Method for improving initial alignment precision of micro-hemisphere gyroscope strapdown inertial navigation system

Abstract

The invention discloses a method for improving initial alignment precision of a micro-hemisphere gyroscope strapdown inertial navigation system, which comprises the following steps of: controlling a gyroscope to carry out self-calibration on a reference position of the strapdown inertial navigation system through a virtual precession technology by utilizing a special working principle of the micro-hemisphere gyroscope, carrying out subtraction on the projection of the gyroscope and the rotation angular velocity of the earth on the reference position, and setting the difference value to be zero, so that the initial alignment precision of the strapdown inertial navigation system is improved. Therefore, the initial alignment precision of the strapdown inertial navigation system can be improved. By adopting the method, the initial alignment precision of the strapdown inertial navigation system is improved, the product cost is not increased, peripheral equipment is not increased, the operation is simple, and the efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of inertial navigation, and in particular relates to a method for improving the initial alignment accuracy of a micro-hemispherical gyroscope strapdown inertial navigation system. Background Art

[0002] The micro-hemispherical gyroscope is a vibrating gyroscope based on the Coriolis effect. Figure 1 In the example, when the shell rotates by Φ around the central axis, the mode shape rotates by θ in the opposite direction relative to the hemispherical shell, and θ = KΦ, where K is the precession factor of the mode shape. By measuring the angle θ through which the mode shape rotates relative to the shell, the angle Φ through which the shell rotates around the central axis can be measured.

[0003] Micro-hemispherical gyros (MHSGs), with their significant advantages of high precision, compact size, and low power consumption, are gaining increasing application in aerospace and other fields both domestically and internationally. They have become an inertial instrument with broad engineering application prospects, following mechanical and optical gyros, and represent a key development direction for high-performance micro-electromechanical (MEMS) gyros. A small number of selected MHSGs have approached or even achieved the performance of tactical-grade gyros (bias drift of 0.1° / h to 10° / h). Their performance is primarily limited by quality defects such as modal frequency splitting and uneven damping distribution. However, strapdown inertial navigation systems (SINS) using MHSGs have become a growing trend, and key technological breakthroughs are urgently needed. With the current accuracy of MHSGs, initial alignment error is a significant source of error affecting system navigation accuracy. Common error factors in SINS include device errors (such as gyro and accelerometer bias and scale factor errors), installation errors, initial condition errors, disturbance errors, and computational errors. Initial condition errors include initial alignment errors, which refer to the initial values of attitude, velocity, and position. In fact, the initial alignment error is a constant comprehensive error that reflects the comprehensive performance of the gyroscope and accelerometer after the strapdown inertial navigation system is powered on.

[0004] Due to the limited accuracy of micro-hemispherical gyroscopes, the initial alignment of micro-hemispherical gyroscope strapdown inertial navigation systems often adopts the transfer alignment method, that is, based on the attitude, velocity and position provided by the reference main inertial navigation, the misalignment angle is estimated through the sensitivity of the micro-hemispherical gyroscope and accelerometer itself, thereby achieving precise alignment. Summary of the Invention

[0005] To overcome the deficiencies in the prior art, the present invention provides a method for improving the initial alignment accuracy of a strapdown inertial navigation system (SINS) using a micro-hemispherical gyroscope. The method utilizes the unique operating principle of the micro-hemispherical gyroscope and employs virtual precession technology to control the gyroscope to perform self-calibration at a SINS reference position. The difference between the angular velocity of the Earth's rotation and the projection of the angular velocity at the reference position is then reset to zero, thereby improving the initial alignment accuracy of the SINS. This method improves the initial alignment accuracy of the SINS without increasing product cost or peripheral equipment, and is simple to operate and highly efficient.

[0006] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0007] Step 1: Before initial alignment, place the strapdown inertial navigation system at any reference position, which is determined by the orientation of the reference main inertial navigation system.

[0008] Step 2: Calculate the angular velocity of the Earth’s rotation that the three gyroscopes are sensitive to at this time: 7.292×10 -5 [0, cos(Lt), sin(Lt)] rad / s, Lt is the latitude of the alignment point;

[0009] Step 3: Control the three gyros to perform self-calibration respectively, and calculate the zero bias of the three gyros, which is consistent with 7.292×10 -5 Make the difference between [0, cos(Lt), sin(Lt)] rad / s and compensate the difference in the gyroscope;

[0010] Step 4: The micro-hemispherical gyro strapdown inertial navigation system is initially aligned at any position.

[0011] Preferably, in step 1, before the initial alignment, the strapdown inertial navigation system is placed in a position where the three axes "X, Y, Z" point to "east, north, and sky" respectively.

[0012] Preferably, in step 1, before the initial alignment, the angle between the actual placement position of the strapdown inertial navigation system and the reference position is controlled within 5°.

[0013] A computer program enables a computer to execute the above-mentioned method for improving the initial alignment accuracy of a strapdown inertial navigation system.

[0014] An electronic device comprises: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the above-mentioned method for improving the initial alignment accuracy of a strapdown inertial navigation system.

[0015] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for initial alignment accuracy of a strapdown inertial navigation system.

[0016] A chip includes: a processor for calling and running a computer program from a memory, so that a device equipped with the chip executes the above-mentioned method for improving the initial alignment accuracy of a strapdown inertial navigation system.

[0017] A computer program product includes a computer storage medium storing a computer program, wherein the computer program includes instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the method for achieving the initial alignment accuracy of the strapdown inertial navigation system is implemented.

[0018] The beneficial effects of the present invention are as follows:

[0019] (1) The present invention proposes a method for improving the initial alignment accuracy of a micro-hemispherical gyro strapdown inertial navigation system by utilizing the unique operating principle of the micro-hemispherical gyro to control the gyro for self-calibration at a reference position and compensate for the difference between the gyro and the projection of the Earth's rotation. This method is simple to operate, has good engineering feasibility, and does not increase product cost or peripheral equipment.

[0020] (2) Under the premise that the accuracy of the micro-hemispherical gyroscope is limited, the present invention can achieve the actual demand for micro-hemispherical strapdown inertial navigation tactical level navigation accuracy (zero bias drift 0.1 to 10° / h).

[0021] (3) The method of the present invention can be widely applied to the carriers of micro-hemispherical gyro strapdown inertial navigation systems of various equipment such as rotating ammunition, aircraft, missiles, combat vehicles, and ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the working principle of the micro-hemispherical gyroscope.

[0023] Figure 2 This is the navigation result of the micro-hemispherical gyro strapdown inertial navigation system without adopting the method of the present invention.

[0024] Figure 3 This is the navigation result of the micro-hemispherical gyro strapdown inertial navigation system using the method of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and examples.

[0026] Initial alignment accuracy is a constant comprehensive error that accumulates over navigation time and is one of the important error sources affecting the positioning accuracy of the strapdown inertial navigation system. Improving initial alignment accuracy often starts from two aspects: inertial devices and inertial navigation systems. Higher-precision inertial devices and more accurately compensated inertial navigation systems can improve initial alignment accuracy to a certain extent. This invention proposes a complete solution based on improving the accuracy of inertial devices. Unlike previous methods of improving the accuracy of inertial devices,

[0027] The technical problem to be solved by the present invention is to improve the accuracy of initial alignment of a micro-hemispherical gyroscope strapdown inertial navigation system under the premise that the accuracy of the micro-hemispherical gyroscope is limited.

[0028] Based on the special working principle of a micro-hemispherical gyroscope, the present invention uses virtual precession technology to control the gyroscope to perform self-calibration at the reference position of a strapdown inertial navigation system. The difference between the angular velocity of the earth's rotation and the projection of the angular velocity at the reference position is calculated and the difference is set to zero, thereby improving the accuracy of the initial alignment of the strapdown inertial navigation system. The specific process is as follows.

[0029] (1) Before initial alignment, place the strapdown inertial navigation system in any reference position (e.g., the three axes "X, Y, and Z" are pointed to "East, North, and Sky" respectively). The reference position can be determined based on the direction of the reference master inertial navigation system.

[0030] (2) Calculate the angular velocity of the Earth's rotation that the three gyroscopes are sensitive to at this time:

[0031] 7.292×10 -5 [0, cos(Lt), sin(Lt)] rad / s (Lt is the latitude of the alignment point);

[0032] (3) Control the three gyros separately for self-calibration and calculate the zero bias of the three gyros, which is consistent with 7.292×10 -5 Make the difference between [0, cos(Lt), sin(Lt)] rad / s and compensate the difference in the gyroscope;

[0033] (4) The micro-hemispherical gyro strapdown inertial navigation system can be initially aligned (transfer alignment) at any position.

[0034] Example:

[0035] The present invention utilizes the special working principle of the micro-hemispherical gyroscope and controls the gyroscope to perform self-calibration at the reference position of the strapdown inertial navigation system through virtual precession technology. The difference between the angular velocity of the earth's rotation and the projection of the angular velocity at the reference position is made and the difference is set to zero, thereby improving the initial alignment accuracy of the strapdown inertial navigation system.

[0036] Before initial alignment, place the strapdown inertial navigation system in any reference position (e.g. the three axes "X, Y, Z" point to "East, North, Sky" respectively). At this time, the Earth rotation magnitudes sensitive to the three gyros are: 7.292×10 -5 [0, cos(Lt), sin(Lt)]rad / s (Lt is the latitude of the alignment point), control the gyro to perform self-calibration, and calculate the zero bias of the three gyros respectively, which is consistent with 7.292×10 -5 The difference is calculated by taking [0, cos(Lt), sin(Lt)] rad / s and compensating the difference in the gyro. After that, the strapdown inertial navigation system can be initially aligned at any position.

[0037] Before initial alignment, the strapdown inertial navigation system can be placed at any reference position without the need for a high-precision turntable or marble slab. The angle between the actual placement position and the reference position can be controlled within 5°, and the reference main inertial navigation system can be used as a direct reference during transfer alignment.

[0038] This method improves the initial alignment accuracy of the micro-hemispherical gyro strapdown inertial navigation system. Using navigation accuracy as the metric, the approach improves the strapdown inertial navigation system's attitude navigation accuracy from 0.16° / 3min (heading attitude angle) and 0.28° / 3min (horizontal attitude angle) to 0.05° / 3min (heading attitude angle) and 0.06° / 3min (horizontal attitude angle), while position navigation accuracy improves from 280m / 3min to 95m / 3min.

[0039] The present invention is designed to address the practical need for micro-hemispherical strapdown inertial navigation systems (SINS) with tactical-level navigation accuracy (bias drift of 0.1 to 10° / h), despite the current limited accuracy of micro-hemispherical gyroscopes in China. The method of the present invention improves the accuracy of initial alignment of a micro-hemispherical gyroscope SINS system without increasing product cost or peripheral reference equipment, and is simple to operate and highly efficient.

Claims

1. A method for improving the initial alignment accuracy of a micro-hemispherical gyro strapdown inertial navigation system, characterized in that: The steps include: Step 1: Before initial alignment, place the strapdown inertial navigation system at any reference position, which is determined by the orientation of the reference main inertial navigation system. Step 2: Calculate the angular velocity of the Earth’s rotation that the three gyroscopes are sensitive to at this time: 7.292×10 -5 [0, cos(Lt), sin(Lt)] rad / s, Lt is the latitude of the alignment point; Step 3: Control the three gyros to perform self-calibration respectively, and calculate the zero bias of the three gyros, which is consistent with 7.292×10 -5 Make the difference between [0, cos(Lt), sin(Lt)] rad / s and compensate the difference in the gyroscope; Step 4: The micro-hemispherical gyro strapdown inertial navigation system is initially aligned at any position.

2. The method for improving the initial alignment accuracy of a micro-hemispherical gyro strapdown inertial navigation system according to claim 1, characterized in that: In step 1, before the initial alignment, the strapdown inertial navigation system is placed in a position where the three axes "X, Y, Z" point to "east, north, and sky" respectively.

3. The method for improving the initial alignment accuracy of a micro-hemispherical gyroscope strapdown inertial navigation system according to claim 1, wherein: In step 1, before the initial alignment, the angle between the actual placement position of the strapdown inertial navigation system and the reference position is controlled within 5°.

4. A computer program, characterized in that The computer program enables a computer to execute the method according to any one of claims 1 to 3.

5. An electronic device, characterized in that: include: processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device performs the method according to any one of claims 1 to 3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.

7. A chip, characterized in that: include: A processor, configured to call and run a computer program from a memory, so that a device equipped with the chip executes the method according to any one of claims 1 to 3.

8. A computer program product, characterized in that The computer program product comprises a computer storage medium storing a computer program, wherein the computer program comprises instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the method according to any one of claims 1 to 3 is implemented.

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