A method for outdoor calibration of installation deflection angles between multiple inertial navigation systems

Abstract

The present invention discloses a method for field calibration of installation deflection angles between multiple inertial navigation systems. First, each inertial navigation system independently performs multiple groups of initial alignments and records the corresponding alignment results. Secondly, each group of self-alignment heading angles of each system is converted into a corresponding attitude array, and the attitude arrays between the systems are calculated and then the installation deflection angles between the systems are inversely solved. Finally, the obtained installation deflection angles between the groups of systems are averaged as the final calibration result of the installation deflection angles between the systems, and a method for selecting the number of self-alignment groups and the duration of a single self-alignment of each inertial navigation system is provided. The present invention provides a pure inertial high-precision field calibration method for installation deflection angles between multiple inertial navigation systems. The multi-group averaging method reduces the system self-alignment error and improves the calibration accuracy of the installation deflection angles between the systems. The method is simple to operate, has integrated calibration, and has strong engineering practicality. It is of great significance to the research on multi-inertial navigation attitude information fusion, master-slave inertial navigation high-precision transmission alignment, etc.

Description

Technical Field

[0001] The invention belongs to the field of external field calibration of installation deflection angles between inertial navigation systems, and in particular relates to an external field calibration method of installation deflection angles between multiple sets of inertial navigation systems. Background Art

[0002] The inertial navigation system can independently provide the vehicle with information such as attitude, speed, and position without the aid of external equipment. It has strong autonomy, good concealment, is not easily affected by external interference, and outputs information continuously. Therefore, it is widely used and important in the military.

[0003] For application scenarios where important carriers such as land-based launch vehicles and large ships have multiple redundant inertial navigation systems and have high requirements for concealment, multiple inertial navigation systems can be networked to achieve information fusion, estimate and compensate corresponding error parameters, further improve the accuracy of the combined pure inertial navigation information, and extend the system readjustment cycle; alignment can also be transmitted through the main and sub-inertial navigation systems to improve the sub-inertial navigation alignment and navigation accuracy, which is of great engineering significance.

[0004] However, the premise for transmitting alignment and attitude information fusion between multiple inertial navigation systems is that the installation angles between the systems must be compensated in advance, and the actual application scenario is the outdoor environment. The optical collimation method needs to take into account the installation of optical collimation equipment, optical path propagation, and collimation target distance. The operation process is complicated, susceptible to external interference, and has poor applicability in outdoor conditions. Especially under the swaying base of the ship, the accuracy of the optical calibration method is difficult to guarantee, and it has strict requirements on weather, hydrology, hull stability and other conditions. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a method for field calibration of installation deflection angles between multiple inertial navigation systems. The method reduces the system self-alignment error by averaging the installation deflection angles of multiple groups of self-alignment calculations of each system, and realizes high-precision calibration of the installation deflection angles between systems. When multiple systems are used in the field, a multi-group self-alignment averaging method is adopted to realize pure inertial calibration of the installation deflection angles between systems. The method is particularly suitable for the occasions of fusion of heading and attitude information of multiple inertial navigation systems and transmission of high-precision heading and attitude information.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A method for field calibration of installation deflection angles between multiple inertial navigation systems is disclosed. Firstly, the self-alignment error caused by random errors of inertial devices including gyro drift and random walk has random characteristics. Multiple groups of self-alignment are designed for each inertial navigation system. Each group of self-alignment heading angles of each inertial navigation system is converted into a corresponding attitude matrix. The attitude matrix between each inertial navigation system is calculated and then the installation deflection angles between each inertial navigation system are inversely solved. Finally, the installation deflection angles between each group of inertial navigation systems are averaged as the final calibration result of the installation deflection angles between each inertial navigation system. The multi-group averaging method reduces the self-alignment error of the inertial navigation system and improves the calibration accuracy of the installation deflection angles between each inertial navigation system. A method for selecting the number of self-alignment groups and the duration of a single self-alignment is also provided.

[0008] Furthermore, the method for selecting the number of self-alignment groups and the duration of a single self-alignment of each inertial navigation system is as follows:

[0009] When the inertial navigation system is a rotation modulation inertial navigation system, in the continuous rotation alignment mode, the system initial alignment heading error caused by random walk is inversely proportional to the square root of time, and the formula is as follows:

[0010]

[0011] Among them, δφ U-ARW is the system initial alignment heading error caused by random walk, RWC E is the angle random walk coefficient of the equivalent east-pointing gyro, T is the single self-alignment time of the system, ω e is the angular velocity of the earth's rotation, and L is the latitude of the system.

[0012] Assuming that the number of self-alignment groups of a single inertial navigation system is N, after averaging the results of multiple self-alignment for each N groups, the standard deviation of the system's initial alignment heading error is The expression is as follows:

[0013]

[0014] Among them, δφ U-ARW is the system's single initial alignment heading error caused by random walk, is the average heading error of the system caused by random walk for multiple initial alignments, RWC E is the angle random walk coefficient of the equivalent east-pointing gyro, T is the single self-alignment time of the system, N is the number of self-alignment groups of a single inertial navigation system, ω e is the angular velocity of the earth’s rotation, L is the latitude of the system, and std(·) represents the standard deviation of the variable.

[0015] Furthermore, the calculation method of the installation deflection angle between the inertial navigation systems is:

[0016] The two inertial navigation systems are marked as inertial navigation system No. 1 RINS1 and inertial navigation system No. 2 RINS2;

[0017] The pitch angle, roll angle and heading angle of the i-th initial alignment of the No. 1 inertial navigation system RINS1 are: θ 1i , γ 1i , 1i (i=1,2,3...N)

[0018] The pitch angle, roll angle and heading angle of the ith initial alignment of the No. 2 inertial navigation system RINS2 are: θ 2i , γ 2i , 2i (i=1,2,3...N)

[0019] The attitude matrix from the carrier coordinate system b1 and b2 of the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 to the navigation coordinate system n is calculated as follows:

[0020]

[0021]

[0022] The attitude matrix between the No. 1 inertial navigation system carrier coordinate system b1 and the No. 2 inertial navigation system carrier coordinate system b2 is as follows:

[0023]

[0024] in, is the attitude matrix of the carrier coordinate system b1 to the navigation coordinate system n of the ith alignment of the No. 1 inertial navigation, is the attitude matrix between the carrier coordinate system b2 and the navigation coordinate system n for the i-th alignment of the No. 2 inertial navigation.

[0025] The installation deflection angle between systems calibrated for the i-th time is:

[0026]

[0027] in, is the attitude matrix from the No. 1 inertial navigation system carrier b1 to the No. 2 inertial navigation system carrier b2, Indicates taking The element corresponding to the 3rd row and 2nd column in the matrix, and so on; arcsin(·) represents the inverse sine operation, arctan(·) represents the inverse tangent operation; Δθ 21_i is the pitch installation deflection angle between systems calibrated for the i-th time, Δγ 21_i is the inter-system roll installation deflection angle calibrated for the i-th time, Δψ 21_i is the heading installation deflection angle between systems calibrated for the i-th time, and N is the number of self-alignment of a single inertial navigation system.

[0028] The average value of the N-times installation deflection calibration between inertial navigation systems is taken as the final installation deflection between systems:

[0029]

[0030] in, is the mean value of the pitch installation deflection angle between systems calibrated N times, is the average of the rolling installation deflection angles between the systems calibrated N times, It is the mean value of the heading installation deviation angle between systems calibrated N times.

[0031] The mean matrix of installation deflection angle between inertial navigation systems is:

[0032]

[0033] In the fusion of heading and attitude information, the method for the No. 2 inertial navigation system RINS2 to align the initial heading and attitude with the No. 1 inertial navigation system RINS1 by compensating the calibrated inter-system installation deflection is as follows:

[0034]

[0035] in, The attitude matrix of the No. 2 INS after compensating the installation angle relative to the No. 1 INS. is the attitude matrix of the No. 2 inertial navigation system itself solved by strapdown, Install the deflection angle mean matrix between INS 1 and INS 2.

[0036] The advantages of the present invention compared with the prior art are:

[0037] (1) There are multiple redundant inertial navigation systems in land-based launch vehicles and large ships. The multi-inertial navigation information fusion or master-slave inertial navigation system transfer alignment scheme based on the platform must be pre-calibrated in the field to compensate for the installation deflection angles between each inertial navigation system. To address this problem, the present invention proposes a field calibration method for the installation deflection angles between multiple inertial navigation systems.

[0038] (2) The present invention makes full use of the random nature of the self-alignment error caused by random errors of inertial devices such as gyro drift and random walk, designs each system to perform multiple sets of self-alignments, and suppresses the self-alignment error of each inertial navigation system by calculating the installation deflection angle by averaging the multiple sets of self-alignments, thereby achieving high-precision calibration of the installation deflection angle between systems.

[0039] (3) The present invention uses the inertial navigation system to calculate the installation deflection angle by multiple self-alignment and take the average to realize the pure inertial calibration of the installation deflection angle between systems. Compared with the optical collimation method, it has strict requirements on the installation, leveling, optical path propagation, collimation target distance, image finding and other aspects of the optical collimation instrument. Especially under the swaying base of the ship, the accuracy of the optical calibration method is difficult to guarantee, and it has strict requirements on weather, hydrology, hull stability and other conditions. The calibration scheme has a simple operation process and strong field applicability. Especially when it is necessary to calibrate the installation deflection angle between multiple systems, the calibration scheme can obtain the calibration results at the same time, realize the integrated calibration of the installation deflection angle between multiple inertial navigation systems, and save the complicated operation caused by the multiple replacement of the collimation target system for optical aiming, and does not require each inertial navigation system to be equipped with a collimation prism or a plane mirror, thereby reducing the cost of a single system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a schematic diagram of the external field calibration method for installation deflection angles between multiple inertial navigation systems of the present invention (two sets are used as an example for explanation).

[0041] Figure 2 This is the simulation result of the deflection angle convergence curve of the self-aligned three-dimensional platform of the No. 1 inertial navigation system RINS1.

[0042] Figure 3 This is the simulation result of the deflection angle convergence curve of the self-aligned three-dimensional platform of the No. 2 inertial navigation system RINS2. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] The present invention provides a method for calibrating the installation deflection angle between multiple inertial navigation systems in an out-of-field manner. First, the self-alignment error caused by the random error of inertial devices including gyro drift and random walk has the random characteristics, so that each inertial navigation system performs multiple groups of self-alignments respectively, and each group of self-alignment heading angles of each inertial navigation system is converted into a corresponding attitude matrix respectively, and the attitude matrix between each inertial navigation system is calculated and then the installation deflection angle between each inertial navigation system is inversely solved; finally, the installation deflection angle between each group of inertial navigation systems is averaged as the final calibration result of the installation deflection angle between each group of inertial navigation systems. The multi-group averaging method reduces the self-alignment error of the inertial navigation system, improves the calibration accuracy of the installation deflection angle between each group of inertial navigation systems, and provides a method for selecting the number of self-alignment groups and the duration of a single self-alignment. Based on the above principle, a simulation experiment is designed to perform simulation analysis and verification on the method for calibrating the installation deflection angle between multiple inertial navigation systems proposed by the present invention.

[0045] The method for selecting the number of self-alignment groups and the duration of a single self-alignment of each inertial navigation system is as follows:

[0046] When the inertial navigation system is a rotation modulation inertial navigation system, in the continuous rotation alignment mode, the system initial alignment heading error caused by random walk is inversely proportional to the square root of time, and the formula is as follows:

[0047]

[0048] Among them, δφ U-ARW is the system initial alignment heading error caused by random walk, RWC E is the angle random walk coefficient of the equivalent east-pointing gyro, T is the single self-alignment time of the system, ω e is the angular velocity of the earth's rotation, and L is the latitude of the system.

[0049] Assuming that the number of self-alignment groups of a single inertial navigation system is N, after averaging the results of multiple self-alignment for each N groups, the standard deviation of the system's initial alignment heading error is The expression is as follows:

[0050]

[0051] Among them, δφ U-ARW is the system's single initial alignment heading error caused by random walk, is the average heading error of the system caused by random walk for multiple initial alignments, RWC E is the angle random walk coefficient of the equivalent east-pointing gyro, T is the single self-alignment time of the system, N is the number of self-alignment groups of a single inertial navigation system, ω e is the angular velocity of the earth’s rotation, L is the latitude of the system, and std(·) represents the standard deviation of the variable.

[0052] From equations (1) to (2), we can see that the longer the single self-alignment time is, the smaller the system initial alignment heading error caused by random walk is; increasing the number of system self-alignment groups N and averaging multiple self-alignments is beneficial to reducing the self-alignment error of each system. Therefore, increasing the single alignment time and increasing the number of system self-alignment groups N are both beneficial to improving the calibration accuracy of the installation deflection angle between systems.

[0053] It should be pointed out that in engineering practice, the initial alignment error caused by random walk is not significantly improved as the alignment time increases, and the compensation residual caused by the time-varying characteristics of the relevant error parameters during the alignment, as well as non-self-alignment errors such as the grating angle measurement temperature term, the shock absorber deformation temperature term, and the shaft clearance eddy compensation residual in the rotary modulation inertial navigation, and environmental interference errors such as shaking gradually become prominent. Generally speaking, the error parameters included in the precise alignment model can be estimated and compensated more accurately by extending the alignment time to reduce their impact on the system alignment accuracy, and the non-self-alignment error parameters can be suppressed by averaging multiple groups. Therefore, the total time t for installing the deflection calibration between the systems is Calib =N·T is constant, for different application scenarios, a better calibration solution can be obtained by reasonably matching the number of system self-alignment groups N and the single self-alignment time T.

[0054] like Figure 1 As shown in the figure, taking two sets of rotation modulation inertial navigation as an example, including No. 1 inertial navigation system RINS1, No. 2 inertial navigation system RINS2, O-ENU coordinate system is the navigation coordinate system n, OX b1 Y b1 Z b1 The coordinate system is the No. 1 inertial navigation system carrier coordinate system b1 system, OX b2 Y b2 Z b2 The coordinate system is the No. 2 inertial navigation system carrier coordinate system b2 system, Δθ 21 is the final calibrated pitch installation angle between the No. 1 INS and the No. 2 INS, Δγ 21 is the final calibrated roll installation deflection angle between the No. 1 INS and the No. 2 INS, Δψ 21 It is the final calibrated heading installation deflection angle between INS 1 and INS 2. The establishment and meaning of the above coordinate system and related symbols help to clearly reveal the physical meaning of the installation deflection angle between INS 1 and INS 2.

[0055] The method for calibrating the installation deflection angle between multiple inertial navigation systems of the present invention specifically comprises the following steps:

[0056] Step 1: Construct a model of inertial device drift. Gyro drift and acceleration bias have slow-changing characteristics. In order to improve the monitoring accuracy of long-duration device drift, gyro drift and acceleration bias are established as a comprehensive model of random constant, first-order Markov and Gaussian white noise. The constructed inertial device drift model is as follows:

[0057]

[0058]

[0059] Among them, ε b , is the random constant drift of the gyro and the random constant zero bias of the accelerometer, which changes with the successive startups of the inertial navigation system. r , is a first-order Markov process, which is used to accurately describe the slow-changing characteristics of gyro drift and accelerometer bias. G , τ A is the correlation time of the first-order Markov process; w gr 、w ar is the white noise of the gyroscope and accelerometer in the first-order Markov process, w g 、w a is the Gaussian white noise of the gyroscope and accelerometer.

[0060] Step 2: Each inertial navigation system is initially aligned, which specifically includes the following steps:

[0061] 2.1 The No. 1 inertial navigation system RINS1 and No. 2 inertial navigation system RINS2 rotate forward and reverse around the azimuth axis at 6° / s relative to the shell for rough alignment;

[0062] 2.2 During the precise alignment, the platform rotates forward and reversely around the azimuth axis at 6° / s relative to the geographic system to perform precise alignment using the compass method.

[0063] 2.3 Precision alignment end time using the east, north, and celestial platform deflection angles φ E ,φ N ,φ U Correct the attitude matrix at the end of the fine alignment After that, the pitch angle θ, roll angle γ, and heading angle ψ of the carrier are calculated as follows:

[0064]

[0065]

[0066]

[0067] Step 3: Calculate the installation deflection between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2:

[0068] The calculation method is explained by taking the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 as examples. The calculation methods for the installation deflection angles between the other systems are the same.

[0069] The pitch angle, roll angle and heading angle of the i-th initial alignment of the No. 1 inertial navigation system RINS1 are:

[0070] θ 1i , γ 1i , 1i (i=1,2,3...N)

[0071] The pitch angle, roll angle and heading angle of the i-th initial alignment of the No. 2 inertial navigation system RINS2 are:

[0072] θ 2i , γ 2i , 2i (i=1,2,3...N)

[0073] The attitude matrix from the carrier coordinate systems b1 and b2 of the No. 1 INS and No. 2 INS to the navigation coordinate system n is calculated as follows:

[0074]

[0075]

[0076] The attitude matrix between the No. 1 inertial navigation system carrier b1 and the No. 2 inertial navigation system carrier b2 is as follows:

[0077]

[0078] in, is the attitude matrix of the carrier coordinate system b1 to the navigation coordinate system n of the ith alignment of the No. 1 inertial navigation, is the attitude matrix between the carrier coordinate system b2 and the navigation coordinate system n for the i-th alignment of the No. 2 inertial navigation.

[0079] The installation deflection angle between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 calibrated for the i-th time is:

[0080]

[0081] in, is the attitude matrix from the No. 1 inertial navigation system carrier b1 to the No. 2 inertial navigation system carrier b2, Indicates taking The element corresponding to the 3rd row and 2nd column in the matrix, and so on; arcsin(·) represents the inverse sine operation, and arctan(·) represents the inverse tangent operation.

[0082] The average value of the N-times installation deflection calibration between the systems is used as the final installation deflection of the pitch angle, roll angle, and heading angle between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2:

[0083]

[0084] Among them, Δθ 21_i is the pitch installation deflection angle between systems calibrated for the i-th time, Δγ 21_i is the inter-system roll installation deflection angle calibrated for the i-th time, Δψ 21_iis the heading installation deflection angle between systems calibrated for the i-th time. N is the number of self-alignment of a single inertial navigation system. ∑(·) is the summation operation. is the mean value of the pitch installation deflection angle between systems calibrated N times, is the average of the rolling installation deflection angles between the systems calibrated N times, It is the mean value of the heading installation deviation angle between systems calibrated N times.

[0085] The installation deflection mean matrix between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 is:

[0086]

[0087] In the fusion of heading and attitude information, the method for the No. 2 inertial navigation system RINS2 to align the initial heading and attitude with the No. 1 inertial navigation system RINS1 by compensating the calibrated inter-system installation deflection is as follows:

[0088]

[0089] in, The attitude matrix of the No. 2 INS after compensating the installation angle relative to the No. 1 INS. is the attitude matrix of the No. 2 inertial navigation system itself solved by strapdown, Install the deflection angle mean matrix between INS 1 and INS 2.

[0090] Step 4: design a simulation experiment to simulate and verify the external field calibration method based on the installation deflection angle between multiple inertial navigation systems proposed in the present invention.

[0091] The simulation experiment is carried out by taking the static base alignment of the land-based launch vehicle as an example. The initial longitude and latitude of the No. 1 and No. 2 inertial navigation systems are 116°E and 39.8°N. The relevant parameters of the inertial devices of the two inertial navigation systems are set as follows: the random constant drift of the gyro corresponding to the No. 1 inertial navigation system RINS1 is 0.001° / h, the first-order Markov process correlation time is 1h, and the random walk coefficient is The mean square error of white noise is 0.0003° / h; the zero bias of the added constant is 20μg, the random error is 2μg, the first-order Markov process correlation time is 1h, and the mean square error of white noise is 2μg. The corresponding gyro random constant drift of the No. 2 inertial navigation system RINS2 is 0.003° / h, the first-order Markov process correlation time is 0.5h, and the random walk coefficient is The white noise mean square error is 0.001° / h; the zero bias of the added constant is 50μg, the random error is 5μg, the first-order Markov process correlation time is 0.5h, and the white noise mean square error is 5μg. Both the No. 1 and No. 2 inertial navigation systems are finely aligned with the inner frame axis pointing to the sky at 6° / s continuous forward and reverse rotation, the alignment time is 10min, the number of alignment groups is 36, and the total calibration time for the installation deflection between the systems is set to: tCli =360min, the initial installation deflection angle is set to: [360″ 1080″ 3600″].

[0092] It should be noted that: in order to fully verify and evaluate the calibration effect, 36 sets of self-alignment simulations were performed on the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 respectively, and the maximum error of the installation deflection calibration result between the systems relative to its true value and its own repeatability were used for evaluation. Figure 1 The installation deflection angle between two inertial navigation systems is taken as an example to illustrate, and a schematic diagram of the installation deflection angle and a calibration calculation method are given, which are also applicable to the calibration of the installation deflection angle between multiple inertial navigation systems.

[0093] Figure 2 The simulation result of the deflection convergence curve of the self-aligned three-dimensional platform of the No. 1 inertial navigation system RINS1 is shown in Figure 1. It can be seen that the three-dimensional initial platform deflection estimated by the alignment filter converges quickly and has a better steady state.

[0094] Figure 3 The simulation results of the convergence curve of the self-aligned three-dimensional platform deflection angle of the No. 2 inertial navigation system RINS2 are shown in Figure 2. It can be seen that the convergence of the three-dimensional initial platform deflection angle estimated by the alignment filter is slower and has relatively large fluctuations compared to the No. 1 inertial navigation system RINS1, but its convergence and stability are still good overall.

[0095] Table 1 is a statistical table of the initial alignment simulation results of the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 of the present invention. 36 sets of self-alignment simulation results of the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 are given, and the subsequent calculation of the installation deflection angle between the systems and the evaluation of the calibration error are based on this data.

[0096] Table 2 is a statistical table of the calibration results of the installation deflection angle between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 of the present invention. It should be noted that the installation deflection angle between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 is calculated according to formulas (6-7) instead of directly making a difference based on the self-alignment attitude results of the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 in Table 1.

[0097] Table 3 is a statistical table of the calibration error of the installation deflection between the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 of the present invention. It should be noted that: in order to fully evaluate the effect of the inter-system installation deflection calibration method proposed in the present invention, the maximum error of the inter-system installation deflection calibration result relative to its true value and its own repeatability are used for evaluation. Based on Table 1, the maximum calibration error of the inter-system installation deflection relative to the true value of each 6 groups before averaging is calculated, and the maximum calibration error of the inter-system installation deflection relative to the true value is recalculated after averaging every 6 groups. It can be seen that after averaging, Δψ 21The maximum calibration error relative to the true value is reduced from 65.70″ to 30.21″, Δθ 21 , Δγ 21 The calibration errors before averaging are also improved. Based on the calculation of the maximum repeatability deviation of the installation angle between each 6 groups of systems before averaging in Table 1, and the maximum repeatability deviation of the installation angle between the systems after averaging each 6 groups, it can be seen that after averaging, Δψ 21 The calibration repeatability deviation is reduced from 29.91″(1σ) to 11.07″(1σ), Δθ 21 , Δγ 21 The maximum calibration repeatability error before averaging has also been improved. And the difference between the two is about In summary, the field calibration method between multiple inertial navigation systems proposed in the present invention is effective.

[0098] Table 1

[0099]

[0100]

[0101] Table 2

[0102]

[0103]

[0104] Among them, the installation deflection angle between the systems is calculated from the self-alignment attitude results of the No. 1 inertial navigation system RINS1 and the No. 2 inertial navigation system RINS2 in Table 1. It needs to be calculated according to formulas (6-7) instead of directly making a difference.

[0105] Table 3

[0106]

[0107] It should be noted that the present invention uses the alignment simulation results of the rotation modulation type inertial navigation system to illustrate the effectiveness of the calibration scheme, but the calibration scheme is also applicable to the strapdown inertial navigation system.

[0108] In summary, the present invention proposes an off-field calibration method for installation deflection angles between multiple inertial navigation systems. The system self-alignment error is reduced by averaging the installation deflection angles of multiple groups of self-alignment calculations of each system, and the pure inertial high-precision calibration of the installation deflection angles between systems is achieved. This is of great significance to the research on the networking fusion of multi-inertial navigation attitude information, and the high-precision attitude information transmission and alignment of the master and slave inertial navigation.

[0109] Parts of the present invention that are not disclosed in detail belong to the common knowledge in the art.

[0110] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A method for calibrating the installation angle of multiple inertial navigation systems in an external field, characterized in that: The calibration results are obtained at the same time to achieve integrated high-precision calibration of the installation deflection angles between multiple inertial navigation systems, including: first, the self-alignment error caused by the random error of inertial devices including gyro drift and random walk has random characteristics, and each set of inertial navigation systems is designed to perform multiple groups of self-alignment, and each set of self-alignment heading angles of each set of inertial navigation systems is converted into a corresponding attitude matrix, and the attitude matrix between each inertial navigation system is calculated and then the installation deflection angle between each inertial navigation system is inversely solved; finally, the installation deflection angles between each set of inertial navigation systems are averaged as the final calibration result of the installation deflection angles between each set of inertial navigation systems. The multi-group averaging method reduces the self-alignment error of the inertial navigation system and improves the calibration accuracy of the installation deflection angles between each set of inertial navigation systems, and a method for selecting the number of self-alignment groups and the duration of a single self-alignment is given; The method for selecting the number of self-alignment groups and the duration of a single self-alignment of each inertial navigation system is as follows: When the inertial navigation system is a rotation modulation inertial navigation system, in the continuous rotation alignment mode, the system initial alignment heading error caused by random walk is inversely proportional to the square root of time, and the formula is as follows: (1) in, is the system initial alignment heading error caused by random walk, is the angle random walk coefficient of the equivalent east-pointing gyroscope, T is the single self-alignment time of the system, is the angular velocity of the earth's rotation, L is the latitude of the system; Assuming that the number of self-alignment groups of a single inertial navigation system is N, after averaging the results of multiple self-alignment for each N groups, the standard deviation of the system's initial alignment heading error is , the expression is as follows: (2) in, is the system's single initial alignment heading error caused by random walk, is the average heading error of the system caused by random walk during multiple initial alignments, is the angle random walk coefficient of the equivalent east-pointing gyro, T is the single self-alignment time of the system, N is the number of self-alignment groups of a single inertial navigation system, is the angular velocity of the earth's rotation, L is the latitude of the system, Represents the standard deviation of the variable.

2. The method for calibrating the installation deflection angle between multiple inertial navigation systems according to claim 1 is characterized in that: The calculation method of the installation deflection angle between the inertial navigation systems is as follows: The two inertial navigation systems are marked as inertial navigation system No. 1 RINS1 and inertial navigation system No. 2 RINS2; The pitch angle, roll angle and heading angle of the i-th initial alignment of the No. 1 inertial navigation system RINS1 are: The pitch angle, roll angle and heading angle of the i-th initial alignment of the No. 2 inertial navigation system RINS2 are: in, ; Carrier coordinate system of No. 1 inertial navigation system RINS1 and No. 2 inertial navigation system RINS2 and The attitude matrix to the navigation coordinate system n is calculated as follows: (3) (4) No. 1 inertial navigation system carrier coordinate system To the No. 2 inertial navigation system carrier coordinate system The posture matrix between them is as follows: (5) in, The carrier coordinate system for the i-th alignment of the No. 1 inertial navigation To the attitude matrix of navigation coordinate system n, The carrier coordinate system for the i-th alignment of the No. 2 inertial navigation The attitude matrix between the navigation coordinate system n; The installation deflection angle between systems calibrated for the i-th time is: (6) in, For the No. 1 inertial navigation system To the No. 2 inertial navigation system The posture matrix between Indicates taking The element corresponding to the 3rd row and 2nd column in the matrix, and so on; represents the inverse sine operation, Represents the inverse tangent operation; is the pitch installation deflection angle between systems calibrated for the i-th time, is the inter-system roll installation deflection angle calibrated for the i-th time, is the heading installation deflection angle between systems calibrated for the i-th time; N is the number of self-alignment of a single inertial navigation system; The average value of the N-times installation deflection calibration between inertial navigation systems is taken as the final installation deflection between systems: (7) in, is the mean value of the pitch installation deflection angle between systems calibrated N times, is the average of the rolling installation deflection angles between systems calibrated N times, is the mean value of the heading installation deflection angle between systems calibrated N times; The mean value matrix of the installation deflection angle between inertial navigation systems is: (8) In the fusion of heading and attitude information, the method for the No. 2 inertial navigation system RINS2 to align the initial heading and attitude with the No. 1 inertial navigation system RINS1 by compensating the calibrated inter-system installation deflection is as follows: (9) in, The attitude matrix of the No. 2 INS after compensating the installation angle relative to the No. 1 INS. is the attitude matrix of the No. 2 inertial navigation system itself solved by strapdown, Install the deflection angle mean matrix between INS 1 and INS 2.

Images