal working area, and recording the total magnetic field measured by the CPT magnetometer; and using the first auxiliary magnetic field, the second auxiliary magnetic field, and the total magnetic field recorded twice to calculate the magnitude of the auxiliary measurement of the magnetic field under test in the target direction and the angle between the magnetic field under test and the target direction.

[0037] Specifically, in the x-axis direction, a first x-axis auxiliary magnetic field generated by the triaxial coil in the x-axis direction is used for the first compensation of the magnetic field to be measured, adjusting the magnetic field to be measured to the ideal working area. The total magnetic field measured by the CPT magnetometer at this time is the first total magnetic field. A second x-axis auxiliary magnetic field generated by the triaxial coil in the x-axis direction is used for the second compensation of the magnetic field to be measured, adjusting the magnetic field to be measured to the ideal working area. The total magnetic field measured by the CPT magnetometer at this time is the second total magnetic field. Based on the first x-axis auxiliary magnetic field, the first total magnetic field, the second x-axis auxiliary magnetic field, and the second total magnetic field, the magnitude of the auxiliary measurement of the magnetic field to be measured in the x-axis direction and the angle between the magnetic field to be measured and the x-axis direction are calculated. The first x-axis auxiliary magnetic field and the second x-axis auxiliary magnetic field are different.

[0038] For the y-axis direction, a first y-axis auxiliary magnetic field generated by the triaxial coil in the y-axis direction is used for the first compensation of the magnetic field to be measured, adjusting the magnetic field to be measured to the ideal working area. The total magnetic field measured by the CPT magnetometer at this time is the third total magnetic field. A second y-axis auxiliary magnetic field generated by the triaxial coil in the y-axis direction is used for the second compensation of the magnetic field to be measured, adjusting the magnetic field to be measured to the ideal working area. The total magnetic field measured by the CPT magnetometer at this time is the fourth total magnetic field. Based on the first y-axis auxiliary magnetic field, the third total magnetic field, the second y-axis auxiliary magnetic field, and the fourth total magnetic field, the magnitude of the auxiliary measurement of the magnetic field to be measured in the y-axis direction and the angle between the magnetic field to be measured and the y-axis direction are calculated. Note that the first y-axis auxiliary magnetic field and the second y-axis auxiliary magnetic field are different.

[0039] For the z-axis direction, the first z-axis auxiliary magnetic field generated by the triaxial coil in the z-axis direction performs the first compensation for the magnetic field to be measured, adjusting it to the ideal working area. The total magnetic field measured by the CPT magnetometer at this point is the fifth total magnetic field. The second z-axis auxiliary magnetic field generated by the triaxial coil in the z-axis direction performs the second compensation for the magnetic field to be measured, adjusting it to the ideal working area. The total magnetic field measured by the CPT magnetometer at this point is the sixth total magnetic field. Based on the first z-axis auxiliary magnetic field, the fifth total magnetic field, the second z-axis auxiliary magnetic field, and the sixth total magnetic field, the magnitude of the auxiliary measurement of the magnetic field to be measured in the z-axis direction and the angle between the magnetic field to be measured and the z-axis direction are calculated. Note that the first z-axis auxiliary magnetic field and the second z-axis auxiliary magnetic field are different.

[0040] For example, such as Figure 4 As shown, B0 is the unknown magnetic field to be measured. A magnetic field of a certain magnitude is generated along any axis of the three-axis coil, such as the x-axis, to assist B0'. This magnetic field is sufficient to completely separate the two CPT signals. Since a new magnetic field is generated in the system, the total magnetic field becomes B1, and magnetic field B1 can be directly measured by the CPT magnetometer. Thus, the known quantities B0' and B1 are obtained. The previously added auxiliary magnetic field B0' is removed, and an auxiliary magnetic field B1' is generated by the x-axis coil, where B0' ≠ B1'. At this time, the CPT magnetometer measures the total magnetic field as B2, thus obtaining the known quantities B1' and B2.

[0041] Therefore, B0', B1, B1', and B2 are all known quantities. To obtain the magnetic field B0 to be measured, it can be solved using the law of cosines. For example... Figure 4 As shown, in triangles AOC and AOD, according to the Law of Cosines: (1) (2) By combining the two equations above, we can obtain the measured magnetic field B0 and... The value of the magnetic field B0 to be measured, and the angle between the magnetic field B0 and the x-axis. Thus, the magnitude of the magnetic field B0 to be measured and its angle with the x-axis are obtained.

[0042] Similarly, by repeating the auxiliary measurement operation in the x direction in the y and z directions, the magnitude of the magnetic field B0 to be measured and its angle with the y-axis, as well as the magnitude of the magnetic field B0 to be measured and its angle with the z-axis, can be calculated.

[0043] Based on the auxiliary measurements of the magnitude of the magnetic field B0 to be measured in the x-direction, the y-direction, and the z-direction, the final value of the magnetic field B0 to be measured is determined. Furthermore, based on the angles between the magnetic field B0 to be measured and the x-axis, the y-axis, and the z-axis, the direction of the magnetic field B0 to be measured is determined.

[0044] Step 3032: Determine the final magnitude of the magnetic field to be measured based on the magnitude of the magnetic field measured in multiple directions.

[0045] In this step, the final magnitude of the magnetic field to be measured can be determined based on one or more of the auxiliary measurements taken in multiple directions. For example, one of the auxiliary measurements in multiple directions can be used as the final magnitude of the magnetic field to be measured. Alternatively, to minimize experimental error, the average of two or three of the auxiliary measurements taken in the x-axis, y-axis, and z-axis directions can be calculated, and the average value can be used as the final magnitude of the magnetic field to be measured.

[0046] This application also provides a CPT magnetometer system, which implements all the steps of the above-mentioned weak magnetic field measurement method based on CPT magnetometer and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0047] Furthermore, the CPT magnetometer system includes a CPT magnetometer and a triaxial coil, which is located on the outer periphery of the oven of the CPT magnetometer.

[0048] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described weak magnetic field measurement method based on a CPT magnetometer and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0049] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0050] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for measuring weak magnetic fields based on a CPT magnetometer, characterized in that, Applied to a CPT magnetometer system, the CPT magnetometer system including a CPT magnetometer and a triaxial coil, the method includes: The CPT magnetometer generates laser light, modulates the laser light, and applies an external magnetic field to obtain multiple CPT transmission signals. An auxiliary magnetic field is generated by the triaxial coil; The auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. The magnetic field to be measured is calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer. The adjustment of the magnetic field to be measured to the ideal working area indicates that two adjacent CPT transmission signals are completely separated.

2. The weak magnetic field measurement method according to claim 1, characterized in that, The auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. The magnetic field to be measured is then calculated based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, including: Using the auxiliary magnetic field, compensation is applied to the magnetic field to be measured in multiple directions to adjust it to the ideal working area. In each direction, based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the magnetic field to be measured in that direction and the angle between the magnetic field to be measured and that direction are calculated. The angle range is... ; The final magnitude of the magnetic field to be measured is determined based on the magnitudes of the magnetic field measured in multiple directions.

3. The weak magnetic field measurement method according to claim 2, characterized in that, Multiple directions include the x-axis, y-axis, and z-axis.

4. The weak magnetic field measurement method according to claim 3, characterized in that, For the x-axis direction, the auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. Based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the magnetic field to be measured in the auxiliary measurement in that direction and the angle between the magnetic field to be measured and the direction are calculated, including: The first x-axis auxiliary magnetic field generated by the x-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the first total magnetic field. The second x-axis auxiliary magnetic field generated by the x-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the second total magnetic field. Based on the first x-axis auxiliary magnetic field, the first total magnetic field, the second x-axis auxiliary magnetic field, and the second total magnetic field, calculate the magnitude of the magnetic field to be measured in the x-axis direction and the angle between the magnetic field to be measured and the x-axis direction.

5. The weak magnetic field measurement method according to claim 3, characterized in that, For the y-axis direction, the auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. Based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the magnetic field to be measured in the auxiliary measurement direction and the angle between the magnetic field to be measured and the direction are calculated, including: The first y-axis auxiliary magnetic field generated by the y-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the third total magnetic field. The second y-axis auxiliary magnetic field generated by the triaxial coil in the y-axis direction is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the fourth total magnetic field. Based on the first y-axis auxiliary magnetic field, the third total magnetic field, the second y-axis auxiliary magnetic field, and the fourth total magnetic field, calculate the magnitude of the magnetic field to be measured in the y-axis direction and the angle between the magnetic field to be measured and the y-axis direction.

6. The weak magnetic field measurement method according to claim 3, characterized in that, For the z-axis direction, the auxiliary magnetic field is used to compensate for the magnetic field to be measured, so as to adjust the magnetic field to be measured to the ideal working area. Based on the auxiliary magnetic field and the total magnetic field measured by the CPT magnetometer, the magnitude of the magnetic field to be measured in the auxiliary measurement direction and the angle between the magnetic field to be measured and the direction are calculated, including: The first z-axis auxiliary magnetic field generated by the z-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the first time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the fifth total magnetic field. The second z-axis auxiliary magnetic field generated by the z-axis direction of the triaxial coil is used to compensate the magnetic field to be measured for the second time, so as to adjust the magnetic field to be measured to the ideal working area. At this time, the total magnetic field measured by the CPT magnetometer is the sixth total magnetic field. Based on the first z-axis auxiliary magnetic field, the fifth total magnetic field, the second z-axis auxiliary magnetic field, and the sixth total magnetic field, calculate the magnitude of the magnetic field to be measured in the z-axis direction and the angle between the magnetic field to be measured and the z-axis direction.

7. The weak magnetic field measurement method according to claim 3, characterized in that, The final magnitude of the magnetic field to be measured is determined based on the magnitudes of the auxiliary measurements taken in multiple directions, including: The final magnitude of the magnetic field to be measured is one of the three auxiliary measurements in the three directions, or the average of two or three of the auxiliary measurements in the three directions is taken as the final magnitude of the magnetic field to be measured.

8. A CPT magnetometer system, characterized in that, The CPT magnetometer system implements the steps of the weak magnetic field measurement method based on the CPT magnetometer as described in any one of claims 1 to 7.

9. The weak magnetic field measurement method according to claim 8, characterized in that, The CPT magnetometer system includes a CPT magnetometer and a triaxial coil, the triaxial coil being disposed on the outer periphery of the oven of the CPT magnetometer.

10. A readable storage medium having a program or instructions stored thereon, characterized in that, When the program or instructions are executed by the processor, they implement the steps of the weak magnetic field measurement method based on the CPT magnetometer as described in any one of claims 1 to 7.

Images