Method, program and equipment for calibrating installation error angles of two inertial navigation systems based on accelerometer information and storage medium

Abstract

The invention provides a method, a program and equipment for calibrating installation error angles of two inertial navigation systems based on accelerometer information and a storage medium. Performing multi-angle conversion on the structure provided with the two inertial navigation systems, acquiring a data matrix output by the triaxial accelerometers of the two inertial navigation systems within a period of time at each angle, and calculating the specific force of the two inertial navigation systems; based on the specific force data sets of the two inertial navigation systems, constructing a to-be-optimized information matrix about the installation attitude error angle by utilizing a physical relation equation; decomposing the information matrix to be optimized, calculating an optimal coordinate transformation matrix according to the decomposed matrix, and calculating a pitching installation error, a rolling installation error and a course installation error between the two inertial navigation systems according to elements in the optimal coordinate transformation matrix. According to the method, the defects of a self-alignment method and a transfer alignment method can be overcome, high-precision rapid calibration of the installation error angle between the two inertial navigation devices can be realized, and the method has practical engineering application significance.

Description

Technical Field

[0001] The present invention belongs to the technical field of inertial navigation systems, and particularly relates to a calibration method, program, device and storage medium for the installation error angles of two inertial navigation systems based on accelerometer information. Background Art

[0002] Inertial navigation systems can provide real-time and reliable attitude information for carriers. Therefore, high-precision attitude estimation is one of the important research directions in the field of inertial navigation systems. The evaluation of the accuracy of the attitude estimation results of inertial navigation systems requires higher-precision attitude information as the reference true value. Considering the real-time, flexibility and wide-area nature of the attitude estimation of carriers, this higher-precision attitude reference information is usually provided by another set of high-precision inertial navigation systems. How to determine the installation attitude error between the low-precision inertial navigation system to be evaluated and the reference high-precision inertial navigation system is an important prerequisite for achieving high-precision attitude evaluation.

[0003] Existing methods for determining the installation error angles between two inertial navigation systems are mainly divided into two categories: self-alignment and transfer alignment. The self-alignment method allows the two inertial navigation systems to perform initial alignment respectively to obtain attitude results, and the installation error angles between the inertial navigation systems are obtained by taking the difference. However, this type of method requires the gyroscope information of the low-precision inertial navigation system, and the error magnitude of the alignment result is often equivalent to or even higher than the magnitude of the attitude evaluation accuracy, which cannot meet the actual requirements.

[0004] The transfer alignment method models the installation error angles and uses the information of the two inertial navigation systems to estimate the installation error angles in real time, and is used to solve the online estimation problem of the time-varying installation error angles of the two inertial navigation systems on large carriers. On the one hand, the estimation accuracy of this type of method is affected by the accuracy of the installation error angle model and the gyroscope accuracy of the low-precision inertial navigation system, and cannot meet the actual requirements. On the other hand, during the attitude evaluation process, the installation positions of the two inertial navigation systems are close, the time-varying characteristics of the installation error angles are weak, and the online estimation method brings an additional computational burden to the inertial navigation system, which is not suitable for the calibration of the installation error angles.

[0005] Therefore, it is necessary to invent a calibration method for the installation error angles of two inertial navigation systems based on accelerometer information, which has a fast calibration speed, high accuracy and good reliability. Summary of the Invention

[0006] The purpose of the present invention is to provide a calibration method, program, device and storage medium for the installation error angles of two inertial navigation systems based on accelerometer information.

[0007] A calibration method for the installation error angles of two inertial navigation systems based on accelerometer information includes:

[0008] Perform multi-angle transformation on the structure equipped with two inertial navigation systems, obtain the data matrices output by the three-axis accelerometers of the two inertial navigation systems over a period of time at each angle, and calculate the specific forces of the two inertial navigation systems; obtain the specific force datasets of the two inertial navigation systems through multi-angle transformation;

[0009] Based on the specific force datasets of the two inertial navigation systems, use the physical relationship equation to construct the information matrix to be optimized regarding the installation attitude error angle; if the information matrix to be optimized is a singular matrix, re-execute the above steps until the obtained information matrix to be optimized is a non-singular matrix;

[0010] Decompose the information matrix to be optimized, calculate the optimal coordinate transformation matrix based on the decomposed matrix, and calculate the pitch installation error, roll installation error, and heading installation error between the two inertial navigation systems according to the elements in the optimal coordinate transformation matrix, completing the calibration of the installation error angles of the two inertial navigation systems.

[0011] Furthermore, at the i-th angle, obtain the data matrix output by the three-axis accelerometer of the first inertial navigation system within T0 time The data matrix output by the three-axis accelerometer of the second inertial navigation system F1 and F2 respectively represent the data output frequencies of the first inertial navigation system and the second inertial navigation system.

[0012] Furthermore, according to Calculate the specific force f of the first inertial navigation system i 1 :

[0013]

[0014] According to Calculate the specific force f of the first inertial navigation system i 2 :

[0015]

[0016] Through N times of angle transformation, obtain the specific force datasets of the two inertial navigation systems And

[0017] Furthermore, based on the specific force datasets F 1 And F 2 , use the physical relationship equation to construct the information matrix A to be optimized regarding the installation attitude error angle;

[0018] A = (F 1 w)(F 2 w) T

[0019] where w is the accelerometer accuracy weight matrix, w = diag(w1,..., w N ), w i is the accuracy weight of the accelerometer at the i-th angle.

[0020] Furthermore, decompose the information matrix A to be optimized;

[0021] A = UDV T

[0022] where each column in matrix U is an eigenvector of AA T ; each column in matrix V is an eigenvector of A T A; matrix D is a diagonal matrix, and each element on the main diagonal is the singular value of the information matrix A to be optimized.

[0023] Furthermore, calculate the optimal coordinate transformation matrix

[0024] The matrix is a 3×3 matrix. According to the elements in the matrix u, v = 1, 2, 3, calculate the pitch installation error θ, roll installation error β, and heading installation error γ between the two inertial navigation systems;

[0025] If then

[0026] Otherwise,

[0027] Furthermore, before starting the calibration, power on and preheat the two inertial navigation systems for a period of time.

[0028] A computer device / system, comprising a memory, a processor, and a computer program stored on the memory, wherein the processor executes the computer program to implement the steps of the above-mentioned method for calibrating the installation error angles of two inertial navigation systems based on accelerometer information.

[0029] A computer-readable storage medium, on which a computer program / instructions are stored, and when the computer program / instructions are executed by a processor, the steps of the above-mentioned method for calibrating the installation error angles of two inertial navigation systems based on accelerometer information are implemented.

[0030] A computer program product, comprising a computer program / instructions, and when the computer program / instructions are executed by a processor, the steps of the above-mentioned method for calibrating the installation error angles of two inertial navigation systems based on accelerometer information are implemented.

[0031] The beneficial effects of the present invention are as follows:

[0032] The present invention can achieve high-precision and rapid calibration of the installation error angles between two inertial navigation systems, avoiding the accuracy degradation caused by low-precision gyroscopes in traditional methods; at the same time, considering the invariance of the installation error angles of the two inertial navigation systems in practical applications, the present invention adopts an offline post-processing calculation method, which reduces the calculation burden of the inertial navigation system and has practical engineering application significance. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the overall process of the present invention.

[0034] Figure 2 It is a schematic diagram of the coordinate systems and placement methods of the two inertial navigation systems provided in the embodiment of the present invention.

[0035] Figure 3 It is a calibration result diagram of the installation error angles of the two inertial navigation systems provided in the embodiment of the present invention.

[0036] Figure 4 It is a diagram of the main performance indicators of the inertial components of the two inertial navigation systems provided in the embodiment of the present invention.

[0037] Figure 5 It is a diagram of the attitude estimation error of the inertial navigation system to be evaluated in the vehicle test provided in the embodiment of the present invention. Detailed Embodiment

[0038] The present invention will be further described below with reference to the drawings.

[0039] The present invention provides a method for calibrating the installation error angles of two inertial navigation systems based on accelerometer information. First, power on and preheat the two inertial navigation systems to ensure normal output data; at the same time, collect the accelerometer output data of the two inertial navigation systems, and perform data preprocessing on the data to weaken the noise influence; transform the horizontal attitude angles of the two inertial navigation systems, and collect multiple groups of accelerometer data to form an accelerometer data set; construct an index function to be optimized for the installation error angles based on the physical relationship using the accelerometer data set, and use the method based on SVD decomposition to optimize and solve the installation error angles. The present invention can make up for the deficiencies of self-alignment and transfer alignment methods, improve the calibration accuracy, reduce the calculation burden of the inertial navigation system, and has practical engineering application significance.

[0040] Step 1: Multiply the structure equipped with two inertial navigation systems by multiple angles, and obtain the data matrices of the three-axis accelerometers of the two inertial navigation systems at each angle for a period of time and calculate the specific forces of the two inertial navigation systems; obtain the specific force data set of the two inertial navigation systems through the multi-angle transformation;

[0041] Obtain the data matrix of the three-axis accelerometers of the first inertial navigation system within T0 time at the i-th angle The data matrix of the three-axis accelerometers of the second inertial navigation system F1 and F2 respectively represent the data output frequencies of the first inertial navigation system and the second inertial navigation system.

[0042] According to calculate the specific force f of the first inertial navigation system i 1 :

[0043]

[0044] According to calculate the specific force f of the first inertial navigation system i 2 :

[0045]

[0046] Through N angular transformations, obtain the specific force data sets of the two inertial navigation systems and

[0047] Step 2: Based on the specific force data sets F 1 and F 2 , use the physical relationship equation to construct the information matrix A to be optimized about the installation attitude error angle;

[0048] A = (F 1 w)(F 2 w) T

[0049] where w is the accelerometer accuracy weight matrix, w = diag(w1,..., w N ), and w i is the accuracy weight of the accelerometer at the i-th angle.

[0050] If the information matrix A to be optimized is a singular matrix, re-execute Step 1 and Step 2 until the obtained information matrix A to be optimized is a non-singular matrix;

[0051] Step 3: Decompose the information matrix A to be optimized;

[0052] A = UDV T

[0053] where each column of matrix U is an eigenvector of AA T ; each column of matrix V is an eigenvector of A T A; matrix D is a diagonal matrix, and each element on the main diagonal is the singular value of the information matrix A to be optimized

[0054] Calculate the optimal coordinate transformation matrix

[0055]

[0056] Among them, the matrix is a 3×3 matrix;

[0057] According to the elements in the matrix where u, v = 1, 2, 3, calculate the pitch installation error θ, roll installation error β and heading installation error γ between the two inertial navigation systems;

[0058] If then

[0059] Otherwise,

[0060] Example 1:

[0061] Step 1: Set up the experimental environment. This example requires two inertial navigation systems with accelerometers, namely the inertial navigation system to be evaluated and the high-precision reference inertial navigation system. Ensure that all calibrations and tests of the two inertial navigation systems have been completed, and the origin of the inertial coordinate system of the two inertial navigation systems is the center of mass of the inertial navigation system, and the x, y, and z axes are the right, front, and up of the inertial navigation system respectively; use a set of rigidly fixed fixtures to connect the two inertial navigation systems, and ensure that the inertial navigation systems are close enough and there will be no obvious deformation during the experiment; complete all power supply and data acquisition preparation work. In this example, the number of test times n is set to 7, the inertial navigation warm-up time t preheat = 1 hour, the data acquisition time t data = 5 minutes, the output frequencies of the two inertial navigations are the same, both 100Hz, F low = F high = 100, and the accelerometer accuracy weight matrix w = diag([1 1...1]).

[0062] Step 2: Power on and warm up the two inertial navigations for 1 hour to ensure the normal working state of the inertial devices.

[0063] Step 3: Place the inertial navigation systems in any way. In this example, the initial placement method is as Figure 2 shown in the left figure; it can be clearly seen from the figure that there is an installation error angle between the coordinate systems I low and I high of the two inertial navigations. In this example, to fully illustrate the usage details, the installation error angle is set relatively large.

[0064] Step 4: Save the accelerometer information output by the two inertial navigation systems. Record the accelerometer data of the two inertial navigations for 5 minutes at the initial position. Each accelerometer outputs 30,000 data, obtaining two data sets, which are respectively and

[0065]

[0066] Among them, and are respectively 30,000 data output by the accelerometers on the x, y, and z axes of the inertial navigation system to be evaluated at the first position, and are respectively 30,000 data output by the accelerometers on the x, y, and z axes of the high-precision reference inertial navigation system at the first position.

[0067] Step 5: Take the mean of the 5-minute accelerometer data output by the two inertial navigations according to the following formula to eliminate the white noise error therein and obtain f1 low and f1 low .

[0068]

[0069] Among them, and are respectively and the i-th row data of and are respectively and the i-th row data of

[0070] Step 6: Determine whether the number of test times is satisfied. If satisfied, execute Step 11; otherwise, execute Step 7.

[0071] Step 7: Adjust the horizontal postures of the two inertial navigations to rotate them by an arbitrary angle α, α > 30 degrees, as Figure 2 shown in the middle figure.

[0072] Step 8: After the two inertial navigation systems complete rotation and become stable, record the 5-minute accelerometer data of the two inertial navigations to obtain and

[0073]

[0074] Among them, and are respectively 30,000 data output by the accelerometers on the x, y, and z axes of the inertial navigation system to be evaluated at the second position, and are respectively 30,000 data output by the accelerometers on the x, y, and z axes of the high-precision reference inertial navigation system at the second position.

[0075] Step 9: Take the mean of the 5-minute accelerometer data output by the two inertial navigations at this position according to the following formula to eliminate the white noise error therein and obtain and

[0076]

[0077] Step 10: Repeat Steps 6 to 9 until the number of tests is met. In this embodiment, the number of tests is set to 7 times.

[0078] Step 11: Recombine the accelerometer data of the two inertial navigation systems at the nine saved positions to obtain and

[0079]

[0080]

[0081] Step 12: Calculate the optimal coordinate transformation matrix. In this embodiment, since the experimental environment remains unchanged and the accuracy of the accelerometer data of the two inertial navigation systems at each position is the same, the weights are taken as an equal-weight matrix, and the information matrix A to be optimized for the installation error angle is constructed as A=(f 1 )(f 2 ) T .

[0082] Step 14: Optimize and decompose the information matrix A to be optimized for the installation error angle to obtain A = UDV T .

[0083] Step 15: Solve the optimal coordinate transformation matrix

[0084] Step 16: Calculate the pitch angle error θ, roll angle error β, and heading angle error γ of the coordinate system of the inertial navigation system to be evaluated relative to the coordinate system of the high-precision inertial navigation system.

[0085] It can be seen from Figure 3 that in this embodiment, the standard deviations of the calibrated pitch angle, roll angle, and heading angle installation error angles are 0.00256°, 0.00510°, and 0.00743° respectively, and all three are less than 0.01°. The present invention has high estimation stability for the installation error angles of the two inertial navigation systems.

[0086] Since the actual installation error angles of the two inertial navigation systems are unknown, it is impossible to directly evaluate the calibration accuracy of the present invention. The calibration accuracy of this embodiment is indirectly evaluated by means of a vehicle test. Specifically, the attitude output by the high-precision inertial navigation system is used as the reference true value, the attitude estimation error of the inertial navigation system to be evaluated is calculated, and on this basis, the attitude estimation error caused by the installation error angle is compensated, and the calibration accuracy of this embodiment is evaluated through the residual attitude estimation error. The main performance indicators of the inertial devices of the two inertial navigation systems used in this embodiment are as Figure 4 shown.

[0087] The installation error angles calibrated by the self-alignment method and the attitude estimation errors after compensating the installation error angles calibrated by the present invention are as Figure 5 shown. It can be clearly seen that the three-axis attitude errors after compensating the installation error angles calibrated by the present invention are significantly smaller than those calibrated by the self-alignment method, which proves that the installation error angles of the present invention have high precision.

[0088] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A calibration method for the installation error angles of two inertial navigation systems based on accelerometer information, characterized in that: The structure equipped with two inertial navigation systems is transformed at multiple angles, and at each angle, the data matrices output by the triaxial accelerometers of the two inertial navigation systems are obtained for a period of time, and the specific forces of the two inertial navigation systems are calculated; The specific force data sets of the two inertial navigation systems are obtained through multi-angle transformation; Based on the specific force data sets of the two inertial navigation systems, an information matrix to be optimized regarding the installation attitude error angles is constructed using physical relationship equations; If the information matrix to be optimized is a singular matrix, the above steps are re-executed until the obtained information matrix to be optimized is a non-singular matrix; The information matrix to be optimized is decomposed, the optimal coordinate transformation matrix is calculated according to the decomposed matrix, and the pitch installation error, roll installation error, and heading installation error between the two inertial navigation systems are calculated according to the elements in the optimal coordinate transformation matrix, completing the calibration of the installation error angles of the two inertial navigation systems.

2. A calibration method for installation error angles of two inertial navigation systems based on accelerometer information according to claim 1, characterized in that: Obtain the data matrix output by the three-axis accelerometer of the first inertial navigation system within time T0 at the i-th angle The data matrix output by the three-axis accelerometer of the second inertial navigation system F1 and F2 respectively represent the data output frequencies of the first inertial navigation system and the second inertial navigation system.

3. A calibration method for installation error angles of two inertial navigation systems based on accelerometer information according to claim 2, characterized in that: According to calculate the specific force of the first inertial navigation system According to Calculate the specific force of the first inertial navigation system Obtain the specific force datasets of two inertial navigation systems through N angular transformations and 4. A calibration method for installation error angles of two inertial navigation systems based on accelerometer information according to claim 3, characterized in that: Comparative force data set F based on two inertial navigation systems 1 With F 2 , using the physical relationship equation to construct the information matrix A to be optimized about the installation posture error angle; A = (F 1 w)(F 2 w) T Among them, w is the accelerometer accuracy weight matrix, w = diag(w1,..., w N ), w i is the accuracy weight of the accelerometer at the i-th angle.

5. A calibration method for the installation error angles of two inertial navigation systems based on accelerometer information according to claim 4, characterized in that: Decompose the information matrix A to be optimized; A = UDV T Among them, each column in matrix U is an eigenvector of AA T ; each column in matrix V is an eigenvector of A T A; matrix D is a diagonal matrix, and each element on the main diagonal is the singular value of the information matrix A to be optimized.

6. A calibration method for the installation error angles of two inertial navigation systems based on accelerometer information according to claim 5, characterized in that: Calculate the optimal coordinate transformation matrix Matrix is a 3×3 matrix. According to the elements in the matrix where u, v = 1, 2, 3, calculate the pitch installation error θ, roll installation error β, and heading installation error γ between two inertial navigation systems; If then Otherwise, γ = 0.

7. A calibration method for the installation error angles of two inertial navigation systems based on accelerometer information according to claim 1, characterized in that: Before starting the calibration, the two inertial navigation systems are powered on and preheated for a period of time.

8. A computer device / equipment / system, comprising a memory, a processor, and a computer program stored on the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having computer programs / instructions stored thereon, characterized in that: When the computer program / instructions are executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program / instructions, characterized in that: When the computer program / instructions are executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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