A reading method for a differential fiber-optic gyroscope

Abstract

This invention belongs to the field of fiber optic gyroscopes (FOGs), specifically relating to a reading method for differential fiber optic gyroscopes (DFOGs), aiming to solve the problems of high noise and small angular velocity measurement range in existing DFOGs. The invention includes: performing low-pass and high-pass filtering on the two equivalent FOG output phases of the DFOG respectively; performing differential operation on the low-pass filtered phase to obtain the low-frequency phase value of the DFOG; taking the high-pass filtered phase of any equivalent FOG as the high-frequency phase value of the DFOG; converting the two frequency band phases into angular velocities and adding them to obtain the main output angular velocity of the DFOG; simultaneously, directly differentially analyzing the two equivalent FOG output phases and converting them into angular velocities as the auxiliary output angular velocity of the DFOG. Since the scale of the auxiliary output angular velocity is much smaller than that of the main output angular velocity, when the main output angular velocity exceeds the measurement period, the auxiliary angular velocity can be used to calibrate the main output value, thus expanding the measurement range of the DFOG. This invention can simultaneously eliminate the common-mode error of the FOG, improve accuracy, and achieve a wide range of angular velocity measurements.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic gyroscopes, and specifically relates to a reading method for differential fiber optic gyroscopes. Background Technology

[0002] A differential fiber optic gyroscope is a fiber optic gyroscope consisting of two broadband light sources of different wavelengths, two photodetectors, two wavelength division multiplexers, a dual-window coupler, a Y-waveguide, and a fiber optic loop. [1] Two fiber optic gyroscopes are constructed in the same Sagnac interference loop. The output phase of the differential fiber optic gyroscope is the result of differential processing of the output phases of the two fiber optic gyroscopes. It has a good suppression effect on the main error source in fiber optic gyroscopes, namely the "Shupe" effect error caused by time-varying temperature.

[0003] The "Shupe" effect error in fiber optic gyroscopes is distributed in the lower frequency range, while noise can be divided into common-mode noise and random noise, distributed in the higher frequency range. Differential fiber optic gyroscopes have a good suppression effect on common-mode error and common-mode noise, which can improve measurement accuracy. However, differential processing of random noise may degrade the performance, especially when the random noise is greater than the common-mode noise. Directly differentiating the output phases of the two fiber optic gyroscopes may increase the noise.

[0004] The basic measurement principle of differential fiber optic gyroscopes is based on the Sagnac effect. The Sagnac effect states that the phase difference between opposing beams in a closed optical path is proportional to the input angular velocity in the direction normal to the closed optical path. This ratio of phase difference to angular velocity is called the Sagnac coefficient, which is proportional to the closed area of ​​the fiber optic loop. Generally, the phase measurement range of a fiber optic gyroscope is limited to the zero-order interference fringe, corresponding to a phase range of -π to +π. Due to the periodicity of the interference signal, the fringe order cannot be accurately determined after the phase crosses the zero-order interference fringe, leading to inaccurate angular velocities. To improve the measurement accuracy of a fiber optic gyroscope, the closed area of ​​the fiber optic loop needs to be increased. However, this increases the Sagnac coefficient, which reduces the range of angular velocities corresponding to the -π to +π phase range. Therefore, there is a trade-off between the measurement accuracy and the measurement range of a fiber optic gyroscope.

[0005] In summary, differential fiber optic gyroscopes suffer from problems such as high noise and a small angular velocity measurement range compared to direct differential gyroscopes.

[0006] The following documents are technical background information related to this invention:

[0007] [1] Yang Yuanhong et al. A dual-light source high-precision fiber optic gyroscope [P]. Chinese Patent, ZL201710448880.2, 2019-12-10 Summary of the Invention

[0008] To address the aforementioned problems in existing technologies, namely the high direct differential noise and small angular velocity measurement range of current differential fiber optic gyroscopes, this invention provides a reading method for a differential fiber optic gyroscope (DFOG), the method comprising:

[0009] The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope.

[0010] Step S100: Obtain the phase of the first fiber optic gyroscope through the first fiber optic gyroscope; obtain the phase of the second fiber optic gyroscope through the second fiber optic gyroscope;

[0011] Step S200: Perform low-pass filtering and high-pass filtering with the same cutoff frequency on the output phase of the first fiber optic gyroscope and the output phase of the second fiber optic gyroscope respectively to obtain the first low-frequency band phase, the first high-frequency band phase, the second low-frequency band phase and the second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band range in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located.

[0012] Step S300: Based on the first low-frequency band phase and the second low-frequency band phase, perform differential processing to obtain the low-frequency band phase of the differential fiber optic gyroscope; select one of the first high-frequency band phase and the second high-frequency band phase as the high-frequency band phase of the differential fiber optic gyroscope.

[0013] Step S400: Convert the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency angular velocity and high-frequency angular velocity, respectively, and add the low-frequency angular velocity and high-frequency angular velocity to obtain the main output angular velocity of the differential fiber optic gyroscope.

[0014] Step S500: The output phase of the first fiber optic gyroscope and the output phase of the second fiber optic gyroscope are directly differentially processed to obtain the differential fiber optic gyroscope phase, and the differential fiber optic gyroscope phase is converted into angular velocity as an auxiliary output angular velocity.

[0015] In step S600, the auxiliary output angular velocity is used to calibrate the main output angular velocity of the differential fiber optic gyroscope, thereby expanding the measurement range of the differential fiber optic gyroscope.

[0016] In some preferred embodiments, the low-pass filtering is implemented by one of a finite-length unit impulse response filter, an infinite-length impulse response filter, a Fourier filter, or other types of filters.

[0017] In some preferred embodiments, the high-pass filtering is implemented in the same way as the low-pass filtering, by adjusting the high-pass filter parameters.

[0018] In some preferred embodiments, the low-pass and high-pass filtering methods and parameters remain unchanged during the same angular velocity reading.

[0019] In some preferred embodiments, the low-frequency angular velocity and the high-frequency angular velocity are obtained by methods including:

[0020] The low-frequency angular velocity is obtained by dividing the low-frequency phase of the differential fiber optic gyroscope by the Sagnac coefficient of the differential fiber optic gyroscope.

[0021] The high-frequency angular velocity is obtained by dividing the high-frequency phase of the differential fiber optic gyroscope by the Sagnac coefficient of the corresponding single fiber optic gyroscope.

[0022] In some preferred embodiments, step S300 specifically includes:

[0023] Based on the first low-frequency band phase and the second low-frequency band phase, differential processing is performed to obtain the low-frequency band phase of the differential fiber optic gyroscope:

[0024]

[0025] in, Indicates the low-frequency phase. Indicates the phase of the first low-frequency band. represents the phase of the second low-frequency band, and h represents the dispersion compensation coefficient;

[0026] Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope.

[0027] In this step, by performing differential processing only on the low-pass filter phase while retaining the characteristics of the high-pass filter phase, the degrading effect of differential processing on random noise in the high-frequency phase can be avoided, thus ensuring the suppression of drift error phase in the low-frequency band.

[0028] In some preferred embodiments, step S400 specifically includes:

[0029] The low-frequency phase and high-frequency phase of the differential fiber optic gyroscope are converted into low-frequency angular velocities and high-frequency angular velocities, respectively. The main output angular velocity of the differential fiber optic gyroscope is obtained by adding the low-frequency angular velocity and the high-frequency angular velocity.

[0030]

[0031] Among them, K SD K represents the Sagnac coefficient of the differential fiber optic gyroscope. sj This represents the Sagnac coefficient of a single fiber optic gyroscope. This indicates the high-frequency phase, and j represents 1 or 2. j is selected based on the fiber optic gyroscope corresponding to the high-frequency phase.

[0032] In some preferred embodiments, the Sagnac coefficient K of the differential fiber optic gyroscope SD The calculation method is as follows:

[0033]

[0034] Where L represents the length of the fiber optic loop, D represents the average diameter of the fiber optic loop, λ1 represents the operating wavelength of the light source of the first fiber optic gyroscope, λ2 represents the operating wavelength of the light source of the second fiber optic gyroscope, and c represents the speed of light in a vacuum.

[0035] The Sagnac coefficient K of the single fiber optic gyroscope Sj The calculation method is as follows:

[0036]

[0037] Where, λ j This indicates the operating wavelength of the light source for a single fiber optic gyroscope.

[0038] In some preferred embodiments, step S600 specifically includes:

[0039] The auxiliary angular velocity is only used to determine the working fringe where the main output angular velocity of the differential fiber optic gyroscope is located, and to calibrate the main output angular velocity of the differential fiber optic gyroscope. Let the auxiliary angular velocity of the differential fiber optic gyroscope be Ω. A Main output angular velocity Ω D The range of angular velocities corresponding to each level of stripe is Ω. (2k-1)π ~Ω (2k+1)π , where Ω (2k-1)π Ω represents the angular velocity corresponding to the (2k-1)π phase. (2k+1)π This represents the angular velocity corresponding to the (2k+1)π phase, where k is an integer. The calibration calculation method is as follows:

[0040] When Ω -π <Ω A ≤Ω π At that time, the output angular velocity is Ω D ;

[0041] When Ω (2k-1)π <Ω A ≤Ω (2k+1)π When k≠0, the output angular velocity is Ω. D +Ω 2kπ Ω 2kπ This represents the angular velocity corresponding to the 2kπ phase.

[0042] In another aspect, the present invention proposes a low-noise, wide-range angular velocity reading system based on a differential fiber optic gyroscope, the system comprising: a signal acquisition module, a filtering module, a phase acquisition module, and an angular velocity acquisition module;

[0043] The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope.

[0044] The signal acquisition module acquires the output signal of the first fiber optic gyroscope through the first fiber optic gyroscope; and acquires the output signal of the second fiber optic gyroscope through the second fiber optic gyroscope.

[0045] The filtering module performs low-pass filtering and high-pass filtering on the first fiber optic gyroscope phase and the second fiber optic gyroscope phase with the same cutoff frequency, respectively, to obtain a first low-frequency band phase, a first high-frequency band phase, a second low-frequency band phase, and a second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located.

[0046] The phase acquisition module performs differential processing based on the first low-frequency band phase and the second low-frequency band phase to obtain the low-frequency band phase of the differential fiber optic gyroscope.

[0047] Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope.

[0048] The angular velocity acquisition module converts the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency and high-frequency angular velocities, respectively. The low-frequency and high-frequency angular velocities are then added to obtain the main output angular velocity of the differential fiber optic gyroscope. The output phases of the first and second fiber optic gyroscopes are directly differentially processed to obtain the differential fiber optic gyroscope phase, which is then converted into angular velocity as an auxiliary output angular velocity. This auxiliary output angular velocity is used to calibrate the main output angular velocity of the differential fiber optic gyroscope, thereby expanding the measurement range of the differential fiber optic gyroscope.

[0049] The beneficial effects of this invention are:

[0050] (1) This invention performs differential processing only on the low-frequency phase of the two fiber optic gyroscopes in the differential fiber optic gyroscope, without performing differential processing on the high-frequency phase. This avoids the degrading effect of differential processing on noise, effectively reduces the noise of the differential fiber optic gyroscope, ensures the suppression of the low-frequency drift error phase, improves the overall effect of differential processing, and thus improves the accuracy of the angular velocity obtained by the gyroscope.

[0051] (2) The present invention converts the direct differential result of the phases of the two fiber optic gyroscopes in the differential fiber optic gyroscope into angular velocity, which is used as an auxiliary angular velocity to determine the working fringe where the main output angular velocity of the differential fiber optic gyroscope is located, and to calibrate the main output angular velocity to expand the angular velocity measurement range. Attached Figure Description

[0052] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0053] Figure 1 This is a flowchart illustrating a reading method for a differential fiber optic gyroscope according to the present invention.

[0054] Figure 2 This is a schematic diagram illustrating the principle of a reading method for a differential fiber optic gyroscope according to the present invention.

[0055] Figure 3 This is an example of the output phase curves and spectrum curves of two fiber optic gyroscopes in a differential fiber optic gyroscope obtained under temperature excitation according to an embodiment of the present invention.

[0056] Figure 4 This invention relates to a temperature-excited differential fiber optic gyroscope and includes the low-frequency phase curves of two fiber optic gyroscopes, the low-frequency phase curve of the differential fiber optic gyroscope, and the high-frequency phase curves of the two fiber optic gyroscopes.

[0057] Figure 5 This invention presents the 1-s average angular velocity curves of two fiber optic gyroscopes and the differential fiber optic gyroscope under temperature excitation in one embodiment of the present invention, as well as the 100-s average angular velocity curves of the two fiber optic gyroscopes and the differential fiber optic gyroscope.

[0058] Figure 6 This is a curve showing the relationship between the output angular velocity and the input angular velocity of two fiber optic gyroscopes and the differential fiber optic gyroscope in an embodiment of the present invention. Detailed Implementation

[0059] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0060] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0061] To more clearly explain the frequency-band differential processing method for the differential fiber optic gyroscope of the present invention, the following will be combined with... Figure 1 and Figure 2 The steps in the embodiments of the present invention will be described in detail below.

[0062] The frequency-band differential processing method for differential fiber optic gyroscopes according to the first embodiment of the present invention includes steps S100-S600, each step of which is described in detail below:

[0063] The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope.

[0064] Differential fiber optic gyroscopes using broadband light sources in the 1310nm and 1550nm bands were placed in a static environment. Temperature excitation was applied to the fiber optic ring using a heating element. Heating was stopped when the temperature reached about 60°C and allowed to drop to room temperature naturally before heating was resumed. This process was repeated three times. The output and temperature of the fiber optic gyroscopes at the two working wavelengths were recorded.

[0065] In this embodiment, the differential fiber optic gyroscope of the 1310nm broadband light source is designated as the first fiber optic gyroscope, and the differential fiber optic gyroscope of the 1550nm broadband light source is designated as the second fiber optic gyroscope.

[0066] Step S100: Obtain the phase of the first fiber optic gyroscope through the first fiber optic gyroscope; obtain the phase of the second fiber optic gyroscope through the second fiber optic gyroscope;

[0067] Figure 3 In Figure (a), the output phase curves of two fiber optic gyroscopes and the recorded temperature curves are shown in Figure (a) under three temperature excitations. The phase curves of the two fiber optic gyroscopes are significantly shifted with temperature changes, exhibiting typical "Shupe" effect error characteristics. Figure 3 In Figure (b), the spectrum curves corresponding to the phase curves of the two fiber optic gyroscopes are shown. After comparison, the common-mode drift error is mainly distributed below 0.008Hz, so the frequency division point is set to 0.008Hz.

[0068] Step S200: Perform low-pass filtering and high-pass filtering with the same cutoff frequency on the first fiber optic gyroscope phase and the second fiber optic gyroscope phase respectively to obtain the first low-frequency band phase, the first high-frequency band phase, the second low-frequency band phase and the second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band range in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located.

[0069] This embodiment obtains the first low-frequency band phase, the first high-frequency band phase, the second low-frequency band phase, and the second high-frequency band phase by using a low-pass filter and a high-pass filter with a cutoff frequency of 0.008Hz. For example... Figure 4As shown in Figure (a), the low-frequency phase curves of the first and second fiber optic gyroscopes, obtained by low-pass filtering with a cutoff frequency of 0.008 Hz, and the low-frequency phase curve of the differential fiber optic gyroscope are presented. Figure 4 As shown in Figure (b), the high-frequency phase curves of the first and second fiber optic gyroscope phases are obtained by high-pass filtering with a cutoff frequency of 0.008 Hz.

[0070] In this embodiment, the low-pass filtering is implemented using a finite-length unit impulse response filter, an infinite-length impulse response filter, a Fourier filter, or another type of filter.

[0071] In this embodiment, the high-pass filtering is implemented in the same way as the low-pass filtering, by adjusting the high-pass filter parameters.

[0072] In this embodiment, the low-pass and high-pass filtering methods and parameters remain unchanged during the same angular velocity reading process.

[0073] Step S300: Based on the first low-frequency band phase and the second low-frequency band phase, perform differential processing to obtain the low-frequency band phase of the differential fiber optic gyroscope.

[0074] Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope.

[0075] In this embodiment, step S300 specifically includes:

[0076] Based on the first low-frequency band phase and the second low-frequency band phase, differential processing is performed to obtain the low-frequency band phase of the differential fiber optic gyroscope:

[0077]

[0078] This indicates the low-frequency phase of the differential fiber optic gyroscope. This indicates the low-frequency phase of the first fiber optic gyroscope. The low-frequency phase of the second fiber optic gyroscope is represented by h, which represents the dispersion compensation coefficient.

[0079] Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope.

[0080] Step S400: Convert the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency angular velocity and high-frequency angular velocity, respectively, and add the low-frequency angular velocity and high-frequency angular velocity to obtain the main output angular velocity of the differential fiber optic gyroscope.

[0081] In this embodiment, step S400 specifically includes:

[0082] The low-frequency angular velocity of the differential fiber optic gyroscope is obtained by dividing the low-frequency phase of the differential fiber optic gyroscope by the Sagnac coefficient of the differential fiber optic gyroscope.

[0083] The high-frequency angular velocity of the differential fiber optic gyroscope is obtained by dividing the high-frequency phase of the differential fiber optic gyroscope by the Sagnac coefficient of the corresponding single fiber optic gyroscope.

[0084] The main output angular velocity Ω of the differential fiber optic gyroscope is obtained by adding the low-frequency angular velocity to the high-frequency angular velocity. D :

[0085]

[0086] Among them, K SD K represents the Sagnac coefficient of the differential fiber optic gyroscope. Sj This represents the Sagnac coefficient of a single fiber optic gyroscope. This indicates the high-frequency phase, and j represents 1 or 2. j is selected based on the fiber optic gyroscope corresponding to the high-frequency phase.

[0087] In this embodiment, the Sagnac coefficient K of the differential fiber optic gyroscope SD The calculation method is as follows:

[0088]

[0089] Where L represents the length of the fiber optic loop, D represents the average diameter of the fiber optic loop, λ1 represents the operating wavelength of the light source of the first fiber optic gyroscope, λ2 represents the operating wavelength of the light source of the second fiber optic gyroscope, and c represents the speed of light in a vacuum.

[0090] The Sagnac coefficient K of the single fiber optic gyroscope Sj The calculation method is as follows:

[0091]

[0092] Where, λ j This indicates the operating wavelength of the light source for a single fiber optic gyroscope.

[0093] Although the steps in the above embodiments are described in the above order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not need to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple variations are all within the protection scope of this invention.

[0094] like Figure 5As shown in Figure (a), the 1-second average angular velocity curves of the two fiber optic gyroscopes measured individually and the differential fiber optic gyroscope are shown. The angular velocity of the differential fiber optic gyroscope is calculated as follows: Figure 4 (a) Low-frequency phase and Figure 4 In (b), the high-frequency phase of the first fiber optic gyroscope is converted into low-frequency angular velocity and high-frequency angular velocity, respectively. The low-frequency angular velocity and the high-frequency angular velocity are added together to obtain the main output angular velocity of the differential fiber optic gyroscope. Figure 5 (b) is the corresponding Figure 5 The 100s average angular velocity curves of the two fiber optic gyroscopes and the differential fiber optic gyroscope in (a) are shown. Data processing results indicate that the error drift peak caused by temperature changes in the differential fiber optic gyroscope has basically disappeared, the frequency-band differential algorithm ensures good differential performance, and the error caused by the "Shupe" effect is significantly suppressed.

[0095] Step S500: The output phase of the first fiber optic gyroscope and the output phase of the second fiber optic gyroscope are directly differentially processed to obtain the differential fiber optic gyroscope phase, and the differential fiber optic gyroscope phase is converted into angular velocity as an auxiliary output angular velocity.

[0096] Step S600: Using the auxiliary output angular velocity, the main output angular velocity of the differential fiber optic gyroscope is calibrated to expand the measurement range of the differential fiber optic gyroscope. The auxiliary angular velocity is only used to determine the working fringe where the main output angular velocity of the differential fiber optic gyroscope is located, and to calibrate the main output angular velocity of the differential fiber optic gyroscope. Let the auxiliary angular velocity of the differential fiber optic gyroscope be Ω. A Main output angular velocity Ω D The range of angular velocities corresponding to each level of stripe is Ω. (2k-1)π ~Ω (2k+1)π , where Ω (2k-1)π Ω represents the angular velocity corresponding to the (2k-1)π phase. (2k+1)π This represents the angular velocity corresponding to the (2k+1)π phase, where k is an integer. The calibration calculation method is as follows:

[0097] When Ω -π <Ω A ≤Ω π At that time, the output angular velocity is Ω D ;

[0098] When Ω (2k-1)π <Ω A ≤Ω (2k+1)π When k≠0, the output angular velocity is Ω. D +Ω 2kπ Ω 2kπ This represents the angular velocity corresponding to a 2kV phase.

[0099] like Figure 6As shown, the curves depict the output angular velocities of the two fiber optic gyroscopes in a differential fiber optic gyroscope and the relationship between the output angular velocity and the input angular velocity of the differential fiber optic gyroscope. Due to the small scaling factor of the auxiliary angular velocity of the differential fiber optic gyroscope, the output phase is small at the same rotational speed. Therefore, the angular velocity range corresponding to the auxiliary angular velocity in the range of -π to +π is large, which can be used to determine the working fringes of the main output angular velocity of the differential fiber optic gyroscope. After calibrating the main output angular velocity, the final calibrated differential fiber optic gyroscope output angular velocity range reaches -157.1° / s to +157.1° / s, which is significantly larger than the angular velocity measurement range of the two single fiber optic gyroscopes (-23.4° / s to +23.4° / s and -27.5° / s to +27.5° / s), indicating a significant expansion of the angular velocity measurement range.

[0100] The second embodiment of the differential fiber optic gyroscope uses a frequency-division differential processing system, the system comprising: a signal acquisition module, a filtering module, a phase acquisition module, and an angular velocity acquisition module;

[0101] The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope.

[0102] The signal acquisition module acquires the output signal of the first fiber optic gyroscope through the first fiber optic gyroscope; and acquires the output signal of the second fiber optic gyroscope through the second fiber optic gyroscope.

[0103] The filtering module performs low-pass filtering and high-pass filtering on the first fiber optic gyroscope phase and the second fiber optic gyroscope phase with the same cutoff frequency, respectively, to obtain a first low-frequency band phase, a first high-frequency band phase, a second low-frequency band phase, and a second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located.

[0104] The phase acquisition module performs differential processing based on the first low-frequency band phase and the second low-frequency band phase to obtain the low-frequency band phase of the differential fiber optic gyroscope.

[0105] Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope.

[0106] The angular velocity acquisition module converts the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency and high-frequency angular velocities, respectively. The low-frequency and high-frequency angular velocities are then added to obtain the main output angular velocity of the differential fiber optic gyroscope. The output phases of the first and second fiber optic gyroscopes are directly differentially processed to obtain the differential fiber optic gyroscope phase, which is then converted into angular velocity as an auxiliary output angular velocity. This auxiliary output angular velocity is used to calibrate the main output angular velocity of the differential fiber optic gyroscope, thereby expanding the measurement range of the differential fiber optic gyroscope.

[0107] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the system described above can be found in the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0108] It should be noted that the differential fiber optic gyroscope frequency-band differential processing system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.

[0109] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the storage device and processing device described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0110] Those skilled in the art will recognize that the modules and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. To clearly illustrate the interchangeability of electronic hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the invention.

[0111] The terms “first”, “second”, etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0112] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0113] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for reading data from a differential fiber optic gyroscope, characterized in that, The method includes: The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope. Step S100: Obtain the phase of the first fiber optic gyroscope through the first fiber optic gyroscope; obtain the phase of the second fiber optic gyroscope through the second fiber optic gyroscope; Step S200: Perform low-pass filtering and high-pass filtering with the same cutoff frequency on the output phase of the first fiber optic gyroscope and the output phase of the second fiber optic gyroscope respectively to obtain the first low-frequency band phase, the first high-frequency band phase, the second low-frequency band phase and the second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band range in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located. Step S300: Based on the first low-frequency band phase and the second low-frequency band phase, perform differential processing to obtain the low-frequency band phase of the differential fiber optic gyroscope; select one of the first high-frequency band phase and the second high-frequency band phase as the high-frequency band phase of the differential fiber optic gyroscope. Step S300 specifically includes: Based on the first low-frequency band phase and the second low-frequency band phase, differential processing is performed to obtain the low-frequency band phase of the differential fiber optic gyroscope: ； in, Indicates the low-frequency phase. Indicates the phase of the first low-frequency band. Indicates the phase of the second low-frequency band. Indicates the dispersion compensation coefficient; Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope. Step S400: Convert the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency angular velocity and high-frequency angular velocity, respectively, and add the low-frequency angular velocity and high-frequency angular velocity to obtain the main output angular velocity of the differential fiber optic gyroscope. Step S400 specifically includes: The low-frequency and high-frequency phases of the differential fiber optic gyroscope are converted into low-frequency and high-frequency angular velocities, respectively. The low-frequency and high-frequency angular velocities are then added together to obtain the main output angular velocity of the differential fiber optic gyroscope. ； in, This represents the Sagnac coefficient of the differential fiber optic gyroscope. This represents the Sagnac coefficient of a single fiber optic gyroscope. denoted by , j represents 1 or 2, and j is selected according to the fiber optic gyroscope corresponding to the high-frequency phase. The methods for obtaining the low-frequency angular velocity and the high-frequency angular velocity include: The low-frequency angular velocity is obtained by dividing the low-frequency phase of the differential fiber optic gyroscope by the Sagnac coefficient of the differential fiber optic gyroscope. Based on the high-frequency phase of the differential fiber optic gyroscope, the high-frequency angular velocity is obtained by dividing it by the Sagnac coefficient of the corresponding single fiber optic gyroscope in the differential fiber optic gyroscope. The Sagnac coefficient of the differential fiber optic gyroscope The calculation method is as follows: ； in, Indicates the length of the fiber optic loop. This represents the average diameter of the fiber optic ring. This indicates the operating wavelength of the light source for the first fiber optic gyroscope. This indicates the operating wavelength of the light source for the second fiber optic gyroscope. This represents the speed of light in a vacuum. The Sagnac coefficient of the single fiber optic gyroscope The calculation method is as follows: ； in, This indicates the operating wavelength of the light source in a single fiber optic gyroscope. Step S500: The output phase of the first fiber optic gyroscope and the output phase of the second fiber optic gyroscope are directly differentially processed to obtain the differential fiber optic gyroscope phase, and the differential fiber optic gyroscope phase is converted into angular velocity as an auxiliary output angular velocity. In step S600, the auxiliary output angular velocity is used to calibrate the main output angular velocity of the differential fiber optic gyroscope, thereby expanding the measurement range of the differential fiber optic gyroscope.

2. The reading method for a differential fiber optic gyroscope according to claim 1, characterized in that, The low-pass filter is implemented using one of a finite-length unit impulse response filter, an infinite-length impulse response filter, or a Fourier filter.

3. The reading method for a differential fiber optic gyroscope according to claim 2, characterized in that, The high-pass filtering is achieved by adjusting the high-pass filter parameters in the same way as the low-pass filtering.

4. The reading method for a differential fiber optic gyroscope according to claim 2, characterized in that, The low-pass and high-pass filtering methods and parameters remain unchanged during the same angular velocity reading.

5. The reading method for a differential fiber optic gyroscope according to claim 1, characterized in that, Step S600 specifically includes: The auxiliary angular velocity is only used to determine the working fringe where the main output angular velocity of the differential fiber optic gyroscope is located, and to calibrate the main output angular velocity of the differential fiber optic gyroscope. Let the auxiliary angular velocity of the differential fiber optic gyroscope be... Main output angular velocity The range of angular velocities corresponding to each level of stripe is: ,in, express The angular velocity corresponding to the phase, express The angular velocity corresponding to the phase, k Representing integers, the calibration calculation method is as follows: when < At that time, the output angular velocity is ; when < and At that time, the output angular velocity is , express The angular velocity corresponding to the phase.

6. A reading system for a differential fiber optic gyroscope, used to implement the reading method for a differential fiber optic gyroscope as described in claim 1, characterized in that, The system includes: a signal acquisition module, a filtering module, a phase acquisition module, and an angular velocity acquisition module; The two fiber optic gyroscopes in the differential fiber optic gyroscope are denoted as the first fiber optic gyroscope and the second fiber optic gyroscope. The signal acquisition module acquires the phase of a first fiber optic gyroscope through a first fiber optic gyroscope and acquires the phase of a second fiber optic gyroscope through a second fiber optic gyroscope. The filtering module performs low-pass filtering and high-pass filtering on the first fiber optic gyroscope phase and the second fiber optic gyroscope phase respectively with the same cutoff frequency to obtain a first low-frequency band phase, a first high-frequency band phase, a second low-frequency band phase and a second high-frequency band phase; the cutoff frequency is the upper limit frequency of the frequency band range in which the common-mode drift error of the two fiber optic gyroscopes in the differential fiber optic gyroscope is located. The phase acquisition module performs differential processing based on the first low-frequency band phase and the second low-frequency band phase to obtain the low-frequency band phase of the differential fiber optic gyroscope. Choose either the first high-frequency phase or the second high-frequency phase as the high-frequency phase of the differential fiber optic gyroscope. The angular velocity acquisition module converts the low-frequency phase and high-frequency phase of the differential fiber optic gyroscope into low-frequency and high-frequency angular velocities, respectively. The low-frequency and high-frequency angular velocities are then added to obtain the main output angular velocity of the differential fiber optic gyroscope. The output phases of the first and second fiber optic gyroscopes are directly differentially processed to obtain the differential fiber optic gyroscope phase, which is then converted into angular velocity as an auxiliary output angular velocity. This auxiliary output angular velocity is used to calibrate the main output angular velocity of the differential fiber optic gyroscope, thereby expanding the measurement range of the differential fiber optic gyroscope.

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