A rotation modulation inertial navigation rotation angle error automatic detection and compensation method

Abstract

The present application belongs to the technical field of inertial navigation, and aims to solve the problem of low precision of the output attitude of inertial navigation. The present application relates to a method for automatically detecting and compensating for the rotation modulation inertial navigation rotation angle error, and has the following characteristics: after the initial attitude information is obtained by the start-up alignment of the inertial navigation system, the precision of the rotation angle error compensation is detected; when the compensation value exceeds the precision range, the inertial navigation attitude information and the rotation angle value are sampled, the least square method is used for fitting to recalculate the rotation angle compensation parameters, the new parameters are obtained, the rotation angle compensation is performed again, and the precision is verified; after the verification, the new parameters are stored for use, and thus the output attitude information of the inertial navigation with higher precision is obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of inertial navigation, and particularly relates to a rotation modulation inertial navigation rotation angle error automatic detection and compensation method. BACKGROUND

[0002] An inertial navigation system (hereinafter referred to as an inertial navigation system) is an autonomous navigation system that does not rely on external information and does not radiate any information to the outside. Its basic working principle is to measure the acceleration of the carrier in the inertial reference frame and perform time domain integration, convert it into the navigation coordinate system, and then obtain the position and attitude of the carrier and other navigation information. At present, laser and optical fiber strapdown inertial navigation systems have been widely used. In order to improve the long navigation accuracy of the inertial navigation system, a rotation modulation technology is often used to modulate the constant error of the inertial device. There are different rotation modulation schemes such as single-axis, double-axis and three-axis in structure. After the inertial navigation system is installed with a rotating mechanism, due to the installation and measurement errors between the rotation center axis and the sensitive axis of the inertial device, there is a large error in the rotation angle compensation, which affects the attitude accuracy of the inertial navigation output. The existing rotation error compensation method generally extracts the periodic error in the output attitude angle information, and uses a trigonometric function fitting method for compensation. The compensation effect is poor and it is difficult to compensate for the implicit non-periodic error. SUMMARY

[0003] The purpose of the present application is to overcome the shortcomings of the prior art and provide a rotation modulation inertial navigation rotation angle error automatic detection and compensation method that can improve the output attitude accuracy of the inertial navigation system.

[0004] The above-mentioned purpose of the present application is realized by the following technical scheme:

[0005] A rotation modulation inertial navigation rotation angle error automatic detection and compensation method, comprising the following steps:

[0006] Step 1: The inertial navigation system is turned on to complete the initial alignment and obtain the initial attitude information. The accuracy threshold that the rotation angle compensation attitude should reach after the inertial device precision of the inertial navigation system is determined, and the number of rotation angle error compensation parameters is determined.

[0007] Step 2: Set the initial value of the rotation angle error compensation parameter. If the inertial navigation system is a new system, the compensation parameter is set to 0. If the rotation compensation parameter has been stored in the inertial navigation system, the existing compensation parameter is read from the storage and assigned to the compensation parameter matrix.

[0008] Step 3: In a rotation modulation period, the set compensation parameter is used to perform polynomial compensation calculation on the inertial navigation attitude information, and the rotation angle information, the inertial navigation attitude information before and after compensation in a certain calculation period are recorded.

[0009] Step 4: After one rotation modulation cycle, obtain the maximum and minimum values ​​of the inertial navigation attitude information before and after compensation, calculate the difference between the maximum and minimum values ​​of the inertial navigation attitude information after compensation, and compare it with the set compensation accuracy threshold. If it exceeds the threshold, new parameters are calculated. If it is lower than the threshold, it means that the existing parameters are available and no new parameters need to be calculated.

[0010] Step 5: Subtract the median value from the attitude information to obtain the inertial navigation attitude information fluctuation error before compensation. Use this error information as the output and the rotation angle measurement information as the input. Use the least squares method to perform polynomial fitting calculation to obtain the new rotation angle measurement error compensation parameters.

[0011] Step 6: Using the new compensation parameters, recalculate the difference between the maximum and minimum values ​​of the compensated attitude information in the next rotation modulation cycle, and compare it with the accuracy threshold. If it meets the accuracy threshold, the new calculated parameters are considered valid and stored for use. If it exceeds the accuracy threshold, the original compensation parameters continue to be used.

[0012] Furthermore, in step 1, the accuracy threshold is represented by M, and based on the existing inertial navigation accuracy requirements, a compensation parameter matrix is ​​generally constructed using 10 parameters:

[0013]

[0014] Furthermore, in step 3, the polynomial compensation calculation formula is:

[0015] h c =h+Aθ

[0016] Where matrix A is the power matrix of the rotation angle measurement information at the calculation time.

[0017] A = {1, a, a} 2 a 3 , ..., a 9 (a is the rotation angle value), h is the inertial navigation attitude information at the calculation time; data is recorded using a 1Hz frequency, recording the inertial navigation attitude information matrix before and after compensation in the current rotation modulation cycle. and and the corresponding rotation angle measurement information power matrix at that time

[0018] Furthermore, in step 5, the error matrix of the inertial navigation attitude information fluctuation before compensation is:

[0019]

[0020] Among them, h m To compensate for the maximum value in the forward inertial navigation attitude information, h l To compensate for the minimum value in the previous inertial navigation attitude information;

[0021] And the new rotation angle error compensation parameter value is:

[0022] θ new =(X T X) -1 X T Y

[0023] Wherein, X is the rotation angle information matrix, X T is the transpose matrix of X matrix.

[0024] The application has the advantages and positive effects:

[0025] 1. The application is aimed at the problem of large error influence on inertial navigation attitude precision caused by rotation angle compensation, and an automatic error detection and compensation method is designed, the calculation of inertial navigation attitude information before and after compensation in a rotation modulation period is used to determine whether the parameters meet the precision requirements, and then the inertial navigation attitude fluctuation error is calculated, the least square method is used for polynomial fitting, the new compensation parameters are obtained, and the effectiveness of the new parameters is further verified, and finally better rotation angle error compensation effect is obtained, and the inertial navigation attitude information precision is improved.

[0026] 2. The method has ingenious design idea and innovation, and better solves the engineering application problem of rotation modulation inertial navigation rotation angle error compensation, realizes automatic rotation angle error detection and compensation, and improves the automation and reliability of the inertial navigation system.

[0027] In summary, the application uses high-order fitting for error compensation by increasing compensation coefficients, and better compensation effect is obtained. DETAILED DESCRIPTION

[0028] Figure 1 is the work flow chart of the method of the application.

[0029] DETAILED DESCRIPTION

[0030] The structure of the application will be further described by combining the drawings and through embodiments. It should be noted that the embodiments are descriptive rather than limiting.

[0031] An automatic detection and compensation method for rotation modulation inertial navigation rotation angle error is realized, please refer to Figure 1 The application point is that: after obtaining initial attitude information by starting alignment of the inertial navigation system, the rotation angle error compensation precision is detected, when the compensation value exceeds the precision range, the sampling inertial navigation attitude information and rotation angle value are used, the least square method fitting is used for re-calculation of the rotation angle compensation parameters, the new parameters are obtained, the rotation angle compensation is re-performed and the precision is verified, the new parameters are stored and used after verification, and higher precision inertial navigation output attitude information is obtained. Specifically, the steps include:

[0032] (1) The inertial navigation system is powered on and completes initial alignment to obtain initial attitude information. The accuracy threshold for rotation angle measurement compensation attitude information is determined based on the accuracy of the inertial devices used in the inertial navigation system, denoted as M. Simultaneously, the number of rotation angle measurement error compensation parameters is determined. Based on the existing inertial navigation accuracy requirements, generally 10 parameters are sufficient. The compensation parameter matrix is ​​denoted as:

[0033]

[0034] (2) Determine the initial values ​​of the angle measurement error compensation parameters: If the inertial navigation system is a new system, set the compensation parameter matrix θ to 0; if the inertial navigation system already stores rotation compensation parameters, read the 10 stored compensation parameters from the memory and assign them all to the matrix θ.

[0035] (3) During one rotation modulation cycle, polynomial compensation calculations are performed on the inertial navigation attitude information using the pre-set compensation parameters. The calculation formula is as follows:

[0036] h c =h+Aθ,

[0037] Where matrix A is the power matrix of the rotation angle measurement information at the calculation time, A = {1, a, a} 2 a 3 , ..., a 9 (a is the rotation angle value), h is the inertial navigation attitude information at the calculation time; data is recorded using a 1Hz frequency, recording the inertial navigation attitude information matrix before and after compensation in the current rotation modulation cycle. and and the corresponding rotation angle measurement information power matrix at that time

[0038] (4) After one rotation modulation cycle, calculate the maximum value h in the pre-compensation inertial attitude information H. m and minimum value h l Compensated inertial navigation attitude information H c The maximum value h in cm and minimum value h cl Then calculate the maximum / minimum difference of the inertial navigation attitude information after compensation. Compare with the set compensation accuracy threshold, if Then perform new parameter calculations, if This indicates that the existing parameters are applicable and no new parameters need to be calculated;

[0039] (5) If new parameter calculation is required, obtain the inertial navigation attitude information fluctuation error matrix before compensation within the rotation modulation period. Taking the error matrix Y as an output matrix and the rotation angle information power matrix X as an input matrix, a polynomial fitting calculation is performed by using a least square method to obtain a new rotation angle error compensation parameter value θ new =(X T X) - 1 X T Y; wherein, X is a rotation angle information power matrix, and XT is a transpose matrix of the X matrix.

[0040] (6) using the new rotation compensation parameter θ new , the maximum value h cnewm and the minimum value h cnewl in the compensated inertial navigation attitude information are obtained again in the next rotation modulation period, and a difference between the maximum and minimum values of the compensated attitude information is calculated If , it is considered that the new calculated parameter is effective, the parameter is stored and used, if , it is considered that the new calculated parameter exceeds the accuracy, and the original compensation parameter is continuously used.

[0041] Although the embodiments of the present application and the drawings are disclosed for the purpose of illustration, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit of the present application and the appended claims, therefore, the scope of the present application is not limited to the disclosed contents of the embodiments and the drawings.

Claims

1. A rotation modulation inertial navigation rotation angle error automatic detection and compensation method, characterized in that: The method comprises the following steps: Step 1, the initial alignment of the inertial navigation system is completed, the initial attitude information is obtained, the precision threshold reached after the rotation angle error compensation attitude is determined according to the precision of the inertial device used by the inertial navigation system, and the number of rotation angle error compensation parameters is determined; Step 2, the initial value of the rotation angle error compensation parameter is set, if the inertial navigation system is a new system, the compensation parameter is set to 0, if the rotation compensation parameter has been stored in the inertial navigation system, the existing compensation parameter is read from the memory and assigned to the compensation parameter matrix; Step 3, in a rotation modulation period, the rotation angle polynomial compensation calculation of the inertial navigation attitude information is performed using the set compensation parameter, and the rotation angle information, the inertial navigation attitude information before and after compensation in a calculation period are recorded; Step 4, after the rotation modulation period ends, the maximum and minimum values of the inertial navigation attitude information before and after compensation are obtained, the maximum and minimum values of the inertial navigation attitude information after compensation are calculated, and the calculated values are compared with the set compensation precision threshold, if the calculated values exceed the threshold, new parameter calculation is performed, if the calculated values are lower than the threshold, it is indicated that the existing parameter can be used, and new parameter calculation is not required; Step 5, the fluctuation error of the inertial navigation attitude information before compensation is obtained by subtracting the median value from the attitude information, the error information is used as an output, the rotation angle information is used as an input, the least square method is used for polynomial fitting calculation, and the new rotation angle error compensation parameter is obtained; Step 6, the new compensation parameter is used to calculate the maximum and minimum values of the attitude information after compensation in the next rotation modulation period, and the precision threshold is judged, if the precision threshold is met, the new calculated parameter is considered effective, the parameter is stored and used, if the precision is exceeded, the original compensation parameter is continuously used.

2. The rotation-modulated inertial navigation rotation angle error automatic detection and compensation method according to claim 1, characterized in that: In step 1, the precision threshold is represented by and according to the existing inertial navigation precision requirements, 10 parameters are used to constitute the compensation parameter matrix: 。 3. The rotation-modulated inertial navigation rotation angle error automatic detection and compensation method according to claim 1, characterized in that: In step 3, the polynomial compensation calculation formula is: ； Wherein, the matrix is the rotation angle information matrix of the calculation time point, is the inertial navigation attitude information of the calculation time point; data recording is performed at a frequency of 1 Hz, and the inertial navigation attitude information matrices before and after compensation in the current rotation modulation period are recorded and the rotation angle information matrix of the corresponding time point thereof​​ 4. The rotation modulation inertial navigation rotation angle error automatic detection and compensation method according to claim 3, characterized in that: In step 5, the fluctuation error matrix of the inertial navigation attitude information before compensation is: ； wherein, is a maximum value in the previous inertial navigation attitude information, is a minimum value in the previous inertial navigation attitude information; And the new rotation angle error compensation parameter value is: ； wherein X is a rotation angle information matrix X T is a transpose matrix of the X matrix.

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