Magnetic field control self-checking system and method for nuclear magnetic resonance gyroscope

Abstract

The invention provides a magnetic field control self-checking system and method for a nuclear magnetic resonance gyroscope, and belongs to the technical field of nuclear magnetic resonance gyroscopes, test parameters are input from an upper computer, an AD signal acquisition circuit converts triaxial magnetic field driving current into digital signals, and the digital signals are simultaneously transmitted to an FPGA operation core; according to the magnetic moment precession amplitude-frequency equation, magnetic moment precession signals are calculated through the test parameters and the digital signals; the amplitude, the frequency and the phase information of the signal are input into the gyro output signal generation module; generating a high-frequency carrier sinusoidal signal carrying low-frequency change characteristics from the amplitude, frequency and phase information of the magnetic moment precession signal through a CORDIC algorithm, and simulating a gyro output signal; and the DA conversion circuit outputs a simulated gyro output signal to test the magnetic field control system, so that rapid self-inspection and performance optimization of the magnetic field control system without real operation of gyro equipment are realized, and the system is used for independent test and evaluation of the magnetic field control system and is suitable for popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear magnetic resonance gyroscopes, and in particular to a magnetic field control self-checking system and method for a nuclear magnetic resonance gyroscope. Background Art

[0002] With its advantages of high precision, small size and low cost, the nuclear magnetic resonance gyroscope is expected to become the core of the chip-level navigation system. The nuclear magnetic resonance gyroscope uses the fixed axis and fixedness of the atomic Larmor precession angular velocity under a constant magnetic field to achieve inertial measurement, and converts the detection laser that irradiates the atomic gas chamber and carries the precession information into photoelectric conversion. Then, the Larmor precession frequency and magnetic field information measured in the gyroscope output signal are extracted by means of magnetic field control, thereby realizing angular velocity measurement and magnetic field control.

[0003] The main function of the magnetic field control system is to calculate the nuclear precession frequency and angular velocity based on the optical detection signal, and to perform closed-loop control of the three-axis magnetic field passing through the gas chamber. Since the performance of the magnetic field control system directly affects the accuracy of the nuclear magnetic resonance gyroscope, the evaluation of the magnetic field control effect is very important.

[0004] The errors of the NMR gyroscope can be divided into two categories:

[0005] One type is closed-loop output error, including magnetic compensation stability and magnetic resonance measurement stability, which is determined by the performance of the magnetic field control system;

[0006] The other type is the error in the nuclear resonator, which mainly comes from the gyro head, including main magnetic field fluctuations, optical frequency shift, main magnetic field inhomogeneity, electron spin magnetic field error, electric quadrupole moment frequency shift and main magnetic field drift.

[0007] The purpose of testing the magnetic field control system is to optimize the magnetic field control hardware and algorithm based on the closed-loop output error. However, the aliasing and superposition of the above-mentioned multiple errors in the nuclear resonator are reflected in the frequency and amplitude of the gyroscope output signal, which brings great difficulties to the testing and evaluation of the magnetic field control system.

[0008] Similar challenges exist in testing the signal processing of other sensors. To overcome the difficulties in testing the signal processing due to the difficulty in obtaining sensor signals or error aliasing, the following technical architecture solutions have been developed:

[0009] ①A radar target simulator amplitude and phase correction method and FPGA implementation structure (CN202411341156.6);

[0010] Because weather radar systems are large, consume high power, and have complex startup procedures, radar simulators are typically used to simulate radar echo signals to test components in the signal processing stages of weather radar systems. This invention proposes an amplitude-phase correction method for radar signal simulation. This method measures the signal frequency, searches for the corresponding amplitude-frequency correction coefficients stored in an FPGA, and implements real-time amplitude-phase correction through complex multiplication.

[0011] However, the table lookup resolution of the above scheme is too low, which easily leads to insufficient accuracy of the analog signal. If the accuracy of the coefficient table is improved, the storage resources will increase significantly. When this scheme is used to simulate the gyroscope output signal, in addition to the resolution problem, there is also the disadvantage that the amplitude-frequency correction coefficient table must be updated to simulate the magnetic field error.

[0012] ② A Hall-effect wheel speed sensor signal simulation system (CN202410814176.4);

[0013] Since the testing of automobile safety systems such as anti-lock braking systems, engine management systems, and transmission control systems requires signal wheels, which are expensive and difficult to control, this invention proposes a Hall-type wheel speed sensor signal simulation system. The ZYNQ main control module controls the external output time of the three constant current source modules within a cycle to change the output current size, and then the signal output module generates a Hall wheel speed simulation signal based on the current.

[0014] However, the signals simulated by this invention are square waves and trapezoidal waves, while the output signal of the nuclear magnetic resonance gyroscope is essentially a form of a high-frequency sinusoidal carrier signal modulating a low-frequency sinusoidal quantity. Therefore, this solution cannot simulate the gyroscope output signal.

[0015] There are two typical methods for testing magnetic field control systems:

[0016] One approach is to directly test the magnetic field control system using the gyrometer output signal. This method can measure the dynamic performance of the magnetic field control system. However, the wide variety of errors in the gyrometer output signal, the aliasing of multiple errors, and the resulting signal inconsistencies present significant challenges in testing the magnetic field control system and its control parameters. Furthermore, the combined influence of the gyrometer's internal parameters makes it difficult to assess the impact of changing just one parameter on the magnetic field control system.

[0017] Another method is to use a signal generator to simulate the gyroscope output signal. This method can accurately set the various parameters of the gyroscope output signal, but it cannot evaluate the dynamic performance of the magnetic field control system or the effect of the magnetic field closed-loop control.

[0018] In summary, the photothermal magnetic coupling of the nuclear magnetic resonance gyro head leads to errors in the magnetic field, causing fluctuations in the main magnetic field and unevenness in the main magnetic field; angular velocity measurement depends on the action of the magnetic field, and the control of the magnetic field is the core of realizing nuclear spin manipulation and detection; there is an urgent need to solve the problem of error compensation of the magnetic field control system; currently, the test of the magnetic field control system usually relies on the actual gyro output signal, but there is a problem of gyro head error aliasing during the test, and it must rely on the turntable and gyro start-up, which is complicated and not convenient enough. Summary of the Invention

[0019] To solve the above-mentioned technical problems, the present invention provides a magnetic field control self-test system and method for a nuclear magnetic resonance gyroscope. The magnetic field control self-test system of the nuclear magnetic resonance gyroscope provides a test signal for the magnetic field control system, which can freely set parameters such as the angular velocity and relaxation time of the simulated gyroscope output signal; and can also simulate the gyroscope output signal in real time according to the magnetic field drive signal, thereby dynamically testing and evaluating the magnetic field closed-loop control effect of the magnetic field control system.

[0020] In a first aspect, a magnetic field control self-test system for a nuclear magnetic resonance gyroscope comprises:

[0021] Host computer, AD signal acquisition circuit, FPGA operation core and DA conversion circuit, including:

[0022] The host computer is used to input test parameters and transmit them to the FPGA operation core through UART serial communication;

[0023] As an example, the host computer is LabVIE host computer.

[0024] The AD signal acquisition circuit is used to convert the three-axis magnetic field driving current into a digital signal, and then input the digital signal into the FPGA operation core through the SPI protocol;

[0025] The FPGA operation core includes: a gyroscope output signal generation module and a magnetic moment precession signal generation module, wherein:

[0026] The magnetic moment precession signal generating module has a built-in magnetic moment precession amplitude-frequency equation, calculates the magnetic moment precession signal through the test parameters and the digital signal; and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module;

[0027] The gyro output signal generating module has a built-in gyro signal output equation, which uses the CORDIC algorithm to convert the amplitude, frequency and phase information of the magnetic moment precession signal into a high-frequency carrier sinusoidal signal with low-frequency variation characteristics to simulate the gyro output signal;

[0028] As an example, the test parameters include: angular velocity, angular acceleration, main magnetic field fluctuation and main magnetic field inhomogeneity parameters.

[0029] As an example, the gyro signal output equation uses a phase generation algorithm to calculate the phase information of the sinusoidal signal in the analog gyro output signal; and then outputs the analog gyro output signal to the DA conversion circuit through the CORDIC algorithm.

[0030] The DA conversion circuit is electrically connected to the gyroscope output signal generating module via an SPI interface and is used to output an analog gyroscope output signal.

[0031] As an example, the DA conversion circuit has a built-in DA chip communication architecture.

[0032] As an example, the AD signal acquisition circuit includes: a transverse magnetic field drive signal acquisition circuit and a longitudinal magnetic field drive signal acquisition circuit; respectively performing analog / digital conversion on the low-frequency magnetic field drive signals of the x-axis and y-axis and the high-frequency magnetic field drive signal of the z-axis;

[0033] The transverse magnetic field drive signal acquisition circuit is used to acquire low-frequency magnetic field drive signals of the x-axis and y-axis;

[0034] The longitudinal magnetic field drive signal acquisition circuit is used to acquire the high-frequency magnetic field drive signal of the z-axis.

[0035] As an example, the transverse magnetic field drive signal acquisition circuit includes: a low-frequency AD conversion circuit, a transverse anti-aliasing filter circuit and a transverse amplification circuit. The low-frequency AD conversion circuit can reduce the common-mode error of the signal and improve the accuracy of AD conversion; the low-frequency anti-aliasing filter circuit performs low-pass filtering on the magnetic field drive signal to prevent high-frequency noise from interfering with the AD conversion; the low-frequency amplification circuit is used to convert the magnetic field drive signal from current form to voltage form for subsequent filtering processing.

[0036] As an example, the longitudinal magnetic field drive signal acquisition circuit includes: a high-frequency AD conversion circuit, a longitudinal anti-aliasing filter circuit and a longitudinal amplification circuit.

[0037] As an example, the DA conversion circuit includes: an amplifier circuit and a DA chip communication architecture.

[0038] As an example, the magnetic moment precession signal generating module includes:

[0039] Sampling filter: used to filter the x-axis low-frequency magnetic field drive signal and separate the polarized magnetic field drive signals of the two rare gases;

[0040] Two sets of frequency discrimination units are used to discriminate the polarized magnetic field driving signals of two rare gases respectively; then the amplitude, frequency, phase information and test parameters of the magnetic moment precession signal are input into the gyro output signal generation module.

[0041] In a second aspect, a magnetic field control self-test method for a nuclear magnetic resonance gyroscope comprises:

[0042] Step 1: Input test parameters from the host computer and transmit them to the FPGA computing core via UART serial communication; at the same time, the AD signal acquisition circuit converts the three-axis magnetic field drive current into a digital signal, and then inputs the digital signal into the FPGA computing core via the SPI protocol;

[0043] Step 2: The magnetic moment precession signal generating module calculates the magnetic moment precession signal by using the built-in magnetic moment precession amplitude-frequency equation, and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module;

[0044] Step 3: The gyro output signal generating module has a built-in gyro signal output equation, and generates a high-frequency carrier sinusoidal signal with low-frequency variation characteristics by using the CORDIC algorithm to simulate the gyro output signal based on the amplitude, frequency and phase information of the magnetic moment precession signal.

[0045] Step 4: The DA conversion circuit is electrically connected to the gyro output signal generating module via the SPI interface to output the analog gyro output signal;

[0046] Step 5: By simulating the gyro output signal and testing the magnetic field control system, rapid self-checking and performance optimization of the magnetic field control system can be achieved without actually running the gyro device.

[0047] Beneficial effects of the present invention:

[0048] The present invention simulates the gyroscope output signal based on the magnetic moment amplitude-frequency characteristic equation of the rare gas in the nuclear magnetic resonance gyroscope and the gyroscope signal output equation. The simulated signal has both controllable non-ideal factors and can reflect the changes of the gyroscope output signal under the magnetic field driving signal in real time according to the rules. The signal is used for magnetic field control system testing, which can provide a solid guarantee for the optimization of the control algorithm and the improvement of system performance.

[0049] The present invention can generate a simulated gyro output signal with adjustable carrier angular velocity and controllable magnetic field error without the need for a real gyro device, which can be used for independent testing and evaluation of the magnetic field control system, thereby achieving rapid self-checking and performance optimization of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1The figure is a schematic diagram of the overall structure of a magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to the present invention.

[0051] Figure 2 The figure is a hardware structure diagram of a magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to the present invention.

[0052] Figure 3 The figure is a schematic diagram of the process principle of a magnetic field control self-test method for a nuclear magnetic resonance gyroscope according to the present invention. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work shall fall within the scope of protection of the present application. Figures 1 to 3 As shown:

[0054] In a first aspect, a magnetic field control self-test system for a nuclear magnetic resonance gyroscope comprises:

[0055] Host computer 5, AD signal acquisition circuit 6, FPGA operation core 2 and DA conversion circuit 1, wherein:

[0056] The host computer 5 is used to input test parameters and transmit them to the FPGA operation core 2 via UART serial communication;

[0057] As an example, the host computer 5 is a LabVIE host computer.

[0058] The AD signal acquisition circuit 6 is used to convert the three-axis magnetic field driving current into a digital signal, and then input the digital signal into the FPGA operation core 7 through the SPI protocol;

[0059] The FPGA operation core 2 includes: a gyro output signal generating module 3 and a magnetic moment precession signal generating module 4, wherein:

[0060] The magnetic moment precession signal generating module 4 has a built-in magnetic moment precession amplitude-frequency equation 22, calculates the magnetic moment precession signal through the test parameters and the digital signal; and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module 3;

[0061] The gyro output signal generating module 3 has a built-in gyro signal output equation, which generates a high-frequency carrier sinusoidal signal with low-frequency variation characteristics through the CORDIC algorithm to simulate the gyro output signal.

[0062] As an example, the test parameters include: angular velocity, angular acceleration, main magnetic field fluctuation and main magnetic field inhomogeneity parameters.

[0063] As an example, the gyro signal output equation uses a phase generation algorithm 23 to calculate the phase information of the sinusoidal signal in the analog gyro output signal; and then outputs the analog gyro output signal to the DA conversion circuit 1 through the CORDIC algorithm 22.

[0064] The DA conversion circuit 1 is electrically connected to the gyro output signal generating module 3 via the SPI interface 21 and is used to output the analog gyro output signal.

[0065] As an example, the DA conversion circuit 1 has a built-in DA chip communication architecture.

[0066] As an example, the AD signal acquisition circuit 6 includes: a transverse magnetic field drive signal acquisition circuit 10 and a longitudinal magnetic field drive signal acquisition circuit 11; respectively performing analog / digital conversion on the low-frequency magnetic field drive signals of the x-axis and y-axis and the high-frequency magnetic field drive signal of the z-axis;

[0067] The transverse magnetic field drive signal acquisition circuit 10 is used to acquire low-frequency magnetic field drive signals of the x-axis and y-axis;

[0068] The longitudinal magnetic field driving signal acquisition circuit 11 is used to acquire the high-frequency magnetic field driving signal of the z-axis.

[0069] As an example, the transverse magnetic field drive signal acquisition circuit 10 includes: a low-frequency AD conversion circuit 16, a transverse anti-aliasing filter circuit 17 and a transverse amplification circuit 18. The low-frequency AD conversion circuit 16 can reduce the common-mode error of the signal and improve the accuracy of AD conversion; the low-frequency anti-aliasing filter circuit 17 performs low-pass filtering on the magnetic field drive signal to prevent high-frequency noise from interfering with the AD conversion; the low-frequency amplification circuit 18 is used to convert the magnetic field drive signal from current form to voltage form for subsequent filtering processing.

[0070] As an example, the longitudinal magnetic field drive signal acquisition circuit 11 includes: a high-frequency AD conversion circuit 15 , a longitudinal anti-aliasing filter circuit 9 and a longitudinal amplification circuit 27 .

[0071] As an example, the structures of the horizontal anti-aliasing filter circuit 17 and the horizontal amplifying circuit 18 are consistent with those of the vertical anti-aliasing filter circuit 9 and the vertical amplifying circuit 27 .

[0072] As an example, the DA conversion circuit 1 includes: an amplifier circuit 14 and a DA chip communication architecture 13 .

[0073] As an example, the magnetic moment precession signal generating module 4 includes:

[0074] Sampling filter 19: used to filter the x-axis low-frequency magnetic field drive signal to separate the polarized magnetic field drive signals of the two rare gases;

[0075] Two sets of frequency discrimination units 20 are used to discriminate the polarized magnetic field driving signals of the two rare gases respectively; and then input the amplitude, frequency, phase information and test parameters of the magnetic moment precession signal into the gyro output signal generation module.

[0076] In a second aspect, a magnetic field control self-test method for a nuclear magnetic resonance gyroscope comprises:

[0077] Step 1: Input test parameters from the host computer and transmit them to the FPGA computing core via UART serial communication; at the same time, the AD signal acquisition circuit converts the three-axis magnetic field drive current into a digital signal, and then inputs the digital signal into the FPGA computing core via the SPI protocol;

[0078] Step 2: The magnetic moment precession signal generating module calculates the magnetic moment precession signal by using the built-in magnetic moment precession amplitude-frequency equation, and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module;

[0079] Step 3: The gyro output signal generating module has a built-in gyro signal output equation, and uses the CORDIC algorithm to convert the amplitude, frequency and phase information of the magnetic moment precession signal into a high-frequency carrier sinusoidal signal with low-frequency variation characteristics to simulate the gyro output signal;

[0080] Step 4: The DA conversion circuit is electrically connected to the gyro output signal generating module via the SPI interface to output the analog gyro output signal;

[0081] Step 5: Testing the magnetic field control system 8 by simulating the gyro output signal, thereby achieving rapid self-checking and performance optimization of the magnetic field control system 8 without actually running the gyro device.

[0082] In order to better understand the design principle of the present invention, the following Figure 3 , the explanation is reiterated as follows:

[0083] (1) Basic principles of nuclear magnetic resonance gyroscope

[0084] Under the action of the static magnetic field B0, the magnetic moment of the atom precesses around the Larmor precession frequency of the static magnetic field. The precession frequency is only related to the main magnetic field B0, but has nothing to do with the motion state of the gyroscope, satisfying:

[0085] ω L =γB0 (1)

[0086] According to this principle, the Larmor precession frequency is measured using detection light. The detection light source rotates synchronously with the carrier. The difference between the measured value and the theoretical value is the carrier motion angular frequency, that is,

[0087] ω obs =ω L -ω R =γB0-ω R (2)

[0088] In formula (2), for common carriers such as airplanes and cars, the carrier angular velocity is much smaller than the precession frequency of the noble gas nuclei, and the fluctuation of the main magnetic field B0 has a huge impact on the measurement results.

[0089] In order to reduce the error caused by the fluctuation of the main magnetic field, two isotopes of rare gas 131Xe are usually detected.

[0090] and the precession frequency of 129Xe, that is

[0091] ω 131 =γ 131 B0-ω R (3)

[0092] ω 129 =γ 129 B0-ω R (4)

[0093] By combining the two equations, the main magnetic field B0 can be eliminated, and the angular frequency calculation formula is obtained:

[0094]

[0095] In this formula, γ 131 and γ 129 is a constant, and the detection result is determined by the observed values of the precession frequencies of the two rare gases and is no longer directly dependent on the main magnetic field B0.

[0096] (2) Magnetic moment precession model (corresponding magnetic moment precession algorithm)

[0097] Frequency detection of a single nucleus is very difficult, and the nucleus needs to be polarized by the horizontal component of the main magnetic moment M xy The measurement of the rotation frequency is used to obtain the measured value of the Larmor precession frequency. The amplitude and phase of the horizontal component of the main magnetic moment satisfy:

[0098]

[0099] Where B1 is the amplitude of the x-axis magnetic field driving signal, T1 is the longitudinal relaxation time, and T2 is the transverse relaxation time. In the formula, Δω=(γB0-ω a )-ω R, where ω a is the x-axis magnetic field driving signal frequency, ω R The carrier angular velocity is sent by the host computer. The magnetic moment precession signal can be generated based on this amplitude and frequency.

[0100] 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 magnetic field control self-test system for a nuclear magnetic resonance gyroscope, characterized in that: include: Host computer, AD signal acquisition circuit, FPGA operation core and DA conversion circuit, including: The host computer is used to input test parameters and transmit them to the FPGA operation core through UART serial communication; The AD signal acquisition circuit is used to convert the three-axis magnetic field driving current into a digital signal, and then input the digital signal into the FPGA operation core through the SPI protocol; The FPGA operation core includes: a gyroscope output signal generation module and a magnetic moment precession signal generation module, wherein: The magnetic moment precession signal generating module has a built-in magnetic moment precession amplitude-frequency equation, calculates the magnetic moment precession signal through the test parameters and the digital signal; and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module; The gyro output signal generating module has a built-in gyro signal output equation, which uses the CORDIC algorithm to convert the amplitude, frequency and phase information of the magnetic moment precession signal into a high-frequency carrier sinusoidal signal with low-frequency variation characteristics to simulate the gyro output signal; The DA conversion circuit is electrically connected to the gyroscope output signal generating module via an SPI interface and is used to output an analog gyroscope output signal.

2. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The host computer used is: LabVIE host computer.

3. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The test parameters include: angular velocity, angular acceleration, main magnetic field fluctuation and main magnetic field inhomogeneity parameters.

4. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The gyro signal output equation adopts a phase generation algorithm to calculate the phase information of the sinusoidal signal in the analog gyro output signal; and then outputs the analog gyro output signal to the DA conversion circuit through the CORDIC algorithm.

5. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The DA conversion circuit includes: an amplifier circuit and a DA chip communication architecture.

6. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The AD signal acquisition circuit includes: a transverse magnetic field drive signal acquisition circuit and a longitudinal magnetic field drive signal acquisition circuit; respectively performing analog / digital conversion on the low-frequency magnetic field drive signals of the x-axis and y-axis and the high-frequency magnetic field drive signal of the z-axis; The transverse magnetic field drive signal acquisition circuit is used to acquire low-frequency magnetic field drive signals of the x-axis and y-axis; The longitudinal magnetic field drive signal acquisition circuit is used to acquire the high-frequency magnetic field drive signal of the z-axis.

7. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 6, characterized in that: The transverse magnetic field drive signal acquisition circuit includes: a low-frequency AD conversion circuit, a transverse anti-aliasing filter circuit and a transverse amplification circuit. The low-frequency AD conversion circuit can reduce the common-mode error of the signal and improve the accuracy of AD conversion; the low-frequency anti-aliasing filter circuit performs low-pass filtering on the magnetic field drive signal to prevent high-frequency noise from interfering with the AD conversion; the low-frequency amplification circuit is used to convert the magnetic field drive signal from current form to voltage form for subsequent filtering processing.

8. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 6, characterized in that: The longitudinal magnetic field drive signal acquisition circuit includes: a high-frequency AD conversion circuit, a longitudinal anti-aliasing filter circuit and a longitudinal amplification circuit.

9. The magnetic field control self-test system for a nuclear magnetic resonance gyroscope according to claim 1, characterized in that: The magnetic moment precession signal generating module includes: Sampling filter: used to filter the x-axis low-frequency magnetic field drive signal and separate the polarized magnetic field drive signals of the two rare gases; Two sets of frequency discrimination units are used to discriminate the polarized magnetic field driving signals of two rare gases respectively; then the amplitude, frequency, phase information and test parameters of the magnetic moment precession signal are input into the gyro output signal generation module.

10. A magnetic field control self-test method for a nuclear magnetic resonance gyroscope, characterized in that: include: Step 1: Input test parameters from the host computer and transmit them to the FPGA computing core via UART serial communication; at the same time, the AD signal acquisition circuit converts the three-axis magnetic field drive current into a digital signal, and then inputs the digital signal into the FPGA computing core via the SPI protocol; Step 2: The magnetic moment precession signal generating module calculates the magnetic moment precession signal by using the built-in magnetic moment precession amplitude-frequency equation, and inputs the amplitude, frequency and phase information of the magnetic moment precession signal into the gyro output signal generating module; Step 3: The gyro output signal generating module has a built-in gyro signal output equation, and uses the CORDIC algorithm to convert the amplitude, frequency and phase information of the magnetic moment precession signal into a high-frequency carrier sinusoidal signal with low-frequency variation characteristics to simulate the gyro output signal; Step 4: The DA conversion circuit is electrically connected to the gyro output signal generating module via the SPI interface to output the analog gyro output signal; Step 5: By simulating the gyro output signal and testing the magnetic field control system, rapid self-checking and performance optimization of the magnetic field control system can be achieved without actually running the gyro device.

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