Reference-level optical fiber gyroscope structure for world time measurement

Abstract

The invention relates to a reference-level optical fiber gyroscope structure for world time measurement, which solves the problems of stress distribution uniformity control and winding accuracy control of a large-volume and large-rotation inertia optical fiber ring through optical fiber ring skeleton structure design and winding method optimization design, and ensures the winding symmetry of the optical fiber ring. A multi-station synchronous curing technology is adopted, so that the optical fiber ring is fully cured, the curing stress is uniformly and symmetrically distributed, and the total strain peak value of the optical fiber ring is controlled at a better level below 500 mu epsilon; and the optical fiber ring skeleton adopts a symmetrical structure form, so that the mechanical strength precision is ensured, and the weight reduction is realized on the premise of ensuring the stability.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber optic gyroscopes, and in particular relates to a large-scale reference-level high-precision fiber optic gyroscope structure used for measuring universal time. Background Art

[0002] High-precision universal time measurement can be applied to the fields of time service, navigation and positioning, and geophysical research, and is of great significance to the fields of social economy, military and national defense. Fiber optic gyroscopes can measure the rotation speed of the earth independently of satellites, base stations and other systems, and then measure universal time. Therefore, they play an important role in universal time measurement technology, especially in domestic independent universal time measurement technology. Most gyroscopes used for universal time measurement at home and abroad are large laser gyroscopes (diameter 4m×4m and above). At present, the best performance of high-precision fiber optic gyroscopes abroad is the reference-level fiber optic gyroscope prototype developed by Honeywell in the United States in 2016, which can be used in metrology, seismology, structural sensing and other fields or as a benchmark for other inertial test equipment. The accuracy of large reference-level high-precision fiber optic gyroscopes used for universal time measurement is 0.788×10-6° / h (1σ, 1h).

[0003] As the demand for accurate, independent universal time measurements grows, the development and use of reference-grade fiber optic gyroscopes has become an urgent task. Summary of the invention

[0004] The purpose of the present invention is to provide a reference-level fiber optic gyroscope structure for world time measurement. By optimizing the design of the fiber optic ring skeleton structure and the winding method, the problems of uniformity control of stress distribution and precise winding control of large-volume and large-rotational inertia fiber optic rings are solved, and the winding symmetry of the fiber optic ring is ensured; multi-station synchronous curing technology is adopted to ensure that the fiber optic ring is fully cured while achieving uniform and symmetrical distribution of curing stress so that the overall strain peak-to-peak value of the fiber optic ring is controlled at a good level below 500με; the fiber optic ring skeleton adopts a symmetrical structure, which not only ensures the mechanical strength accuracy, but also achieves weight reduction under the premise of ensuring stability.

[0005] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0006] A reference-level fiber optic gyroscope structure for world time measurement comprises a first shielding inner cover, a heat-insulating gasket, a second shielding inner cover, a heat-insulating column, a fiber optic ring coil, a fiber optic ring skeleton, a Y-waveguide, a first shielding outer cover and a second shielding outer cover; the structure is connected in a layered stacking manner, and from bottom to top, the structure comprises the first shielding inner cover, the heat-insulating gasket, the second shielding inner cover, the heat-insulating column, the fiber optic ring skeleton, the first shielding outer cover and the second shielding outer cover; the fiber optic ring coil is wound in a cavity of the fiber optic ring skeleton, the Y-waveguide is installed in the fiber optic ring skeleton, the total length of the fiber optic ring coil is 50-70 km, and the winding method is a sixteen-level symmetrical winding method.

[0007] It also includes an insulation base plate, a mounting bracket and an insulation outer cover. The mounting bracket has threaded holes on its surface, which are respectively threadedly connected to the insulation base plate, the insulation outer cover, the second shielding outer cover, the first shielding outer cover, the second shielding inner cover and the insulation column.

[0008] The first shielding outer cover and the second shielding outer cover are provided with lug flanges, and the mounting bracket is threadedly connected with the lug flanges.

[0009] The upper surface of the mounting bracket includes circle A, circle B and circle C. N threaded holes are arranged on the upper surface of the mounting bracket, distributed on the circumference of circle A, and are used to be threadedly connected to the flange of the lug of the second shielding outer cover; M threaded holes are arranged on the upper surface of the mounting bracket, distributed on the circumference of circle B, and are used to be threadedly connected to the flange of the lug of the first shielding outer cover; threaded holes are arranged on the side of the mounting bracket, and are used to be threadedly connected to the thermal insulation outer cover; P threaded holes are arranged on the upper surface of the mounting bracket, distributed on the circumference of circle C, and are used to be fixedly connected to the insulation column 6, N, M and P are all positive integers, the diameter of circle A is greater than the diameter of circle B, and the diameter of circle B is greater than the diameter of circle C.

[0010] The optical fiber ring skeleton is provided with an annular groove and a linear groove. The two ends of the linear groove are respectively connected to the inner circle side wall of the annular groove, which is used for the optical fiber ring coil pigtail to transition to the gyroscope circuit assembly surface and the optical path assembly surface; the Y waveguide is fixedly installed in the annular groove.

[0011] When curing the optical fiber ring coil, a multi-light source synchronous curing method is adopted. The specific method is as follows: it includes multiple curing boxes, which are evenly distributed around the optical fiber ring coil. During curing, multiple curing boxes are opened at the same time to achieve multi-light source synchronous curing.

[0012] The optical fiber ring frame adopts a symmetrical structure, and a gap of 0.5 to 0.8 mm is left between the optical fiber ring coil and the inner circle side wall of the optical fiber ring frame.

[0013] The heat-insulating columns and heat-insulating gaskets are made of materials with low temperature expansion coefficients, and the first shielding outer cover, the second shielding inner cover, the second shielding outer cover and the first shielding inner cover are made of iron-nickel alloy magnetic shielding materials.

[0014] A plurality of reference surface mounting bosses are arranged on the optical fiber ring skeleton, the diameter of the reference surface mounting bosses is 90-110 mm, and the mounting surface accuracy is 0.05-0.15.

[0015] The optical fiber ring coil is bonded to the optical fiber ring frame by epoxy glue.

[0016] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0017] (1) The present invention provides a large reference-grade fiber optic gyroscope structure for measuring universal time, which adopts a sixteen-level symmetrical winding method to improve the temperature stability of a large fiber optic ring. The sixteen-level symmetrical method reduces the number of times the position of the fiber-releasing wheel is exchanged, which is more conducive to improving control accuracy and reducing error rate.

[0018] (2) The present invention provides a reference-level fiber optic gyroscope structure for measuring universal time, which realizes the neat winding of ultra-long fiber optic rings, and the longest fiber optic ring that can be wound is 70 km.

[0019] (3) The reference-level fiber optic gyroscope structure for world time measurement of the present invention preferably adopts a three-layer heat insulation design, each layer is relatively sealed and contactless, and air flow between layers is avoided. The inner layer structure heat insulation column and heat insulation gasket are made of low temperature expansion coefficient materials to reduce deformation caused by external temperature changes, that is, to achieve bonding and long-term stability of the fiber optic ring; the middle layer formed by the first shielding outer cover and the second shielding inner cover and the outer layer formed by the second shielding outer cover and the first shielding inner cover are selected from iron-nickel alloy magnetic shielding materials to reduce the internal temperature change rate and weaken the influence of the magnetic field, thereby reducing the influence of the magnetic field on the zero bias.

[0020] (4) The reference-level fiber optic gyroscope structure for measuring universal time of the present invention preferably adopts a multi-light source uniform synchronous curing method, so that a larger range of the circumference of the fiber optic ring coil is cured simultaneously, making the curing of the fiber optic ring more uniform and reducing the internal residual stress. While the multi-light source curing causes the temperature of the ring body at the curing part to increase, as the fiber optic ring rotates, the heat of the ring body away from the direct irradiation part of the light source can be dissipated in time, reducing the thermal stress of the fiber optic ring curing, so as to improve the temperature performance of the fiber optic ring after curing.

[0021] (5) The present invention provides a reference-level fiber optic gyroscope structure for measuring universal time, which has excellent zero-bias accuracy, and has obvious advantages in terms of quality, reliability, and controllable technical status. It also has great room for improvement and broad application prospects in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a reference-level fiber optic gyroscope for measuring universal time according to the present invention;

[0023] Figure 2 This is a schematic diagram of the mounting bracket structure of Example 1 of the present invention, wherein Figure 2 a is a schematic diagram of the front view of the mounting bracket structure. Figure 2 b is a schematic diagram of the reverse side of the mounting bracket structure;

[0024] Figure 3 This is a schematic diagram of the optical fiber ring skeleton of Example 1 of the present invention, wherein Figure 3 a is a front view schematic diagram of the optical fiber ring skeleton structure; Figure 3 b is a schematic diagram of the reverse side of the optical fiber ring skeleton structure. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] The present invention provides a large reference-level high-precision fiber optic gyroscope structure for measuring world time, such as Figure 1 As shown, it includes a thermal insulation bottom plate 1, a mounting bracket 2, a first shielding inner cover 3, a thermal insulation gasket 4, a second shielding inner cover 5, a thermal insulation column 6, an optical fiber ring coil 7, an optical fiber ring skeleton 8, a Y waveguide 9, a first shielding outer cover 10, a second shielding outer cover 11, and a thermal insulation outer cover 12;

[0027] Example 1

[0028] like Figure 2 The figure shows the schematic diagram of the structure of the mounting bracket 2 of the present invention. The mounting bracket 2 plays a bearing role and is a square structure with a symmetrical structural design form, which not only reduces the weight but also reduces the impact of installation errors caused by the deformation of the structural parts. The wall thickness of the mounting flange is 28-30 mm, and is 29 mm in this embodiment. The upper surface of the mounting bracket 2 is evenly distributed with 4 threaded holes 22 on the circumference, distributed on a circle with a diameter of 1530 mm, and is used to be fixedly connected with the mounting lug flange of the second shielding outer cover 11. The upper surface of the mounting bracket 2 is evenly distributed with 3 threaded holes 21 on the circumference, distributed on a circle with a diameter of 1300 mm, and is used to be fixedly connected with the mounting lug flange of the first shielding outer cover 10. The upper surface of the mounting bracket 2 is evenly distributed with 9 threaded holes 23 on the circumference, distributed on a circle with a diameter of 990 mm, and is used to pass through the first shielding inner cover 3, the thermal insulation gasket 4, and the second shield The inner shielding cover 5 is fixedly connected, a plurality of threaded holes 24 are evenly distributed on the side of the mounting bracket 2 for fixed connection with the thermal insulation outer cover 12, four threaded holes 25 are evenly distributed on the circumference of the upper surface of the mounting bracket 2, distributed on a circle with a diameter of 1140 mm, for fixed connection with the thermal insulation column 6, the mounting bracket 2 is provided with a plurality of weight reduction grooves 26, a plurality of threaded holes 27 are provided on the lower bottom surface of the mounting bracket 2 for fixed connection with the thermal insulation bottom plate 1, and the mounting bracket 2 is provided with four mounting bosses 28 as mounting reference surfaces for fixing with the marble slab.

[0029] The optical fiber ring skeleton 8 and the first shielding inner cover 3 form an annular cavity, and the interior of the annular cavity is used to fix the optical fiber ring coil 7. A large optical fiber ring precision fiber arrangement control process is adopted to achieve large arc precision winding and fiber arrangement of 135um thin-diameter optical fiber, and achieve neat winding of optical fibers. The optical fibers across the turns are orthogonally arranged, and the optical fibers across the layers are neat without defects such as protrusions and collapses. A hexadecane symmetrical winding method is adopted to ensure the winding symmetry of the optical fiber ring. A multi-light source synchronous curing method is adopted when curing the optical fiber ring coil 7. The specific method is as follows: it includes multiple curing boxes, and the curing boxes are evenly distributed around the optical fiber ring coil. During curing, multiple curing boxes are opened at the same time to achieve multi-light source synchronous curing.

[0030] The first shielding cover 10 and the second shielding cover 11 are provided with four offset grooves at the bottom, which can realize internal wiring and facilitate structural assembly, and the assembly process is good.

[0031] like Figure 3 A is a schematic diagram of the structure of the optical fiber ring skeleton 8 of the present invention. The annular cavity of the optical fiber ring skeleton 8 is used to place the optical fiber ring coil 7. A gap of 0.5 to 0.8 mm is left between the optical fiber ring coil 7 and the inner ring side wall of the optical fiber ring skeleton 8. The optical fiber ring coil 7 is bonded to the U-shaped groove 81 of the optical fiber ring skeleton by epoxy glue. An annular groove 84 is left on the optical fiber ring skeleton 8 for the pigtail to enter the optical path assembly surface. Two threaded holes 83 are distributed in the annular groove 84 of the optical fiber ring skeleton 8 for installing the Y waveguide 9. There is a linear groove 85 on the optical fiber ring skeleton 8 for the pigtail to enter the circuit assembly surface. A circular groove 86 is provided in the middle of the optical fiber ring skeleton 8 for connecting the ring tooling bracket. The optical fiber ring skeleton 8 is provided with 6 light holes 82 for fixing with the threaded holes of the heat insulation column 6. The optical fiber ring skeleton 8 is provided with a number of weight-reducing grooves 87. The optical fiber ring skeleton 8 uses materials with dimensional stability and small deformation to solve the deformation problem of structural parts under super-large diameters, and can also ensure the accuracy of the fiber winding while reducing weight. Therefore, this project has realized the large-size optical fiber ring system and completed the research on the precise fiber arrangement control method of large optical fiber rings, realizing the precise control of the arrangement position of the optical fiber in the axial and circumferential directions of the entire optical fiber ring skeleton, with a control accuracy better than 0.02mm; through the research on the long-field micro-magnification video surveillance system, it has achieved an imaging distance of more than 500mm between the imaging lens of the video surveillance system and the center position of the optical fiber ring annulus, meeting the project's micro-magnification requirements for longer imaging distances.

[0032] The heat-insulating columns 6 and the heat-insulating gaskets 4 are made of materials with low temperature expansion coefficients, and the first shielding outer cover 10 , the second shielding inner cover 5 , the second shielding outer cover 11 and the first shielding inner cover 3 are made of iron-nickel alloy magnetic shielding materials.

[0033] The fiber ring is wound with precise hexadecane symmetry. The fiber ring is a frameless ring wound with adhesive, which effectively reduces the impact of the environment on the fiber optic gyroscope. Photonic crystal fiber with low sensitivity to temperature and magnetic field is selected to effectively reduce the Shupe error of the fiber ring and improve the temperature performance of the fiber optic gyroscope, thus realizing a large-size fiber ring system of 70km.

[0034] like Figure 3 b is a schematic diagram of the structure of the optical fiber ring skeleton 8 of the present invention. The optical fiber ring skeleton 8 is provided with 7 reference surface mounting bosses 88, the boss diameter is 90-110mm, 100mm in this embodiment, the mounting surface accuracy is 0.05~0.15, 0.1mm in this embodiment, and is used to connect with the insulation column 6.

[0035] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0036] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A reference-grade fiber optic gyroscope structure for measuring universal time, characterized in that: The invention comprises a first shielding inner cover (3), a heat insulating gasket (4), a second shielding inner cover (5), a heat insulating column (6), an optical fiber ring coil (7), an optical fiber ring frame (8), a Y waveguide (9), a first shielding outer cover (10) and a second shielding outer cover (11); the optical fiber ring coil (7) is connected in a layered stacking manner, and from bottom to top, the first shielding inner cover (3), the heat insulating gasket (4), the second shielding inner cover (5), the heat insulating column (6), the optical fiber ring frame (8), the first shielding outer cover (10) and the second shielding outer cover (11) are sequentially arranged; the optical fiber ring coil (7) is wound in the cavity of the optical fiber ring frame (8), the Y waveguide (9) is installed in the optical fiber ring frame (8), the total length of the optical fiber of the optical fiber ring coil (7) is 50-70 km, and the winding method is a sixteen-level symmetrical winding method.

2. A reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: It also includes a heat-insulating base plate (1), a mounting bracket (2) and a heat-insulating outer cover (12); threaded holes are provided on the surface of the mounting bracket (2) and are respectively threadedly connected to the heat-insulating base plate (1), the heat-insulating outer cover (12), the second shielding outer cover (11), the first shielding outer cover (10), the second shielding inner cover (5) and the heat-insulating column (6).

3. A reference-grade fiber optic gyroscope structure for measuring universal time according to claim 2, characterized in that: The first shielding outer cover (10) and the second shielding outer cover (11) are provided with lug flanges, and the mounting bracket (2) is threadedly connected to the lug flanges.

4. A reference-grade fiber optic gyroscope structure for measuring universal time according to claim 3, characterized in that: The upper surface of the mounting bracket (2) comprises a circle A, a circle B and a circle C. The upper surface of the mounting bracket (2) is provided with N threaded holes, distributed on the circumference of circle A, for being threadedly connected to the flanged lug of the second shielding outer cover (11); the upper surface of the mounting bracket (2) is provided with M threaded holes, distributed on the circumference of circle B, for being threadedly connected to the flanged lug of the first shielding outer cover (10); the side surface of the mounting bracket (2) is provided with threaded holes, for being threadedly connected to the heat-insulating outer cover (12); the upper surface of the mounting bracket (2) is provided with P threaded holes, distributed on the circumference of circle C, for being fixedly connected to the heat-insulating column 6, N, M and P are all positive integers, the diameter of circle A is greater than the diameter of circle B, and the diameter of circle B is greater than the diameter of circle C.

5. The reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: The optical fiber ring frame (8) is provided with an annular groove (84) and a linear groove (85), and the two ends of the linear groove (85) are respectively connected to the inner circle side wall of the annular groove (84) for transition of the optical fiber ring coil pigtail to the gyroscope circuit assembly surface and the optical path assembly surface; the Y waveguide (9) is fixedly installed in the annular groove (84).

6. A reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: When curing the optical fiber ring coil (7), a multi-light source synchronous curing method is adopted. The specific method is as follows: a plurality of curing boxes are included, and the curing boxes are evenly distributed around the optical fiber ring coil (7). During curing, the plurality of curing boxes are opened at the same time to achieve multi-light source synchronous curing.

7. The reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: The optical fiber ring frame (8) adopts a symmetrical structure, and a gap of 0.5 to 0.8 mm is left between the optical fiber ring coil (7) and the inner circle side wall of the optical fiber ring frame (8).

8. The reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: The heat-insulating columns (6) and the heat-insulating gaskets (4) are made of materials with a low temperature expansion coefficient, and the first shielding outer cover (10), the second shielding inner cover (5), the second shielding outer cover (11) and the first shielding inner cover (3) are made of iron-nickel alloy magnetic shielding materials.

9. The reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: A plurality of reference surface mounting bosses (88) are arranged on the optical fiber ring skeleton (8); the diameter of the reference surface mounting bosses (88) is 90-110 mm, and the mounting surface accuracy is 0.05-0.

15.

10. The reference-grade fiber optic gyroscope structure for measuring universal time according to claim 1, characterized in that: The optical fiber ring coil (7) is bonded to the optical fiber ring frame (8) by epoxy glue.

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