阅读说明：本技术 一种光纤陀螺振铃效应误差抑制系统及抑制方法 (System and method for suppressing ringing effect error of fiber optic gyroscope ) 是由 张琛 凌卫伟 杜石鹏 段威 刘金辉 陈超人 于 2021-11-08 设计创作，主要内容包括：本发明提供一种光纤陀螺振铃效应误差抑制系统及抑制方法,抑制系统包括宽谱光源、光纤干涉仪、PIN光电二极管、温度传感器和信号处理电路,所述信号处理电路至少包括I/V转换电路、高速模拟开关电路、主控芯片(或其它主控芯片)和反馈驱动电路。本发明在设计中采用了单独的PIN光电二极管器件,有效抑制陀螺干涉信号中梳状脉冲带来的振铃效应,并且根据光纤陀螺中光纤环的温度变化信息,对高速模拟开关电路的采样的开关门限和采样点分布进行调整,使得被采样的信号一直处在稳定区域,进而有效抑制了温度漂移误差和角振动、冲击误差,大幅度提升光纤陀螺产品的工程化性能。(The invention provides a ringing effect error suppression system and a ringing effect error suppression method for an optical fiber gyroscope, wherein the suppression system comprises a wide-spectrum light source, an optical fiber interferometer, a PIN photodiode, a temperature sensor and a signal processing circuit, and the signal processing circuit at least comprises an I/V conversion circuit, a high-speed analog switch circuit, a main control chip (or other main control chips) and a feedback driving circuit. According to the invention, an independent PIN photodiode device is adopted in the design, the ringing effect caused by comb pulses in the interference signal of the gyroscope is effectively inhibited, and the distribution of the sampling switching threshold and the sampling points of the high-speed analog switching circuit is adjusted according to the temperature change information of the optical fiber ring in the optical fiber gyroscope, so that the sampled signal is always in a stable region, the temperature drift error, the angular vibration and the impact error are effectively inhibited, and the engineering performance of the optical fiber gyroscope product is greatly improved.)

1. A ringing effect error suppression system of a fiber optic gyroscope is characterized by comprising a wide spectrum light source, a fiber optic interferometer, a PIN photodiode, a temperature sensor and a signal processing circuit, wherein the signal processing circuit at least comprises an I/V conversion circuit, a high-speed analog switch circuit, a low-pass filtering amplification circuit, a differential operational amplification circuit, an analog-to-digital conversion circuit, a main control chip, a digital-to-analog conversion circuit and a feedback drive circuit;

the temperature sensor is used for collecting temperature information of a fiber ring in the fiber interferometer and transmitting the temperature information to the main control chip;

the PIN photodiode is used for converting an interference output signal of the optical fiber interferometer into a current signal;

the I/V conversion circuit is used for converting the current signal into a voltage signal;

the high-speed analog switch circuit is used for filtering comb-shaped pulses in a time domain through on-off control;

the low-pass amplification filter circuit is used for further performing low-pass filtering and gain amplification on the time-domain filtered electric signal;

the differential operational amplifier circuit is used for converting the gain-amplified electric signal into a double-end output;

the analog/digital conversion circuit is used for converting the analog electric signals input in a differential mode into serial or parallel digital signals and inputting the digital signals into the main control chip;

the main control chip is used for generating a phase modulation waveform and a feedback waveform according to the parameters of the fiber optic gyroscope system, and acting on the fiber optic interferometer through the digital/analog conversion circuit and the feedback drive circuit; and adjusting the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring acquired by the temperature sensor.

2. The system for suppressing ringing effect error of an optical fiber gyroscope according to claim 1, wherein the main control chip is configured to adjust the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring collected by the temperature sensor, and includes:

calculating a temperature difference value between the acquired temperature value of the optical fiber ring and a temperature reference value, and performing negative adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit when the temperature difference value is a negative value and reaches a negative adjustment value;

when the temperature difference value is a positive value and reaches a forward adjustment value, performing forward adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit;

and in the process of carrying out negative or positive adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit, keeping the closed-loop gain stable and the output noise of the fiber-optic gyroscope to be the lowest, and stopping adjustment.

3. The fiber optic gyroscope ringing error suppression system of claim 2, wherein the distribution of sample points comprises locations of sample points and densities of sample points.

4. The system for suppressing ringing error of fiber optic gyroscope of claim 1, wherein the temperature sensor is configured to collect temperature information of a fiber ring in the fiber optic interferometer and transmit the temperature information to the main control chip, and the system comprises:

and reading the temperature information of the optical fiber ring in the optical fiber interferometer by adopting a digital temperature sensor input mode, a platinum resistor sampling input mode or a fluorescence optical fiber temperature measurement input mode.

5. A ringing error suppression method of a fiber optic gyroscope based on a ringing error suppression system of the fiber optic gyroscope is characterized in that the ringing error suppression system of the fiber optic gyroscope comprises a wide spectrum light source, a fiber optic interferometer, a PIN photodiode, a temperature sensor and a signal processing circuit, wherein the signal processing circuit at least comprises an I/V conversion circuit, a high-speed analog switch circuit, a main control chip and a feedback drive circuit; the inhibition method comprises the following steps:

the PIN photodiode converts an interference output signal of the optical fiber interferometer into a current signal, and the current signal is converted into a voltage signal through an I/V conversion circuit;

the temperature sensor collects the temperature information of the optical fiber ring in the optical fiber interferometer and transmits the temperature information to the main control chip;

comb-shaped pulses in the electric signals are filtered out in a time domain through on-off control of a high-speed analog switch circuit;

according to the electric signal after time domain filtering, the main control chip generates a phase modulation waveform and a feedback waveform, and acts on the optical fiber interferometer through a feedback driving circuit; the main control chip also adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring acquired by the temperature sensor.

6. The method for suppressing ringing error in a fiber optic gyroscope of claim 5, further comprising:

and matching the resistance-capacitance parameters of the I/V conversion circuit so that the output of the I/V conversion circuit is kept stable.

7. The method for suppressing ringing effect errors of an optical fiber gyroscope according to claim 6, wherein the main control chip further adjusts the switching threshold and the distribution of sampling points of the high-speed analog switching circuit according to the temperature information of the optical fiber ring collected by the temperature sensor, and the method comprises:

calculating a temperature difference value between the acquired temperature value of the optical fiber ring and a temperature reference value, and performing negative adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit when the temperature difference value is a negative value and reaches a negative adjustment value;

when the temperature difference value is a positive value and reaches a forward adjustment value, performing forward adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit;

and in the process of carrying out negative or positive adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit, keeping the closed-loop gain stable and the output noise of the fiber-optic gyroscope to be the lowest, and stopping adjustment.

8. The method of claim 7, wherein the distribution of sampling points comprises locations of the sampling points and densities of the sampling points.

Technical Field

The invention relates to the field of optical fiber sensing in the photoelectronic technology, in particular to a ringing effect error suppression system and a ringing effect error suppression method of an optical fiber gyroscope.

Background

The Fiber Optic Gyroscope (Fiber Optic Gyroscope) is an all-solid-state design angular velocity sensor based on the optical Sagnac effect, has the advantages of high reliability, wide precision adaptation range and the like, and is widely applied to multiple directions such as servo tracking control, attitude measurement, navigation guidance and the like.

The basis for realizing the function of the fiber-optic gyroscope is real-time detection of output optical signals of the interferometer by a photoelectric conversion device. The photoelectric conversion device commonly used at present is essentially an optical fiber communication device, the design is more prone to control the error rate of digital signals, the application requirements of the optical fiber gyroscope per se are not completely matched, and the prominent problem is zero offset error caused by ringing effect.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides a system and a method for suppressing ringing effect errors of a fiber optic gyroscope.

According to a first aspect of the invention, a ringing error suppression system of a fiber optic gyroscope is provided, which comprises a wide spectrum light source, a fiber optic interferometer, a PIN photodiode, a temperature sensor and a signal processing circuit, wherein the signal processing circuit at least comprises an I/V conversion circuit, a high-speed analog switch circuit, a low-pass filtering amplification circuit, a differential operational amplification circuit, an analog/digital conversion circuit, a main control chip, a digital/analog conversion circuit and a feedback drive circuit;

the temperature sensor is used for collecting temperature information of a fiber ring in the fiber interferometer and transmitting the temperature information to the main control chip; the PIN photodiode is used for converting an interference output signal of the optical fiber interferometer into a current signal; the I/V conversion circuit is used for converting the current signal into a voltage signal; the high-speed analog switch circuit is used for filtering comb-shaped pulses in a time domain through on-off control; the low-pass amplification filter circuit is used for further performing low-pass filtering and gain amplification on the time-domain filtered electric signal; the differential operational amplifier circuit is used for converting the gain-amplified electric signal into a double-end output; the analog/digital conversion circuit is used for converting the analog electric signals input in a differential mode into serial or parallel digital signals and inputting the digital signals into the main control chip; the main control chip is used for generating a phase modulation waveform and a feedback waveform according to the parameters of the fiber optic gyroscope system, and the phase modulation waveform and the feedback waveform act on the fiber optic interferometer through the digital/analog conversion circuit and the feedback drive circuit; and adjusting the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring acquired by the temperature sensor.

On the basis of the technical scheme, the invention can be improved as follows.

Optionally, the main control chip is configured to adjust a switching threshold and distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring collected by the temperature sensor, and includes: calculating a temperature difference value between the acquired temperature value of the optical fiber ring and a temperature reference value, and performing negative adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit when the temperature difference value is a negative value and reaches a negative adjustment value; when the temperature difference value is a positive value and reaches a forward adjustment value, performing forward adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit; and in the process of carrying out negative or positive adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit, keeping the closed-loop gain stable and the output noise of the fiber-optic gyroscope to be the lowest, and stopping adjustment.

Optionally, the distribution of sampling points includes positions of the sampling points and densities of the sampling points.

Optionally, the temperature sensor is configured to collect temperature information of the optical fiber ring in the optical fiber interferometer, and transmit the temperature information to the main control chip, and the temperature sensor includes: and reading the temperature information of the optical fiber ring in the optical fiber interferometer by adopting a digital temperature sensor input mode, a platinum resistor sampling input mode or a fluorescence optical fiber temperature measurement input mode.

According to a second aspect of the present invention, there is provided a method for suppressing ringing errors of a fiber optic gyroscope, the method comprising: the PIN photodiode converts an interference output signal of the optical fiber interferometer into a current signal, and the current signal is converted into a voltage signal through an I/V conversion circuit; the temperature sensor collects the temperature information of the optical fiber ring in the optical fiber interferometer and transmits the temperature information to the main control chip; comb-shaped pulses in the electric signals are filtered out in a time domain through on-off control of a high-speed analog switch circuit; according to the electric signal after time domain filtering, the main control chip generates a phase modulation waveform and a feedback waveform, and acts on the optical fiber interferometer through a feedback driving circuit; the main control chip also adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring acquired by the temperature sensor.

Optionally, the method further includes: and matching the resistance-capacitance parameters of the I/V conversion circuit so that the output of the I/V conversion circuit is kept stable.

Optionally, the main control chip further adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring collected by the temperature sensor, and includes: calculating a temperature difference value between the acquired temperature value of the optical fiber ring and a temperature reference value, and performing negative adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit when the temperature difference value is a negative value and reaches a negative adjustment value; when the temperature difference value is a positive value and reaches a forward adjustment value, performing forward adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit; and in the process of carrying out negative or positive adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switching circuit, keeping the closed-loop gain stable and the output noise of the fiber-optic gyroscope to be the lowest, and stopping adjustment.

Optionally, the distribution of sampling points includes positions of the sampling points and densities of the sampling points.

According to the system and the method for inhibiting the ringing effect error of the optical fiber gyroscope, an optical fiber gyroscope scheme adopting an independent PIN photodiode device is designed, the ringing effect caused by comb-shaped pulses in interference signals is effectively inhibited, and the switching threshold and the sampling points of a high-speed analog switching circuit are distributed according to the temperature change information of an optical fiber ring in the optical fiber gyroscope, so that the sampled signals are in a stable area, the temperature drift error, the angular vibration error and the impact error are effectively inhibited, and the engineering performance of the optical fiber gyroscope product is greatly improved.

Drawings

FIG. 1 is a diagram illustrating ringing effects;

FIG. 2-1 is a schematic diagram of a comb-shaped pulse signal of a fiber optic gyroscope, and FIG. 2-2 is a schematic diagram of an enlarged ringing effect of FIG. 2-1;

FIG. 3 is a schematic structural diagram of a ring effect error suppression system of a fiber optic gyroscope according to the present invention;

FIG. 4-1 is a diagram illustrating a conventional debugging result of a high-speed analog switch circuit by a main control chip;

FIG. 4-2 is a schematic diagram showing the follow-up adjustment result of the main control chip to the high-speed analog switch circuit after temperature change;

fig. 5 is a flowchart of a method for suppressing ringing errors of a fiber optic gyroscope according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the adjustment of the high speed analog switch circuit based on temperature information.

In the drawings, the names of the components represented by the respective reference numerals are as follows:

1. the device comprises a wide-spectrum light source, a 2 optical fiber interferometer, a 3 PIN photodiode, a 4I/V conversion circuit, a 5 high-speed analog switch circuit, a 6 low-pass amplification filter circuit, a 7 differential operational amplifier circuit, an 8 analog/digital conversion circuit, a 9 main control chip, a 10 digital/analog conversion circuit, a 11 feedback driving circuit, a 12 temperature sensor.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Before explaining the ring effect suppression system of the fiber optic gyroscope provided by the embodiment of the invention, the ring effect of the fiber optic gyroscope and the zero offset error caused by the ring effect are introduced.

Ringing is an oscillating effect with a certain decay rate occurring near the edges when the signal is rapidly switched. In the time domain, the ringing is caused by the ripple in the Sinc function, i.e. the impulse response of a perfect low-pass filter. Mathematically called gibbs phenomenon, in which the ringing effect is schematically shown in figure 1.

The interference output signal of the fiber-optic gyroscope contains comb-shaped pulses with large amplitude, the pulses are invalid signals, and direct sampling can cause large demodulation errors. In practice, a scheme of sampling a signal in a mode of avoiding pulses and filtering out pulse signals by using a high-speed analog switch is adopted. However, because the ringing effect (harmonic components) caused by the comb-like pulses can have a coupling effect on the flat area of the signal, the flat area exhibits a series of overshoots and oscillations as the pulse energy is released.

The comb-shaped pulse signal of the fiber-optic gyroscope is shown in figure 2-1, and the ringing effect caused by the comb-shaped pulse signal is shown in figure 2-2. Due to the nonideality of the optical fiber gyroscope digital/analog conversion circuit and the feedback drive circuit, the actual modulation signal cannot ensure the completely accurate waveform proportion, the rising edge time and the falling edge time generated when the modulation phase changes are not strictly equal, the asymmetry of the modulated waveform and the inconsistency of left and right peak pulses in the demodulation period can be caused, the optical fiber gyroscope zero offset error is generated after the signal is sampled and demodulated, and the influence range on the flat area changes along with the working environment and the working state.

Firstly, when the temperature changes, the refractive index of the optical fiber ring of the optical fiber gyroscope and the length of the optical fiber can change, which directly causes the change of the transition time of the optical fiber interferometer, because the modulation waveform period is not changed, the pulse output by interference becomes wider, the corresponding ringing effect wave coverage is larger, and the demodulated signal also generates a zero offset drift error along with the temperature change. Also, changes in the modulation waveform with temperature can cause the interferometric output pulses to vary.

In addition, in the process that the optical fiber gyroscope directly senses angular acceleration such as angular vibration, impact and the like, interference signals in a demodulation period generate half-period signals on two sides of comb-shaped pulses (parts) to be shifted up and down, the amplitude of the left half pulse and the amplitude of the right half pulse are changed, and corresponding ringing errors are also changed. The continuous angular vibration can cause the gyro system to be continuously incapable of closing a loop, and the two sides of the pulse are always changed to form an up-down offset signal, so that a gyro vibration error is caused. Similarly, transient impacts can also cause transient fiber optic gyroscope impact errors.

If the generation of the original comb pulse ringing effect can be controlled in the circuit design, the problem of environmental errors caused by the comb pulse ringing effect can be fundamentally solved.

Based on this, the invention provides a ring effect error suppression system of a fiber optic gyroscope as shown in fig. 3, which mainly comprises a wide spectrum light source 1, a fiber optic interferometer 2, a PIN photodiode 3, an I/V conversion circuit 4, a high-speed analog switch circuit 5, a low-pass amplification filter circuit 6, a differential operational amplifier circuit 7, an analog-to-digital conversion circuit 8, a main control chip 9, a digital-to-analog conversion circuit 10, a feedback drive circuit 11, a temperature sensor 12, other configuration circuits and the like.

The temperature sensor 12 is configured to collect temperature information of the optical fiber loop in the optical fiber interferometer 2, and transmit the temperature information to the main control chip 9. The temperature information of the optical fiber ring in the optical fiber interferometer 2 can be read by adopting a digital temperature sensor input mode, a platinum resistor sampling input mode or a fluorescence optical fiber temperature measurement input mode.

A PIN photodiode 3 for converting an interference output signal of the fiber interferometer 2 into a current signal; an I/V conversion circuit 4 for converting the current signal into a voltage signal; a high-speed analog switch circuit 5 for filtering comb-like pulses in the time domain by on-off control; the main control chip 9 is configured to generate a phase modulation waveform and a feedback waveform according to the electrical signal after time domain filtering, and act on the optical fiber interferometer 2 through the feedback driving circuit 11; and adjusting the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5 according to the temperature information of the optical fiber ring acquired by the temperature sensor 12.

The function of each component in the ringing effect error suppression system of the fiber optic gyroscope is described as follows:

temperature sensor 12: the temperature information of the optical fiber ring in the optical fiber interferometer 2 of the optical fiber gyroscope is collected and transmitted to the main control chip 9.

PIN photodiode 3: the PIN photodiode 3 has a bandwidth of more than 3GHz and a junction capacitance of less than 0.5pF, and is a nearly ideal optical fiber gyro photoelectric conversion device, and the ringing effect of the PIN photodiode is negligible.

I/V conversion circuit 4: the PIN photodiode 3 is converted into a current signal which needs to be converted into a voltage signal which is easier to sample, and the I/V conversion circuit 4 is designed and realized and simultaneously impedance matching is completed; by optimizing the configuration of proper resistance-capacitance parameters (related to the selection of a specific conversion device), the smooth transition of the pulse attenuation part is adjusted, and overshoot and oscillation are avoided. High bandwidth, low noise FET input operational amplifiers can be used, with the JFET input producing little current noise, and the amplifier itself has excellent bandwidth, accuracy and sensitivity.

High-speed analog switch circuit 5: the high-speed analog switch circuit 5 is used for filtering comb pulses in a time domain by on-off control, avoiding interference output distortion caused by pulse widening due to circuit signal amplification and optical path parameter change, and can select ADG721 or DG612 and the like.

The low-pass amplification filter circuit 6: and the signals subjected to time domain filtering by the high-speed analog switch circuit 5 are subjected to gain amplification, so that the signal-to-noise ratio of the signals is improved, and high-frequency signal noise is filtered.

Differential operational amplifier circuit 7: the signal is converted into double-end output through the differential operational amplifier circuit 7, and the influence of common-mode noise can be effectively inhibited.

Analog/digital conversion circuit 8: the differential input is converted into parallel or serial digital signals through an analog-to-digital conversion circuit, and the conversion bit number is selected according to the precision requirement and input to the main control chip 9.

The main control chip 9: as a core device for digital signal processing and algorithm implementation, the main control chip 9 may be an FPGA, and the main control chip 9 performs various functions such as signal modulation, information sampling, signal demodulation, data integration, closed-loop gain control, error compensation, rotational speed output, and output of closed-loop feedback waveforms. Wherein digital superposition of the phase modulation waveform and the feedback step wave can be achieved. The main control chip 9 adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5 according to the temperature information of the optical fiber ring collected by the temperature sensor.

Digital/analog conversion circuit 10: the digital output of the main control chip 9 is converted into an analog signal including a modulation waveform, a feedback waveform, and the like.

The feedback drive circuit 11: the waveform signal output from the digital/analog conversion circuit 10 is converted into a desired effect to be given to the fiber interferometer 2.

The main control chip 9 adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5 according to the temperature information of the optical fiber ring collected by the temperature sensor, and the specific adjusting method comprises the following steps: calculating a temperature difference value between the acquired temperature value of the optical fiber ring and a temperature reference value, and performing negative adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5 when the temperature difference value is a negative value and reaches a negative adjustment value; when the temperature difference value is a positive value and reaches a forward adjustment value, performing forward adjustment on the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5; during the process of adjusting the switching threshold and the sampling point distribution of the high-speed analog switching circuit 5 in a negative direction or a positive direction, the closed-loop gain is kept stable, the output noise of the fiber-optic gyroscope is kept to be the lowest, and the adjustment is stopped.

It will be appreciated that the length and refractive index of the fibre loop constituting the fibre optic interferometer 2 will vary with temperature, resulting in a change in the transit time, and that the comb pulses of the interferometric output signal will be broadened due to misalignment of the modulation waveform and the transit time. In addition, variations in the device parameters (including digital-to-analog converter and driving circuit) of the modulation and feedback channels, as well as variations in the configured rc parameters, can also cause variations in the modulation waveform edges, which also causes broadening of the comb pulse signal. Under the condition of temperature change, time-domain filtering and sampling parameter setting which are debugged at normal temperature are not suitable. Therefore, according to the embodiment of the present invention, a processing scheme for time-domain filtering and real-time adjustment of the sampling position is designed according to the change of the pulse broadening along with the temperature, wherein a schematic diagram of a conventional debugging result is shown in fig. 4-1, and when the temperature of the optical fiber ring changes, a schematic diagram of follow-up adjustment is shown in fig. 4-2.

The specific adjustment scheme is that under the condition that the hardware of the fiber-optic gyroscope system is determined, the input of the temperature sensor is used as reference, and the switch threshold and the distribution of sampling points are adjusted through the program design in the main control chip 9 according to the change rule of the comb pulse broadening. With the temperature change, the comb pulse expands to the left, the analog switch threshold expands to the left, the sampling point shrinks to the left, and the closed loop gain is correspondingly adjusted. Comb pulses are expanded rightwards, an analog switch threshold is expanded rightwards, sampling points are reduced rightwards, and closed loop gains are correspondingly adjusted. In short, when the temperature of the collected optical fiber ring is higher than the reference temperature value, the optical fiber ring expands, and the pulse of the optical fiber ring expands towards two sides; when the temperature of the optical fiber ring is lower than the reference temperature value, the optical fiber ring contracts, and the pulse of the optical fiber ring is close to the middle, so that the switching threshold and the distribution of sampling points of the high-speed analog switch circuit 5 need to be adjusted no matter the pulse expands to both sides or contracts to the middle, so that the sampled signal is always in a stable region.

By the scheme, the influence of comb pulse broadening of the interference signal is suppressed, and the sampled signal is always in a stable region by adjusting the position and the number of sampling points. Therefore, the gyro can realize low-noise output in a normal temperature environment, and the zero-bias stability in a temperature change state can be ensured. The relationship between the pulse broadening and the analog switch threshold and the change of the sampling point can be obtained through calculation and also can be obtained through testing and accumulated experience.

Referring to fig. 5, a method for suppressing ringing effect error of a fiber optic gyroscope according to an embodiment of the present invention is provided, including: the temperature sensor collects the temperature information of the optical fiber ring in the optical fiber interferometer and transmits the temperature information to the main control chip; the PIN photodiode converts an interference output signal of the optical fiber interferometer into a current signal, and the current signal is converted into a voltage signal through an I/V conversion circuit; comb-shaped pulses in the electric signals are filtered out in a time domain through on-off control of a high-speed analog switch circuit; according to the electric signal after time domain filtering, the main control chip generates a phase modulation waveform and a feedback waveform, and acts on the optical fiber interferometer through a feedback driving circuit; the main control chip also adjusts the switching threshold and the distribution of sampling points of the high-speed analog switch circuit according to the temperature information of the optical fiber ring acquired by the temperature sensor.

Specifically, referring to fig. 6, a detailed description is given of the method for suppressing ringing effect errors of the fiber-optic gyroscope, which mainly includes the following steps:

(1) the optical fiber gyroscope with the PIN photodiode device is combined to form a schematic diagram, and an optical fiber gyroscope hardware system is built with the aim of not causing overshoot and oscillation of pulse signals, and specifically comprises the following steps:

the output of the wide-spectrum light source is connected with the optical fiber interferometer to provide the reference light wave for the optical fiber interferometer. And after the optical interference is finished in the interferometer, the output is connected with a PIN photodiode device to finish the photoelectric conversion of the interference signal. And then connected with an I/V conversion circuit to convert the current signal of the photoelectric conversion into a voltage signal which is easy to sample and process. And the control threshold of the high-speed analog switch circuit is controlled by the main control chip. The high-speed analog switch circuit outputs the signal after completing the time domain filtering to the low-pass amplification filter circuit, and signal-to-noise ratio improvement and high-frequency noise filtering are completed. And outputting the signal to a differential operational amplifier circuit to suppress common-mode noise. The signals are output to an AD conversion circuit and converted into parallel or serial digital signals. And outputting the data to a main control chip for digital signal processing and closed-loop control algorithm realization. And the output is sent to a DA conversion circuit and a level conversion circuit, the output of a modulation waveform and a feedback waveform is carried out, and the digital output of a rotating speed signal is carried out. The waveform of the DA conversion circuit is connected with the optical fiber interferometer through the driving circuit, and phase modulation and closed-loop control are carried out on the optical fiber interferometer.

And designing the resistance-capacitance matching parameters of the I/V conversion circuit, checking the output of the I/V conversion circuit by using a high-speed oscilloscope, and if the output spike pulse does not meet the requirements according to the designed parameters, adjusting the resistance-capacitance parameters of the I/V conversion circuit until the output of the I/V conversion circuit is stable.

(2) Combining the servo adjustment schematic diagram of comb pulse widening to adjust the threshold and sampling point of the high-speed analog switch in real time, designing and realizing a corresponding adjustment program in a main control chip, specifically: after the optical fiber gyroscope is started and self-checked, stable internal temperature information of the optical fiber gyroscope is read, and the internal temperature information can be input by a digital temperature sensor, platinum resistance sampling input or fluorescence optical fiber temperature measurement input and the like.

The read temperature is compared with a reference temperature (which may be 25 ℃ or other set temperature) to make a difference, and the positive or negative of the difference is judged. And judging whether the difference value reaches an adjustment threshold, wherein the threshold is determined by a stepping value, the stepping value is synchronously controlled by a waveform modulation generator, and the gyro temperature data is repeatedly read if the difference value does not reach the threshold. If the temperature change reaches the negative adjustment threshold (at the moment, the comb pulse expands to the left), the threshold and the sampling point distribution of the high-speed analog switch are adjusted in a negative direction according to a calculation result or an empirical formula. Similarly, if the temperature change reaches a positive adjustment threshold (at which time the comb pulse spreads to the right), the threshold of the high speed analog switch and the sample point distribution are adjusted negatively.

And after the adjustment is finished, the analog switch threshold and the distribution of the sampling points are locked. And adjusting the gain control module according to the influence of the sampling distribution on the closed-loop gain, so as to ensure the closed-loop control and the stable output.

Compared with the prior art, the ringing effect error suppression system and the ringing effect error suppression method for the fiber optic gyroscope provided by the embodiment of the invention have the following beneficial effects:

(1) by utilizing the design of the PIN photodiode and the back-end circuit thereof, the energy release characteristic of the pulse signal is changed, the influence of the ringing effect is fundamentally inhibited, the effective sampling interval of the signal is expanded, and the zero offset error caused by signal demodulation is avoided;

(2) by reading temperature information and programming in the main control chip, the threshold and the sampling point of the high-speed analog switch are adjusted in real time, and the zero-offset stability of the optical fiber gyroscope is effectively improved under the condition of variable temperature on the premise of not influencing closed-loop gain.

(3) The beneficial effect of the scheme is also reflected in the adaptability of the fiber-optic gyroscope to dynamic environments such as vibration, impact and the like.

It should be noted that, in the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to relevant descriptions of other embodiments for parts that are not described in detail in a certain embodiment.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.