A four-position horizontal gyro bias residual compensation method based on heading error

Abstract

The present invention discloses a four-position horizontal gyro bias residual compensation method based on heading error, belonging to the technical field of inertial navigation. The method utilizes the alignment result of a turntable and an inertial navigation system to compensate for the horizontal gyro bias residual, does not require prior knowledge of the inertial navigation system, and is particularly suitable for improving the system accuracy and readjusting calibration parameters of the inertial navigation system before use. It is also suitable for parameter correction of a long-term stored inertial navigation system. In addition, the method can quickly complete the secondary compensation of the horizontal gyro residual while realizing the turntable-based inertial navigation system accuracy test. The method has the advantages of being fast, simple to operate, high in accuracy, and good practicality.

Description

Technical Field

[0001] The present invention relates to the field of inertial navigation technology, and in particular to a four-position horizontal gyro bias residual compensation method based on heading error. Background Art

[0002] Inertial navigation systems (INSs) are widely used in both military and civilian applications due to their strong autonomy and comprehensive navigation information output. They can autonomously and in real time provide information on a vehicle's position, velocity, and attitude. However, the computational complexity of INSs involves integral calculations, and inertial component biases, particularly gyro biases, can lead to divergent navigation errors. Therefore, to improve the navigation accuracy of INSs, gyro bias compensation is crucial, particularly secondary compensation of calibrated gyro residuals.

[0003] Currently, gyro bias estimation is often performed during the fine alignment phase of initial alignment, using a Kalman filter to estimate the gyro bias residual. For example, authorized invention CN106092140B provides a gyro bias estimation method, and authorized invention CN110887507B discloses a method for rapidly estimating all biases of an inertial measurement unit. However, these methods require the correct setting of the key error matrix parameters of the filter based on an effective understanding of the system error parameters to achieve error estimation. In addition, fine alignment requires a long time for the estimated gyro bias residual to converge and stabilize, and the accuracy of the estimation is affected by the alignment attitude error and observability. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the above-mentioned technologies and proposes a four-position horizontal gyro bias residual compensation method based on heading error. The method utilizes the alignment results of a turntable and an inertial navigation system to compensate for the horizontal gyro bias residual. Prior knowledge of the inertial navigation system is not required and the method is particularly suitable for improving the system accuracy and readjusting the calibration parameters of the inertial navigation system before use. It is also suitable for parameter correction of the inertial navigation system that is stored for a long time. In addition, the method can quickly complete the secondary compensation of the horizontal gyro residual while realizing the turntable-based inertial navigation system accuracy test. The method has the advantages of being fast, simple to operate, highly accurate, and having good practicality.

[0005] To achieve the above object, the present invention is implemented through the following scheme:

[0006] A four-position horizontal gyro bias residual compensation method based on heading error, the specific steps are as follows:

[0007] Step 1: Install the inertial navigation system horizontally on the turntable surface, ensuring that the heading axis of the inertial navigation system is parallel to the outer frame axis of the turntable;

[0008] Step 2, point the inertial navigation system on the turntable plane toward true north;

[0009] Step 3: Record the heading value when the inertial navigation system is 0°, which is the first heading value ψ0; then rotate the turntable 90° clockwise, and the inertial navigation system will be quickly re-aligned. Record the heading value when the inertial navigation system is 90°, which is the second heading value ψ 90 Then rotate the turntable 90° clockwise, and the inertial navigation system will be quickly re-aligned. The heading value when the inertial navigation system is 180° is recorded as the third heading value ψ 180 Then rotate the turntable 90° clockwise, and quickly re-align the inertial navigation system. Record the heading value when the inertial navigation system heading is 270°, which is the fourth heading value ψ 270 ;

[0010] Step 4: Repeat step 3 three times, record the alignment results of each time, and calculate the average alignment values ​​of the turntable at 0°, 90°, 180°, and 270°.

[0011]

[0012]

[0013] Among them, ψ 0i , ψ 90i , ψ 180i , ψ 270i These are the three alignment values ​​of the turntable at 0°, 90°, 180°, and 270°;

[0014] Step 5: According to the four heading values ​​recorded by the inertial navigation system and Calculate the heading value and the heading deviation of the four bearings:

[0015]

[0016]

[0017]

[0018]

[0019] Step 6: According to the initial alignment heading error limit formula:

[0020]

[0021] Where Δψ U is the heading alignment error, δε E is the equivalent east gyro bias, L is the geographical latitude of the inertial navigation system, ωie is the angular velocity of the Earth's rotation;

[0022] Converted into the following equivalent zero bias calculation formula:

[0023] δε E =Δψ U ω ie cos(L) (6)

[0024] When the heading of the inertial navigation system is 0° or 180°, that is, the Y axis of the inertial navigation system is facing north or south, and the X axis of the inertial navigation system is pointing east or west, then:

[0025] δε E =Δψ0ω ie cos(L) (7)

[0026] -δε E =Δψ 180 ω ie cos(L) (8)

[0027] According to formulas (7)-(8), the gyro bias residual in the horizontal x-axis direction is:

[0028]

[0029] Among them, δε x , δε y is the horizontal gyro bias residual of the inertial navigation system;

[0030]

[0031] From formula (9) and formula (10), it can be seen that the calculation of the horizontal gyro bias requires the known latitude information of the location of the inertial navigation system. The latitude information L can be obtained through Beidou or GPS satellite positioning methods, and the positioning error is acceptable within 100m. The angular velocity of the earth's rotation ω ie is a known constant, 15.04106° / h;

[0032] Step 7: Obtain the horizontal gyro bias residual δε of the inertial navigation system in step 6 x , δε y Compensate the X and Y gyros entering the inertial navigation system separately.

[0033] Furthermore, in step 2:

[0034] For a turntable pointing to true north, directly start the inertial navigation system for quick alignment;

[0035] For turntables without true north orientation, angular position offset compensation is performed by turning the turntable. The offset compensation process is as follows: first, start the inertial navigation system for quick alignment, record the initial alignment heading value, then use the heading value as the offset for the turntable's azimuth zero position. Then, rotate the turntable to zero the inertial navigation system heading, and then restart the inertial navigation system for quick alignment.

[0036] Compared with the prior art, the advantages of the present invention are:

[0037] The present invention does not require understanding of the prior error characteristics of the inertial navigation system, and the zero bias residual calculation accuracy is high and the time is short. It is particularly suitable for inertial navigation accuracy testing based on a turntable, and realizes secondary compensation of gyro residuals. It has the advantages of fast speed, simple operation, high accuracy and good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Flowchart of Four-position Horizontal Gyro Bias Residual Compensation DETAILED DESCRIPTION

[0039] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0040] Reference Figure 1 , the sight line process of the present invention is as follows:

[0041] Step 1: Install the inertial navigation system horizontally on the turntable surface. Ensure that the heading axis of the inertial navigation system is parallel to the outer frame axis of the turntable, or within a certain small angle range, generally less than 5°. Start the turntable and run it to the zero position.

[0042] Step 2: For turntables with geographic orientation (true north), directly start the inertial navigation system for quick alignment; for turntables without true north, use the turntable rotation to compensate for angular position offset. The steps are as follows: First, start the inertial navigation system for quick alignment, record the initial alignment heading value, then use the heading value as the offset item for the turntable's azimuth zero position, rotate the turntable so that the inertial navigation system heading is zero (facing north), and then restart the inertial navigation system for quick alignment;

[0043] Step 3: After the quick alignment in step 2 is completed, record the heading value when the inertial navigation system is 0°, which is the first heading value ψ0; then rotate the turntable 90° clockwise, and re-align the inertial navigation system quickly. Record the heading value when the inertial navigation system is 90°, which is the second heading value ψ 90 Then rotate the turntable 90° clockwise, and the inertial navigation system will be quickly re-aligned. The heading value when the inertial navigation system is 180° is recorded as the third heading value ψ 180Then rotate the turntable 90° clockwise, and quickly re-align the inertial navigation system. Record the heading value when the inertial navigation system heading is 270°, which is the fourth heading value ψ 270 ;

[0044] Step 4: Repeat step 3 three times, record the alignment results of each time, and calculate the average alignment values ​​of the turntable at 0°, 90°, 180°, and 270°.

[0045]

[0046]

[0047] Among them, ψ 0i , ψ 90i , ψ 180i , ψ 270i These are the three alignment values ​​of the turntable at 0°, 90°, 180°, and 270°.

[0048] Step 5: According to the four heading values ​​recorded by the inertial navigation system (Unit: °), calculate the heading value and the heading deviation of the four directions:

[0049]

[0050]

[0051]

[0052]

[0053] Step 6: According to the initial alignment heading error limit formula:

[0054]

[0055] Where Δψ U is the heading alignment error, δε E is the equivalent east gyro bias, L is the geographical latitude of the inertial navigation system, ω ie is the angular velocity of the Earth's rotation;

[0056] Converted into the following equivalent zero bias calculation formula:

[0057] δε E =Δψ U ω ie cos(L) (6)

[0058] When the heading of the inertial navigation system is 0° or 180°, that is, the Y axis of the inertial navigation system is facing north or south, and the X axis of the inertial navigation system is pointing east or west, then:

[0059] δε E =Δψ0ω ie cos(L) (7)

[0060] -δε E =Δψ 180 ω ie cos(L) (8)

[0061] Subtracting (8) from (7) and simplifying it, we can get the gyro bias residual in the horizontal x-axis direction:

[0062]

[0063] Similarly, the gyro bias residual in the horizontal y-axis direction is:

[0064]

[0065] Among them, δε x , δε y is the horizontal gyro bias residual of the inertial navigation system.

[0066] From formulas (9) to (10), it can be seen that the calculation of the horizontal gyro zero bias requires the known latitude information of the location of the inertial navigation system. The latitude information L can be obtained through satellite positioning methods such as Beidou and GPS. The positioning error is acceptable within 100m. The angular velocity of the earth's rotation ω ie is a known constant, 15.04106° / h.

[0067] Step 7: Obtain the horizontal gyro bias residual δε of the inertial navigation system in step 6 x , δε y Compensate the X and Y gyros entering the inertial navigation system separately.

[0068] Example 1

[0069] In order to verify the correctness and effectiveness of the method proposed in the present invention, a navigation-grade laser gyro strapdown inertial navigation system is taken as an example as Example 1, and the horizontal gyro zero bias residual calculation and compensation are performed. The inertial navigation system is installed on a three-axis turntable (taking a turntable without true north as an example), and the turntable is started to return to zero and then the inertial navigation system is started for rapid alignment. Assuming that the recorded alignment heading information is 45.35°, the outer ring axis of the turntable is rotated by -45.35° through the "relative position mode". When the turntable is turned to stop, the heading of the inertial navigation system is near 0°.

[0070] After the above operations are completed, re-align quickly and record the alignment navigation values ​​3 times. The average value is assumed to be 0.067°.

[0071] In the "Relative Position Mode", rotate the turntable 90° and then quickly re-align. After alignment is complete, record the alignment navigation values ​​3 times, assuming the average is 90.102°;

[0072] In the "Relative Position Mode", rotate the turntable 90° and then quickly re-align. After alignment is complete, record the alignment navigation values ​​3 times, assuming the average is 180.141°;

[0073] In the "Relative Position Mode", rotate the turntable 90° and then quickly re-align. After alignment is complete, record the alignment navigation values ​​3 times, assuming the average is 270.068°;

[0074] Assuming that the latitude of the inertial navigation system is 40° north latitude, the residuals of the gyro zero bias of the x and y axes that can be calculated using (9) and (10) are: 0.0074° / h and -0.0034° / h respectively. The original zero bias value plus the calculated zero bias residual can achieve the compensation of the gyro zero bias residual.

[0075] An inertial navigation system was installed on a vehicle for data collection. The zero bias before and after compensation was used for navigation calculations, and compared with the true value provided by the high-precision inertial navigation. The results obtained were: after compensation, the position error was reduced from 50m to 10m, the velocity error was reduced from 15m / s to 5m / s, and the attitude error was reduced from 8 arc minutes to 2 arc minutes, proving the correctness of the method provided by the present invention.

[0076] The contents not described in detail in this specification belong to the prior art that can be searched by professionals in this field.

Claims

1. A four-position horizontal gyro bias residual compensation method based on heading error, characterized in that: The specific steps are as follows: Step 1: Install the inertial navigation system horizontally on the turntable surface, ensuring that the heading axis of the inertial navigation system is parallel to the outer frame axis of the turntable; Step 2, point the inertial navigation system on the turntable plane toward true north; Step 3: Record the heading value when the inertial navigation system heading is 0°, which is the first heading value. Then rotate the turntable 90° clockwise, and the inertial navigation system will be quickly re-aligned. The heading value when the inertial navigation system is 90° is recorded as the second heading value. Then rotate the turntable 90° clockwise, and the inertial navigation system will be quickly re-aligned. The heading value when the inertial navigation system is 180° is recorded as the third heading value. Then rotate the turntable 90° clockwise, and quickly re-align the inertial navigation system. Record the heading value when the inertial navigation system heading is 270°, which is the fourth heading value. ; Step 4: Repeat step 3 three times, record the alignment results of each time, and calculate the average alignment values ​​of the turntable at 0°, 90°, 180°, and 270°. , , , ; ， ； ， ； in, 、 、 、 These are the three alignment values ​​of the turntable at 0°, 90°, 180°, and 270°; Step 5: According to the four heading values ​​recorded by the inertial navigation system 、 、 and , calculate the heading value and the heading deviation of the four directions: （1） （2） （3） （4） Step 6: According to the initial alignment heading error limit formula: （5） in, is the heading alignment error, is the equivalent east gyro bias, is the geographical latitude of the inertial navigation system’s location, is the angular velocity of the Earth's rotation; The calculation formula for converting into equivalent east gyro bias is as follows: （6） When the heading of the inertial navigation system is 0° or 180°, that is, the Y axis of the inertial navigation system is facing north or south, and the X axis of the inertial navigation system is pointing east or west, then: （7） （8） According to formulas (7)-(8), the gyro bias residual in the horizontal x-axis direction is: （9） in, 、 is the horizontal gyro bias residual of the inertial navigation system; （10） From formula (9) and formula (10), it can be seen that the calculation of the horizontal gyro zero bias requires the known latitude information of the location of the inertial navigation system. The latitude information L can be obtained through Beidou or GPS satellite positioning methods, and the positioning error is within 100m; the angular velocity of the earth's rotation is is a known constant, 15.04106° / h; Step 7: Obtain the horizontal gyro bias residual of the inertial navigation system in step 6 、 Compensate the X and Y gyros entering the inertial navigation system separately.

2. The method for compensating the four-position horizontal gyro bias residual based on heading error according to claim 1, characterized in that: In step 2: For a turntable pointing to true north, directly start the inertial navigation system for quick alignment; For a turntable without true north orientation, angular position offset compensation is performed by turning the turntable. The offset compensation process is as follows: first, start the inertial navigation system for rapid alignment, record the heading value of the initial alignment, then use the heading value as the offset item of the turntable's azimuth zero position, rotate the turntable to make the inertial navigation system heading zero, and then restart the inertial navigation system for rapid alignment.

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