Closed-loop compensation method for inhibiting wavelength dependence of scale factor of fiber-optic gyroscope

Abstract

The invention belongs to the technical field of fiber-optic gyroscopes, and particularly discloses a closed-loop compensation method for inhibiting the scale factor wavelength dependence of a fiber-optic gyroscope, which comprises the following steps of: calculating a reset light intensity error at a step wave reset moment by utilizing the aperiodicity of an interference curve of a wide-spectrum light source fiber-optic gyroscope, and monitoring the change of central wavelength in real time; by dynamically adjusting and compensating the step wave reset height, real-time closed-loop control is carried out, so that the light intensity value during step wave reset is equal to the light intensity value before reset; and finally, compensating the wavelength dependence of the scale factor of the fiber-optic gyroscope by utilizing a mathematical model of the step wave reset height compensation variation and the scale factor variation. The method solves the problem that the scale factor stability of the fiber-optic gyroscope is reduced due to the change of the scale factor of the fiber-optic gyroscope along with the central wavelength.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber optic gyroscopes, and particularly relates to a closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope. Background Art

[0002] A fiber optic gyroscope is an angular rate sensor based on the Sagnac effect, featuring high precision, small volume, and large dynamic range. In a fiber optic gyroscope, a closed-loop control method is usually adopted to feedback-control the phase difference sensed by the fiber loop using a Y-waveguide phase modulator, which not only improves the linearity of the scale factor of the fiber optic gyroscope but also increases the maximum measurement range of the fiber optic gyroscope. However, in dynamic angle measurement and high-speed rotation scenarios, the scale factor error remains the main error source for the fiber optic gyroscope to measure the rotational speed.

[0003] Fiber optic gyroscopes usually use a broadband light source similar to a superluminescent diode (SLD) to increase the coherence length of the interference light, thereby reducing the Kerr effect and Shupe effect in the optical path. However, the central wavelength of the broadband light source is not stable and has certain fluctuations over time, temperature, and light intensity. In traditional engineering applications, it is difficult to measure the change amount of the central wavelength, and usually, additional complex optical systems and signal processing systems need to be added, which is unacceptable for fiber optic gyroscopes with limited volume. Due to the wavelength dependence of the scale factor of the fiber optic gyroscope, the stability of the scale factor of the fiber optic gyroscope decreases, restricting the application of the fiber optic gyroscope in measurement fields such as high-precision and large rotational speed. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that the scale factor of the fiber optic gyroscope changes with the central wavelength, resulting in a decrease in the stability of the scale factor of the fiber optic gyroscope, and a closed-loop compensation method for suppressing the wavelength dependence of the scale factor of the fiber optic gyroscope is proposed.

[0005] The technical solution of the present invention is as follows: A closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope includes the following steps: Set the modulation sequence and modulation amplitude of the fiber optic gyroscope to generate a modulation signal, and set the reset threshold and reset height of the staircase wave; Demodulate the rotational speed error and gain error according to the demodulation sequence, and then input the demodulated rotational speed error into a rotational speed integrator and a staircase wave integrator to generate a staircase wave signal, realizing a primary closed-loop control feedback for the rotational speed; input the gain error into a reference voltage integrator to adjust the reference voltage of the D / A converter in the subsequent feedback channel, so that the gain coefficient of the feedback channel remains unchanged, realizing a secondary closed-loop control for the feedback gain; If the staircase wave signal exceeds the reset threshold of the staircase wave, a reset is triggered. According to the staircase wave reset state and the modulation sequence state, the reset light intensity error is demodulated according to the staircase wave reset light intensity error demodulation sequence; if the staircase wave signal does not exceed the reset threshold of the staircase wave, the staircase wave signal is superimposed on the modulation signal. After triggering the reset, the demodulated reset light intensity error is accumulated and integrated by the staircase wave reset height compensation integrator to calculate the compensated digital quantity of the staircase wave reset height. The compensated digital quantity of the staircase wave reset height is truncated, and then the staircase wave signal is reset to achieve a three - closed - loop control feedback of the staircase wave reset height; the truncated compensated digital quantity of the staircase wave reset height is smoothed and filtered, and the compensation quantity reference value under the reference condition is collected, and the smoothed compensated digital quantity of the staircase wave reset height is divided by the compensation quantity reference value to obtain the reset height compensation change quantity. According to the mathematical relationship between the reset height compensation change quantity and the scale factor change quantity, the scale factor compensation coefficient is calculated. The original number of the fiber optic gyro is multiplied by the scale factor compensation coefficient to obtain the compensated rotational speed value output, realizing the suppression of the wavelength dependence of the scale factor.

[0006] Preferably, the modulation sequence is , where is the staircase wave reset height value, and the corresponding phase difference is 2π; is the modulation digital quantity; the duration of each modulation amplitude is , and the period of the modulation sequence is , is the transit time of light propagating in the fiber optic loop; the modulation sequence makes the phase difference generated by the two interfering light beams be , is arbitrarily set within the range of (π / 2, π); The light intensity signal corresponding to the modulation sequence is converted into a digital signal by an A / D converter, and the signal digital quantity corresponding to the modulation sequence is collected through an FPGA , , and , and the signal digital quantity sequence obtained is .

[0007] Preferably, the demodulation method of the rotational speed error is specifically:

[0008] Among them, represents the rotational speed error; The rotational speed error is input to the rotational speed integrator for accumulation to obtain the rotational speed value :

[0009] Input the rotational speed value into the stepped wave integrator for accumulation to obtain a stepped wave signal :

[0010] The stepped wave integrator integrates once every 1 transit time.

[0011] Preferably, when the stepped wave signal exceeds the reset threshold of the stepped wave, trigger a reset. According to the stepped wave reset state and the modulation sequence state, demodulate the reset light intensity error according to the stepped wave reset light intensity error demodulation sequence, which specifically includes the following steps: Set the upper threshold and the lower threshold of the reset threshold of the stepped wave; If the stepped wave signal is greater than the upper threshold , then perform a positive reset on the stepped wave, that is: ; Among them, represents the stepped wave after positive reset, is the stepped wave signal, is the stepped wave reset height value; If the stepped wave signal is less than the lower threshold value , then perform a negative reset on the stepped wave, that is:

[0012] Among them, represents the stepped wave after negative reset; If the stepped wave signal is less than or equal to the upper threshold and greater than or equal to the lower threshold, no reset is performed; When the modulation sequence at the time of reset is , it is positive modulation. When the modulation sequence at the time of reset is , it is negative modulation; among them, is the modulation digital quantity; When performing positive reset under positive modulation and negative reset under negative modulation, demodulate the reset light intensity error.

[0013] Preferably, when the set stepped wave reset phase difference is equal to 2π, the reset light intensity error is caused by the non-periodicity of the wide-spectrum light source interference curve; When performing positive reset under positive modulation, the stepped wave reset light intensity error demodulation sequence is:

[0014] When performing negative reset under negative modulation, the stepped wave reset light intensity error demodulation sequence is: 。

[0015] Preferably, the formula for truncating the digital quantity of the stepped wave reset height compensation is:

[0016] where represents the digital quantity of the stepped wave reset height compensation after truncation, represents taking the integer of the divisor, represents the digital quantity of the stepped wave reset height compensation, represents the number of digits for truncation, which is related to the response time of the fiber optic gyroscope.

[0017] Preferably, the reset of the stepped wave signal to achieve a three - loop closed - loop control feedback of the stepped wave reset height specifically includes the following steps: Dynamically adjust the reset height of the stepped wave according to the stepped wave reset state to obtain the adjusted reset height of the stepped wave ; Perform stepped wave reset according to the adjusted reset height of the stepped wave to obtain the reset stepped wave; Superimpose the reset stepped wave with the modulation signal to achieve a three - loop closed - loop control feedback of the stepped wave reset height.

[0018] Preferably, the method for dynamically adjusting the reset height of the stepped wave according to the stepped wave reset state is specifically: If the stepped wave reset state is positive reset under positive modulation, then subtract the digital quantity of the stepped wave reset height compensation after truncation from the reset height of the stepped wave under the modulation of the signal digital quantity , and add the digital quantity of the stepped wave reset height compensation after truncation to the reset height of the stepped wave under the modulation of the signal digital quantity ; If the stepped wave reset state is negative reset under negative modulation, then subtract the digital quantity of the stepped wave reset height compensation after truncation from the reset height of the stepped wave under the modulation of the signal digital quantity , and add the digital quantity of the stepped wave reset height compensation after truncation to the reset height of the stepped wave under the modulation of the signal digital quantity .

[0019] Preferably, performing stepped wave reset according to the adjusted reset height of the stepped wave is specifically: If it is positive reset, the formula for the reset stepped wave is:

[0020] where is a stepped wave signal; If it is a positive reset, the stepped wave after reset The calculation formula is: .

[0021] Preferably, the mathematical relationship between the reset height compensation variation and the scale factor variation is a linear equation or a polynomial equation, and the coefficients of the linear equation or the polynomial equation are related to the fiber optic gyro parameters and are obtained by fitting using numerical calculation methods.

[0022] The beneficial effects of the present invention are: 1. Directly extract the relevant information of the central wavelength change from the interference signal, without affecting the demodulation and closed-loop control of the original rotation speed error and gain error, and can monitor the central wavelength change in real time; 2. Use closed-loop integral control to effectively reduce the influence of random noise and short-term disturbances; 3. The reset height compensation amount is insensitive to the optical power, so the manufacturing deviation and aging of the light source do not affect the compensation model, and it has strong adaptability; 4. It is implemented in the FPGA, without changing the existing optical path and hardware, and the engineering implementation is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a block diagram of the fiber optic gyro.

[0024] Figure 2 Shown is a flowchart of a closed-loop compensation method for suppressing the wavelength dependence of the scale factor of the fiber optic gyro.

[0025] Figure 3 Shown is the interference curve of the broadband light source.

[0026] Figure 4 Shown is the interference light intensity in the presence of rotation speed phase and gain errors.

[0027] Figure 5 Shown is the interference light intensity during positive reset under positive modulation.

[0028] Figure 6 Shown is the interference light intensity during negative reset under negative modulation.

[0029] Figure 7 Shown is the reset height of the adjusted stepped wave during positive reset under positive modulation.

[0030] Figure 8 Shown is the reset height of the adjusted stepped wave during negative reset under negative modulation.

[0031] Figure 9 Shown is the modulation depth When it is 7π / 8, the compensation model of the reset height compensation variation and the scale factor variation. Detailed implementation manners

[0032] The exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary, intended to illustrate the principles and spirit of the present invention, and not to limit the scope of the present invention.

[0033] The block diagram of the fiber optic gyroscope is as Figure 1 shown. According to the Sagnac effect of the fiber optic gyroscope, the phase difference between the two interfering light beams caused by the rotation speed is:

[0034] wherein, is the length of the fiber optic loop, is the diameter of the fiber optic loop, is the central wavelength, is the pi, is the transmission speed of light in vacuum, is the input angular rate.

[0035] In the fiber optic gyroscope, the Y waveguide phase modulator is used to change the phase of the two light beams , and its expression is:

[0036] wherein, is the applied voltage; is the spacing of the planar electrodes; is the overlap integral factor of the electric field and the light field; is the length of the modulation electrode; is the extraordinary light refractive index; is the electro-optic coefficient; is the central wavelength.

[0037] In the fiber optic gyroscope, the digital quantity is converted into an analog quantity after passing through the D / A converter and the operational amplifier, and is applied to the Y waveguide phase modulator. Therefore, the feedback phase modulated by the Y waveguide is:

[0038] wherein, is the gain of the D / A converter, is the gain of the amplifier, is the output digital quantity of the fiber optic gyroscope.

[0039] In the closed-loop control system, the feedback phase is equal in magnitude and opposite in direction to the Sagnac phase:

[0040] Therefore, the scale factor of the fiber optic gyroscope is:

[0041] wherein, is the modulation coefficient of the Y waveguide, .

[0042] In engineering applications, the staircase wave signal cannot increase infinitely and needs to be reset. To reduce the influence of the gain coefficient change of the feedback channels such as the staircase wave reset and the high and low temperature characteristics of the Y waveguide phase modulator on the rotation speed error, the gain error is usually demodulated and secondary closed-loop control is performed to keep the phase difference at the reset moment always 2π. Assuming that the digital quantity of the reset height of the staircase wave is , then

[0043] Substituting the above formula into the calculation formula of the scale factor of the fiber optic gyroscope, the scale factor of the fiber optic gyroscope is:

[0044] It can be seen that for a fiber optic gyroscope using closed-loop control, its scale factor is proportional to the fiber loop length , the fiber loop diameter and the reset height , and inversely proportional to the central wavelength .

[0045] Embodiment 1: As Figure 2 shown, a closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope, which utilizes the non-periodicity of the interference curve of a fiber optic gyroscope with a broadband light source, calculates the reset light intensity error at the reset moment of the staircase wave, and monitors the change of the central wavelength in real time; by dynamically adjusting and compensating the reset height of the staircase wave, the light intensity value at the reset of the staircase wave is made equal to the light intensity value before reset through real-time closed-loop control; finally, using the mathematical model of the compensation change amount of the reset height of the staircase wave and the change amount of the scale factor, the compensation for the wavelength dependence of the scale factor of the fiber optic gyroscope is realized, including the following steps: S1. Set the modulation sequence and modulation amplitude of the fiber optic gyroscope to generate a square wave modulation signal, so that the fiber optic gyroscope includes 4 modulation states within two adjacent transit times in a cycle, and set the reset threshold and reset height of the staircase wave; The fiber optic gyroscope usually uses a broadband light source as the light source, and its interference curve is non-periodic. The interference amplitude decreases with the increase of the interference fringe order and finally loses the interference characteristics. The interference curve of the broadband light source is as shown in Appendix Figure 3As shown, the expression for the interference light intensity is:

[0046] Wherein, represents the interference light intensity, is the central wavelength, represents the cosine function, represents the natural exponential function, is the input optical power, is the spectral width, is the phase difference between the two beams of light in the fiber optic loop.

[0047] The modulation sequence is , wherein, is the step wave reset height value, and the corresponding phase difference is 2π; is the modulation digital quantity; the duration of each modulation amplitude is , and the period of the modulation sequence is , is the transit time of light propagating in the fiber optic loop; the phase difference generated by the modulation sequence for the two interfering light beams is , and the modulation depth is arbitrarily set within the range of (π / 2, π). When taking , then ; the light intensity signal corresponding to the modulation sequence is converted into a digital signal through an A / D converter and collected by an FPGA, and the corresponding signal digital quantity sequence is , and is stored in the corresponding register according to the state machine. When there are rotational speed phase and gain errors, the interference light intensity generated by the modulation sequence is as Figure 4 shown.

[0048] S2. Demodulate the rotational speed error and gain error according to the demodulation sequence. The rotational speed error outputs the rotational speed value through a rotational speed integrator, and the rotational speed value is input to a step wave integrator to generate a step wave signal, realizing the first closed-loop control feedback of the fiber optic gyroscope to the rotational speed; The demodulation method of the rotational speed error is specifically:

[0049] Wherein, represents the rotational speed error; Input the rotational speed error into the rotational speed integrator for accumulation to obtain the rotational speed value :

[0050] Input the rotational speed value into the step wave integrator for accumulation to obtain the step wave signal :

[0051] The stepped wave integrator integrates once every one transit time; The demodulation method of the gain error is specifically as follows:

[0052] Wherein, represents the gain error.

[0053] S3. When the stepped wave signal exceeds the reset threshold of the stepped wave, trigger a reset, and according to the stepped wave reset state and the modulation sequence state, demodulate the reset light intensity error according to the stepped wave reset light intensity error demodulation sequence; Set the upper threshold and the lower threshold of the reset threshold of the stepped wave:

[0054]

[0055] Judge whether the stepped wave signal exceeds the threshold value. If the digital quantity of the stepped wave signal is greater than the upper threshold , then perform a positive reset on the stepped wave, that is: ; Wherein, represents the stepped wave after positive reset, is the stepped wave signal, is the stepped wave reset height value; If the stepped wave signal is less than the lower threshold value , then perform a negative reset on the stepped wave, that is:

[0056] Wherein, represents the stepped wave after negative reset.

[0057] If the stepped wave signal is less than or equal to the upper threshold and greater than or equal to the lower threshold, no reset is performed.

[0058] When the modulation sequence at the time of reset is , it is positive modulation. When the modulation sequence at the time of reset is , it is negative modulation; when performing positive reset under positive modulation and negative reset under negative modulation, demodulate the reset light intensity error; the interference light intensity when performing positive reset under positive modulation is as Figure 5 shown, and the stepped wave reset light intensity error demodulation sequence is:

[0059] The interference light intensity when performing negative reset under negative modulation is as Figure 6As shown, the stepped-wave reset optical intensity error demodulation sequence is as follows: .

[0060] S4. After triggering the reset, the stepped-wave reset height compensation integrator accumulatively integrates the reset optical intensity error to calculate the compensated digital quantity of the stepped-wave reset height :

[0061] S5. Modify the stepped-wave reset height, and calculate the change amount of the reset height compensation; to improve the stability margin of the closed-loop control of the reset optical intensity error and reduce the influence of noise, truncate the compensated digital quantity of the stepped-wave reset height:

[0062] wherein, represents the compensated digital quantity of the stepped-wave reset height after truncation, represents taking the integer of the divisor, represents the number of truncated bits, is related to the response time of the fiber optic gyroscope, and then add / subtract according to the stepped-wave reset state and the stepped-wave reset height to dynamically adjust the reset height of the stepped-wave as shown in Figure 7 and Figure 8 specifically: If the stepped-wave reset state is positive reset under positive modulation, the reset height of the stepped-wave under the signal digital quantity modulation should subtract the compensated digital quantity of the stepped-wave reset height, and the calculation formula is:

[0063] wherein, represents the adjusted reset height of the stepped-wave; the reset height of the stepped-wave under the signal digital quantity modulation should add the compensated digital quantity of the stepped-wave reset height, and the calculation formula is; ; If the stepped-wave reset state is negative reset under negative modulation, the reset height of the stepped-wave under the signal digital quantity modulation should subtract the compensated digital quantity of the stepped-wave reset height, and the calculation formula is:

[0064] the reset height of the stepped-wave under the signal digital quantity modulation should add the compensated digital quantity of the stepped-wave reset height, and the calculation formula is:

[0065] By adjusting the reset height value in real time under different reset states, the change of the central wavelength can be tracked.

[0066] The stepped-wave reset height compensation digital quantity is smoothed and filtered to obtain , and the reset height compensation amount under the reference environmental conditions is collected and set as . When the central wavelength changes, the compensation amount of the stepped-wave reset height also changes, and the change amount of the stepped-wave reset height compensation is:

[0067] Among them, the smoothing filter selects a sliding window or a low-pass filter.

[0068] By adjusting the stepped-wave reset height to change the phase difference at the reset moment, the light intensity value at the reset time is made equal to the light intensity value before the reset. There is a formula:

[0069] Among them, is the compensation phase difference corresponding to the reset height compensation amount. According to the above formula, the central wavelength and the compensation phase difference mathematical relationship can be obtained, and the mathematical relationship between the central wavelength change amount and the reset height compensation change amount can be obtained.

[0070] When the central wavelength changes, the light intensity at the reset moment is not equal to the light intensity value before the reset, and the light intensity difference at the stepped-wave reset moment is no longer zero. After the demodulation and closed-loop control in steps S3 to S5, the compensation amount of the stepped-wave reset height also changes, and the change amount of the stepped-wave reset height compensation is:

[0071] Among them, is the reference reset height compensation amount, is the reset height compensation amount after the change of the central wavelength.

[0072] S6. According to the mathematical relationship between the reset height compensation change amount and the scale factor change amount, the scale factor compensation coefficient is calculated; the mathematical relationship between the reset height compensation change amount and the scale factor change amount is a linear equation or a polynomial equation, and the coefficients of the linear equation or the polynomial equation are related to the fiber optic gyro parameters and are obtained by fitting using numerical calculation methods. According to the light intensity equation before and after the reset, the relationship between the reset height compensation phase difference and the central wavelength can be calculated. Since the relationship between the fiber optic gyro scale factor and the central wavelength is as shown in the formula , therefore, a mathematical model between the reset height compensation change amount and the scale factor change amount can be established. By using numerical calculation methods, the reset height compensation change amount with the change amount of the scale factor is fitted to a linear term or a polynomial compensation model, and its coefficients are related to parameters such as the set modulation depth When the modulation depth is , the compensation model and coefficients of the reset height compensation change amount and the scale factor change amount are as Figure 9 shown

[0073] Due to the modulation depth set in step S1 When using a linear term compensation model , the scale factor compensation coefficient

[0074] S7. Multiply the original data of the fiber optic gyro by the scale factor compensation coefficient to obtain the compensated rotational speed value output, realizing the suppression of the wavelength dependence of the scale factor; Multiply the rotational speed value in the demodulation data of the fiber optic gyro in step S2 by the scale factor compensation coefficient to obtain the rotational speed value output compensated with the center wavelength

[0075] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations without departing from the essence of the present invention based on the technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. A closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope, characterized in that, It includes the following steps: Set the modulation sequence and modulation amplitude of the fiber optic gyroscope to generate a modulation signal, and set the reset threshold and reset height of the staircase wave; Demodulate the rotation speed error and gain error according to the demodulation sequence, and then input the demodulated rotation speed error into the rotation speed integrator and the staircase wave integrator to generate a staircase wave signal, realizing the first closed-loop control feedback of the rotation speed; input the gain error into the reference voltage integrator to adjust the reference voltage of the D / A converter in the subsequent feedback channel, so that the gain coefficient of the feedback channel remains unchanged, realizing the second closed-loop control of the feedback gain; If the staircase wave signal exceeds the reset threshold of the staircase wave, trigger a reset, and demodulate the reset light intensity error according to the staircase wave reset state and the modulation sequence state according to the staircase wave reset light intensity error demodulation sequence; if the staircase wave signal does not exceed the reset threshold of the staircase wave, then superimpose the staircase wave signal and the modulation signal; After triggering the reset, accumulate and integrate the demodulated reset light intensity error through the staircase wave reset height compensation integrator to calculate the compensation digital quantity of the staircase wave reset height; Truncate the compensation digital quantity of the staircase wave reset height, and then reset the staircase wave signal to realize the third closed-loop control feedback of the staircase wave reset height; smooth-filter the truncated compensation digital quantity of the staircase wave reset height, collect the compensation quantity reference value under the reference condition, and divide the smoothed compensation digital quantity of the staircase wave reset height by the compensation quantity reference value to obtain the reset height compensation change quantity; Calculate the scale factor compensation coefficient according to the mathematical relationship between the reset height compensation change quantity and the scale factor change quantity; Multiply the original number of the fiber optic gyroscope by the scale factor compensation coefficient to output the compensated rotation speed value, realizing the suppression of the wavelength dependence of the scale factor.

2. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 1, wherein The modulation sequence is , where is the staircase wave reset height value, and the corresponding phase difference is 2π; is the modulation digital quantity; the duration of each modulation amplitude is , and the period of the modulation sequence is , is the transit time of light propagating in the fiber loop; The modulation sequence causes the phase difference generated by the two interfering light beams to be , arbitrarily set within the range of (π / 2, π); The optical intensity signal corresponding to the modulation sequence is converted into a digital signal by an A / D converter, and the digital quantity of the signal corresponding to the modulation sequence is collected by an FPGA , , and , and the obtained sequence of signal digital quantities is .

3. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of the fiber optic gyroscope according to claim 2, characterized in that The demodulation method of the rotation speed error is specifically as follows: Among them, represents the rotational speed error; The rotational speed error is input into a rotational speed integrator for accumulation to obtain a rotational speed value : The rotational speed value is input into a stepped wave integrator for accumulation to obtain a stepped wave signal : The staircase wave integrator integrates once every 1 transit time.

4. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 2, wherein When the staircase wave signal exceeds the reset threshold of the staircase wave, trigger a reset, and demodulate the reset light intensity error according to the staircase wave reset state and the modulation sequence state according to the staircase wave reset light intensity error demodulation sequence, which specifically includes the following steps: Set the upper threshold of the reset threshold of the staircase wave and the lower threshold ; If the staircase wave signal is greater than the upper threshold , then perform a positive reset on the staircase wave, i.e.: ； Among them, represents the stepped wave after positive reset, is the stepped wave signal, is the stepped wave reset height value; If the staircase wave signal is less than the lower threshold value , then perform a negative reset on the staircase wave, i.e.: Among them, represents the sawtooth wave after negative reset; If the staircase wave signal is less than or equal to the upper threshold and greater than or equal to the lower threshold, no reset is performed; When the modulation sequence at reset is it is positive modulation, and when the modulation sequence at reset is it is negative modulation; where is the modulation digital quantity. During positive reset under positive modulation and negative reset under negative modulation, demodulate the reset light intensity error.

5. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 4, characterized in that, When the set staircase wave reset phase difference is equal to 2π, the reset light intensity error is caused by the non-periodicity of the broadband light source interference curve; When performing positive reset under positive modulation, the stepped-wave reset optical intensity error demodulation sequence is as follows: When performing negative reset under negative modulation, the stepped wave reset optical intensity error demodulation sequence is as follows: 。 6. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 1, characterized in that, The formula for truncating the compensation digital quantity of the staircase wave reset height is: Among them, represents the digital quantity of the stepped wave reset height compensation after truncation, represents rounding the divisor, represents the digital quantity of the stepped wave reset height compensation, represents the number of truncated bits, which is related to the response time of the fiber optic gyroscope.

7. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 5, characterized in that, The reset of the staircase wave signal to realize the third closed-loop control feedback of the staircase wave reset height specifically includes the following steps: Dynamically adjust the reset height of the staircase wave according to the staircase wave reset state to obtain the reset height of the adjusted staircase wave ; Perform staircase wave reset according to the adjusted reset height of the staircase wave to obtain the reset staircase wave; Superimpose the reset staircase wave and the modulation signal to realize the third closed-loop control feedback of the staircase wave reset height.

8. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 7, characterized in that The method for dynamically adjusting the reset height of the staircase wave according to the staircase wave reset state is specifically as follows: If the step wave reset state is positive reset under positive modulation, then subtract the step wave reset height compensation digital quantity after truncation from the step wave reset height under the signal digital quantity modulation, and add the step wave reset height compensation digital quantity after truncation to the step wave reset height under the signal digital quantity modulation; If the stepped wave reset state is negative reset under negative modulation, then subtract the compensated digital quantity of the reset height of the stepped wave after truncation from the reset height of the stepped wave under the signal digital quantity modulation, and add the compensated digital quantity of the reset height of the stepped wave after truncation to the reset height of the stepped wave under the signal digital quantity modulation.

9. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 7, characterized in that, The staircase wave reset according to the adjusted reset height of the staircase wave is specifically: If it is a positive reset, the sawtooth wave after reset The calculation formula is as follows: Among them, is a staircase wave signal; If it is a positive reset, the stepped wave after reset The calculation formula is as follows: 。 10. The closed-loop compensation method for suppressing the wavelength dependence of the scale factor of a fiber optic gyroscope according to claim 1, characterized in that, The mathematical relationship between the reset height compensation variation and the scale factor variation is a linear equation or a polynomial equation. The coefficients of the linear equation or the polynomial equation are related to the parameters of the fiber optic gyroscope and are obtained by fitting using numerical calculation methods.

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