Low-cost optical fiber inertial navigation latitude-free north-seeking device

Abstract

The invention discloses a low-cost optical fiber inertial navigation latitude-free north seeking device which comprises a frame, a fixing frame, a three-axis accelerometer assembly, a three-axis optical fiber gyroscope assembly, an algorithm processing unit and an external device. The three-axis accelerometer assembly comprises first limiting grooves formed in one side of the frame, every two first limiting grooves are perpendicular to each other, the perpendicularity does not exceed 0.01, three-axis accelerometer bodies are installed in the first limiting grooves through bolts, every two three-axis accelerometer bodies are perpendicular to each other, and the perpendicularity does not exceed 0.01. According to the optical fiber inertial navigation latitude-free north-seeking device, the accelerations of the optical fiber inertial navigation latitude-free north-seeking device in three orthogonal directions can be measured through the arranged three-axis accelerometer assembly, so that information such as the speed, the acceleration and the angular speed of the optical fiber inertial navigation latitude-free north-seeking device is calculated, and the stability of the optical fiber inertial navigation latitude-free north-seeking device during use is improved.

Description

Technical Field

[0001] The present invention relates to the field of track detection technology, and in particular to a low-cost fiber optic inertial navigation non-latitude north-finding device. Background Art

[0002] The fiber optic gyro north-seeking device is a rapid orientation device for measuring the north azimuth. It has the characteristics of high precision, long life, and simple structure. It is widely used in the initial azimuth aiming of tanks or weapons.

[0003] At present, for track detection in scenarios such as high-speed railways and freight railways, inertial navigation equipment is usually used for initial alignment and then inertial navigation solution is performed to calculate the attitude and heading in real time. This method requires the use of local longitude and latitude information for alignment.

[0004] However, in underground scenarios such as subway tracks or high-speed rail garages, the longitude and latitude information in the alignment phase cannot be obtained due to satellite navigation limitations, which results in the inability to use the fiber optic gyro north-seeking device normally, thereby reducing the effectiveness of the fiber optic gyro north-seeking device. It is urgent to design a low-cost fiber optic inertial navigation latitude-free north-seeking device to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a low-cost fiber optic inertial navigation non-latitude north-finding device 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] It includes a frame, a fixing frame, a three-axis accelerometer assembly, a three-axis fiber optic gyroscope assembly, an algorithm processing unit and an external device;

[0008] The three-axis accelerometer assembly includes a first limit groove opened on one side of the frame, the first limit grooves are perpendicular to each other, and the verticality does not exceed 0.01, the three-axis accelerometer body is bolted in the first limit groove, and the three-axis accelerometer body is perpendicular to each other, and the verticality does not exceed 0.01.

[0009] The three-axis accelerometer assembly can measure the acceleration of the fiber-optic inertial navigation non-latitude north-seeking device in three orthogonal directions, thereby calculating information such as the speed, acceleration, and angular velocity of the fiber-optic inertial navigation non-latitude north-seeking device, thereby increasing the stability of the fiber-optic inertial navigation non-latitude north-seeking device during use.

[0010] The three-axis fiber optic gyroscope assembly includes a second limiting groove opened on one side of the frame, the second limiting grooves are perpendicular to each other, and the verticality does not exceed 0.01, the three-axis fiber optic gyroscope body bolts are installed in the second limiting grooves, and the three-axis fiber optic gyroscope bodies are perpendicular to each other, and the verticality does not exceed 0.01.

[0011] The fixing frame is fixedly mounted on one side of the frame, a bolt hole slot is provided on one side of the fixing frame, the external device is arranged on one side of the frame, and an external joint is provided on one side of the external device.

[0012] The algorithm processing unit comprises the following steps:

[0013] S1: Use the three-axis accelerometer assembly to measure the device posture and obtain a digital horizontal platform;

[0014] S2: The earth rotation component in the IMU coordinate system is collected using a three-axis fiber optic gyro assembly;

[0015] S3: Convert the data collected by the three-axis fiber optic gyro assembly to a digital horizontal platform to obtain the celestial component of the earth's rotation;

[0016] S4: Calculate the local latitude using the celestial component of the Earth's rotation:

[0017] S5: Find north using the calculated local latitude.

[0018] The calculation includes determining a horizontal coordinate system according to the three-axis accelerometer assembly, performing digital leveling after obtaining the horizontal coordinate system, and converting the output of the three-axis fiber optic gyroscope assembly into the horizontal coordinate system.

[0019] The output of the three-axis fiber optic gyroscope assembly in the horizontal coordinate system is integrated to obtain the celestial angular velocity increment θ within time T. u , according to the formula The local latitude is calculated, the projection of the output of the three-axis fiber optic gyroscope assembly on the horizontal plane is calculated, and the north is sought through the component of the earth's rotation angular velocity in the horizontal plane sensed by the three-axis fiber optic gyroscope assembly.

[0020] The direction of the Earth's rotation is along the direction of the Earth's center - the North Pole. The angular velocity of the Earth's rotation is decomposed along the geographic coordinate system. The projection of the Earth's rotation on the local horizontal plane is along the north-south direction, pointing to the local north.

[0021] The size of the Earth's rotation projection is ω ie sinL, where L is the local latitude, the north-seeking device is leveled, and after digital leveling, the sensitive axis of the three-axis fiber optic gyroscope assembly will be located in the local horizontal plane.

[0022] After leveling, the angular velocity component of the earth's rotation sensed by the three-axis fiber optic gyroscope assembly is ω ie sinLcosθ, where θ is in the horizontal plane.

[0023] When seeking north, the output angular velocity ω of the three-axis fiber optic gyroscope body after digital leveling is used. GThe angle between the sensitive axis of the three-axis fiber optic gyroscope assembly and the geographic north direction is calculated to be

[0024] In the above technical solution, the present invention provides a low-cost fiber optic inertial navigation latitude-free north-finding device, which has the following beneficial effects:

[0025] 1. The three-axis accelerometer assembly can measure the acceleration of the fiber-optic inertial navigation non-latitude north-seeking device in three orthogonal directions, thereby calculating the speed, acceleration, angular velocity and other information of the fiber-optic inertial navigation non-latitude north-seeking device, thereby increasing the stability of the fiber-optic inertial navigation non-latitude north-seeking device during use.

[0026] 2. The three-axis fiber optic gyro assembly can measure the three-axis angular velocity of the fiber optic inertial navigation non-latitude north-seeking device in real time and output the angular velocity and angle in three orthogonal directions, thereby improving the stability of the fiber optic inertial navigation non-latitude north-seeking device during use.

[0027] 3. The algorithm processing unit can use three-axis low-cost optical fiber in conjunction with a static detection algorithm to first measure the latitude, and then use the measured latitude to find the north, thereby preventing the situation where the north-finding device cannot obtain the initial position when in use and only relies on the inertial device measurement data to find the north. As a result, the fiber-optic inertial navigation non-latitude north-finding device automatically enters the north-finding process after power-on without manual operation or the assistance of other equipment, thereby increasing the work efficiency of the fiber-optic inertial navigation non-latitude north-finding device when in use, thereby reducing the overall cost of the fiber-optic inertial navigation non-latitude north-finding device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 A schematic structural diagram of a fiber optic inertial navigation non-latitude north-finding device is provided for an embodiment of a low-cost fiber optic inertial navigation non-latitude north-finding device of the present invention.

[0030] Figure 2 A schematic diagram of the projection of the earth's rotation on the local horizontal plane is provided for an embodiment of a low-cost fiber-optic inertial navigation non-latitude north-finding device of the present invention.

[0031] Figure 3 A schematic diagram of leveling a gyro north finder provided in an embodiment of a low-cost fiber-optic inertial navigation non-latitude north-finding device of the present invention.

[0032] Figure 4 A schematic diagram of a gyro north-seeking device for low-cost fiber-optic inertial navigation without latitude is provided in accordance with an embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 1. Frame; 2. Fixing frame; 3. Three-axis accelerometer assembly; 4. Three-axis fiber optic gyroscope assembly; 5. External device; 6. First limiting groove; 7. Three-axis accelerometer body; 8. Second limiting groove; 9. Three-axis fiber optic gyroscope body; 10. Bolt hole groove; 11. External connector. DETAILED DESCRIPTION

[0035] 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.

[0036] like Figure 1-4 As shown, an embodiment of the present invention provides a low-cost fiber optic inertial navigation non-latitude north-finding device.

[0037] It includes a frame 1, a fixing frame 2, a three-axis accelerometer assembly 3, a three-axis fiber optic gyroscope assembly 4, an algorithm processing unit and an external device 5;

[0038] The three-axis accelerometer assembly 3 includes a first limit groove 6 opened on one side of the frame 1. The first limit grooves 6 are perpendicular to each other, and the verticality does not exceed 0.01. The three-axis accelerometer body 7 is bolted in the first limit groove 6. The three-axis accelerometer body 7 is perpendicular to each other, and the verticality does not exceed 0.01.

[0039] The three-axis accelerometer assembly 3 can measure the acceleration of the fiber-optic inertial navigation non-latitude north-finding device in three orthogonal directions, thereby calculating information such as the speed, acceleration and angular velocity of the fiber-optic inertial navigation non-latitude north-finding device, thereby increasing the stability of the fiber-optic inertial navigation non-latitude north-finding device during use.

[0040] Reference Figure 1 The three-axis fiber optic gyroscope assembly 4 of this embodiment includes a second limiting groove 8 opened on one side of the frame 1, and the second limiting grooves 8 are perpendicular to each other, and the verticality does not exceed 0.01. The three-axis fiber optic gyroscope body 9 is bolted in the second limiting groove 8, and the three-axis fiber optic gyroscope body 9 is perpendicular to each other, and the verticality does not exceed 0.01.

[0041] The three-axis fiber optic gyro assembly 4 can measure the three-axis angular velocity of the fiber optic inertial navigation non-latitude north-seeking device in real time and output the angular velocity and angle in three orthogonal directions, thereby improving the stability of the fiber optic inertial navigation non-latitude north-seeking device during use.

[0042] The fixing frame 2 is fixedly installed on one side of the frame 1 , a bolt hole slot 10 is opened on one side of the fixing frame 2 , the external device 5 is arranged on one side of the frame 1 , and an external joint 11 is arranged on one side of the external device 5 .

[0043] Reference Figure 2In this embodiment, the algorithm processing unit includes the following steps:

[0044] S1: Use the three-axis accelerometer assembly 3 to measure the device posture and obtain a digital horizontal platform;

[0045] S2: The earth rotation component in the IMU coordinate system is collected using the three-axis fiber optic gyro assembly 4;

[0046] S3: converting the data collected by the three-axis fiber optic gyro assembly 4 to a digital horizontal platform to obtain the celestial component of the earth's rotation;

[0047] S4: Calculate the local latitude using the celestial component of the Earth's rotation:

[0048] S5: Find north using the calculated local latitude.

[0049] The algorithm processing unit can use three-axis low-cost optical fiber in conjunction with a static detection algorithm to first measure latitude, and then use the measured latitude to find the north, thereby preventing the situation where the north-finding device cannot obtain the initial position when in use and only relies on the inertial device measurement data to find the north. As a result, the fiber-optic inertial navigation non-latitude north-finding device automatically enters the north-finding process after power-on without manual operation or the assistance of other equipment, thereby increasing the work efficiency of the fiber-optic inertial navigation non-latitude north-finding device when in use, thereby reducing the overall cost of the fiber-optic inertial navigation non-latitude north-finding device.

[0050] The calculation includes determining a horizontal coordinate system according to the three-axis accelerometer assembly 3, performing digital leveling after obtaining the horizontal coordinate system, and converting the output of the three-axis fiber optic gyroscope assembly 4 into the horizontal coordinate system.

[0051] The output of the three-axis fiber optic gyro assembly 4 in the horizontal coordinate system is integrated to obtain the celestial angular velocity increment θ within time T. u , according to the formula The local latitude is calculated, the projection of the output of the three-axis fiber optic gyroscope assembly 4 on the horizontal plane is calculated, and the north is sought through the component of the earth's rotation angular velocity in the horizontal plane sensed by the three-axis fiber optic gyroscope assembly 4.

[0052] The direction of the Earth's rotation is along the direction of the Earth's center - the North Pole. The angular velocity of the Earth's rotation is decomposed along the geographic coordinate system. The projection of the Earth's rotation on the local horizontal plane is along the north-south direction, pointing to the local north.

[0053] Reference Figure 3 , the size of the earth's rotation projection in this embodiment is ω ie sinL, where L is the local latitude, the north-seeking device is leveled, and after digital leveling, the sensitive axis of the three-axis fiber optic gyroscope assembly 4 will be located in the local horizontal plane.

[0054] Reference Figure 4After leveling in this embodiment, the angular velocity component of the earth's rotation sensed by the three-axis fiber optic gyro assembly 4 is ω ie sinLcosθ, where θ is in the horizontal plane.

[0055] When seeking north, the angular velocity ω is output by the three-axis fiber optic gyroscope body 9 after digital leveling. G The calculated angle between the 4th sensitive axis of the three-axis fiber optic gyroscope assembly and the geographic north direction is

[0056] Working principle: First, use the three-axis accelerometer component 3 to measure the device attitude and obtain a digital horizontal platform. Use the three-axis fiber optic gyroscope component 4 to collect the earth's rotation component in the IMU coordinate system, convert the data collected by the three-axis fiber optic gyroscope component 4 to the digital horizontal platform, and obtain the earth's rotation celestial component. Use the earth's rotation celestial component to calculate the local latitude, and use the calculated local latitude to find north.

[0057] 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 low-cost fiber-optic inertial navigation non-latitude north-finding device, characterized in that: It comprises a frame (1), a fixing frame (2), a three-axis accelerometer assembly (3), a three-axis fiber optic gyroscope assembly (4), an algorithm processing unit and an external device (5); The three-axis accelerometer assembly (3) comprises a first limiting groove (6) provided on one side of the frame (1), wherein the first limiting grooves (6) are perpendicular to each other in pairs, and the perpendicularity does not exceed 0.01; the three-axis accelerometer body (7) is boltedly mounted in the first limiting groove (6), and the three-axis accelerometer body (7) is perpendicular to each other in pairs, and the perpendicularity does not exceed 0.

01.

2. A low-cost fiber-optic inertial navigation non-latitude north-finding device according to claim 1, characterized in that: The three-axis fiber optic gyroscope assembly (4) comprises a second limiting groove (8) provided on one side of the frame (1), the second limiting grooves (8) are perpendicular to each other, and the perpendicularity does not exceed 0.01, the three-axis fiber optic gyroscope body (9) is bolted in the second limiting groove (8), and the three-axis fiber optic gyroscope body (9) is perpendicular to each other, and the perpendicularity does not exceed 0.

01.

3. A low-cost fiber-optic inertial navigation latitude-free north-finding device according to claim 1, characterized in that: The fixing frame (2) is fixedly mounted on one side of the frame (1), a bolt hole slot (10) is provided on one side of the fixing frame (2), the external connection device (5) is arranged on one side of the frame (1), and an external joint (11) is provided on one side of the external connection device (5).

4. A low-cost fiber-optic inertial navigation latitude-free north-finding device according to claim 1, characterized in that: The algorithm processing unit comprises the following steps: S1: Use the three-axis accelerometer assembly (3) to measure the device posture and obtain a digital horizontal platform; S2: The earth rotation component in the IMU coordinate system is collected using a three-axis fiber optic gyro assembly (4); S3: converting the data collected by the three-axis fiber optic gyro assembly (4) onto a digital horizontal platform to obtain the celestial component of the earth's rotation; S4: Calculate the local latitude using the celestial component of the Earth's rotation: S5: Find north using the calculated local latitude.

5. A low-cost fiber-optic inertial navigation latitude-free north-finding device according to claim 4, characterized in that: The calculation comprises determining a horizontal coordinate system according to the three-axis accelerometer assembly (3), performing digital leveling after obtaining the horizontal coordinate system, and converting the output of the three-axis fiber optic gyroscope assembly (4) into the horizontal coordinate system.

6. A low-cost fiber-optic inertial navigation non-latitude north-finding device according to claim 5, characterized in that: The output of the three-axis fiber optic gyroscope assembly (4) in the horizontal coordinate system is integrated to obtain the celestial angular velocity increment θ within the time T. u , according to the formula The local latitude is calculated, the projection of the output of the three-axis fiber optic gyroscope assembly (4) on the horizontal plane is calculated, and the north is sought through the component of the earth's rotation angular velocity in the horizontal plane sensed by the three-axis fiber optic gyroscope assembly (4).

7. A low-cost fiber-optic inertial navigation non-latitude north-finding device according to claim 6, characterized in that: The direction of the Earth's rotation is along the direction of the Earth's center - the North Pole. The angular velocity of the Earth's rotation is decomposed along the geographic coordinate system. The projection of the Earth's rotation on the local horizontal plane is along the north-south direction, pointing to the local north.

8. The low-cost fiber-optic inertial navigation non-latitude north-finding device according to claim 7, characterized in that: The size of the Earth's rotation projection is ω ie sinL, where L is the local latitude, the north-seeking device is leveled, and after digital leveling, the sensitive axis of the three-axis fiber optic gyroscope assembly (4) will be located in the local horizontal plane.

9. A low-cost fiber-optic inertial navigation latitude-free north-finding device according to claim 8, characterized in that: After leveling, the angular velocity component of the earth's rotation sensed by the three-axis fiber optic gyroscope assembly (4) is ω ie sinLcosθ, where θ is in the horizontal plane.

10. A low-cost fiber-optic inertial navigation non-latitude north-finding device according to claim 9, characterized in that: When seeking north, the three-axis fiber optic gyroscope body (9) outputs an angular velocity ω after digital leveling. G The angle between the sensitive axis of the three-axis fiber optic gyroscope assembly (4) and the geographic north direction is calculated to be:

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