Broad-spectrum light source resonant fiber gyroscope based on superheterodyne method

Abstract

The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method belongs to the technical field of resonant fiber gyroscope, and particularly relates to a wide-spectrum light source resonant fiber gyroscope; it solves the problem that when the existing resonant fiber gyroscope based on wide-spectrum light source uses high-frequency modulation to suppress relative intensity noise, it is necessary to adjust the parameters of the subsequent filter in real time according to the modulation frequency, resulting in too frequent system adjustments, cumbersome operations, and difficulty in realizing the integration of such gyroscopes, which is not convenient for the promotion and application of such gyroscopes; the digital system includes a mixer I, an integrator, a voltage-controlled oscillator, a reference signal generating unit, a phase detector, a low-pass filter II, a mixer II and a crystal oscillator. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method is suitable for measuring speed signals.

Description

Technical Field

[0001] The invention relates to the technical field of resonant fiber gyroscopes, and in particular to a wide-spectrum light source resonant fiber gyroscope. Background Art

[0002] In recent years, with the development of industries such as manned space flight, deep space exploration, and conventional ammunition guidance, the performance requirements for inertial devices have become increasingly higher.

[0003] The resonant fiber gyroscope (RFOG) is a high-precision inertial device based on the Sagnac effect. Its basic principle is to detect the angular rate of rotation by detecting the resonant frequency difference between two light beams transmitted in opposite directions in a ring resonator. Compared with the first generation of interferometric fiber gyroscopes, to achieve the same detection accuracy, the optical fiber required for RFOG is much shorter, which not only reduces the size of the system, but also reduces the drift caused by the uneven temperature distribution in the fiber ring, providing a feasible solution for the development of high-performance inertial devices.

[0004] The existing common RFOGs all use narrow-linewidth laser light sources with high coherence and long coherence length, in order to make the resonance curve produced by the resonant cavity narrower and improve the detection accuracy of the gyro system. However, the core sensitive element used for the rotation signal in the RFOG, namely the fiber ring resonator, is generally composed of polarization-maintaining fiber. The long coherence length will cause the backscattered light in the fiber loop to easily interfere with the main light wave, which will bring a series of strong parasitic noises including backscattering noise, polarization noise, nonlinear Kerr effect noise, etc., which greatly limits the actual accuracy and engineering application of RFOG.

[0005] Due to the above-mentioned disadvantages of narrow-linewidth laser light sources with high coherence and long coherence length, resonant fiber gyroscopes based on wide-spectrum light sources have gradually become a research hotspot in the RFOG field in recent years.

[0006] Compared with narrow-linewidth laser light sources, the optical signals generated by low-coherence wide-spectrum light sources have weak temporal coherence. Using wide-spectrum light sources as the light source of the gyroscope system can effectively reduce parasitic noise; however, the spectrum of the wide-spectrum light source is relatively wide, which means that it contains many frequency components. The random beat frequencies between unrelated frequency components will cause power fluctuations of the light source, thereby generating relative intensity noise that greatly limits the sensitivity of the gyroscope.

[0007] In order to suppress the relative intensity noise, an effective method used by the existing resonant fiber gyroscope based on a wide-spectrum light source is to use high-frequency modulation. However, in the process of modulating the optical signal, the frequency characteristics of the demodulated signal to be modulated will change frequently and significantly. Therefore, the parameters of the subsequent filter and other signal processing systems must be adjusted in real time according to the modulation frequency. Otherwise, the frequency of the demodulated signal may be located at the edge of the filter passband, resulting in unstable output. The frequent adjustment of the system not only brings difficulties in actual operation, but also is not conducive to the integrated development of RFOG, limiting the wide application of RFOG. Summary of the invention

[0008] The present invention proposes a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method, which solves the problem that when the existing resonant fiber gyroscope based on a wide-spectrum light source uses high-frequency modulation to suppress relative intensity noise, it is necessary to adjust the parameters of the subsequent filter in real time according to the modulation frequency, resulting in too frequent system adjustments and cumbersome operations, and it is difficult to achieve the integration of such gyroscopes, which is not convenient for the promotion and application of such gyroscopes.

[0009] The digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method of the present invention has the following technical solutions:

[0010] The digital system includes a mixer I, an integrator, a voltage-controlled oscillator, a reference signal generating unit, a phase detector, a low-pass filter II, a mixer II and a crystal oscillator;

[0011] The crystal oscillator is used to generate a frequency f i The first output terminal of the crystal oscillator is connected to the first input terminal of the mixer II; the output terminal of the mixer II is connected to the input terminal of the low-pass filter II; the output terminal of the low-pass filter II is connected to the second input terminal of the phase detector;

[0012] The first input terminal of the phase detector is used to receive the reference signal generated by the reference signal generating unit. The reference signal frequency is equal to the modulation frequency. The modulation frequency is f mod The output end of the phase detector is connected to the input end of the integrator; the output end of the integrator is connected to the input end of the voltage-controlled oscillator; the output end of the voltage-controlled oscillator is respectively connected to the second input end of the mixer I and the second input end of the mixer II;

[0013] The first input end of the mixer I is used to receive the original signal to be demodulated, and the frequency of the original signal to be demodulated is equal to the modulation frequency; the output end of the mixer I is used to output the frequency f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal.

[0014] Further, a preferred embodiment is provided, wherein the output end of the mixer II is used to output a frequency of f mod ′ and the difference frequency signal with frequency f mod ′+2f i The sum frequency term signal is sent to low pass filter II;

[0015] Further, a preferred embodiment is provided, wherein the low-pass filter II is used to filter out the frequency f mod ′+2f i The sum frequency term signal, the output frequency is f mod ’ signal to the second input terminal of the phase detector.

[0016] Furthermore, a preferred embodiment is provided, wherein the output end of the voltage controlled oscillator is used to output a frequency of f i +f mod ’ output signal.

[0017] The present invention also proposes a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method, and its technical solution is as follows:

[0018] The gyroscope includes a wide-spectrum light source, a circulator, a Y-waveguide, an optical coupler I, an optical coupler II, an optical fiber ring, a photodetector, an analog-to-digital interface, a digital-to-analog interface, a modulation signal generation module, a digital system, and a filtering module;

[0019] The digital system is the digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method;

[0020] The broadband light source is used to emit an optical signal to output to the first port of the circulator, and output to the Y waveguide through the second port of the circulator;

[0021] The modulation signal generation module is used to generate a modulated sinusoidal electrical signal, and convert the modulated sinusoidal electrical signal into a continuous analog signal through a digital-to-analog interface and then output it to the Y waveguide to modulate the optical signal to obtain two modulated optical signals; wherein the frequency of the modulated sinusoidal electrical signal is the adjustment frequency;

[0022] The Y waveguide is used to inject two modulated optical signals into the optical fiber ring through optical coupler I and optical coupler II respectively, and make the two modulated optical signals circulate several times in the optical fiber ring in the clockwise direction and the counterclockwise direction respectively, thereby generating two multi-light beams in opposite directions;

[0023] The optical fiber ring is used to return two multi-light beams in opposite directions along the optical path to the Y waveguide through optical coupler I and optical coupler II, and form interference light at the intersection end of the Y waveguide, and output the interference light to the photodetector through the third port of the circulator;

[0024] The photoelectric detector is used to convert the interference light into an electrical signal and output the electrical signal to the analog-to-digital interface;

[0025] The analog-to-digital interface is used to convert the electrical signal into a digital signal as an original signal to be demodulated, and output the original signal to be demodulated to the first input terminal of the mixer I of the digital system;

[0026] The filtering module is used to filter the digital system output frequency f i A stable signal with a frequency of f i The difference frequency signal and the frequency f i +2f mod The sum frequency term signal is used to obtain the speed information.

[0027] Further, a preferred embodiment is provided, wherein the filtering module includes a bandpass filter, a phase-sensitive detector, a low-pass filter I and a phase shifter;

[0028] The center frequency of the bandpass filter is f i ; The output end of the bandpass filter is connected to the first input end of the phase-sensitive detector; the second input end of the phase-sensitive detector is connected to the output end of the phase shifter; the output end of the phase-sensitive detector is connected to the input end of the low-pass filter I.

[0029] Furthermore, a preferred embodiment is provided, wherein the output end of the mixer I of the digital system is connected to the input end of the bandpass filter of the filtering module; the output end of the crystal oscillator of the digital system is connected to the input end of the phase shifter of the filtering module; and the output end of the low-pass filter I of the filtering module is used to output rotational speed information.

[0030] Furthermore, a preferred embodiment is provided, wherein the coupling efficiency of the optical coupler I and the optical coupler II is not less than 98%.

[0031] Furthermore, a preferred embodiment is provided, wherein the analog-to-digital interface is an analog-to-digital converter ADC.

[0032] Furthermore, a preferred embodiment is provided, wherein the digital-to-analog interface is a digital-to-analog converter DAC.

[0033] The present invention has the following beneficial effects:

[0034] 1. The wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the present invention reduces the interference between the backscattered light and the main light wave in the fiber loop through a low-coherence wide-spectrum light source, and effectively suppresses the interference of parasitic noise on the rotation speed information.

[0035] 2. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method of the present invention is characterized bymod The original signal to be demodulated is demodulated to a frequency of f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal, so that the subsequent stages can be targeted at the desired intermediate frequency signal f i Make the best design; for example, use a center frequency of f i The signal is filtered by a bandpass filter to obtain the frequency f i The intermediate frequency signal, whose amplitude is proportional to the amplitude of the measured signal, is used to obtain the speed information. Even if the original demodulated signal changes with the modulation frequency, the frequency of the intermediate frequency signal always remains f i The invention is stable and unchanged, and there is no need to frequently adjust the parameters of the filter, which improves the ability of the system to suppress noise and harmonic response. It solves the problem that when the existing resonant fiber optic gyroscope based on a wide-spectrum light source uses high-frequency modulation to suppress relative intensity noise, it is necessary to adjust the parameters of the subsequent filter in real time according to the modulation frequency, resulting in too frequent system adjustments, cumbersome operations, and difficulty in realizing the integration of such gyroscopes, which is not convenient for the promotion and application of such gyroscopes. For example, when the amplitude of the measured signal is low and an amplifier circuit is needed to amplify the signal, a special design can be used to amplify the signal at the frequency f. i An amplifier circuit with good linearity and frequency response characteristics is provided to ensure accurate amplification of the demodulated signal without distortion.

[0036] 3. The wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the present invention uses a simple optical path structure design and an optimized digital signal processing module. Compared with the traditional RFOG system, it uses fewer optical devices, reduces the system volume, and is more conducive to subsequent further engineering packaging and application.

[0037] The wide-spectrum light source resonant fiber optic gyroscope based on the superheterodyne method of the present invention is suitable for measuring rotation speed signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the structure of a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method in one embodiment of the present invention;

[0040] Figure 2It is a Simulink simulation diagram of a digital system of a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method in one embodiment of the present invention;

[0041] Figure 3 A schematic diagram of an output signal of the integrator 13 in one embodiment of the present invention;

[0042] Figure 4 FIG. 1 is a schematic diagram of output signals of a voltage-controlled oscillator 14 and a crystal oscillator 19 in one embodiment of the present invention; wherein: Figure 4 The upper part of the figure is a schematic diagram of the output signal of the voltage controlled oscillator 14; Figure 4 The lower half of the figure is a schematic diagram of the output signal of the crystal oscillator 19. DETAILED DESCRIPTION

[0043] In order to make the technical solutions and advantages of the present invention more clearly described, the specific implementation methods of the present invention will be further described in detail and completely in conjunction with the accompanying drawings. The various implementation methods described below are only part of the preferred solutions of the present invention, rather than all implementation methods; the various implementation methods described below are intended to explain the present invention and cannot be understood as limitations on the present invention; the reasonable combination of technical features defined in the various implementation methods of the present invention, and all other implementation methods obtained by ordinary technicians in the field without creative work based on the implementation methods of the present invention, are within the scope of protection of the present invention.

[0044] Implementation Method 1: Combination Figures 1 to 4 This embodiment is described. This embodiment provides a digital system of a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method. The specific implementation contents are as follows:

[0045] A digital system of a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method, the digital system comprising a mixer I9, an integrator 13, a voltage-controlled oscillator 14, a reference signal generating unit 15, a phase detector 16, a low-pass filter II 17, a mixer II 18 and a crystal oscillator 19;

[0046] The crystal oscillator 19 is used to generate a frequency f i The first output terminal of the crystal oscillator 19 is connected to the first input terminal of the mixer Ⅱ 18; the output terminal of the mixer Ⅱ 18 is connected to the input terminal of the low-pass filter Ⅱ 17; the output terminal of the low-pass filter Ⅱ 17 is connected to the second input terminal of the phase detector 16;

[0047] The first input terminal of the phase detector 16 is used to receive the reference signal generated by the reference signal generating unit 15. The reference signal frequency is equal to the modulation frequency. The modulation frequency is f modThe output end of the phase detector 16 is connected to the input end of the integrator 13; the output end of the integrator 13 is connected to the input end of the voltage-controlled oscillator 14; the output end of the voltage-controlled oscillator 14 is respectively connected to the second input end of the mixer Ⅰ9 and the second input end of the mixer Ⅱ18;

[0048] The first input terminal of the mixer I9 is ​​used to receive the original signal to be demodulated, and the frequency of the original signal to be demodulated is equal to the modulation frequency; the output terminal of the mixer I9 is ​​used to output the frequency f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal.

[0049] In this embodiment, the frequency is f mod The original signal to be demodulated is demodulated to a frequency of f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal is convenient for subsequent signal processing by filters; for example, the center frequency is f i The signal is filtered by a bandpass filter to obtain the frequency f i The intermediate frequency signal, whose amplitude is proportional to the amplitude of the measured signal, is used to obtain the speed information. Even if the original demodulated signal changes with the modulation frequency, the frequency of the intermediate frequency signal always remains f i It is stable and does not require frequent adjustment of the filter parameters. It solves the problem that when the existing resonant fiber optic gyroscope based on a wide-spectrum light source uses high-frequency modulation to suppress relative intensity noise, it is necessary to adjust the parameters of the subsequent filter in real time according to the modulation frequency, resulting in too frequent system adjustments, cumbersome operations, and difficulty in realizing the integration of such gyroscopes, which is not convenient for the promotion and application of such gyroscopes.

[0050] Implementation Method 2: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the first embodiment. The specific implementation contents are as follows:

[0051] The output end of the mixer II 18 is used to output a frequency of f mod ′ and the difference frequency signal with frequency f mod ′+2f i The sum frequency term signal is sent to low pass filter Ⅱ17;

[0052] Implementation Method 3: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the second embodiment. The specific implementation contents are as follows:

[0053] The low-pass filter II 17 is used to filter out the frequency f mod ′+2f i The sum frequency term signal, the output frequency is f mod ’ signal to the second input terminal of the phase detector 16.

[0054] Implementation Method 4: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the third embodiment. The specific implementation contents are as follows:

[0055] The output end of the voltage controlled oscillator 14 is used to output a frequency f i +f mod ’ output signal.

[0056] Implementation Method 5: Combination Figures 1 to 4 This embodiment is described. This embodiment provides a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method. The specific implementation contents are as follows:

[0057] A wide-spectrum light source resonant fiber gyroscope based on superheterodyne method, the gyroscope comprising a wide-spectrum light source 1, a circulator 2, a Y waveguide 3, an optical coupler I 4, an optical coupler II 5, an optical fiber ring 6, a photodetector 7, an analog-to-digital interface, a digital-to-analog interface, a modulation signal generation module 21, a digital system and a filtering module;

[0058] The digital system is a digital system of a wide-spectrum light source resonant fiber gyroscope based on a superheterodyne method as described in any one of embodiments 1 to 4;

[0059] The broadband light source 1 is used to emit an optical signal to be output to the first port of the circulator 2, and output to the Y waveguide 3 through the second port of the circulator 2;

[0060] The modulation signal generating module 21 is used to generate a modulated sinusoidal electrical signal, and convert the modulated sinusoidal electrical signal into a continuous analog signal through a digital-to-analog interface and then output it to the Y waveguide 3, modulate the optical signal, and obtain two modulated optical signals; wherein the frequency of the modulated sinusoidal electrical signal is the adjustment frequency;

[0061] The Y waveguide 3 is used to inject two modulated optical signals into the optical fiber ring 6 through the optical coupler I 4 and the optical coupler II 5 respectively, and make the two modulated optical signals circulate several times in the optical fiber ring 6 in the clockwise direction and the counterclockwise direction respectively, thereby generating two multi-light beams in opposite directions;

[0062] The optical fiber ring 6 is used to return two multi-light beams in opposite directions along the optical path to the Y waveguide 3 through the optical coupler I4 and the optical coupler II5, and form interference light at the intersection end of the Y waveguide 3, and output the interference light to the photodetector 7 through the third port of the circulator 2;

[0063] The photoelectric detector 7 is used to convert the interference light into an electrical signal and output the electrical signal to the analog-to-digital interface;

[0064] The analog-to-digital interface is used to convert the electrical signal into a digital signal as an original signal to be demodulated, and output the original signal to be demodulated to the first input terminal of the mixer I9 of the digital system;

[0065] The filtering module is used to filter the digital system output frequency f i A stable signal with a frequency of f i The difference frequency signal and the frequency f i +2f mod The sum frequency term signal is used to obtain the speed information.

[0066] Implementation Method 6: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the fifth embodiment. The specific implementation contents are as follows:

[0067] The filtering module includes a bandpass filter 10, a phase-sensitive detector 11, a low-pass filter I 12 and a phase shifter 20;

[0068] The center frequency of the bandpass filter 10 is f i ; The output end of the bandpass filter 10 is connected to the first input end of the phase-sensitive detector 11; the second input end of the phase-sensitive detector 11 is connected to the output end of the phase shifter 20; the output end of the phase-sensitive detector 11 is connected to the input end of the low-pass filter Ⅰ12.

[0069] Implementation Method 7: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in Embodiment 6. The specific implementation contents are as follows:

[0070] The output end of the mixer Ⅰ9 of the digital system is connected to the input end of the bandpass filter 10 of the filtering module; the output end of the crystal oscillator 19 of the digital system is connected to the input end of the phase shifter 20 of the filtering module; the output end of the low-pass filter Ⅰ12 of the filtering module is used to output the rotation speed information.

[0071] In this embodiment, the input end of the bandpass filter 10 is connected to the output end of the mixer I9 of the digital system to obtain the frequency fi The difference frequency signal and the frequency f i +2f mod The sum frequency term signal.

[0072] In this embodiment, the input end of the phase shifter 20 is connected to the crystal oscillator 19 of the digital system to obtain a frequency of f i of stable signal.

[0073] In this embodiment, the bandpass filter 10 is used to output the frequency f of the digital system of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method. i The difference frequency signal with frequency f i +2f mod The sum frequency term signal is filtered to obtain a stable frequency of f i The amplitude of the intermediate frequency signal is proportional to the amplitude of the original signal to be demodulated.

[0074] In this implementation, the rotation speed information is used as the output of the gyro system.

[0075] In this embodiment, the frequency is f mod The original signal to be demodulated is demodulated to a frequency of f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal is obtained by the superheterodyne method, that is, the fixed intermediate frequency signal is obtained.

[0076] The significance of using the superheterodyne method to obtain a fixed intermediate frequency signal is not only that the subsequent filter can be designed in a targeted manner, but also that all subsequent parts can be designed in a targeted and optimal manner.

[0077] For example, the design of subsequent filters can use a center frequency of f i The signal is filtered by a band-pass digital filter, or an analog filter which is not limited by sampling rate and sampling error and is more suitable for the continuous signal output by the gyroscope is used;

[0078] For example, in the design of other subsequent parts, when the amplitude of the measured signal is low and an amplifier circuit is needed to amplify the signal, a special design can be made at the frequency f i An amplifier circuit with good linearity and frequency response characteristics is used to ensure accurate amplification of the demodulated signal without distortion.

[0079] In this embodiment, the method for obtaining the rotation speed information by using the wide spectrum light source resonant fiber optic gyroscope based on the superheterodyne method is the superheterodyne method, which is specifically as follows:

[0080] The first input terminal of the mixer I9 of the digital system receives the original signal to be demodulated. The frequency of the original signal to be demodulated is the same as the modulation frequency f mod Consistency;

[0081] The original demodulated signal and the output signal of the voltage-controlled oscillator 14 are mixed at the mixer I9; wherein the frequency of the output signal of the voltage-controlled oscillator 14 is f i +f mod ', this frequency is controlled by the input voltage of the voltage-controlled oscillator 14, i.e. the output of the integrator 13;

[0082] The crystal oscillator 19 generates a frequency f i The stable signal of the voltage controlled oscillator 14 is f i +f mod The signal of ′ is mixed with this signal at mixer II 18 to generate a frequency of f mod ′ and the difference frequency signal with frequency f mod ′+2f i The sum frequency term signal is then filtered out by low-pass filter Ⅱ17, and the output frequency is f mod 'The signal is given to the phase detector 16;

[0083] The reference signal generation unit 15 generates and modulates the frequency f mod The reference signal of the same frequency as the output frequency of the low-pass filter Ⅱ17 is f mod The signal of ' is phase-detected in the phase detector 16, and there are three situations:

[0084] When f mod >f mod ', at this time the output voltage of the phase detector 16 is negative, and is applied to the voltage input terminal of the voltage controlled oscillator 14 after passing through the integrator 13, which will increase the output frequency of the voltage controlled oscillator 14, thereby making f mod ′ approaches f mod , until f mod =f mod ′;

[0085] When f mod <f mod ', at this time the output voltage of the phase detector 16 is positive, which will cause the output frequency of the voltage-controlled oscillator 14 to decrease and also cause f mod ′ approaches f mod , until f mod =f mod ′;

[0086] When f mod =f mod', at this time the output voltage of the phase detector 16 is zero, the output voltage of the integrator 13 is also 0, and the output frequency of the voltage-controlled oscillator 14 remains unchanged, which is always f i +f mod .

[0087] So after the digital system stabilizes, the frequency is f mod The original demodulated signal and the frequency of the voltage controlled oscillator 14 output are f i +f mod The signal is mixed to generate a frequency of f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal.

[0088] Then pass through the center frequency f i After filtering with a bandpass filter 10, the frequency is stabilized to f i The intermediate frequency signal has an amplitude proportional to the amplitude of the original signal to be demodulated.

[0089] The crystal oscillator 19 generates a frequency f i The stable signal is output to an input end of the phase sensitive detector 11 through the phase shifter 20, and the frequency is stable at f i The intermediate frequency signal is simultaneously output to another input terminal of the phase-sensitive detector 11;

[0090] Finally, the output of the phase-sensitive detector 11 is filtered by a low-pass filter I 12 to obtain a rotation speed signal.

[0091] Implementation Method 8: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the fifth embodiment. The specific implementation contents are as follows:

[0092] The coupling efficiency of the optical coupler I4 and the optical coupler II5 is not less than 98%.

[0093] Implementation Method 9: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the fifth embodiment. The specific implementation contents are as follows:

[0094] The analog-to-digital interface is an analog-to-digital converter ADC8.

[0095] Implementation Method 10: Combination Figures 1 to 4 This embodiment is described. This embodiment is a further limitation of the wide-spectrum light source resonant fiber gyroscope based on the superheterodyne method described in the fifth embodiment. The specific implementation contents are as follows:

[0096] The digital-to-analog interface is a digital-to-analog converter DAC22.

[0097] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable changes and improvements to the present invention, reasonable combinations of implementation modes and equivalent substitutions based on the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide-spectrum light source resonant fiber gyroscope based on superheterodyne method, characterized in that: The gyroscope comprises a wide spectrum light source (1), a circulator (2), a Y waveguide (3), an optical coupler I (4), an optical coupler II (5), an optical fiber ring (6), a photodetector (7), an analog-to-digital interface, a digital-to-analog interface, a modulation signal generation module (21), a digital system and a filtering module; The digital system is a digital system of a wide-spectrum light source resonant fiber optic gyroscope based on a superheterodyne method; The broadband light source (1) is used to emit an optical signal which is output to a first port of the circulator (2), and is output to a Y waveguide (3) through a second port of the circulator (2); The modulation signal generation module (21) is used to generate a modulated sinusoidal electrical signal, and convert the modulated sinusoidal electrical signal into a continuous analog signal through a digital-to-analog interface and output it to the Y waveguide (3), modulating the optical signal to obtain two modulated optical signals; wherein the frequency of the modulated sinusoidal electrical signal is the adjustment frequency; The Y waveguide (3) is used to inject two modulated optical signals into the optical fiber ring (6) through the optical coupler I (4) and the optical coupler II (5), respectively, and to make the two modulated optical signals circulate several times in the optical fiber ring (6) in the clockwise direction and the counterclockwise direction, respectively, so as to generate two multi-light beams in opposite directions; The optical fiber ring (6) is used to return two multi-light beams in opposite directions along the optical path to the Y waveguide (3) through the optical coupler I (4) and the optical coupler II (5), and to form interference light at the intersection end of the Y waveguide (3), and to output the interference light to the photodetector (7) through the third port of the circulator (2); The photoelectric detector (7) is used to convert the interference light into an electrical signal and output the electrical signal to an analog-to-digital interface; The analog-to-digital interface is used to convert the electrical signal into a digital signal as an original signal to be demodulated, and output the original signal to be demodulated to the first input terminal of the mixer I (9) of the digital system; The filtering module is used to filter the digital system output frequency f i A stable signal with a frequency of f i The difference frequency signal and the frequency f i +2f mod The sum frequency term signal is used to obtain the speed information; The digital system comprises a mixer I (9), an integrator (13), a voltage-controlled oscillator (14), a reference signal generating unit (15), a phase detector (16), a low-pass filter II (17), a mixer II (18) and a crystal oscillator (19); The crystal oscillator (19) is used to generate a frequency f i The first output terminal of the crystal oscillator (19) is connected to the first input terminal of the mixer II (18); the output terminal of the mixer II (18) is connected to the input terminal of the low-pass filter II (17); the output terminal of the low-pass filter II (17) is connected to the second input terminal of the phase detector (16); The first input terminal of the phase detector (16) is used to receive the reference signal generated by the reference signal generating unit (15), the reference signal frequency is equal to the modulation frequency, and the modulation frequency is f mod The output end of the phase detector (16) is connected to the input end of the integrator (13); the output end of the integrator (13) is connected to the input end of the voltage-controlled oscillator (14); the output end of the voltage-controlled oscillator (14) is respectively connected to the second input end of the mixer I (9) and the second input end of the mixer II (18); The first input terminal of the mixer I (9) is used to receive the original signal to be demodulated, and the frequency of the original signal to be demodulated is equal to the modulation frequency; the output terminal of the mixer I (9) is used to output the signal with a frequency of f i The difference frequency signal with frequency f i +2f mod The sum frequency term signal.

2. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 1, characterized in that: The output terminal of the mixer II (18) is used to output a frequency of f mod ′ and the difference frequency signal with frequency f mod ′+2f i The sum frequency term signal is sent to low pass filter II (17).

3. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 2, characterized in that: The low-pass filter II (17) is used to filter out the frequency f mod ′+2f i The sum frequency term signal, the output frequency is f mod ’ signal to the second input terminal of the phase detector (16).

4. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 3, characterized in that: The output end of the voltage controlled oscillator (14) is used to output a frequency f i +f mod ’ output signal.

5. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 1, characterized in that: The filtering module comprises a bandpass filter (10), a phase-sensitive detector (11), a low-pass filter I (12) and a phase shifter (20); The center frequency of the bandpass filter (10) is f i ; The output end of the bandpass filter (10) is connected to the first input end of the phase-sensitive detector (11); the second input end of the phase-sensitive detector (11) is connected to the output end of the phase shifter (20); the output end of the phase-sensitive detector (11) is connected to the input end of the low-pass filter I (12).

6. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 5, characterized in that: The output end of the mixer I (9) of the digital system is connected to the input end of the bandpass filter (10) of the filtering module; the output end of the crystal oscillator (19) of the digital system is connected to the input end of the phase shifter (20) of the filtering module; the output end of the low-pass filter I (12) of the filtering module is used to output the rotation speed information.

7. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 1, characterized in that: The coupling efficiency of the optical coupler I (4) and the optical coupler II (5) is not less than 98%.

8. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 1, characterized in that: The analog-to-digital interface is an analog-to-digital converter ADC (8).

9. The wide-spectrum light source resonant fiber gyroscope based on superheterodyne method according to claim 1, characterized in that: The digital-to-analog interface is a digital-to-analog converter DAC (22).

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