Nuclear magnetic resonance angular velocity sensor system and relaxation error suppression method

Abstract

The invention provides a nuclear magnetic resonance angular velocity sensor system and a relaxation error suppression method. The nuclear magnetic resonance angular velocity sensor system comprises an atomic gas chamber, a lambda / 4 wave plate, a first laser, a second laser, a first collimating lens, a second collimating lens, a first linear polarizer, a second linear polarizer, a three-axis magnetic field coil, an oven, a photoelectric detector, a magnetic shielding barrel, a PBS and a balance photoelectric detector. A static magnetic field, a modulation magnetic field and pumping light are longitudinally applied to a nuclear magnetic resonance angular velocity sensor system; detecting light and a nucleon resonance magnetic field are transversely applied, so that the nuclear magnetic resonance angular velocity sensor is in a working state; the influence of electron spin relaxation time instability on nuclear precession frequency measurement is considered, a nuclear precession frequency measurement error is suppressed, and the angular velocity measurement performance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of atomic sensors, and in particular to a nuclear magnetic resonance angular velocity sensor system and a relaxation error suppression method. By appropriately matching a reference frequency with a nuclear precession frequency, the nuclear precession frequency measurement error caused by the instability of electron spin relaxation time is compensated, thereby improving the performance of the nuclear magnetic resonance angular velocity sensor. Background Art

[0002] In recent years, with the rapid development of atomic physics, atomic sensors have gradually received attention and importance; nuclear magnetic resonance angular velocity sensors, with their advantages of high precision and small size, are the development direction of inertial navigation in the future.

[0003] The angular velocity measurement of the sensor is obtained by extracting the precession frequency of 129Xe and 131Xe nucleons, and the nuclear precession signal is obtained by the embedded electron paramagnetic resonance magnetometer. The performance of the embedded magnetometer directly affects the measurement of the precession frequency of the nucleons. The electron spin relaxation time, as one of the key indicators of the magnetometer system, its instability will directly cause the measurement error of the nuclear magnetic resonance angular velocity sensor. Therefore, it is necessary to conduct applied research on the electron spin relaxation error suppression method. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a nuclear magnetic resonance angular velocity sensor system and a relaxation error suppression method, which overcomes the influence of the instability of electron spin relaxation time on the measurement of nuclear precession frequency, and compensates for the nuclear precession frequency measurement error caused by the instability of electron spin relaxation time by properly matching the reference frequency with the nuclear precession frequency, thereby greatly improving the measurement performance of angular velocity.

[0005] A nuclear magnetic resonance angular velocity sensor system and a relaxation error suppression method, wherein:

[0006] A nuclear magnetic resonance angular velocity sensor system, comprising:

[0007] Atomic gas chamber, λ / 4 wave plate, first laser, second laser, first collimating lens, second collimating lens, first linear polarizer, second linear polarizer, three-axis magnetic field coil, oven, photodetector, magnetic shielding barrel, PBS, balanced photodetector;

[0008] in:

[0009] The atomic gas chamber is used as: the atomic gas chamber of the nuclear magnetic resonance angular velocity sensor, which is the core sensitive element of the nuclear magnetic resonance angular velocity sensor;

[0010] The λ / 4 wave plate is used to provide circularly polarized pumping light;

[0011] The first laser is used to provide pumping light for the nuclear magnetic resonance angular velocity sensor;

[0012] The second laser is used as a detection light source to provide detection light;

[0013] The first collimating lens is used to collimate the pumping light;

[0014] The second collimating lens is used to collimate the detection light;

[0015] The first linear polarizer and the second linear polarizer are used to provide linear polarized light with a stable polarization state;

[0016] The three-axis magnetic field coil is used to generate a working magnetic field;

[0017] The oven is used for heat insulation of the atomic gas chamber;

[0018] The photoelectric detector is used for post-bubble detection in the pumping light path;

[0019] The magnetic shielding barrel is used to shield the environmental magnetic field;

[0020] The PBS and the balanced photodetector together constitute a balanced differential detection module for realizing the detection of magnetic field signals;

[0021] As an example, the working magnetic field includes: a static magnetic field, a modulation magnetic field, a nuclear resonance magnetic field and a reference magnetic field.

[0022] A relaxation error suppression method based on a nuclear magnetic resonance angular velocity sensor system includes:

[0023] Step 1: Apply a static magnetic field, a modulated magnetic field, and pumping light to the nuclear magnetic resonance angular velocity sensor system longitudinally; and apply detection light and a nuclear resonance magnetic field transversely, so that the nuclear magnetic resonance angular velocity sensor is in a working state.

[0024] Step 2: Obtain the nuclear precession signal, use a phase-locked loop to lock the nuclear precession phase, and obtain the nuclear precession frequency;

[0025] As an example, the nucleus includes: 129 Xe and 131 Xe.

[0026] As an example, since the nuclear magnetic resonance angular velocity sensor uses the nuclear precession signal to sense the angular velocity, the Bloch equation formula of the nuclear precession signal is designed as:

[0027]

[0028] Where: K + is the transverse magnetic moment of the nucleus, K zis the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, is the transversely applied nuclear resonance magnetic field, T2 is the transverse spin relaxation time of the nucleus, and B is the longitudinal static magnetic field.

[0029] Solving formula (1), we can get the expression of the nuclear precession signal on the x and y axes, as shown in formula (2):

[0030]

[0031] Where: K x is the x-axis magnetic moment of the nucleus, K y is the y-axis magnetic moment of the nucleus, K z is the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, B is the longitudinal static magnetic field, B i is the transversely applied nuclear resonance magnetic field amplitude, T2 is the nuclear transverse spin relaxation time, ω i is the nuclear resonance magnetic field frequency.

[0032] As an example, the formula for solving the precession frequency of the nucleus is designed as:

[0033]

[0034] Where: B is the longitudinal static magnetic field, ω r is the angular velocity, and β is the influence of the phase delay of the nuclear signal.

[0035] As an example, it can be seen from the formula (3) that the instability of the longitudinal static magnetic field will affect the precession frequency of the nuclei, so it is necessary to calculate the angular velocity ω caused by the longitudinal static magnetic field. r Measurement errors are suppressed; dual-nuclear 129 Xe and 131 The Xe differential angular velocity measurement method combines the nuclear gyromagnetic ratio characteristics to suppress the precession frequency error of the nucleus. The design formula (4) is as follows:

[0036]

[0037] Where: r ' is the measured angular velocity; this dual-nuclear differential method can eliminate the error caused by the unstable longitudinal static magnetic field B and improve the accuracy of angular velocity measurement.

[0038] As an example, since the error in the nuclear signal phase delay β and the difficulty in achieving the relationship between the nuclear transverse spin relaxation time and the nuclear gyromagnetic ratio are difficult to satisfy, the above error is difficult to eliminate through the dual-nuclear differential method, so the error in the nuclear signal phase delay β needs to be suppressed.

[0039] As an example, the nuclear magnetic resonance angular velocity sensor uses an embedded electron paramagnetic resonance magnetometer to measure the nuclear precession frequency. According to the electron spin Bloch equation, the electron magnetic moment signal can be obtained as shown in formula (5). The signal form at this time is used to analyze the nuclear precession signal.

[0040]

[0041] Where: M x is the electron magnetic moment signal, τ is the current electron spin relaxation time, M z is the z-axis electron magnetic moment, γ Rb is the gyromagnetic ratio of Rb, J i is a Bessel function with coefficient γ Rb B c / ω c , B c is the modulation magnetic field amplitude, ω c is the current modulation magnetic field frequency.

[0042] Step 3: Use the FID method to measure the transverse spin relaxation time of the nucleus, combine the nucleus gyromagnetic ratio and the precession frequency of the nucleus, and calculate the optimized reference signal frequency ω through the reference frequency selection formula. ref ';

[0043] The reference frequency selection formula is designed as:

[0044]

[0045] in, and Nucleon 129 Xe and nucleons 131 Xe transverse spin relaxation time, γ 129 and γ 131 Nucleon 129 Xe and nucleons 131 Gyromagnetic ratio of Xe, ω 129 and ω 131 Nucleon 129 Xe and nucleons 131 The precession frequency of Xe, γ Rb B is the resonance frequency of Rb, ω c0 is the initial modulation magnetic field frequency, ω c is the current modulation magnetic field frequency, τ0 is the initial electron spin relaxation time, and τ is the current electron spin relaxation time;

[0046] Step 4: Apply a transverse reference magnetic field to stabilize the reference signal phase, perform precise measurement of the nuclear precession frequency, and finally obtain the angular velocity signal.

[0047] Beneficial effects of the present invention:

[0048] Considering the influence of the instability of electron spin relaxation time on the measurement of nuclear precession frequency, a method for suppressing electron spin relaxation error based on reference frequency correction is proposed to suppress the measurement error of nuclear precession frequency and improve the angular velocity measurement performance.

[0049] This method is scientifically and reliably designed. By properly matching the reference frequency with the nuclear precession frequency, it compensates for the nuclear precession frequency measurement error caused by the instability of the electron spin relaxation time, greatly improving the angular velocity measurement performance and making it suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a general flow chart of a relaxation error suppression method for a nuclear magnetic resonance angular velocity sensor system.

[0051] Figure 2 This is a schematic diagram of the structure of a nuclear magnetic resonance angular velocity sensor system of the present invention. (Direction indications of coordinate axes x, y, and z are provided)

[0052] Figure 3 The present invention is a schematic diagram of the principle of a relaxation error suppression method for a nuclear magnetic resonance angular velocity sensor system using an FID method to measure the nuclear transverse spin relaxation time.

[0053] Figure 4 A primary demodulation result data diagram of an electron paramagnetic resonance magnetometer embedded in a relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system of the present invention; including nuclear 129 Xe precession signal and 131 The Xe precession signal is used to measure the precession frequency of nuclei and realize the selection of reference frequency.

[0054] Figure 5 The figure is a schematic diagram of the angular velocity measurement corresponding to the temperature fluctuation of the atomic gas chamber after selecting the reference frequency in a relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system of the present invention. DETAILED DESCRIPTION

[0055] Below, reference Figures 1 to 5 As shown, a nuclear magnetic resonance angular velocity sensor system and a relaxation error suppression method, wherein:

[0056] Reference Figure 2 As shown, a nuclear magnetic resonance angular velocity sensor system comprises:

[0057] Atomic gas chamber 101, λ / 4 wave plate 102, first laser 103, second laser 104, first collimating lens 105, second collimating lens 106, first linear polarizing plate 107, second linear polarizing plate 108, three-axis magnetic field coil 109, oven 110, photodetector 111, magnetic shielding barrel 112, PBS 113, balanced photodetector 114;

[0058] in:

[0059] The atomic gas chamber 101 is used as: the atomic gas chamber of the nuclear magnetic resonance angular velocity sensor, which is the core sensitive element of the nuclear magnetic resonance angular velocity sensor;

[0060] The λ / 4 wave plate 102 is used to provide circularly polarized pumping light;

[0061] The first laser 103 is used to provide pumping light for the nuclear magnetic resonance angular velocity sensor;

[0062] The second laser 104 is used as a detection light source to provide detection light;

[0063] The first collimating lens 105 is used to collimate the pumping light;

[0064] The second collimating lens 106 is used to collimate the detection light;

[0065] The first linear polarizer 107 and the second linear polarizer 108 are used to provide linear polarized light with stable polarization state;

[0066] The three-axis magnetic field coil 109 is used to generate a working magnetic field;

[0067] The oven 110 is used for heat insulation of the atomic gas chamber 101;

[0068] The photodetector 111 is used for post-bubble detection in the pumping light path;

[0069] The magnetic shielding barrel 112 is used to shield the environmental magnetic field;

[0070] The PBS 113 and the balanced photodetector 114 together constitute a balanced differential detection module for realizing the detection of magnetic field signals;

[0071] The nuclear magnetic resonance angular velocity sensor is put into operation by applying a static magnetic field, a modulated magnetic field, and pumping light longitudinally, and applying a detection light and a nuclear resonance magnetic field transversely.

[0072] As an example, the working magnetic field includes: a static magnetic field, a modulation magnetic field, a nuclear resonance magnetic field and a reference magnetic field.

[0073] Reference Figure 1As shown, a relaxation error suppression method for a nuclear magnetic resonance angular velocity sensor system comprises:

[0074] Step 1: Apply a static magnetic field, a modulated magnetic field, and pumping light to the nuclear magnetic resonance angular velocity sensor system longitudinally; and apply detection light and a nuclear resonance magnetic field transversely, so that the nuclear magnetic resonance angular velocity sensor is in a working state.

[0075] Step 2: Obtain the nuclear precession signal, use a phase-locked loop to lock the nuclear precession phase, and obtain the nuclear precession frequency;

[0076] As an example, the nucleus includes: 129 Xe and 131 Xe.

[0077] As an example, since the nuclear magnetic resonance angular velocity sensor uses the nuclear precession signal to sense the angular velocity, the Bloch equation formula of the nuclear precession signal is designed as:

[0078]

[0079] Where: K + is the transverse magnetic moment of the nucleus, K z is the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, B + is the transversely applied nuclear resonance magnetic field, B + =B i cosω i t, T2 is the transverse spin relaxation time of the nucleus, and B is the longitudinal static magnetic field.

[0080] Solving formula (1), we can get the expression of the nuclear precession signal on the x and y axes, as shown in formula (2):

[0081]

[0082] Where: K x is the x-axis magnetic moment of the nucleus, K y is the y-axis magnetic moment of the nucleus, K z is the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, B i is the transversely applied nuclear resonance magnetic field amplitude, ω i is the nuclear resonance magnetic field frequency, T2 is the nuclear transverse spin relaxation time, and B is the longitudinal static magnetic field.

[0083] As an example, the formula for solving the precession frequency of the nucleus is designed as:

[0084]

[0085] Where: B is the longitudinal static magnetic field, ω ris the angular velocity, and β is the influence of the phase delay of the nuclear signal.

[0086] As an example, it can be seen from the formula (3) that the instability of the longitudinal static magnetic field will affect the precession frequency of the nuclei, so it is necessary to calculate the angular velocity ω caused by the longitudinal static magnetic field. r Measurement errors are suppressed; dual-nuclear 129 Xe and 131 The Xe differential angular velocity measurement method combines the nuclear gyromagnetic ratio characteristics to suppress the precession frequency error of the nucleus. The design formula (4) is as follows:

[0087]

[0088] This dual-nuclear differential method can eliminate the error caused by the unstable static magnetic field B and improve the accuracy of angular velocity measurement.

[0089] As an example, since the error in the nuclear signal phase delay β and the difficulty in achieving the relationship between the nuclear transverse spin relaxation time and the nuclear gyromagnetic ratio are difficult to satisfy, the above error is difficult to eliminate through the dual-nuclear differential method, so the error in the nuclear signal phase delay β needs to be suppressed.

[0090] As an example, the nuclear magnetic resonance angular velocity sensor uses an embedded electron paramagnetic resonance magnetometer to measure the precession frequency of the nucleus. According to the Bloch equation, an electron magnetic moment signal can be obtained, as shown in formula (5);

[0091]

[0092] Among them: the electron magnetic moment signal is used to detect the precession signal of the nucleus and to measure the precession frequency of the nucleus.

[0093] Considering the transversely applied reference magnetic field The signal form at this time is used to analyze the nuclear precession signal.

[0094] As an example, in order to achieve nuclear resonance, a nuclear resonance magnetic field needs to be applied on the x-axis. At this time, the x-axis magnetic field signal contains two parts: the nuclear resonance magnetic field and the nuclear precession signal, and the y-axis magnetic field signal only contains the nuclear precession signal; the nuclear signal phase measurement is obtained by extracting the y-axis nuclear signal phase;

[0095] By demodulating formula (5) once, the y-axis magnetic field signal can be obtained, as shown in formula (6);

[0096]

[0097] Solving formula (6), we can get the reference magnetic field The phase information of the first demodulation process is used to detect the nucleus precession phase and the reference signal phase.

[0098] As an example, the precession frequency of the nucleus is equal to the nuclear resonance frequency, and the phase delay of the nuclear signal satisfies The phase of the measured signal is related to the frequency of the applied magnetic field signal. There are differences in the phase measurement values ​​corresponding to magnetic field signals of different frequencies; as shown in formula (7):

[0099]

[0100] Where: γ Rb B is the resonance frequency of Rb, ω c0 is the initial modulation magnetic field frequency, τ0 is the initial electron spin relaxation time, ω 129 is the resonance frequency of 129Xe, is the phase delay of 129Xe, ω 131 is the resonance frequency of 131Xe, is the phase delay of 131Xe. The above phase signal is the phase measurement value of each parameter obtained after the electron magnetic moment is demodulated once. The phase signal of 129Xe and 131Xe is used as the phase input of the phase-locked loop for the measurement of the nuclear precession frequency, and the reference signal phase is used to suppress the phase error of the electron paramagnetic resonance magnetometer.

[0101] During the measurement, parameter instabilities usually occur in the longitudinal static magnetic field B and the current electron spin relaxation time τ. The reference phase is locked by adjusting ω c When the longitudinal static magnetic field fluctuates, by adjusting ω c It can suppress the longitudinal static magnetic field error and eliminate the measurement signal phase error caused by the instability of the static magnetic field. When the current electron spin relaxation time changes, ω will also change to achieve reference phase stability. c .

[0102] As an example, due to the inconsistency between the reference signal and the precession frequency of the nucleus, 129 Xe and 131 The phase measurement error of Xe still exists. At this time, the detected nucleon precession phase signal is shown in formula (8):

[0103]

[0104] The above phase signals are the actual measured 129Xe and 131Xe phase values ​​when the electron spin relaxation time is unstable; the acquisition of the precession frequency of the nucleus is achieved through a phase-locked loop scheme.

[0105] As an example, the phase error measured by the electron paramagnetic resonance magnetometer is considered to be the phase delay of the nuclear signal. The nuclear phase delay error when the electron spin relaxation time changes is shown in formula (9):

[0106] Among them, the measured reference signal phase satisfies:

[0107] arctan(γ Rb B+ω c +ω ref )τ=arctan(γ Rb B+ω c0 +ω ref )τ0;

[0108]

[0109] The above nuclear phase delay error is introduced into formula (3) to calculate the nuclear precession frequency error.

[0110] The nuclear phase delay error will cause the nuclear precession frequency to shift, which will eventually lead to the angular velocity measurement error, as shown in formula (10):

[0111]

[0112] The above formula is used to express the angular velocity measurement error caused by the electron paramagnetic resonance magnetometer. By making the angular velocity measurement error zero, the error can be suppressed.

[0113] As an example, Formula 5 to Formula 10 are all used for analyzing the precession signal.

[0114] Step 3: Use the FID method to measure the transverse spin relaxation time of the nucleus, combine the nucleus gyromagnetic ratio and the precession frequency of the nucleus, and calculate the optimized reference signal frequency ω through the reference frequency selection formula. ref ';reference Figure 3 As shown; by fitting the envelope curve, the spin relaxation time of the nucleus is obtained;

[0115] The reference frequency selection formula is designed as formula (12):

[0116]

[0117] in, and Nucleon 129 Xe and nucleons 131 Xe transverse spin relaxation time, γ 129 and γ 131 Nucleon 129 Xe and nucleons 131 Gyromagnetic ratio of Xe, ω129 and ω 131 Nucleon 129 Xe and nucleons 131 The precession frequency of Xe, γ Rb B is the resonance frequency of Rb, ω c0 is the initial modulation magnetic field frequency, ω c is the current modulation magnetic field frequency, τ0 is the initial electron spin relaxation time, and τ is the current electron spin relaxation time;

[0118] As an example, the angular velocity measurement error Δω caused by the instability of the electron spin relaxation time is Error The reference signal frequency ω is included ref , by selecting a suitable reference frequency value, it satisfies Δω Error = 0, at which point the electron spin relaxation error is suppressed; the optimized reference frequency is selected as shown in formula (11):

[0119]

[0120] By selecting the reference frequency as the above parameters, the angular velocity error can be suppressed.

[0121] As an example, Formula 11 is a formula for selecting a reference frequency point, and Formula 12 is a simplified form of Formula 11.

[0122] Step 4: Apply a transverse reference magnetic field to stabilize the reference signal phase, perform precise measurement of the nuclear precession frequency, and finally obtain the angular velocity signal.

[0123] Reference Figure 4 As shown, the first demodulation result of the embedded electron paramagnetic resonance magnetometer includes 129 Xe and 131 The Xe precession signal is used to measure the precession frequency of nuclei and realize the selection of reference frequency.

[0124] It should be noted that, for the method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions involved are not necessarily required by the present application.

[0125] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0126] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0127] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0128] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0129] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0130] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0131] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0132] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nuclear magnetic resonance angular velocity sensor system, characterized in that: include: Atomic gas chamber, λ / 4 wave plate, first laser, second laser, first collimating lens, second collimating lens, first linear polarizer, second linear polarizer, three-axis magnetic field coil, oven, photodetector, magnetic shielding barrel, PBS, balanced photodetector; The atomic gas chamber is used as: an atomic gas chamber of a nuclear magnetic resonance angular velocity sensor; The λ / 4 wave plate is used to provide circularly polarized pumping light; The first laser is used to provide pumping light for the nuclear magnetic resonance angular velocity sensor; The second laser is used as a detection light source to provide detection light; The first collimating lens is used to collimate the pumping light; The second collimating lens is used to collimate the detection light; The first linear polarizer and the second linear polarizer are used to provide linear polarized light with a stable polarization state; The three-axis magnetic field coil is used to generate a working magnetic field; The oven is used for heat insulation of the atomic gas chamber; The photoelectric detector is used for post-bubble detection in the pumping light path; The magnetic shielding barrel is used to shield the environmental magnetic field; The PBS 113 and the balanced photodetector 114 together constitute a balanced differential detection module for realizing the detection of magnetic field signals; The nuclear magnetic resonance angular velocity sensor is put into operation by applying a static magnetic field, a modulated magnetic field, and pumping light longitudinally, and applying a detection light and a nuclear resonance magnetic field transversely.

2. A nuclear magnetic resonance angular velocity sensor system according to claim 1, characterized in that: The working magnetic field includes: a static magnetic field, a modulation magnetic field, a nuclear resonance magnetic field and a reference magnetic field.

3. A relaxation error suppression method for a nuclear magnetic resonance angular velocity sensor system according to claim 1, characterized in that: include: Step 1: applying a static magnetic field, a modulated magnetic field, and a pumping light to the nuclear magnetic resonance angular velocity sensor system longitudinally; and applying a detection light and a nuclear resonance magnetic field transversely, so that the nuclear magnetic resonance angular velocity sensor is in a working state; Step 2: Obtain the nuclear precession signal, use a phase-locked loop to lock the nuclear precession phase, and obtain the nuclear precession frequency; Step 3: Use the FID method to measure the transverse spin relaxation time of the nucleus, combine the nucleus gyromagnetic ratio and the precession frequency of the nucleus, and calculate the optimized reference signal frequency ω through the reference frequency selection formula. ref '; As shown in FIG3; By fitting the envelope curve, the transverse spin relaxation time of the nucleus is obtained; The reference frequency selection formula is designed as formula (12): in, and Nucleon 129 Xe and nucleons 131 Xe transverse spin relaxation time, γ 129 and γ 131 Nucleon 129 Xe and nucleons 131 Gyromagnetic ratio of Xe, ω 129 and ω 131 Nucleon 129 Xe and nucleons 131 The precession frequency of Xe, γ Rb B is the resonance frequency of Rb, ω c0 is the initial modulation magnetic field frequency, ω c is the current modulation magnetic field frequency, τ0 is the initial electron spin relaxation time, and τ is the current electron spin relaxation time; Step 4: Apply a transverse reference magnetic field to stabilize the reference signal phase, perform precise measurement of the nuclear precession frequency, and finally obtain the angular velocity signal.

4. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 3, characterized in that: The nucleus comprises: 129 Xe and 131 Xe.

5. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 4, characterized in that: Since the nuclear magnetic resonance angular velocity sensor uses the nuclear precession signal to sense the angular velocity, the Bloch equation formula of the nuclear precession signal is designed as: Where: K + is the transverse magnetic moment of the nucleus, K z is the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, B + is the transversely applied nuclear resonance magnetic field, B + =B i cosω i t, T2 is the transverse spin relaxation time of the nucleus, and B is the longitudinal static magnetic field; Solving formula (1), we can get the expression of the nuclear precession signal on the x and y axes, as shown in formula (2): Where: K x is the x-axis magnetic moment of the nucleus, K y is the y-axis magnetic moment of the nucleus, K z is the longitudinal magnetic moment of the nucleus, γ is the gyromagnetic ratio of the nucleus, B i is the transversely applied nuclear resonance magnetic field amplitude, ω i is the nuclear resonance magnetic field frequency, T2 is the nuclear transverse spin relaxation time, and B is the longitudinal static magnetic field.

6. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 5, characterized in that: The formula for solving the precession frequency of the nucleus is designed as: Where: B is the longitudinal static magnetic field, ω r is the angular velocity, β is the effect of the phase delay of the nuclear signal; It can be known from the formula (3) that the instability of the longitudinal static magnetic field will affect the precession frequency of the nuclei, so the angular velocity ω caused by the longitudinal static magnetic field needs to be r Measurement errors are suppressed; dual-nuclear 129 Xe and 131 The Xe differential angular velocity measurement method combines the nuclear gyromagnetic ratio characteristics to suppress the precession frequency error of the nucleus. The design formula (4) is as follows: This dual-nuclear differential method can eliminate the error caused by the unstable longitudinal static magnetic field B and improve the accuracy of angular velocity measurement.

7. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 6, characterized in that: Since the error of the nuclear signal phase delay β and the transverse spin relaxation time of the nucleus are difficult to satisfy the relationship of the nuclear gyromagnetic ratio, the above error is difficult to eliminate by the dual-nucleon differential method, so the error of the nuclear signal phase delay β needs to be suppressed.

8. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 7, characterized in that: The nuclear magnetic resonance angular velocity sensor uses an embedded electron paramagnetic resonance magnetometer to measure the precession frequency of the nucleus. According to the Bloch equation, an electron magnetic moment signal can be obtained, as shown in formula (5); Among them: M x is the electron magnetic moment signal, τ is the current electron spin relaxation time, M z is the z-axis electron magnetic moment, γ Rb is the gyromagnetic ratio of Rb, J i is a Bessel function with coefficient γ Rb B c / ω c , B c is the modulation magnetic field amplitude, ω c is the current modulation magnetic field frequency; Considering the transversely applied reference magnetic field The signal form at this time is used to analyze the nuclear precession signal.

9. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 8, characterized in that: In order to realize nuclear resonance, a nuclear resonance magnetic field needs to be applied on the x-axis. At this time, the x-axis magnetic field signal contains two parts: the nuclear resonance magnetic field and the nuclear precession signal, and the y-axis magnetic field signal only contains the nuclear precession signal. The nuclear signal phase measurement is obtained by extracting the y-axis nuclear signal phase. By demodulating formula (5) once, the y-axis magnetic field signal can be obtained, as shown in formula (6); Solving formula (6), we can get the reference magnetic field Phase information of The primary demodulation process is used to detect the phase of the nucleus precession and the phase of the reference signal.

10. The relaxation error suppression method of a nuclear magnetic resonance angular velocity sensor system according to claim 9, characterized in that: The precession frequency of the nucleus is equal to the nuclear resonance frequency, and the phase delay of the nuclear signal satisfies The phase of the measured signal is related to the frequency of the applied magnetic field signal. There are differences in the phase measurement values ​​corresponding to magnetic field signals of different frequencies; as shown in formula (7): Where: γ Rb B is the resonance frequency of Rb, ω c0 is the initial modulation magnetic field frequency, τ0 is the initial electron spin relaxation time, ω 129 is the resonance frequency of 129Xe, is the phase delay of 129Xe, ω 131 is the resonance frequency of 131Xe, is the phase delay of 131Xe; the above phase signal is the phase measurement value of each parameter obtained after the electron magnetic moment is demodulated once; the phase signals of 129Xe and 131Xe are used as the phase input of the phase-locked loop for the measurement of the nuclear precession frequency, and the reference signal phase is used to suppress the phase error of the electron paramagnetic resonance magnetometer; During the measurement, parameter instabilities usually occur in the longitudinal static magnetic field B and the current electron spin relaxation time τ. The reference phase is locked by adjusting ω c When the longitudinal static magnetic field fluctuates, by adjusting ω c It can suppress the longitudinal static magnetic field error and eliminate the phase error of the measurement signal caused by the instability of the longitudinal static magnetic field. When the current electron spin relaxation time changes, ω will also change to achieve reference phase stability. c ; Due to the inconsistency between the reference signal and the precession frequency of the nucleus, 129 Xe and 131 The phase measurement error of Xe still exists. At this time, the detected nucleon precession phase signal is shown in formula (8): The above phase signal is the actual measured phase value of 129Xe and 131Xe when the electron spin relaxation time is unstable. The acquisition of the precession frequency of the nucleus is achieved through a phase-locked loop scheme; The phase error measured by the electron paramagnetic resonance magnetometer is considered to be the phase delay of the nuclear signal. The nuclear phase delay error when the current electron spin relaxation time changes is shown in formula (9): Among them, the measured reference signal phase satisfies: arctan(γ Rb B+ω c +oh ref )τ=arctan(γ Rb B+ω c0 +oh ref )τ0; The above nucleon phase delay error is substituted into formula (3) to calculate the nucleon precession frequency error; The nuclear phase delay error will cause the nuclear precession frequency to shift, which will eventually lead to the angular velocity measurement error, as shown in formula (10): The above formula is used to express the angular velocity measurement error caused by the electron paramagnetic resonance magnetometer. By making the angular velocity measurement error 0, the error can be suppressed. Angular velocity measurement error Δω caused by the instability of electron spin relaxation time Error The reference frequency ω is included ref , by selecting a suitable reference frequency value, it satisfies Δω Error = 0, at which point the electron spin relaxation error is suppressed; the optimized reference frequency is shown in formula (11): By selecting the reference frequency as the above parameters, the angular velocity error can be suppressed.

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