Fully digital closed-loop angular velocity detection system and method based on low-coherence light

Abstract

The present invention discloses a fully digital closed-loop angular velocity detection system and method based on low-coherence light. In the present invention, a resonant cavity is used to realize the interference of multiple light beams, and the angular velocity is detected by detecting the change in the intensity of the interference light after the clockwise and counterclockwise light beams pass through the resonant cavity, and the system is closed by using the equivalent frequency shift of a sawtooth wave. In the present invention, a fully digital signal processing technology is adopted, and the signal processing system includes a digital / analog and analog / digital conversion module, a modulation and demodulation module, a servo control module, a frequency shift drive module and a low-pass filter module. The frequency of the sawtooth wave is determined by a frequency control word, and its size is equal to half of the resonant frequency difference between the resonant cavity in the clockwise and counterclockwise directions. The frequency control word is used as the output of the angular velocity detection system after passing through the low-pass filter module. Closed-loop detection can effectively improve the linearity of the system output and the dynamic range of angular velocity detection.

Description

Technical Field

[0001] The present invention relates to the field of signal detection technology, and in particular to a fully digital closed-loop angular velocity detection system and method based on low-coherence light. Background Art

[0002] An optical gyroscope is a high-precision inertial sensor that uses the optical Sagnac effect to detect angular velocity. It primarily includes the interferometric fiber-optic gyroscope (IFOG) and the resonator optical gyroscope (ROG). ROGs can be further categorized as resonator fiber-optic gyroscopes (RFOG) and resonator micro-optic gyroscopes (RMOG). The IFOG uses a multi-turn optical fiber ring as its sensing element and detects angular velocity by measuring the intensity of the interference light from clockwise and counterclockwise light beams. For a given diameter, its theoretical sensitivity is positively correlated with the ring length. The ROG uses a high-definition optical ring resonator as its sensing element. It utilizes multiple turns of a light beam within the resonator to enhance the optical Sagnac effect and detects angular velocity by measuring the resonant frequency difference between clockwise and counterclockwise light beams. Its theoretical sensitivity is half the product of the cavity length and the cavity resolution. Therefore, under the same diameter and fiber length, ROG has higher detection sensitivity.

[0003] In traditional ROGs, high-precision detection of the resonant frequency difference caused by rotation often requires a highly coherent light source, which undoubtedly enhances many optical parasitic effects, such as backscattering, polarization fluctuations, and the Kerr effect. These enhanced parasitic effects increase the complexity of system signal processing and limit improvements in system accuracy, hindering system miniaturization.

[0004] In systems based on low-coherence light, using a low-coherence light source as the system light source can reduce parasitic effects related to the coherence of the light source in the system from the source, thereby improving the stability of the system. At the same time, in ROG systems based on low-coherence light, angular velocity detection is based on the principle of light intensity detection. Therefore, high-precision angular velocity detection can be achieved without the need for a complex frequency-locked loop, greatly reducing the complexity of angular velocity detection. However, in angular velocity detection systems based on low-coherence light, they rely on power detection technology, so the linear range of the system's open-loop output is smaller than that of traditional open-loop ROG systems. As the angular velocity of rotation increases, the nonlinearity of the system output also gradually increases, which severely limits the practical application of angular velocity detection systems based on low-coherence light. Therefore, in order to reduce the nonlinearity of the system output and improve the dynamic range of the system, it is crucial to perform closed-loop detection in angular velocity detection systems based on low-coherence light.

[0005] In traditional ROGs, angular velocity detection is achieved through frequency detection, so a closed-loop approach can be achieved by simply shifting the center frequency of a beam of incoming light through sawtooth frequency shifting. However, in ROG systems based on low-coherence light, angular velocity detection is achieved through power detection. Furthermore, compared to traditional ROGs, the beam undergoes two modulations before and after entering the cavity, with the second modulation offsetting the first. Therefore, achieving closed-loop control in this system cannot be achieved simply by shifting the center frequency of a single-frequency beam. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of the existing technology and provide a fully digital closed-loop angular velocity detection system and method that uses a low-coherence light source as an emission source, a transmissive optical resonant cavity as an angular velocity sensitive element, and a sawtooth wave equivalent frequency shift to achieve a closed loop. The optical resonant cavity has the function of frequency selection and filtering of the input light. According to the optical Sagnac effect, the resonant cavity has different filtering characteristics for clockwise and counterclockwise optical paths at different rotational angular velocities, so that the interference light power of the clockwise and counterclockwise light beams after passing through the resonant cavity changes with the rotation. Based on this characteristic, the rotational angular velocity of the system can be detected. At the same time, the sawtooth wave equivalent frequency shift is used to simultaneously change the overall center frequency of the clockwise and counterclockwise light entering the cavity, so that the filtering characteristics of the resonant cavity for the clockwise and counterclockwise light beams remain consistent, so that the interference light intensity of the clockwise and counterclockwise light beams always reaches a maximum value. Therefore, the rotational angular velocity of the system can be obtained by detecting this sawtooth wave frequency shift, thereby achieving a closed loop.

[0007] The technical solutions of the present invention are as follows:

[0008] The present invention first provides a fully digital closed-loop angular velocity detection system based on low-coherence light, which includes an optical system consisting of a low-coherence light source, a photodetector, a three-terminal circulator, a push-pull Y-branch, and an optical resonant cavity; and a fully digital signal processing system consisting of a digital-to-analog (D / A) conversion module, an analog-to-digital (A / D) conversion module, a modulation and demodulation module, a servo control module, a frequency shift drive module, and a low-pass filter module.

[0009] The low-coherence light source is connected to the first port of a three-port circulator, the second port of the three-port circulator is connected to the input end of a push-pull Y branch, and the two output ends of the push-pull Y branch are respectively connected to the same-side ports of two couplers of a transmission optical resonant cavity; the third port of the three-port circulator is connected to the input end of a photodetector; the output signal of the photodetector is input into a modulation and demodulation module through an A / D module; the modulation signal generated by the modulation and demodulation module acts on the push-pull Y branch through a D / A module, and the demodulation signal generated by the modulation and demodulation module acts on the push-pull Y branch through a servo control module, a frequency shift drive module, and a D / A module in sequence. The output of the servo control module passes through a low-pass filter and is input into an external data recorder as the output signal of the system.

[0010] As a preferred solution of the present invention, the modulation and demodulation module generates a reference signal with the same frequency as the modulation signal U1 (t) to demodulate the electrical signal to obtain a demodulated signal.

[0011] As a preferred embodiment of the present invention, the demodulated signal of the modulation and demodulation module generates a frequency control word (FCW) after passing through the servo control module and is sent to the frequency shift drive module. Based on the value of the FCW, the frequency shift drive module generates a sawtooth wave signal having a frequency equal to half the difference between the resonant frequencies of the resonant cavity in the clockwise and counterclockwise directions and an amplitude equal to the full-wave voltage of the push-pull Y branch. After passing through the D / A module, the signal acts on the push-pull Y branch, so that the resonant cavity has the same filtering characteristics for low-coherence light entering the cavity in the clockwise and counterclockwise directions, thereby ensuring that the light intensity detected at the photodetector always reaches the maximum value.

[0012] As a preferred solution of the present invention, the output of the servo control module is passed through a low-pass filter and used as the output signal of the angular velocity detection system, and is output to an external data recorder.

[0013] The present invention also provides a detection method using the detection system, which comprises the following steps:

[0014] (1) Light emitted by a low-coherence light source enters the three-port circulator through the first port of the three-port circulator, then enters the push-pull Y branch through the second port of the three-port circulator, and enters the transmissive optical resonant cavity from the clockwise and counterclockwise directions respectively, and is transmitted multiple times in the transmissive optical resonant cavity. After that, the clockwise and counterclockwise light beams pass through the push-pull Y branch again and interfere at the push-pull Y branch. Finally, the interference light beam passes through the circulator and enters the photodetector through the third port of the three-port circulator;

[0015] (2) Signal modulation:

[0016] The low-coherence light emitted by the low-coherence light source is phase-modulated at the push-pull Y branch, wherein the driving signal for the phase modulation of the push-pull Y branch is the modulation signal U1(t) generated by the modulation and demodulation module;

[0017] (3) Signal demodulation:

[0018] The interference signal generated at the push-pull Y branch enters the photodetector through the circulator and is converted into an electrical signal. After that, it passes through the A / D module and enters the modulation and demodulation module. The modulation and demodulation module generates a reference signal with the same frequency as the modulation signal U1(t) to demodulate the electrical signal.

[0019] (4) Implementation of closed loop:

[0020] The demodulated signal from the modulation and demodulation module passes through the servo control module to generate a frequency control word (FCW) and send it to the frequency shift drive module. Based on the FCW value, the frequency shift drive module generates a sawtooth wave signal with a frequency equal to half the difference between the resonant frequencies of the clockwise and counterclockwise beams and an amplitude equal to the full-wave voltage of the push-pull Y branch. After passing through the D / A module, it acts on the push-pull Y branch, ensuring that the resonant cavity has the same filtering characteristics for low-coherence light entering the cavity clockwise and counterclockwise, thereby ensuring that the light intensity detected by the photodetector always reaches the maximum value.

[0021] (5) System signal output:

[0022] When the system is stationary, the resonant cavity has the same filtering characteristics for the clockwise and counterclockwise incident light beams, and the intensity of the interference light beam at the push-pull Y branch reaches its maximum value. When the system rotates, the resonant cavity has different filtering characteristics for the clockwise and counterclockwise incident light beams, and the interference light intensity at the push-pull Y branch changes accordingly with the rotation speed. Therefore, the angular velocity can be detected by detecting the change in the optical power of the light signal after interference. When the system is closed-loop, the intensity of the interference light will always remain at the maximum value, and the change in the intensity of the interference light of the clockwise and counterclockwise beams caused by the rotation will be reflected in the output of the servo control module. After passing through a low-pass filter, it can be used as the output signal of the angular velocity detection system and output to an external data recorder. Finally, after calibration, the angular velocity detection value of the system can be obtained.

[0023] The present invention has the beneficial effects:

[0024] 1. The fully digital closed-loop angular velocity detection system and method based on low-coherence light provided by the present invention utilizes low-coherence light as a light source, which can greatly reduce optical parasitic effects including backscattering and polarization fluctuations, thereby greatly improving the stability of the system.

[0025] 2. The present invention provides a fully digital closed-loop angular velocity detection system and method based on low-coherent light. The optical resonant cavity in the system can be a fiber ring resonator or an optical waveguide ring resonator. Therefore, the closed-loop solution proposed in the present invention can be applied to both resonant fiber gyroscopes and resonant micro-optical gyroscopes, thereby greatly expanding the scope of application of the present invention and greatly helping to achieve the miniaturization of angular velocity detection systems.

[0026] 3. The fully digital closed-loop angular velocity detection system and method based on low-coherent light provided by the present invention adopts a fully digital signal processing system and utilizes digital sawtooth wave equivalent frequency shift to achieve closed loop, which improves the stability of the system and is conducive to the realization of system miniaturization.

[0027] 4. The fully digital closed-loop angular velocity detection system and method based on low-coherence light provided by the present invention utilizes sawtooth wave equivalent frequency shifting to respectively change the overall center frequency of the clockwise and counterclockwise light entering the cavity, so that the filtering characteristics of the resonant cavity for the clockwise and counterclockwise light beams remain consistent, thereby ensuring that the interference light intensity of the clockwise and counterclockwise light beams always has a maximum value. At this time, the system will always operate at the resonant frequency point, thereby greatly improving the linearity of the system output and increasing the dynamic range of the system angular velocity detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a fully digital closed-loop angular velocity detection system and method based on low-coherence light;

[0029] Figure 2 It is a curve diagram of the output after signal demodulation.

[0030] Figure 3 This is a schematic diagram of the equivalent frequency shift of a sawtooth wave, where V 2π is the full-wave voltage of the push-pull Y branch, f0 is the center frequency of the light source, f s It is half of the resonant frequency difference between the clockwise and counterclockwise light beams caused by rotation.

[0031] Figure 4 This is a schematic diagram of the relationship between the clockwise and counterclockwise resonant frequencies before and after the closed loop when the system rotates, where Δf is the resonant frequency difference between the clockwise and counterclockwise light beams caused by the rotation, and FSR is the free spectral width of the resonant cavity.

[0032] Figure 5 It is a schematic diagram of a specific implementation case of a fully digital closed-loop angular velocity detection system and method based on low-coherence light.

[0033] In the figure: 1. Low-coherence light source, 2. Photodetector, 3. Circulator, 4. Push-pull Y-branch, 5. Transmissive optical resonator, including transmissive fiber ring resonator and transmissive optical waveguide ring resonator, 6. A / D module, 7. Modulation and demodulation module, 8. Servo control module, 9. Frequency shift drive module, 10. Low-pass filter module, 11. D / A module, 12. Data acquisition device. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to examples and drawings, but the present invention is not limited thereto.

[0035] Example 1

[0036] like Figure 1 As shown, the fully digital closed-loop angular velocity detection system based on low-coherence light provided in this embodiment includes an optical system consisting of a low-coherence light source, a photodetector, a three-terminal circulator, a push-pull Y-branch, and a transmissive optical resonant cavity, and a fully digital signal processing system consisting of a digital-to-analog (D / A) conversion module, an analog-to-digital (A / D) conversion module, a modulation and demodulation module, a servo control module, a frequency shift drive module, and a low-pass filter module.

[0037] The low-coherence light source is connected to the first port of a three-port circulator, the second port of the three-port circulator is connected to the input end of a push-pull Y branch, and the two output ends of the push-pull Y branch are respectively connected to the same-side ports of two couplers of a transmission optical resonant cavity; the third port of the three-port circulator is connected to the input end of a photodetector; the output signal of the photodetector is input into a modulation and demodulation module through an A / D module; the modulation signal generated by the modulation and demodulation module acts on the push-pull Y branch through a D / A module, and the demodulation signal generated by the modulation and demodulation module acts on the push-pull Y branch through a servo control module, a frequency shift drive module, and a D / A module in sequence. The output of the servo control module passes through a low-pass filter and is input into an external data recorder as the output signal of the system.

[0038] The fully digital closed-loop angular velocity detection method using the above system includes the following steps:

[0039] (1) The light emitted by the low-coherence light source enters the three-port circulator through the first port of the three-port circulator, then enters the push-pull Y branch through the second port of the three-port circulator, and enters the transmission optical resonator from the clockwise and counterclockwise directions respectively, and is transmitted multiple times in the transmission optical resonator. After that, the clockwise and counterclockwise light beams pass through the push-pull Y branch again and interfere at the push-pull Y branch. Finally, the interference light beam passes through the circulator and enters the photodetector through the third port of the three-port circulator; (2) Signal modulation:

[0040] The low-coherence light emitted by the low-coherence light source is phase-modulated at the push-pull Y branch, wherein the driving signal for the phase modulation of the push-pull Y branch is the modulation signal U1(t) generated by the modulation and demodulation module;

[0041] (3) Signal demodulation:

[0042] The interference signal generated at the push-pull Y branch enters the photodetector through the circulator and is converted into an electrical signal. After that, it passes through the A / D module and enters the modulation and demodulation module. The modulation and demodulation module generates a reference signal with the same frequency as the modulation signal U1(t) to demodulate the electrical signal.

[0043] (4) Implementation of closed loop:

[0044] The demodulated signal from the modulation and demodulation module passes through the servo control module to generate a frequency control word (FCW) and send it to the frequency shift drive module. Based on the FCW value, the frequency shift drive module generates a sawtooth wave signal with a frequency equal to half the difference between the resonant frequencies of the clockwise and counterclockwise beams and an amplitude equal to the full-wave voltage of the push-pull Y branch. After passing through the D / A module, it acts on the push-pull Y branch, ensuring that the resonant cavity has the same filtering characteristics for low-coherence light entering the cavity clockwise and counterclockwise, thereby ensuring that the light intensity detected by the photodetector always reaches the maximum value.

[0045] (5) System signal output:

[0046] When the system is stationary, the resonant cavity has the same filtering characteristics for the clockwise and counterclockwise incident light beams, and the intensity of the interference light beam at the push-pull Y branch reaches its maximum value. When the system rotates, the resonant cavity has different filtering characteristics for the clockwise and counterclockwise incident light beams, and the interference light intensity at the push-pull Y branch changes accordingly with the rotation speed. Therefore, the angular velocity can be detected by detecting the change in the optical power of the light signal after interference. When the system is closed-loop, the intensity of the interference light will always remain at the maximum value, and the change in the intensity of the interference light of the clockwise and counterclockwise beams caused by the rotation will be reflected in the output of the servo control module. After passing through a low-pass filter, it can be used as the output signal of the angular velocity detection system and output to an external data recorder. Finally, after calibration, the angular velocity detection value of the system can be obtained.

[0047] like Figure 2 As shown in the figure, the present invention provides an output demodulation curve for a fully digital closed-loop angular velocity detection system and method based on low-coherence light. As can be seen from the demodulation curve, when the system is stationary, that is, the resonant cavity has the same filtering characteristics for clockwise and counterclockwise light beams, the demodulation output is 0. When the system rotates, the resonant cavity's filtering characteristics for clockwise and counterclockwise light beams differ, and the corresponding demodulation output is no longer equal to 0. By calibrating the relationship between the rotational angular velocity and the demodulation output, the system's rotational angular velocity can be directly obtained based on the system's output value.

[0048] like Figure 3 As shown in the figure, the present invention provides a schematic diagram of sawtooth wave equivalent frequency shifting. The digital sawtooth wave signal is generated by the output of the frequency shifting drive module through the D / A module. Its frequency is equal to half the difference between the resonant frequencies of the clockwise and counterclockwise light beams, and its amplitude is equal to the full-wave voltage of the push-pull Y branch. Applying the sawtooth wave signal to the push-pull Y branch achieves frequency shifting in opposite directions of the clockwise and counterclockwise light beams, thereby ensuring that the clockwise and counterclockwise light beams have the same resonant frequency.

[0049] like Figure 4 As shown, the present invention provides a schematic diagram of the relationship between the clockwise and counterclockwise frequencies of a fully digital closed-loop angular velocity detection system and method based on low-coherence light before and after the loop is closed. Half of the difference in the resonant frequency of the resonant cavity in the clockwise and counterclockwise directions is the frequency of the sawtooth wave equivalent frequency-shifted signal. Since this system uses a low-coherence light source, its spectral width is much larger than one FSR of the resonant cavity. Therefore, the change in the resonant frequency of the clockwise and counterclockwise light beams within one FSR is used in the figure to represent the overall change. When the system rotates, the filtering characteristics of the resonant cavity for the clockwise and counterclockwise light beams before the loop is closed will differ. However, after the system is closed, the filtering characteristics of the resonant cavity for the clockwise and counterclockwise light beams remain consistent.

[0050] like Figure 5 The figure shows an implementation example of a fully digital closed-loop angular velocity detection system based on low-coherence light. The angular velocity detection system includes a low-coherence light source 1, a photodetector 2, a three-port circulator 3, a push-pull Y-branch 4, a transmissive optical resonant cavity 5, an A / D module 6, a modulation and demodulation module 7, a servo control module 8, a frequency-shifting drive module 9, a low-pass filter module 10, two D / A modules 11, and a data recorder 12. The low-coherence light source is connected to the first port of the three-port circulator. The second port of the three-port circulator is connected to the input and output of the push-pull Y-branch, entering the transmissive optical resonant cavity in clockwise and counterclockwise directions. The third port of the three-port circulator is connected to the input of the photodetector. After multiple transmissions within the resonant cavity, the clockwise and counterclockwise light beams interfere at the push-pull Y-branch and then pass through the port of circulator 3 to connect to the photodetector. The output signal of the photodetector passes through the A / D module, modulation and demodulation module, servo control module, frequency-shifting drive module, and D / A module in sequence before acting on the push-pull Y-branch to achieve a closed loop. The system's modulation signal is generated by a modem module. The servo controller's output signal passes through a low-pass filter and is collected by a data recorder. After calibration, it can be used as the system's angular velocity output. The present invention uses low-coherence light as the light source and utilizes digital sawtooth equivalent frequency shifting to achieve a closed-loop system, effectively improving system stability, output linearity, and the dynamic range of the system's angular velocity detection.

Claims

1. A fully digital closed-loop angular velocity detection system based on low-coherence light, characterized in that: It includes an optical system consisting of a low-coherence light source, a photodetector, a three-terminal circulator, a push-pull Y-branch, and a transmissive optical resonant cavity, and a fully digital signal processing system consisting of a digital / analog conversion (D / A) module, an analog / digital conversion (A / D) module, a modulation and demodulation module, a servo control module, a frequency shift drive module, and a low-pass filter module. The low-coherence light source is connected to the first port of a three-port circulator, the second port of the three-port circulator is connected to the input end of a push-pull Y branch, and the two output ends of the push-pull Y branch are respectively connected to the same-side ports of two couplers of a transmissive optical resonant cavity; the third port of the three-port circulator is connected to the input end of a photodetector; the output signal of the photodetector is input to a modulation and demodulation module through an A / D module; the modulation signal generated by the modulation and demodulation module is applied to the push-pull Y branch through a D / A module, and the demodulation signal generated by the modulation and demodulation module is applied to the push-pull Y branch through a servo control module, a frequency shift driving module, and a D / A module in sequence. The output of the servo control module is input to an external data recorder as the output signal of the system after passing through a low-pass filter; The demodulated signal from the modulation and demodulation module passes through the servo control module to generate a frequency control word (FCW) and send it to the frequency shift drive module. Based on the FCW value, the frequency shift drive module generates a sawtooth wave signal with a frequency equal to half the difference between the resonant cavity's resonant frequencies in the clockwise and counterclockwise directions and an amplitude equal to the full-wave voltage of the push-pull Y branch. After passing through the D / A module, it acts on the push-pull Y branch, ensuring that the resonant cavity has the same filtering characteristics for low-coherence light entering the cavity in the clockwise and counterclockwise directions, thereby ensuring that the light intensity detected by the photodetector always reaches the maximum value. The output of the servo control module passes through a low-pass filter and is used as the output signal of the angular velocity detection system and output to an external data recorder.

2. The low-coherence light-based fully digital closed-loop angular velocity detection system according to claim 1, characterized in that: The modulation and demodulation module generates a reference signal with the same frequency as the modulation signal U1 (t) to demodulate the electrical signal to obtain a demodulated signal.

3. A detection method using the detection system according to any one of claims 1-2, characterized in that: The following steps are involved: (1) Light emitted by a low-coherence light source enters the three-port circulator through the first port of the three-port circulator, then enters the push-pull Y branch through the second port of the three-port circulator, and enters the transmissive optical resonant cavity from the clockwise and counterclockwise directions respectively, and is transmitted multiple times in the transmissive optical resonant cavity. After that, the clockwise and counterclockwise light beams pass through the push-pull Y branch again and interfere at the push-pull Y branch. Finally, the interference light beam passes through the circulator and enters the photodetector through the third port of the three-port circulator; (2) Signal modulation: The low-coherence light emitted by the low-coherence light source is phase-modulated at the push-pull Y branch, wherein the driving signal for the phase modulation of the push-pull Y branch is the modulation signal U1(t) generated by the modulation and demodulation module; (3) Signal demodulation: The interference signal generated at the push-pull Y branch enters the photodetector through the circulator and is converted into an electrical signal. After that, it passes through the A / D module and enters the modulation and demodulation module. The modulation and demodulation module generates a reference signal with the same frequency as the modulation signal U1(t) to demodulate the electrical signal. (4) Implementation of closed loop: The demodulated signal from the modulation and demodulation module passes through the servo control module to generate a frequency control word (FCW) and send it to the frequency shift drive module. Based on the FCW value, the frequency shift drive module generates a sawtooth wave signal with a frequency equal to half the difference between the resonant frequencies of the clockwise and counterclockwise beams and an amplitude equal to the full-wave voltage of the push-pull Y branch. After passing through the D / A module, it acts on the push-pull Y branch, ensuring that the resonant cavity has the same filtering characteristics for low-coherence light entering the cavity clockwise and counterclockwise, thereby ensuring that the light intensity detected by the photodetector always reaches the maximum value. (5) System signal output: When the system is stationary, the resonant cavity has the same filtering characteristics for the clockwise and counterclockwise incident light beams, and the intensity of the interference light beam at the push-pull Y branch reaches its maximum value. When the system rotates, the resonant cavity has different filtering characteristics for the clockwise and counterclockwise incident light beams, and the interference light intensity at the push-pull Y branch changes accordingly with the rotation speed. Therefore, the angular velocity can be detected by detecting the change in the optical power of the light signal after interference. When the system is closed-loop, the intensity of the interference light will always remain at the maximum value, and the change in the intensity of the interference light of the clockwise and counterclockwise beams caused by the rotation will be reflected in the output of the servo control module. After passing through a low-pass filter, it can be used as the output signal of the angular velocity detection system and output to an external data recorder. Finally, after calibration, the angular velocity detection value of the system can be obtained.

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