Single-axis laser rotation modulation inertial navigation system

Abstract

The application discloses a single-shaft laser rotary modulation inertial navigation system and belongs to the technical field of inertial navigation, and solves the problems that the existing inertial navigation system is large in size and not suitable for narrow application space; the single-shaft laser rotary modulation inertial navigation system comprises a shell, a single-shaft rotary modulation indexing mechanism and a rotary table body; the single-shaft rotary modulation indexing mechanism comprises a stator and a rotor, the stator is fixed at the bottom of the shell, and the rotor is connected with the rotary table body; the rotary table body comprises an IMU mounting frame mounted on the rotor, and an inertial measurement unit is arranged in the IMU mounting frame. In the application, the single-shaft rotary modulation indexing mechanism drives the rotary table body to rotate, the inertial measurement unit is uniformly and periodically rotated around the single shaft, constant errors are modulated into alternating currents, integral self-cancellation is realized, and the long-time navigation precision of the system is improved; the whole structure is designed to be light in weight, small in size and high in integration, the precision in a full-temperature environment and the airborne environmental adaptability are improved, and the demand of military airborne high-precision navigation is met.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation technology, and more particularly to a single-axis laser rotation modulation inertial navigation system. Background Technology

[0002] Laser gyroscope inertial navigation systems are autonomous, high-precision navigation devices widely used in military airborne applications. Their navigation accuracy is significantly affected by the constant drift error of the laser gyroscope, and error accumulation can easily occur during long-term navigation. Single-axis rotation modulation technology, by driving the inertial measurement unit (IMU) to rotate periodically, can effectively modulate and average the gyroscope's constant drift error, improving the system's long-term navigation accuracy.

[0003] Existing single-axis laser rotation modulation inertial navigation systems generally suffer from the following defects: First, the indexing mechanism is too large, with its height and outer diameter exceeding the standard, making it unsuitable for the limited installation space of military airborne systems; second, the shaft structure is prone to gaps in a wide temperature range environment, resulting in poor rotational accuracy and stability, which affects the rotation modulation effect; third, the drive, angle measurement, and conductive transmission components are scattered, resulting in low integration, exposed cables, and insufficient vibration and shock resistance, making it difficult to meet the stringent mechanical environment requirements of airborne systems; fourth, it is impossible to balance lightweight and rigidity in the overall structure, the assembly process is complex, and the reliability is difficult to meet the standards for military aircraft use.

[0004] To address the aforementioned issues, there is an urgent need to develop a single-axis laser rotation modulation inertial navigation system that is compact in size, has stable accuracy across all temperatures, high integration, and strong environmental adaptability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a single-axis laser rotation modulation inertial navigation system, which solves the problems of existing inertial navigation systems being large in size and unsuitable for small application spaces.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A single-axis laser rotation modulation inertial navigation system includes a housing, a single-axis rotation modulation indexing mechanism, and a rotary table. The housing contains a single-axis rotary modulation indexing mechanism and a rotary table. The single-axis rotary modulation indexing mechanism includes a stator and a rotor. The stator is fixed to the bottom of the housing, and the rotor is connected to the rotary table. The rotary table includes an IMU mounting frame, which is mounted on the rotor, and an inertial measurement unit is installed inside the IMU mounting frame.

[0007] In this scheme, a single-axis rotation modulation indexing mechanism drives the rotary table to rotate, enabling the inertial measurement unit to rotate uniformly and periodically around a single axis. The constant error is modulated into a flow rate, and the integral self-cancels out, improving the long-term navigation accuracy of the system. The entire structure is designed to be lightweight, achieving miniaturization and high integration, improving accuracy in all-temperature environments and adaptability to airborne environments, and meeting the high-precision navigation requirements of military airborne systems.

[0008] Furthermore, a positioning hole is provided on the top of the rotor, which is fixedly connected to the positioning shaft at the bottom of the IMU mounting frame; connecting ears are provided around the IMU mounting frame, which are fixed to the threaded holes on the top of the rotor by screws.

[0009] In this design, the rotor and IMU mounting frame are positioned by a hole-shaft fit. The IMU mounting frame is equipped with a mounting surface for a dedicated single-axis rotary modulation indexing mechanism to ensure flatness and perpendicularity requirements.

[0010] Furthermore, the inertial measurement unit includes a platform, with vibration dampers installed on both sides of the platform. The platform is fixed inside the IMU mounting frame by the vibration dampers. Inside the platform are three single-axis laser gyroscopes that are mutually orthogonal to each other and three accelerometers that are mutually orthogonal to each other.

[0011] In this scheme, the inertial measurement unit rotates synchronously along the IMU mounting frame on a single axis to achieve gyroscope drift error modulation compensation.

[0012] Furthermore, the secondary power supply board A, the data acquisition circuit board, and the IF module are respectively mounted on three different sides of the IMU mounting frame.

[0013] In this design, the entire IMU mounting frame and inertial measurement unit occupy a relatively small volume, resulting in high space utilization.

[0014] Furthermore, the outer casing includes a base and a middle shell; the base and the middle shell are detachably mounted. The base has an annular base flange inside, and the stator is fixed in the circular cavity inside the base flange; the stator has a boss on its outer periphery, and the boss is connected to the threaded hole on the edge of the base flange by screws. The central shell is a hollow cavity that runs vertically through the interior, and the rotating platform is located inside the central shell.

[0015] In this scheme, the stator of the single-axis rotary modulation indexing mechanism is fixed in the inner cavity of the base flange, and the rotor is fixedly connected to the IMU mounting frame. By reducing the height of the single-axis rotary modulation indexing mechanism, the center of gravity of the entire rotary table is lowered, the mounting surface between the stator and the base is increased, and the length of the hole-shaft fit between the stator and the base is increased, thereby achieving stability and reliability during the rotation of the rotary table.

[0016] Furthermore, the two sides of the central housing are designed with partitions. On one side of the partition, the navigation computer board and the satellite guide board are installed, and a side cover is installed on the outside of the navigation computer board and the satellite guide board. On the other side of the partition, the mother board and the secondary power supply board B are installed, and a front cover is installed on the outside of the mother board and the secondary power supply board B.

[0017] In this solution, the navigation computer board and satellite navigation board are encapsulated using side cover plates, and the motherboard and secondary power supply board B are encapsulated using front cover plates. The entire device has good sealing performance, is easy to maintain later, and has low maintenance costs.

[0018] Furthermore, an upper cover plate is installed on the top of the middle shell; a bottom cover plate is installed on the bottom of the base.

[0019] Furthermore, the base is equipped with four external connectors, including three circular connectors and one radio frequency connector.

[0020] Furthermore, the outer wall of the base is designed with diagonal reinforcing ribs; the side walls of the middle shell adopt a thin-walled weight-reduction design.

[0021] The beneficial effects of this invention are: The single-axis laser rotation modulation inertial navigation system provided by this invention adds a single-axis rotation modulation indexing mechanism inside the housing, driving the inertial measurement unit to rotate uniformly / reciprocally around a single axis. The constant error is modulated into a current flow, and the integral self-cancels out. Through lightweight structural design, all structural components have undergone weight reduction optimization design, ensuring sufficient strength support while achieving a significant weight reduction, meeting the product's total weight requirement of 7Kg.

[0022] The single-axis rotary modulation indexing mechanism adopts a fully coaxial nested integrated design, with drive, angle measurement, and conductive transmission components built-in, no exposed cables, simple structure, and excellent vibration and shock resistance. The single-axis rotary modulation indexing mechanism has a compact structure with an outer diameter of φ175mm and a total height of 50mm, which is perfectly adapted to the narrow installation space of military airborne applications, solving the problem of space constraints.

[0023] The base, single-axis rotary modulation indexing mechanism, and IMU mounting frame adopt a hole-shaft mating design, adapting to harsh airborne environments with wide temperature ranges, low air pressure, vibration, and impact, ensuring high reliability. The IMU mounting frame has been optimized, reducing the rotation diameter of the rotary table to a minimum of φ175mm, thereby reducing the overall size of the device. The base and the central housing are assembled with screws to form the entire external frame of the product. This differs from the traditional one-piece base design, which creates a blind deep cavity, resulting in poor manufacturability and increased processing costs. Attached Figure Description

[0024] Figure 1This is a schematic diagram of the external structure of a single-axis laser rotation modulation inertial navigation system according to the present invention; Figure 2 This is an exploded structural diagram of a single-axis laser rotation modulation inertial navigation system according to the present invention; Figure 3 This is an assembly diagram of the base, single-axis rotation modulation indexing mechanism, and rotary table in this invention; Figure 4 This is an assembly schematic diagram of the base, single-axis rotation modulation and indexing mechanism and rotary table body from another perspective in this invention; Figure 5 This is a schematic diagram of the structure of the rotary table in this invention; Figure 6 This is a schematic diagram of the structure of the inertial measurement unit in this invention; Figure 7 This is a schematic diagram of the IMU mounting frame in this invention; Figure 8 This is a schematic diagram of the central shell structure in this invention; Figure 9 This is a schematic diagram of the base structure in this invention.

[0025] Figure label: 1. Outer shell; 11. Base; 111. Base flange; 12. Middle shell; 13. Side cover plate; 14. Front cover plate; 15. Top cover plate; 16. Bottom cover plate; 17. External connector; 2. Single-axis rotary modulation indexing mechanism; 21. Stator; 211. Boss; 22. Rotor; 221. Positioning hole; 3. Rotary stage; 31. IMU mounting frame; 311. Positioning shaft; 312. Connecting ear; 32. Inertial measurement unit; 321. Stage; 322. Single-axis laser gyroscope; 323. Accelerometer; 33. Vibration damper; 41. Secondary power supply board A; 42. Data acquisition circuit board; 43. IF module; 44. Navigation computer board; 45. Satellite guide plate; 46. Mother board; 47. Secondary power supply board B. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Specific embodiments of the present invention are described below to facilitate understanding by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various modifications are obvious as long as they fall within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0027] like Figure 1 and Figure 2As shown, this embodiment provides a single-axis laser rotation modulation inertial navigation system, which solves the problems of existing inertial navigation systems being large in size and unsuitable for confined application spaces; specifically, it includes: 1. Outer casing; 2. Single-axis rotary modulation indexing mechanism; and 3. Rotary table. The outer casing 1 includes a base 11 and a middle casing 12; the base 11 and the middle casing 12 are detachably mounted. The single-axis rotary modulation indexing mechanism 2 includes a stator 21 and a rotor 22; as shown... Figure 3 and Figure 4 As shown, the stator 21 is fixed inside the base 11; the rotor 22 is connected to the rotary table 3. The rotary table 3 includes an IMU mounting frame 31 and an inertial measurement unit 32 disposed inside the IMU mounting frame 31, as shown... Figure 5 As shown. The IMU mounting frame 31 is located inside the central housing 12, and the bottom of the IMU mounting frame 31 is connected to the rotor 22. The single-axis rotation modulation indexing mechanism 2 drives the IMU mounting frame 31 and the inertial measurement unit 32 to rotate, realizing the uniform periodic rotation of the inertial measurement unit 32 around a single axis. The constant error is modulated into the flow rate, and the integral self-cancels out, improving the long-term navigation accuracy of the system.

[0028] The base 11 has an annular base flange 111 inside, and the stator 21 is fixed in the circular cavity inside the base flange 111. Four bosses 211 are provided on the periphery of the stator 21, and each of the four bosses 211 is connected to a threaded hole on the edge of the base flange 111 by four M6 screws. By reducing the height of the single-axis rotation modulation indexing mechanism 2, the center of gravity of the entire rotary table 3 is lowered, the mounting surface between the stator 21 and the base 11 is increased, and the length of the hole-shaft fit between the stator 21 and the base 11 is lengthened, thus achieving stability and reliability during the rotation of the rotary table 3.

[0029] The rotor 22 has a positioning hole 221 on its top, which is fixedly connected to the positioning shaft 311 at the bottom of the IMU mounting frame 31. Five connecting ears 312 are arranged around the IMU mounting frame 31, and each of the five connecting ears 312 is fixed to a threaded hole on the top of the rotor 22 by five M5 screws. The rotor 22 and the IMU mounting frame 31 are positioned by a hole-shaft fit. The IMU mounting frame 31 has a mounting surface for a dedicated single-axis rotation modulation indexing mechanism 2 to ensure flatness and perpendicularity requirements.

[0030] like Figure 6As shown, the inertial measurement unit 32 includes a platform 321, a single-axis laser gyroscope 322, and an accelerometer 323. Vibration dampers 33 are mounted on both sides of the platform 321, and the platform 321 is fixed inside the IMU mounting frame 31 by the vibration dampers 33. Three mutually orthogonal single-axis laser gyroscopes 322 and three mutually orthogonal accelerometers 323 are installed inside the platform 321. The inertial measurement unit 32 rotates synchronously with the IMU mounting frame 31 along a single axis to achieve gyroscope drift error modulation compensation.

[0031] like Figure 7 As shown, the IMU mounting frame 31 is designed with a hollow square frame at the top and a partial flange mounting at the bottom. This component features optimized structural design, with rationally designed reinforcing ribs providing reliable mounting support and rotation functionality for the internal inertial measurement unit 32. To reduce the overall product size, the rotation diameter of the IMU mounting frame 31 is minimized to only φ175mm. The secondary power supply board A41, data acquisition circuit board 42, and IF module 43 are mounted on three different sides of the IMU mounting frame 31, respectively. The entire IMU mounting frame 31 and inertial measurement unit 32 occupy a small volume, resulting in high space utilization.

[0032] like Figure 8 As shown, the central housing 12 is a hollow cavity that runs vertically through the interior. Two partitions are designed on the two sides of the central housing 12. A navigation computer board 44 and a satellite navigation board 45 are mounted on one side partition, with a side cover 13 installed on the outside of the navigation computer board 44 and the satellite navigation board 45. A motherboard 46 and a secondary power supply board B47 are mounted on the other side partition. External connectors are electrically connected to various circuit boards and the single-axis rotary modulation and indexing mechanism 2 via the motherboard 46. A front cover 14 is installed on the outside of the motherboard 46 and the secondary power supply board B47. By using the side cover 13 to encapsulate the navigation computer board 44 and the satellite navigation board 45, and the front cover 14 to encapsulate the motherboard 46 and the secondary power supply board B47, the entire device has good sealing properties, facilitates later maintenance, and has low maintenance costs.

[0033] A top cover plate 15 is installed on the top of the middle housing 12; a bottom cover plate 16 is installed on the bottom of the base 11.

[0034] The base 11 is also equipped with four external connectors 17, including three J599 circular connectors and one TNC RF connector, to enable the product to connect with external systems.

[0035] like Figure 9 As shown, the outer wall of the base 11 is designed with diagonal reinforcing ribs; a thin-walled + diagonal reinforcing rib structure is adopted to increase the structural strength of the product.

[0036] The side walls of the middle housing 12 adopt a thin-walled weight-reduction design to reduce the overall weight of the machine.

[0037] The working principle of this embodiment: In this embodiment, the inertial measurement unit 32 is fixed to the single-axis rotation modulation and positioning mechanism 2. The single-axis laser gyroscope 322 and accelerometer 323 respectively sense the angular velocity vector of the carrier coordinate system relative to the inertial coordinate system. The force vector in the carrier coordinate system The navigation platform utilizes a computer, known as a "mathematical platform." This platform uses gyroscopes to measure the carrier's angular velocity to calculate the attitude matrix. It extracts the carrier's attitude and heading information from the elements of the attitude matrix and uses the attitude matrix to transform the accelerometer 323 output from the carrier coordinate system to the navigation coordinate system. Combined with externally input satellite navigation information, it then calculates navigation information such as velocity and position.

[0038] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention and should be understood as not limiting the scope of protection of the invention to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed herein without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the invention.

Claims

1. A single-axis laser rotation modulation inertial navigation system, characterized in that: It includes a housing (1), a single-axis rotary modulation indexing mechanism (2), and a rotary table (3); The outer shell (1) is equipped with a single-axis rotary modulation indexing mechanism (2) and a rotary table (3). The single-axis rotary modulation indexing mechanism (2) includes a stator (21) and a rotor (22). The stator (21) is fixed to the bottom of the outer shell (1), and the rotor (22) is connected to the rotary table (3). The rotary table (3) includes an IMU mounting frame (31), which is mounted on the rotor (22). An inertial measurement unit (32) is provided inside the IMU mounting frame (31).

2. The single-axis laser rotation modulation inertial navigation system according to claim 1, characterized in that: The rotor (22) is provided with a positioning hole (221) at the top, and the positioning hole (221) is fixedly connected to the positioning shaft (311) at the bottom of the IMU mounting frame (31); the IMU mounting frame (31) is provided with a connecting ear (312) around it, and the connecting ear (312) is fixed to the threaded hole at the top of the rotor (22) by screws.

3. The single-axis laser rotation modulation inertial navigation system according to claim 1, characterized in that: The inertial measurement unit (32) includes a platform (321), and vibration dampers (33) are installed on both sides of the platform (321). The platform (321) is fixed inside the IMU mounting frame (31) by the vibration dampers (33). Inside the platform (321) are three single-axis laser gyroscopes (322) that are mutually orthogonal to each other and three accelerometers (323) that are mutually orthogonal to each other.

4. The single-axis laser rotation modulation inertial navigation system according to claim 3, characterized in that: The IMU mounting frame (31) has a secondary power supply board A (41), a data acquisition circuit board (42), and an IF module (43) mounted on three different sides.

5. The single-axis laser rotation modulation inertial navigation system according to claim 1, characterized in that: The outer casing (1) includes a base (11) and a middle casing (12); the base (11) and the middle casing (12) are detachably installed; The base (11) is provided with an annular base flange (111) inside, and the stator (21) is fixed in the circular cavity inside the base flange (111); the stator (21) is provided with a boss (211) on the periphery, and the boss (211) is connected to the threaded hole on the edge of the base flange (111) by screws. The central shell (12) is a hollow cavity that runs vertically through the interior, and the rotating platform (3) is located inside the central shell (12).

6. The single-axis laser rotation modulation inertial navigation system according to claim 5, characterized in that: The two sides of the central housing (12) are designed with partitions. On one side of the partition, a navigation computer board (44) and a satellite guide board (45) are installed, and a side cover plate (13) is installed on the outside of the navigation computer board (44) and the satellite guide board (45); on the other side of the partition, a mother board (46) and a secondary power supply board B (47) are installed, and a front cover plate (14) is installed on the outside of the mother board (46) and the secondary power supply board B (47).

7. The single-axis laser rotation modulation inertial navigation system according to claim 5, characterized in that: The top of the middle housing (12) is fitted with an upper cover plate (15); the bottom of the base (11) is fitted with a bottom cover plate (16).

8. The single-axis laser rotation modulation inertial navigation system according to any one of claims 5 to 7, characterized in that: The base (11) is also provided with four external connectors (17), including three circular connectors and one radio frequency connector.

9. The single-axis laser rotation modulation inertial navigation system according to any one of claims 5 to 7, characterized in that: The outer wall of the base (11) is designed with diagonal reinforcing ribs; the side wall of the middle shell (12) adopts a thin-walled weight-reducing design.

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