Miniaturized optical fiber strapdown inertial navigation system based on three-axis integrated vibrating beam accelerometer

Abstract

The invention discloses a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer, which comprises an inertial measurement unit and an outer cover assembly, the inertial measurement unit is arranged in the outer cover assembly, and the inertial measurement unit is at least used for completing measurement and navigation calculation of inertial motion parameters of a carrier. The outer cover assembly is at least used for avoiding the influence of the external environment on the inertial measurement unit and ensuring the normal work of the inertial measurement unit. According to the optical fiber strapdown inertial navigation system provided by the invention, on the premise of not high requirements on horizontal attitude and autonomous positioning precision, indexes such as equipment volume, weight and power consumption are further reduced by replacing a small-volume accelerometer and optimizing the structural size, so that the burden of carriers such as airplanes and unmanned aerial vehicles can be reduced, and the operation efficiency and maneuverability of the carriers can be improved; and the platform can be applied to some small or micro aircrafts and ground machines with limited space, and the application friendliness and the user experience of the platform are enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber strapdown inertial navigation, and in particular to a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer. Background Art

[0002] Fiber optic inertial navigation is a system that uses the characteristics of light signals propagating in a fiber optic ring to sense the carrier's motion posture and position changes. It usually includes a fiber optic gyroscope and an accelerometer. These sensors can detect the angular velocity and acceleration of an object in three-dimensional space, and calculate the object's posture and position information by processing the data;

[0003] Currently, common accelerometers are divided into quartz accelerometers, vibrating beam accelerometers, and MEMS accelerometers. Quartz accelerometers are known for their low noise, high stability, and reliability, but they consume a lot of power, are large in size, and are expensive; MEMS accelerometers are small in size and light in weight, but they are noisy; and vibrating beam accelerometers are a new type of digital inertial sensor based on the force-frequency characteristics of vibrating beams. They have outstanding advantages such as high precision, small size, low power consumption, fast response, low cost, and strong overload capacity, and have been widely used in tactical weapon systems. At the same time, based on the natural frictionless structure of the quartz vibrating beam and the characteristics of direct pulse frequency output, it is the most likely solution to achieve high-precision, high-reliability, and strategic-level applications, and has become a hot spot in the future research of high-precision military accelerometers;

[0004] At present, with the development of fiber-optic inertial technology, the advantages of fiber-optic inertial navigation have been further developed. At present, fiber-optic inertial navigation is equipped in batches in sea, land, air and civil fields. However, the existing fiber-optic strapdown inertial navigation is large in size and cannot adapt to the needs of higher precision, lower energy consumption and more integration of equipment. Therefore, it is urgent to design a miniaturized fiber-optic strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer comprises an inertial measurement unit and a housing assembly, wherein the inertial measurement unit is arranged in the housing assembly, the inertial measurement unit is at least used to complete the measurement and navigation solution of the inertial motion parameters of the carrier, and the housing assembly is at least used to prevent the external environment from affecting the inertial measurement unit and ensure the normal operation of the inertial measurement unit;

[0008] The inertial measurement unit includes a three-axis embedded fiber optic gyroscope, a navigation settlement module, a power board, a main body bracket, a gyroscope control box and a three-axis accelerometer. The three-axis embedded fiber optic gyroscope is arranged on the main body bracket, the gyroscope control box and the three-axis accelerometer are both arranged in the main body bracket, and the power board and the navigation settlement module are both arranged in the outer cover assembly.

[0009] The number of the three-axis embedded fiber optic gyroscopes is three, and the three three-axis embedded fiber optic gyroscopes are respectively fixedly mounted on the circumference of the main body bracket.

[0010] The outer cover assembly includes a shielding shell, an upper cover and a bottom plate. The upper cover is arranged on the upper side of the shielding shell, and the bottom plate is arranged on the lower side of the shielding shell.

[0011] The power board is fixedly installed on one side of the inner wall of the shielding shell, the navigation settlement module is fixedly installed on the other side of the inner wall of the shielding shell, the main body bracket is located in the shielding shell, and the main body bracket is fixedly connected to the bottom plate.

[0012] The three-axis embedded fiber optic gyroscope includes a magnetic shielding lower cover, a fiber ring, a ring frame, a Y-waveguide and a magnetic shielding upper cover. The fiber ring is arranged on the inner wall circumference of the magnetic shielding lower cover, the ring frame is arranged on the inner wall circumference of the fiber ring, the Y-waveguide is arranged between the ring frames, the magnetic shielding upper cover is arranged on one side of the ring frame, and the edge of the magnetic shielding upper cover is in contact with the edge of the magnetic shielding lower cover.

[0013] A connecting sleeve is provided between the magnetic shielding upper cover and the ring frame, a fixing bolt is provided on one side of the magnetic shielding upper cover, and the fixing bolt is inserted into the connecting sleeve.

[0014] The three-axis embedded fiber optic gyroscope, the navigation settlement module, the gyroscope control box and the three-axis accelerometer are all electrically connected to the power board.

[0015] The three-axis embedded fiber optic gyroscope is electrically connected to the gyroscope control box, and the gyroscope control box and the three-axis accelerometer are both electrically connected to the navigation settlement module.

[0016] An external connector is provided on one side of the shielding shell, and the external connector is electrically connected to the navigation settlement module, and the external connector is also electrically connected to the power board.

[0017] A plurality of heat dissipation teeth are arranged on the outer side of the shielding shell, and the heat dissipation teeth are at least used to improve the heat dissipation performance of the optical fiber strapdown inertial navigation system.

[0018] In the above technical solution, the miniaturized optical fiber strapdown inertial navigation system based on the three-axis integrated vibrating beam accelerometer provided by the present invention has the following beneficial effects:

[0019] (1) The optical fiber strapdown inertial navigation system provided by the present invention can reduce the burden on carriers such as aircraft and unmanned aerial vehicles, improve their operating efficiency and maneuverability, and be applicable to some small or micro aircraft and ground machines with limited space, thereby enhancing the platform's application friendliness and user experience, thereby improving the applicability of the optical fiber strapdown inertial navigation system when in use, by replacing a small-volume accelerometer and optimizing the structural dimensions to further reduce the equipment volume, weight, power consumption and other indicators.

[0020] (2) The optical fiber strapdown inertial navigation system provided by the present invention has lower power consumption by reducing its volume, which can extend the operation time of the carrier and reduce energy consumption, thereby improving the practicality of the optical fiber strapdown inertial navigation system when used.

[0021] (3) The optical fiber strapdown inertial navigation system provided by the present invention can fully enclose the internal components by means of the magnetic shielding lower cover and the magnetic shielding upper cover, thereby providing a stable magnetic environment and avoiding the error introduced by the gyro drift caused by the low-frequency magnetic field, thereby improving the accuracy of the optical fiber strapdown inertial navigation system when in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0023] Figure 1 A schematic diagram of the structure of the device provided for the embodiment of the miniaturized optical fiber strapdown inertial navigation system based on the three-axis integrated vibrating beam accelerometer of the present invention.

[0024] Figure 2 A schematic diagram of the external structure of a device provided in an embodiment of a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer of the present invention.

[0025] Figure 3 A schematic diagram of the device decomposition structure provided for an embodiment of a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer of the present invention.

[0026] Figure 4 A schematic diagram of the decomposed structure of a three-axis embedded fiber optic gyroscope is provided for an embodiment of a miniaturized fiber optic strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to the present invention.

[0027] Figure 5 A schematic diagram of the electrical connection structure of the device provided in an embodiment of the miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer of the present invention.

[0028] Figure 6 A schematic diagram of the device signal exchange structure provided for an embodiment of a miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer of the present invention.

[0029] 1. Outer cover assembly; 2. Shielding shell; 3. Upper cover; 4. Bottom plate; 5. Inertial measurement unit; 6. Three-axis embedded fiber optic gyroscope; 7. Navigation settlement module; 8. Power board; 9. External connector; 10. Electrical connector; 11. Main body bracket; 12. Gyro control box; 13. Three-axis accelerometer; 14. Magnetic shielding lower cover; 15. Fiber optic ring; 16. Ring frame; 17. Y waveguide; 18. Magnetic shielding upper cover; 19. Connecting sleeve; 20. Fixing bolts. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] like Figure 1-6 As shown, the miniaturized optical fiber strapdown inertial navigation system based on the three-axis integrated vibrating beam accelerometer provided in the embodiment of the present invention includes an inertial measurement unit 5 and a housing assembly 1, wherein the inertial measurement unit 5 is arranged in the housing assembly 1, and the inertial measurement unit 5 is at least used to complete the measurement and navigation solution of the inertial motion parameters of the carrier, and the housing assembly 1 is at least used to prevent the external environment from affecting the inertial measurement unit 5, so as to ensure the normal operation of the inertial measurement unit 5;

[0032] The inertial measurement unit 5 includes a three-axis embedded fiber optic gyroscope 6, a navigation settlement module 7, a power board 8, a body bracket 11, a gyroscope control box 12 and a three-axis accelerometer 13. The three-axis embedded fiber optic gyroscope 6 is arranged on the body bracket 11, the gyroscope control box 12 and the three-axis accelerometer 13 are both arranged in the body bracket 11, the power board 8 and the navigation settlement module 7 are both arranged in the outer cover assembly 1, and a connecting sleeve 19 is arranged between the magnetic shielding upper cover 18 and the ring frame 16, and a fixed Bolt 20, and the fixing bolt 20 is inserted into the connecting sleeve 19, the three-axis embedded fiber optic gyroscope 6, the navigation settlement module 7, the gyroscope control box 12 and the three-axis accelerometer 13 are all electrically connected to the power board 8, the three-axis embedded fiber optic gyroscope 6 is electrically connected to the gyroscope control box 12, the gyroscope control box 12 and the three-axis accelerometer 13 are all electrically connected to the navigation settlement module 7, the number of the three-axis embedded fiber optic gyroscope 6 is three, and the three three-axis embedded fiber optic gyroscopes 6 are respectively fixedly mounted on the sides of the main body bracket 11.

[0033] Specifically, in this embodiment, the inertial measurement unit 5 mainly completes the functions of inertial information collection and processing, initial alignment, navigation solution, etc., outputs navigation information such as carrier position, attitude, heading, speed, etc., and outputs navigation information to the outside through the measurement and navigation solution of the carrier inertial motion parameters, and can accept control instructions, satellite navigation data and DVL data. The sensor synchronous sampling control, time synchronization, external interface communication and internal navigation solution of the optical fiber strapdown inertial navigation are all completed by the navigation solution module;

[0034] The outer cover component 1 is mainly used to provide a relatively stable working space for the inertial measurement unit (IMU), realize the sealing of the whole machine, isolate the complex external environment, protect the internal IMU and other important stand-alone module-level components, and has heat dissipation and electromagnetic shielding functions;

[0035] The main body bracket 11 is used to install the three-axis embedded fiber optic gyroscope 6 and the three-axis accelerometer 13. The material of the main body bracket 11 is aviation aluminum, with a mass density of 7800kg / m3, an elastic modulus of 7×1010Pa, and a yield strength of 505MPa. The material structure has the characteristics of high stability and high strength. The main body bracket 11 is deep-cryogenically treated before fine processing to fully release internal stress and improve structural stability, so that the main body bracket 11 has sufficient rigidity to ensure that it will not resonate with the fiber optic gyroscope. The three three-axis embedded fiber optic gyroscopes 6 are respectively installed on the main body bracket 11 perpendicular to each other.

[0036] The present invention provides a miniaturized fiber-optic strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer, wherein an outer cover assembly 1 comprises a shielding shell 2, an upper cover 3 and a bottom plate 4, wherein the upper cover 3 is arranged on the upper side of the shielding shell 2, the bottom plate 4 is arranged on the lower side of the shielding shell 2, the power supply board 8 is fixedly mounted on one side of the inner wall of the shielding shell 2, the navigation settlement module 7 is fixedly mounted on the other side of the inner wall of the shielding shell 2, the main body bracket 11 is located in the shielding shell 2, and the main body bracket 11 is fixedly connected to the bottom plate 4, an external connector 9 is arranged on one side of the shielding shell 2, the external connector 9 is electrically connected to the navigation settlement module 7, and the external connector 9 is also electrically connected to the power supply board 8, and a plurality of heat dissipation teeth are arranged on the outer side of the shielding shell 2, and the heat dissipation teeth are at least used to improve the heat dissipation performance of the fiber-optic strapdown inertial navigation.

[0037] In another embodiment provided by the present invention, the shielding shell 2 is a load-bearing structural member for the inertial measurement unit 5. The shielding shell 2 is made of rust-proof aluminum 6061-T6 material as a whole to form a multi-cavity structure. The upper cover 3 and the bottom plate 4 are both made of rust-proof aluminum 6061-T6 material and cooperate with the shielding shell to form a closed space. The contact parts between the upper cover 3 and the bottom plate 4 and the shielding shell 2 are filled with conductive rubber rope to seal and rust-proof the system. The material of the shielding shell 2 is selected to have good corrosion resistance. Oxidation, painting, three-proof, sealing and other means are applied to isolate the influence of external environment such as solar radiation, humidity, wind and rain, hail, salt spray, dust, mold, etc. on the inertial measurement component to ensure the normal operation of the equipment. The navigation settlement module 7 and the power board 8 are directly bonded and installed on the inner surface of the shielding shell through different adapters, and external communication is completed through the external connector 9. A number of heat dissipation teeth can dissipate the heat generated by the internal electronic components to the external air in time through heat conduction and heat radiation.

[0038] The present invention provides a miniaturized fiber-optic strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer, wherein the three-axis embedded fiber-optic gyroscope 6 comprises a magnetic shielding lower cover 14, a fiber ring 15, a ring frame 16, a Y-waveguide 17 and a magnetic shielding upper cover 18, wherein the fiber ring 15 is arranged on the inner wall circumference of the magnetic shielding lower cover 14, the ring frame 16 is arranged on the inner wall circumference of the fiber ring 15, the Y-waveguide 17 is arranged between the ring frames 16, the magnetic shielding upper cover 18 is arranged on one side of the ring frame 16, and the edge of the magnetic shielding upper cover 18 is in contact with the edge of the magnetic shielding lower cover 14.

[0039] In another embodiment provided by the present invention, the internal components can be fully wrapped by the magnetic shielding lower cover 14 and the magnetic shielding upper cover 18 to provide a stable magnetic environment and avoid interference from the external magnetic field. The magnetic shielding lower cover 14 and the magnetic shielding upper cover 18 provide a low magnetic resistance magnetic circuit in the magnetic field to guide the magnetic lines of force through themselves so that the magnetic field avoids sensitive components. Shielding material is provided on both sides of the magnetic shielding lower cover 14 and the magnetic shielding upper cover 18. The thickness of the shielding material is 0.5 mm. The inner magnetic shielding adopts an overlapping method to solve the magnetic leakage phenomenon of the structural gap.

[0040] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A miniaturized fiber-optic strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer, characterized in that: The invention comprises an inertial measurement unit (5) and a housing component (1), wherein the inertial measurement unit (5) is arranged in the housing component (1), the inertial measurement unit (5) is at least used to complete the measurement and navigation solution of the inertial motion parameters of the carrier, and the housing component (1) is at least used to prevent the external environment from affecting the inertial measurement unit (5) and ensure the normal operation of the inertial measurement unit (5); The inertial measurement unit (5) comprises a three-axis embedded fiber optic gyroscope (6), a navigation settlement module (7), a power supply board (8), a main body bracket (11), a gyroscope control box (12) and a three-axis accelerometer (13); the three-axis embedded fiber optic gyroscope (6) is arranged on the main body bracket (11), the gyroscope control box (12) and the three-axis accelerometer (13) are both arranged in the main body bracket (11), and the power supply board (8) and the navigation settlement module (7) are both arranged in the outer cover component (1).

2. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The number of the three-axis embedded fiber optic gyroscopes (6) is three, and the three three-axis embedded fiber optic gyroscopes (6) are respectively fixedly mounted on the circumference of the body bracket (11).

3. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The outer cover assembly (1) comprises a shielding shell (2), an upper cover (3) and a bottom plate (4); the upper cover (3) is arranged on the upper side of the shielding shell (2), and the bottom plate (4) is arranged on the lower side of the shielding shell (2).

4. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The power board (8) is fixedly mounted on one side of the inner wall of the shielding shell (2), the navigation settlement module (7) is fixedly mounted on the other side of the inner wall of the shielding shell (2), the main body bracket (11) is located in the shielding shell (2), and the main body bracket (11) is fixedly connected to the bottom plate (4).

5. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The three-axis embedded fiber optic gyroscope (6) comprises a magnetic shielding lower cover (14), a fiber ring (15), a ring frame (16), a Y waveguide (17) and a magnetic shielding upper cover (18), wherein the fiber ring (15) is arranged on the inner wall circumference of the magnetic shielding lower cover (14), the ring frame (16) is arranged on the inner wall circumference of the fiber ring (15), the Y waveguide (17) is arranged between the ring frames (16), the magnetic shielding upper cover (18) is arranged on one side of the ring frame (16), and the edge of the magnetic shielding upper cover (18) is in contact with the edge of the magnetic shielding lower cover (14).

6. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: A connecting sleeve (19) is provided between the magnetic shielding upper cover (18) and the ring frame (16), a fixing bolt (20) is provided on one side of the magnetic shielding upper cover (18), and the fixing bolt (20) is inserted into the connecting sleeve (19).

7. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The three-axis embedded fiber optic gyroscope (6), the navigation settlement module (7), the gyroscope control box (12) and the three-axis accelerometer (13) are all electrically connected to the power board (8).

8. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: The three-axis embedded fiber optic gyroscope (6) is electrically connected to the gyroscope control box (12), and the gyroscope control box (12) and the three-axis accelerometer (13) are both electrically connected to the navigation settlement module (7).

9. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: An external connector (9) is provided on one side of the shielding shell (2), and the external connector (9) is electrically connected to the navigation settlement module (7), and the external connector (9) is also electrically connected to the power board (8).

10. The miniaturized optical fiber strapdown inertial navigation system based on a three-axis integrated vibrating beam accelerometer according to claim 1, characterized in that: A plurality of heat dissipation teeth are arranged on the outside of the shielding shell (2), and the heat dissipation teeth are at least used to improve the heat dissipation performance of the optical fiber strapdown inertial navigation system.

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