Method for suppressing long-term drift of equivalent sensitive area of optical fiber ring

Abstract

The invention belongs to the technical field of fiber-optic gyroscope zero offset and scale factor long-term drift suppression, and particularly relates to a method for suppressing long-term drift of an equivalent sensitive area of a fiber-optic ring. A homogenization and de-homogenization analysis thought and a finite element analysis approach are adopted to establish, verify and calibrate thermodynamic parameters of each non-metallic material of each component of the optical fiber ring, and a mathematical model for long-time drift of circumferential strain, radial strain and three-dimensional stress of an infinitesimal segment of the optical fiber ring along with environmental conditions such as time, temperature and the like is established; and calculating the long-time drift of the effective refractive index of the fast axis of each infinitesimal section, and finally obtaining the average long-time drift and discrete characteristic of the effective refractive index of the fast axis of the optical fiber ring, thereby analyzing the long-time drift characteristic of the scale factor of the optical fiber gyroscope. And on the contrary, aiming at a scale factor long-term drift peak value requirement, according to the model, thermodynamic parameters and geometric proportions of non-metallic materials forming the optical fiber ring are optimized, and finally long-term drift suppression of the equivalent sensitive area of the optical fiber ring is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of long-term drift suppression of zero bias and scale factor of optical fiber gyroscopes, and in particular relates to a method for suppressing long-term drift of equivalent sensitive area of ​​an optical fiber ring. Background Art

[0002] As a new generation of all-solid-state inertial instrument, fiber optic gyroscopes sense the rotational angular velocity information of the loaded object along its sensitive axis based on the Sagnac working principle. The development of fiber optic gyroscopes not only relies on precise system architecture design and lean signal processing technology, but also benefits from the rapid development of basic process research such as fiber optic communications and optical waveguides. Compared with mechanical gyroscopes, fiber optic gyroscopes have inherent advantages such as long life, light weight, low power consumption, low cost, and easy processing. They have broad application prospects in defense fields such as aviation, aerospace, and navigation. In the aviation industry, fiber optic gyroscopes have replaced the previous generation of mechanical gyroscopes and are mass-equipped in inertial navigation and attitude stabilization platforms of various aircraft.

[0003] During the long-term operation of the fiber optic gyroscope, the zero bias and scale factor drift slowly over the whole life, which deteriorates the stability and reliability of the product performance. Through theoretical analysis and high-acceleration test verification, it is found that the long-term slow drift of the zero bias and scale factor of the fiber optic gyroscope is functionally related to the long-term slow drift of the fiber optic ring length, average diameter and fast-axis effective refractive index. Due to the symmetrical winding process of the fiber optic ring, the long-term drift of the zero bias of the fiber optic gyroscope is greatly alleviated, while the long-term drift of the scale factor still exists, becoming a key factor limiting the stability of the fiber optic gyroscope over its entire life.

[0004] The long-term drift of the scale factor of the closed-loop fiber optic gyroscope is mainly affected by the long-term drift of the average wavelength of the optical signal at the optical path terminal and the long-term drift of the equivalent sensitive area of ​​the optical fiber ring. In view of the long-term drift of the average wavelength of the optical signal at the optical path terminal, the real-time monitoring and tracking technology of the average wavelength is used at home and abroad to suppress the long-term drift of the average wavelength. However, there has been a lack of direct and effective technical solutions to the long-term drift of the equivalent sensitive area of ​​the optical fiber ring. In this regard, the intrinsic frequency tracking technology is generally adopted at home and abroad, which can solve the problem of temperature sensitivity of the scale factor. However, this technology changes the influencing factors of the long-term drift of the equivalent sensitive area of ​​the optical fiber ring from the long-term drift of the optical fiber ring length and average diameter before the technology is adopted to the long-term drift of the average diameter of the optical fiber ring and the effective refractive index of the fast axis after the technology is adopted, which increases the difficulty of analysis. Summary of the invention

[0005] The technical problem solved by the present invention is as follows: in view of the problem that the long-term drift of the equivalent sensitive area of ​​the optical fiber ring leads to the long-term drift of the scale factor of the optical fiber gyroscope, a mathematical model of the long-term change of the optical fiber ring length, average diameter, and fast-axis effective refractive index over time at any temperature point is established and fully verified. According to the user's requirements for the long-term drift of the zero bias and scale factor of the optical fiber gyroscope, based on the model, the temperature, time characteristics and geometric proportions of the thermodynamic parameters of the non-metallic materials constituting the optical fiber ring are reversely optimized to achieve the goal of suppressing the long-term drift peak-to-peak value of the optical fiber ring length, average diameter, and fast-axis effective refractive index.

[0006] The technical solution of the present invention:

[0007] A method for suppressing long-term drift of equivalent sensitive area of ​​an optical fiber ring, the method comprising:

[0008] Step 1: Measure the time function of the thermodynamic parameters of each component material of the optical fiber ring under constant temperature;

[0009] Step 2: The optical fiber ring is regarded as an orthotropic composite material with the same lateral parameters and different circumferential parameters, and the three-dimensional thermodynamic parameters of the optical fiber ring are obtained by analyzing the two-dimensional mechanical parameter calculation method of the composite material;

[0010] Step 3: According to step 1 and step 2, the time function of the equivalent thermodynamic parameters of the optical fiber ring in the transverse direction and the circumferential direction under the constant temperature state is obtained;

[0011] Step 4: Calculate the transverse and circumferential strains of the optical fiber ring according to the results of step 3, obtain the time function of the circumferential strain of each layer of the optical fiber ring, and further obtain the time function of the circumferential stress of each layer of the optical fiber ring;

[0012] Step 5: Decompose the fiber ring by finite element according to certain rules, and calculate the time function of the three-dimensional stress of each microelement segment according to the result of step 4, based on the vector sum of the internal force of the fiber ring being zero and the orthogonal decomposition of the force, and further obtain the time function of the three-dimensional strain of each microelement segment; the three dimensions refer to: radial, axial, and circumferential directions;

[0013] Step 6: Calculate the change of the fast axis effective refractive index according to the result of step 5, obtain the time function of the change of the fast axis effective refractive index of each micro-element segment, and further obtain the time function of the average value of the fast axis effective refractive index of all micro-element segments;

[0014] Step 7: Calculate the change in the length of the optical fiber ring according to the result of step 5, accumulate the circumferential strain of each microelement segment, and obtain the time function of the change in the length of the optical fiber ring;

[0015] Step 8: Calculate the change in average diameter of the optical fiber ring according to the result of step 5, accumulate the radial strains of the micro-element segments with the same circumferential coordinates of the optical fiber ring, and obtain the time function of the change in average diameter of the optical fiber ring;

[0016] Step 9: According to the results of step 6, step 7, and step 8, the drift of the fiber optic gyroscope scale factor is calculated to obtain the time function of the fiber optic gyroscope scale factor; according to the results of step 5 and step 6, the drift of the fiber optic gyroscope zero bias is calculated to obtain the time function of the fiber optic gyroscope zero bias.

[0017] Furthermore,

[0018] In step 1, the components of the optical fiber ring include: cladding, inner coating layer, outer coating layer, ring glue, and bonding glue; the thermodynamic parameters include: Young's modulus, Poisson's ratio, and linear thermal expansion coefficient.

[0019] Furthermore,

[0020] In step 2, the three-dimensional thermodynamic parameters of the optical fiber ring include: equivalent thermodynamic parameters of the optical fiber ring in the lateral direction and the circumferential direction.

[0021] Furthermore,

[0022] In step 9, the time function of the FOG zero bias is a functional relationship between the FOG zero bias drift and the fiber ring parameters.

[0023] Furthermore,

[0024] The functional relationship between the fiber optic gyroscope zero bias drift and the fiber optic ring parameters is:

[0025]

[0026] Wherein, ΔΩ represents the zero bias drift of the fiber gyroscope, λ represents the average wavelength of the optical signal transmitted by the fiber ring, c represents the speed of light in a vacuum, L represents the length of the fiber ring, and D represents the average diameter of the fiber ring;

[0027] They represent the phase change of the optical signal passing through the micro-element segment of the optical fiber with length coordinates z and Lz and length δz respectively, represents the temperature change rate in the fiber microelement segment with length coordinate z, Lz and length δz, n represents the effective refractive index of the fiber's fast axis, α T The subscript T represents temperature.

[0028] Furthermore,

[0029] The zero bias drift of the fiber gyroscope is related to the effective refractive index n of the fast axis of each micro-element segment inside the fiber ring and its change dn, as well as the circumferential strain of each micro-element segment. There is a functional relationship between the change in the effective refractive index of the fast axis dn and the three-dimensional stress on the microelement segment:

[0030]

[0031] Among them, T nfast represents the stress along the fast axis, T nslow represents the stress along the slow axis perpendicular to the fast axis, T nθ represents the stress in the length direction perpendicular to both the fast and slow axes, and the stress in the above formula is positive; E represents the Young's modulus of the material; the change in the effective refractive index of the fast axis dn has a functional relationship with the three-dimensional strain of the microelement segment:

[0032]

[0033] Furthermore,

[0034] The zero bias drift of the fiber optic gyroscope is also related to the length L and average diameter D of the fiber optic ring.

[0035] Furthermore,

[0036] In step 9, the time function of the fiber optic gyroscope scale factor is a functional relationship between the fiber optic gyroscope scale factor and the fiber ring parameter.

[0037] Furthermore,

[0038] The functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring parameters is:

[0039]

[0040] After real-time tracking of the eigenfrequency of the fiber optic gyroscope, the functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring changes to:

[0041]

[0042] The “→” is used to indicate the correlation between the scaling factor and the above parameters.

[0043] Furthermore,

[0044] The scale factor drift of the fiber gyroscope is related to the length L of the fiber ring or the average value n of the fast axis effective refractive index and the average diameter D;

[0045] The change in the length of the optical fiber ring is obtained by accumulating the circumferential strain of the micro-element segment inside the optical fiber ring;

[0046] The average diameter change of the optical fiber ring is to accumulate the radial strain of the micro-element segments with the same circumferential coordinates to obtain the inner and outer contours of the optical fiber ring, and then calculate the average value of the inner and outer contours;

[0047] The average value of the fast axis effective refractive index of the optical fiber ring is obtained according to the zero bias calculation formula. The fast axis effective refractive index of each micro-element segment inside the optical fiber ring is determined, and the average value is calculated after the maximum and minimum values ​​are determined.

[0048] Beneficial effects of the present invention:

[0049] By measuring the temperature and time functions of the thermodynamic parameters of the components of the optical fiber ring, and drawing on the calculation ideas of homogenization and dehomogenization, key parameters such as the optical fiber ring length, average diameter, fast-axis effective refractive index and its mean are calculated relatively simply, thereby obtaining the time functions of the optical fiber gyroscope zero bias and scale factor under constant temperature working conditions. Through continuous verification and calibration of the model, a forward design method for the optical fiber ring material parameters is directly provided for the long-term drift peak-to-peak value of the optical fiber gyroscope zero bias and scale factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Flowchart for modeling the long-term drift of fiber optic gyroscope bias and scale factor. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0052] The technical solution of the present invention adopts the analysis ideas of homogenization and dehomogenization and the finite element analysis approach to establish, verify and calibrate the thermodynamic parameters of each non-metallic material (inner coating, outer coating, ring glue, bonding glue) of each component of the optical fiber ring, and the long-term drift with time, temperature and other environmental conditions. The mathematical model of the long-term drift of the circumferential strain, radial strain and three-dimensional stress of the micro-element segment of the optical fiber ring with time, temperature and other environmental conditions is established. In the fully calibrated mathematical model, the circumferential strain of each micro-element segment is integrated according to a certain numbering rule to obtain the long-term drift of the optical fiber ring length, and the radial strain of each micro-element segment is integrated according to a certain numbering rule to obtain the long-term drift of the average diameter of the optical fiber ring, the long-term drift of the three-dimensional stress of each micro-element segment, and the long-term drift of the fast axis effective refractive index of each micro-element segment is calculated. Finally, the average long-term drift and discrete characteristics of the fast axis effective refractive index of the optical fiber ring are obtained, thereby analyzing the long-term drift characteristics of the optical fiber gyroscope scale factor. Conversely, in response to the long-term drift peak requirements of the scale factor, it is a more reliable technical approach to optimize the thermodynamic parameters and geometric proportions of the non-metallic materials that make up the optical fiber ring based on the model, and ultimately achieve long-term drift suppression of the equivalent sensitive area of ​​the optical fiber ring.

[0053] The fiber ring is a ring-shaped body, and the geometric parameters that characterize its appearance characteristics are the inner diameter (inner radius), outer diameter (outer radius), and height. When calculating the time function of the length, average diameter, and fast-axis equivalent refractive index of the fiber ring of the fiber optic gyroscope, the finite element method is used to decompose the fiber ring into: the radial length is equal to the difference between the outer radius and the inner radius of the fiber ring, divided by the number of fiber ring layers, the axial length is equal to the height of the fiber ring divided by the average number of turns per layer, and the circumferential length is divisible by the average circumference of the turns. For example: the number of fiber ring layers is 64, the average number of turns per layer is 88, and the circumferential length of the micro-element segment is equal to the length of the number of turns divided by 360. Then the number of micro-element segments decomposed into the fiber ring is 64×88×360=2027520. The more micro-element segments there are, the more accurate the time function of the length, average diameter, and fast-axis effective refractive index of the fiber ring is, but the amount of calculation is extremely large.

[0054] The finite element analysis method can be used to more accurately calculate the comprehensive thermodynamic parameters of the optical fiber ring. The temperature and time functions of the thermodynamic parameters (Young's modulus, Poisson's ratio, linear thermal expansion coefficient) of the component materials of the optical fiber ring (cladding, inner coating, outer coating, winding, adhesive) are brought into the finite element model to obtain the transverse (radial, axial) and circumferential comprehensive thermodynamic parameters of the optical fiber ring. It is found that the circumferential comprehensive thermodynamic parameters of the optical fiber ring are quite different from the transverse (radial, axial) comprehensive thermodynamic parameters, while the transverse (radial, circumferential) comprehensive thermodynamic parameters are basically equivalent. It is concluded that the optical fiber ring is an orthogonal anisotropic composite material. By referring to the analytical formula of two-dimensional composite materials, basically the same calculation results are obtained. The calculation ideas of homogenization and dehomogenization are introduced into the optical fiber ring calculation program, which alleviates the huge amount of calculation of direct finite element decomposition of the optical fiber ring.

[0055] The functional relationship between the fiber optic gyroscope zero bias drift and the fiber optic ring parameters is:

[0056]

[0057] Where: ΔΩ represents the zero bias drift of the fiber gyroscope, λ represents the average wavelength of the optical signal transmitted by the fiber ring, c represents the speed of light in a vacuum, L represents the length of the fiber ring, and D represents the average diameter of the fiber ring.

[0058] They represent the phase change of the optical signal passing through the micro-element segment of the optical fiber with length coordinates z and Lz and length δz respectively, represents the temperature change rate in the fiber microelement segment with length coordinate z, Lz and length δz, and n represents the effective refractive index of the fiber in the fast axis. Since a small number of fiber gyroscope schemes can also transmit optical signals in the slow axis, the subscript fast is omitted. In the above formula, α T The subscript T represents temperature, and can also be replaced by other symbols, such as F to represent force, then Represents the phase change of the light signal caused by the change in force, corresponding to Represents the rate of change of force.

[0059] It can be seen that the zero bias drift of the fiber gyroscope at this moment is related to the effective refractive index n and its change dn of the fast axis of each micro-element segment inside the fiber ring at this moment, as well as the length strain of each micro-element segment. (It is the same physical concept as the circumferential strain of the optical fiber ring). Among them, the change in the effective refractive index of the fast axis dn has a functional relationship with the three-dimensional stress of the micro-element segment at this moment:

[0060]

[0061] Among them, T nfast represents the stress along the fast axis, T ns low represents the stress along the slow axis perpendicular to the fast axis, T nθ represents the stress in the length direction perpendicular to both the fast and slow axes. The stress in the above formula is positive. E represents the Young's modulus of the material. Since strain ε and stress T exist in the field of elastic mechanics Therefore, the change in the effective refractive index of the fast axis dn has a functional relationship with the three-dimensional strain of the microelement segment at this moment:

[0062]

[0063] Since the fast axis of the optical fiber changes randomly during the process of winding into a ring, the above stress and strain present a random angle with the fast axis of the ring-wound optical fiber. It is necessary to perform orthogonal decomposition of the stress and strain on the fast axis and slow axis to obtain the specific fast axis and slow axis stress and strain on each microelement segment, which will not be repeated here.

[0064] It can be seen that the zero bias drift of the fiber optic gyroscope at this moment is also related to the length L of the fiber optic ring at this moment and the average diameter D at this moment. The calculation method is analyzed in the calculation of the fiber optic gyroscope scale factor drift.

[0065] The functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring parameters is:

[0066]

[0067] After real-time tracking of the eigenfrequency of the fiber optic gyroscope, the functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring changes to:

[0068]

[0069] “→” is used here to indicate the correlation between the scale factor and the above parameters. Since the scale factor is also affected by the circuit parameters, it does not represent an equal relationship and “=” is not used.

[0070] It can be seen that the scale factor drift of the fiber gyroscope at this moment is related to the length L of the fiber ring at this moment or the average value n of the fast axis effective refractive index and the average diameter D. The change in the length of the fiber ring is obtained by directly accumulating the circumferential strain of the micro-element segments inside the fiber ring. The change in the average diameter of the fiber ring is related to the radial strain of each micro-element segment inside the fiber ring, but it is not directly accumulated. Instead, it is necessary to accumulate the radial strain of the micro-element segments with the same circumferential coordinates, depict the inner and outer contours of the fiber ring, and then calculate the average value of the inner and outer contours to obtain the average value of the fast axis effective refractive index of the fiber ring. It is necessary to obtain the fast axis effective refractive index of each micro-element segment inside the fiber ring at this moment according to the above zero bias calculation formula, determine its maximum and minimum values, and then calculate the average value.

[0071] like Figure 1 As shown, a method for suppressing long-term drift of equivalent sensitive area of ​​an optical fiber ring provided by an embodiment of the present invention comprises the following steps:

[0072] Step 1: Measure the time function of thermodynamic parameters (Young's modulus, Poisson's ratio, linear thermal expansion coefficient) of each component material of the optical fiber ring (cladding, inner coating, outer coating, ring adhesive, bonding adhesive) under constant temperature;

[0073] Step 2: Using the homogenization idea, the optical fiber ring is regarded as an orthotropic composite material with basically the same transverse (radial and axial) parameters and different circumferential parameters. The calculation method of the two-dimensional mechanical parameters of the composite material is used to obtain the three-dimensional thermodynamic parameters of the optical fiber ring through the analytical formula, that is, the transverse (radial and axial) and circumferential equivalent thermodynamic parameters of the optical fiber ring;

[0074] Step 3: Substitute the measured value of step 1 into step 2 to obtain the time function of the equivalent thermodynamic parameters of the optical fiber ring in the transverse and circumferential directions under the constant temperature state;

[0075] Step 4: Substitute the result of step 3 into the calculation program of the transverse and circumferential strain of the optical fiber ring to obtain the time function of the circumferential strain of each layer of the optical fiber ring, and further obtain the time function of the circumferential stress of each layer of the optical fiber ring;

[0076] Step 5: Decompose the fiber ring by finite element according to certain rules. Based on the fact that the vector sum of the internal force of the fiber ring is zero and the orthogonal decomposition of the force, and drawing on the idea of ​​dehomogenization, bring the result of step 4 into the calculation program to obtain the time function of the three-dimensional (radial, axial, and circumferential) stress of each microelement segment, thereby further obtaining the time function of the three-dimensional (radial, axial, and circumferential) strain of each microelement segment;

[0077] Step 6: Substitute the result of step 5 into the fast axis effective refractive index change calculation program to obtain the time function of the change of the effective refractive index of the fast axis (or slow axis) of each micro-element segment, and further obtain the time function of the average value of the effective refractive index of the fast axis (or slow axis) of all micro-element segments;

[0078] Step 7: Substitute the result of step 5 into the optical fiber ring length change calculation program, accumulate the circumferential strain of each microelement segment, and obtain the time function of the optical fiber ring length change;

[0079] Step 8: Substitute the result of step 5 into the calculation program of the average diameter change of the optical fiber ring, accumulate the radial strains of the micro-element segments with the same circumferential coordinates of the optical fiber ring, and obtain the time function of the average diameter change of the optical fiber ring;

[0080] Step 9: Substitute the results of step 6, step 7, and step 8 into the FOG scale factor drift calculation program to obtain the time function of the FOG scale factor; substitute the results of step 5 and step 6 into the FOG zero bias drift calculation program to obtain the time function of the FOG zero bias.

[0081] The technical solution of the present invention measures the temperature and time functions of the thermodynamic parameters of the components of the optical fiber ring, draws on the calculation ideas of homogenization and dehomogenization, and relatively simply calculates the key parameters of the optical fiber ring, such as the length, average diameter, fast-axis effective refractive index and its mean, thereby obtaining the time functions of the zero bias and scale factor of the optical fiber gyroscope under constant temperature working conditions. Through continuous verification and calibration of the model, a forward design method for the optical fiber ring material parameters is directly provided for the long-term drift peak-to-peak value of the zero bias and scale factor of the optical fiber gyroscope.

Claims

1. A method for suppressing the long-term drift of the equivalent sensitive area of ​​an optical fiber ring, characterized in that: The method comprises: Step 1: Measure the time function of the thermodynamic parameters of each component material of the optical fiber ring under constant temperature; Step 2: The optical fiber ring is regarded as an orthotropic composite material with the same lateral parameters and different circumferential parameters, and the three-dimensional thermodynamic parameters of the optical fiber ring are obtained by analyzing the two-dimensional mechanical parameter calculation method of the composite material; Step 3: According to step 1 and step 2, the time function of the equivalent thermodynamic parameters of the optical fiber ring in the transverse direction and the circumferential direction under the constant temperature state is obtained; Step 4: Calculate the transverse and circumferential strains of the optical fiber ring according to the results of step 3, obtain the time function of the circumferential strain of each layer of the optical fiber ring, and further obtain the time function of the circumferential stress of each layer of the optical fiber ring; Step 5: Decompose the fiber ring by finite element according to certain rules, and calculate the time function of the three-dimensional stress of each microelement segment according to the result of step 4, based on the vector sum of the internal force of the fiber ring being zero and the orthogonal decomposition of the force, and further obtain the time function of the three-dimensional strain of each microelement segment; the three dimensions refer to: radial, axial, and circumferential directions; Step 6: Calculate the change of the fast axis effective refractive index according to the result of step 5, obtain the time function of the change of the fast axis effective refractive index of each micro-element segment, and further obtain the time function of the average value of the fast axis effective refractive index of all micro-element segments; Step 7: Calculate the change in the length of the optical fiber ring according to the result of step 5, accumulate the circumferential strain of each microelement segment, and obtain the time function of the change in the length of the optical fiber ring; Step 8: Calculate the change in average diameter of the optical fiber ring according to the result of step 5, accumulate the radial strains of the micro-element segments with the same circumferential coordinates of the optical fiber ring, and obtain the time function of the change in average diameter of the optical fiber ring; Step 9: According to the results of step 6, step 7, and step 8, the drift of the fiber optic gyroscope scale factor is calculated to obtain the time function of the fiber optic gyroscope scale factor; according to the results of step 5 and step 6, the drift of the fiber optic gyroscope zero bias is calculated to obtain the time function of the fiber optic gyroscope zero bias.

2. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 1, characterized in that: In step 1, the components of the optical fiber ring include: cladding, inner coating layer, outer coating layer, ring glue, and bonding glue; the thermodynamic parameters include: Young's modulus, Poisson's ratio, and linear thermal expansion coefficient.

3. The method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 2, characterized in that: In step 2, the three-dimensional thermodynamic parameters of the optical fiber ring include: equivalent thermodynamic parameters of the optical fiber ring in the lateral direction and the circumferential direction.

4. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 3, characterized in that: In step 9, the time function of the FOG zero bias is a functional relationship between the FOG zero bias drift and the fiber ring parameters.

5. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 4, characterized in that: The functional relationship between the fiber optic gyroscope zero bias drift and the fiber optic ring parameters is: Wherein, ΔΩ represents the zero bias drift of the fiber gyroscope, λ represents the average wavelength of the optical signal transmitted by the fiber ring, c represents the speed of light in a vacuum, L represents the length of the fiber ring, and D represents the average diameter of the fiber ring; They represent the phase change of the optical signal passing through the micro-element segment of the optical fiber with length coordinates z and Lz and length δz respectively, represents the temperature change rate in the fiber microelement segment with length coordinate z, Lz and length δz, n represents the effective refractive index of the fiber's fast axis, α T The subscript T represents temperature.

6. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 5, characterized in that: The zero bias drift of the fiber gyroscope is related to the effective refractive index n of the fast axis of each micro-element segment inside the fiber ring and its change dn, as well as the circumferential strain of each micro-element segment. There is a functional relationship between the change in the effective refractive index of the fast axis dn and the three-dimensional stress on the microelement segment: Among them, T nfast represents the stress along the fast axis, T nslow represents the stress along the slow axis perpendicular to the fast axis, T nθ represents the stress in the length direction perpendicular to both the fast and slow axes, and the stress in the above formula is positive; E represents the Young's modulus of the material; the change in the effective refractive index of the fast axis dn has a functional relationship with the three-dimensional strain of the microelement segment:

7. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 6, characterized in that: The zero bias drift of the fiber optic gyroscope is also related to the length L and average diameter D of the fiber optic ring.

8. The method for suppressing the long-term drift of the equivalent sensitive area of ​​an optical fiber ring according to claim 6, characterized in that: In step 9, the time function of the fiber optic gyroscope scale factor is a functional relationship between the fiber optic gyroscope scale factor and the fiber ring parameter.

9. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 8, characterized in that: The functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring parameters is: After real-time tracking of the eigenfrequency of the fiber optic gyroscope, the functional relationship between the fiber optic gyroscope scale factor and the fiber optic ring changes to: The "→" is used to indicate the correlation between the scaling factor and the above parameters.

10. A method for suppressing long-term drift of equivalent sensitive area of ​​optical fiber ring according to claim 9, characterized in that: The scale factor drift of the fiber gyroscope is related to the length L of the fiber ring or the average value n of the fast axis effective refractive index and the average diameter D; The change in the length of the optical fiber ring is obtained by accumulating the circumferential strain of the micro-element segment inside the optical fiber ring; The average diameter change of the optical fiber ring is to accumulate the radial strain of the micro-element segments with the same circumferential coordinates to obtain the inner and outer contours of the optical fiber ring, and then calculate the average value of the inner and outer contours; The average value of the fast axis effective refractive index of the optical fiber ring is obtained according to the zero bias calculation formula. The fast axis effective refractive index of each micro-element segment inside the optical fiber ring is determined, and the average value is calculated after the maximum and minimum values ​​are determined.

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