Calibration method for main parameters of optical strapdown inertial navigation system

Abstract

The invention discloses a method for calibrating main parameters of an optical strapdown inertial navigation system, which comprises the following steps: mounting an inertial navigation component on a double-shaft turntable, and carrying out multi-direction reference adjustment on the position of the turntable; adjusting a machine body shaft to a WSU direction, rotating a rotary table azimuth shaft by 180 degrees after rotating a navigation state for 20 seconds, and calculating and correcting accelerometer zero constant values of an X axis and a Y axis; adjusting the body shaft to the DES direction, rotating the azimuth axis of the turntable around the W direction by 180 degrees after rotating the navigation state for 20 seconds, calculating the zero constant value of the accelerometer of the Z axis and correcting the zero constant value; adjusting an airframe shaft to a WSU direction, calculating gyroscopic drift values of a Y axis and a Z axis, adjusting the airframe shaft to an NWU direction, calculating a gyroscopic drift value of an X axis, and correcting a gyroscopic scale coefficient of a corresponding axial direction; and adjusting the environment temperature of the rotary table to a preset range, calculating gyroscopic drift values, accelerometer zero correction values and meter scale coefficient correction values corresponding to the X axis, the Y axis and the Z axis, and performing fitting compensation so as to ensure that the system can output high-precision parameter information.

Description

Technical Field

[0001] The present application relates to the field of Monte Carlo calibration methods, and specifically to a calibration method for the main parameters of an optical strapdown inertial navigation system. Background Art

[0002] Strapdown inertial navigation systems (SINs) have become the primary navigational aid for aircraft, providing information such as acceleration, velocity, position, heading, and attitude. These systems utilize a rigid connection method to internally mount sensitive components (gyroscopes and accelerometers). This significantly increases computational complexity and places higher precision demands on these components.

[0003] Because the operating environment of the vehicle in which the system operates varies widely, the system itself and its sensitive components are affected by environmental changes such as temperature. Furthermore, they are subject to parameter drift and accuracy degradation over time. Therefore, a calibration method is needed to ensure that the system outputs high-precision parameter information during operation. Summary of the Invention

[0004] The purpose of this application is to provide a calibration method for the main parameters of an optical strapdown inertial navigation system to ensure that the strapdown inertial navigation system outputs high-precision parameter information during operation.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] A method for calibrating main parameters of an optical strapdown inertial navigation system, comprising:

[0007] Mounting the inertial navigation component on a dual-axis turntable and performing multi-directional reference adjustment on the turntable position;

[0008] Adjust the body axis to the WSU direction, switch to the navigation state for 20 seconds, rotate the turntable azimuth axis 180°, calculate the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes, and correct them; adjust the body axis to the DES direction, switch to the navigation state for 20 seconds, rotate the turntable azimuth axis 180° around the W direction, calculate the second north acceleration error, and the accelerometer zero constant of the Z axis, and correct them;

[0009] Adjust the body axis to the WSU direction, calculate the gyro drift values ​​of the Y and Z axes, adjust the body axis to the NWU direction, calculate the gyro drift value of the X axis, and based on the gyro drift values ​​of the X, Y, and Z axes, correct the gyro scale coefficients of the corresponding axes;

[0010] The turntable ambient temperature is adjusted to a preset range, the body axis position is adjusted to multiple preset directions, and the corresponding preset formulas are used to calculate the gyro drift value, accelerometer zero correction value, and accelerometer scale factor correction value corresponding to the X, Y, and Z axes, and perform fitting compensation;

[0011] Among them, WSUEND are west, south, sky, east, north, and earth directions respectively, and the azimuth axis is the axis pointing to the U direction.

[0012] Optionally, calculating the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes and correcting them includes: using a first target formula to calculate the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes and correcting them, wherein the first target formula includes:

[0013]

[0014] in, Represent the acceleration errors in the east and north directions, V e2 、V e1 Represents the eastward velocity 10 seconds before and after; V n2 、V n1 They represent the northward velocity 10 seconds before and after respectively;

[0015] according to Calculate the accelerometer zero constant δ for the X and Y axes respectively x , δ y :

[0016]

[0017] Calculate δ based on the actual number of tests x , δ y Average value And correct the corresponding zero constant:

[0018]

[0019] The calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis includes: calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis using a second target formula, wherein the second target formula includes:

[0020]

[0021] in, Indicates the second north acceleration error, V n2 、V n1 Represents the northward speed 10 seconds before and after, according to Calculate the Z accelerometer constant zero position δ respectively z And make compensation:

[0022]

[0023] Calculate δ based on the actual number of tests z Average value And correct the corresponding zero constant:

[0024]

[0025] Among them, delta_x0 is the X-axis gyro drift constant, delta_y0 is the X-axis gyro drift constant, and delta_z0 is the X-axis gyro drift constant.

[0026] Optionally, calculating the gyro drift values ​​of the Y and Z axes and calculating the gyro drift value of the X axis includes:

[0027] When the body axis is adjusted to the WSU direction, record the gyro drift value D y 、D z , calculate D according to the actual number of tests y 、D z Average value And correct the corresponding gyro drift constant value:

[0028]

[0029] When the body axis is adjusted to the NWU direction, record the gyro drift value D X , calculate D according to the actual number of tests X Average value And correct the corresponding gyro drift constant value:

[0030]

[0031] Where drift_y0 is the y-axis gyro drift constant, drift_z0 is the z-axis gyro drift constant, and drift_x0 is the x-axis gyro drift constant.

[0032] Optionally, the correcting the gyro scale coefficients of the corresponding axes based on the gyro drift values ​​of the X, Y, and Z axes includes:

[0033] After adjusting the inertial guidance component body axis to WSU, rotate the inertial guidance component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ θ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ θ- , calculate and correct K_gxz and K_gxf according to the following formula:

[0034]

[0035] After adjusting the inertial navigation component body axis to NWU, rotate the inertial navigation component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ γ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ γ- , calculate and correct K_gyz and K_gyf according to the following formula:

[0036]

[0037] After adjusting the inertial navigation component body axis to WSU, rotate the inertial navigation component around U at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ φ+ , rotate the inertial navigation component around D at an angular velocity ω for n times to calculate δ φ- , calculate and correct K_gzz, K_gzf according to the following formula:

[0038]

[0039]

[0040] Among them, K_gxz is the positive scale coefficient of the X-axis gyro, K_gxf is the negative scale coefficient of the X-axis gyro, K_gyz is the positive scale coefficient of the Y-axis gyro, K_gyf is the negative scale coefficient of the Y-axis gyro, K_gzz is the positive scale coefficient of the Z-axis gyro, K_gzf is the negative scale coefficient of the Z-axis gyro, δ θ+ Indicates the output angle difference when the pitch is in the positive direction, δ θ- Indicates the output angle difference when the pitch is in the negative direction, δ γ+ Indicates the output angle difference when the roll is in the positive direction, δ γ- Indicates the output angle difference when the roll is in the negative direction, δ φ+ Indicates the output angle difference when the heading is in positive motion, δ φ- Indicates the output angle difference when the heading is in negative direction, and n is the number of rotations.

[0041] Optionally, the calculation of the gyro drift values, accelerometer zero correction values, and accelerometer scale factor correction values ​​corresponding to the X, Y, and Z axes using corresponding preset formulas includes:

[0042] After adjusting the body axis to WSU, rotate the turntable 180° to WNU. After the turntable is in place, measure H, Dy, and Dz 20 seconds later, and calculate Dx and

[0043] Dx=sign(sin((H avg+45)*π / 180*(HH avg ) / 14.6))

[0044]

[0045] Among them, H is the heading value, H avg is the average heading value of this drift test, is the acceleration error in the east and north directions, is the accelerometer zero correction;

[0046] After adjusting the coordinate system to DES, test γ, H2, Rotate the turntable 180° around E to the UWN position, and test after the turntable stabilizes for 20 seconds.

[0047]

[0048] Among them, γ and H2 are the roll angle and heading angle after navigation, is the X-axis scale factor correction, is the north acceleration error, is the error of the celestial acceleration corresponding to the X-axis pointing to the ground, is the error of the celestial acceleration corresponding to the X-axis pointing upward;

[0049] Adjust the coordinate system to WUN and test Then rotate the turntable 180° around E to the WDS position and wait for the turntable to stabilize for 20 seconds before testing. and

[0050]

[0051] in, is the Y-axis scale factor correction value, is the error of the celestial acceleration corresponding to the Y-axis pointing upward, The error of the Y-axis celestial acceleration corresponding to the ground;

[0052] After adjusting the coordinate system to WND, test Then rotate the turntable 180° around E to the WSU position and wait for the turntable to stabilize for 20 seconds before testing. and

[0053]

[0054] in, is the Z-axis scale factor correction, is the error of the celestial acceleration corresponding to the Z axis pointing to the ground, It is the error of the celestial acceleration corresponding to the Z-axis pointing upward.

[0055] Optionally, performing fitting compensation on the gyro drift value, the accelerometer zero correction value, and the accelerometer scale factor correction value includes:

[0056] Use the gyro drift value fitting formula to fit the compensation:

[0057]

[0058] Use the accelerometer zero correction fitting formula to fit the compensation:

[0059]

[0060]

[0061] Use the calibration coefficient correction fitting formula to fit the compensation:

[0062]

[0063] Among them, T_G X _nn(N) is the new x-axis gyro drift temperature compensation coefficient, T_G X _nn(O) is the original x-axis gyro drift temperature compensation coefficient, T_A X _nn(N) is the new x-axis accelerometer zero temperature compensation coefficient, T_A X _nn(O) is the original x-axis accelerometer zero temperature compensation coefficient, T_KA x _nn(N) is the new x-axis accelerometer scale factor, T_KA x _nn(O) is the original x-axis accelerometer scale factor.

[0064] Optionally, the step of mounting the inertial navigation component on a dual-axis turntable and performing multi-directional reference adjustment on the position of the turntable includes:

[0065] Mount the inertial navigation component on a dual-axis turntable and turn the body axis toward ENU. Calculate the average pulse number N of the Y accelerometer over 30 seconds. Y1 The turntable rotates 180° around the U axis to the WSU position, and the average pulse number N of the Y accelerometer in 30 seconds is calculated again. Y2 , calculate the horizontal deflection angle δ1 of the turntable, and correct the zero position parameters of the pitch axis turntable according to δ1:

[0066] δ1=(N Y2 -N Y1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0067] =(N Y2 -NY1 ) / 2*0.6″

[0068] Where: Ka = 3 × 10 -4 m / s / n, repeat this step until δ1≤1';

[0069] Point the body axis toward EDN and calculate the average pulse number N of the X accelerometer for 30 seconds. X1 , rotate 180° around the turntable azimuth axis to the WUN position, and calculate the average pulse number N of the X accelerometer for 30 seconds again X2 , calculate the azimuth deflection angle δ2 of the X accelerometer sensitive axis, and adjust the turntable spindle zero position correction parameters according to δ2:

[0070] δ2=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0071] =(N X2 -N X1 ) / 2*0.6″

[0072] Where: Ka = 3 × 10 -4 m / s / n;

[0073] After the reference position adjustment is completed, the initial position is set as ENU, and other positions are determined based on it;

[0074] Adjust the turntable to a horizontal position with the body axis pointing to ENU, and calculate the average number of pulses N for X plus 30s. X1 , the turntable azimuth axis rotates 180° to the WSU position, and calculates X again plus the average pulse number N for 30 seconds X2 , calculate the eastward horizontal δ3 of the turntable:

[0075] δ3=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0076] =(N X2 -N X1 ) / 2*0.6″

[0077] Where: Ka = 3 × 10 -4 m / s / n, δ3≤1'.

[0078] Compared with the prior art, the present invention has the following advantages:

[0079] By utilizing hardware resources such as a turntable and temperature control, the working state and signal output of the optical strapdown inertial navigation system in a real working environment are simulated. On the basis of conventional calibration, the errors caused by the calibration equipment, temperature changes, and the polarity of sensitive components are taken into account. On the basis of separately correcting the key calibration parameters, various calibration parameters are compensated to achieve high-precision calibration, which can greatly improve the accuracy of the optical strapdown inertial navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 This is a flow chart of a method for calibrating the main parameters of an optical strapdown inertial navigation system according to the present application. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0082] As mentioned in the background of this application, due to the wide range of variations in the operating environment of the vehicle in which the system is located, the system itself and its sensitive components are affected by environmental changes such as temperature. On the other hand, they themselves have the characteristics of parameter drift and accuracy degradation over time, making it impossible to guarantee the output accuracy of parameter information. To address the above-mentioned shortcomings, this application discloses a method for calibrating the main parameters of an optical strapdown inertial navigation system to ensure that the strapdown inertial navigation system outputs high-precision parameter information during operation.

[0083] It should be noted that the calibration coordinate system in the embodiment of the present application is a right-hand horizontally mounted system, and the coordinate system abbreviations are: East (E), South (S), West (W), North (N), and Sky (U), and the azimuth axis is the axis pointing to the U direction. The calibration method of the present application can be calibrated using debugging software. Before calibration, the system can be prepared for calibration, for example: power-on check of the system: place the three axes of the system flat on the operating table according to the positions of "West (W), South (S), Sky (U)", connect the cables, and power on for use after checking that they are correct; check the output parameters: check the output pulses of the X and Y axis accelerometers, which should be within the range of (-5000 ~ 5000), and the output pulse of the Z axis accelerometer should be within the range of (200000 ~ 500000). In this embodiment: ENU means: Northeast Sky, WSU means Southwest Sky, UEN means Northeast Sky, EDN means East Earth North, EUS means East Earth South, and DES means Southeast Earth.

[0084] The following will describe in detail how the solution of this application solves the above technical problems with reference to the accompanying drawings.

[0085] See also Figure 1 In an embodiment of the present application, a method for calibrating the main parameters of an optical strapdown inertial navigation system includes:

[0086] S101: Install the inertial navigation component on a dual-axis turntable, and perform multi-directional reference adjustment on the position of the turntable.

[0087] It is understood that before calibrating the main parameters of the inertial navigation system, the system can be calibrated, that is, the turntable position can be adjusted in multiple directions. For example, in one implementation, the inertial navigation component is installed on a dual-axis turntable, and the turntable position can be adjusted in multiple directions.

[0088] Mount the inertial navigation component on a dual-axis turntable and turn the body axis toward ENU. Calculate the average pulse number N of the Y accelerometer over 30 seconds. Y1 The turntable rotates 180° around the U axis to the WSU position, and the average pulse number N of the Y accelerometer in 30 seconds is calculated again. Y2 , calculate the horizontal deflection angle δ1 of the turntable, and correct the zero position parameters of the pitch axis turntable according to δ1:

[0089] δ1=(N Y2 -N Y1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0090] =(N Y2 -N Y1 ) / 2*0.6″

[0091] Where: Ka = 3 × 10 -4 m / s / n, repeat this step until δ1≤1';

[0092] Point the body axis toward EDN and calculate the average pulse number N of the X accelerometer for 30 seconds. X1 , rotate 180° around the turntable azimuth axis to the WUN position, and calculate the average pulse number N of the X accelerometer for 30 seconds again X2 , calculate the azimuth deflection angle δ2 of the X accelerometer sensitive axis, and adjust the turntable spindle zero position correction parameters according to δ2:

[0093] δ2=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0094] =(N X2 -N X1 ) / 2*0.6″

[0095] Where: Ka = 3 × 10 -4 m / s / n;

[0096] After the reference position adjustment is completed, the initial position is set as ENU, and other positions are determined based on it;

[0097] Adjust the turntable to a horizontal position with the body axis pointing to ENU, and calculate the average number of pulses N for X plus 30s. X1 , the turntable azimuth axis rotates 180° to the WSU position, and calculates X again plus the average pulse number N for 30 seconds X2 , calculate the eastward horizontal δ3 of the turntable:

[0098] δ3=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600

[0099] =(N X2 -N X1 ) / 2*0.6″

[0100] Where: Ka = 3 × 10 -4 m / s / n, requiring δ3≤1'.

[0101] S102. Adjust the aircraft body axis to the WSU direction. After switching to the navigation state for 20 seconds, rotate the turntable azimuth axis 180°. Calculate the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes, and correct them. Adjust the aircraft body axis to the southeast of the DES direction. After switching to the navigation state for 20 seconds, rotate the turntable azimuth axis 180° about the W direction. Calculate the second north acceleration error and the accelerometer zero constant of the Z axis, and correct them.

[0102] Exemplarily, in one implementation, calculating and correcting the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes, includes: calculating and correcting the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes using a first target formula, wherein the first target formula includes:

[0103]

[0104] in, Represent the acceleration errors in the east and north directions, V e2 、V e1 Respectively represent the eastward velocity 10 seconds before and after; V n2 、V n1 They represent the northward velocity 10 seconds before and after respectively;

[0105] according to Calculate the accelerometer zero constant δ for the X and Y axes respectively x , δ y :

[0106]

[0107] Calculate δ based on the actual number of tests x , δ y Average value And correct the corresponding zero constant:

[0108]

[0109] The calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis includes: calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis using a second target formula, wherein the second target formula includes:

[0110]

[0111] in, Indicates the second north acceleration error, V n2 、V n1 Represents the northward speed 10 seconds before and after, according to Calculate the Z accelerometer constant zero position δ respectively z And make compensation:

[0112]

[0113] Calculate δ based on the actual number of tests z Average value And correct the corresponding zero constant:

[0114]

[0115] Among them, delta_x0 is the X-axis gyro drift constant, delta_y0 is the X-axis gyro drift constant, and delta_z0 is the X-axis gyro drift constant.

[0116] Among them, after the correction is completed, the test results should meet the debugging index requirements in Table 1.

[0117] Table 1

[0118]

[0119] S103, adjust the body axis to the WSU direction for alignment, and record the gyro drift value D when the alignment is completed. y 、D z , calculate D according to the actual number of tests y 、D z Average value And correct the corresponding gyro drift constant value:

[0120]

[0121] Adjust the body axis to the WSU direction for alignment, and record the gyro drift value D at the end of alignment. X , repeat the operation appropriately and calculate D according to the actual number of tests X The average value D X And correct the corresponding gyro drift constant value:

[0122]

[0123] Where drift_y0 is the y-axis gyro drift constant, drift_z0 is the z-axis gyro drift constant, and drift_x0 is the x-axis gyro drift constant.

[0124] Exemplarily, based on the gyro drift values ​​of the X, Y, and Z axes, correcting the gyro scale coefficients of the corresponding axes may include:

[0125] After adjusting the inertial guidance component body axis to WSU, rotate the inertial guidance component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ θ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ θ- , calculate and correct K_gxz and K_gxf according to the following formula:

[0126]

[0127] After adjusting the inertial navigation component body axis to NWU, rotate the inertial navigation component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ γ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ γ- , calculate and correct K_gyz and K_gyf according to the following formula:

[0128]

[0129] After adjusting the inertial navigation component body axis to WSU, rotate the inertial navigation component around U at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ φ+ , rotate the inertial navigation component around D at an angular velocity ω for n times to calculate δ φ- , calculate and correct K_gzz, K_gzf according to the following formula:

[0130]

[0131] Among them, K_gxz is the positive scale coefficient of the X-axis gyro, K_gxf is the negative scale coefficient of the X-axis gyro, K_gyz is the positive scale coefficient of the Y-axis gyro, K_gyf is the negative scale coefficient of the Y-axis gyro, K_gzz is the positive scale coefficient of the Z-axis gyro, K_gzf is the negative scale coefficient of the Z-axis gyro, δ θ+ Indicates the output angle difference when the pitch is in the positive direction, δ θ- Indicates the output angle difference when the pitch is in the negative direction, δ γ+ Indicates the output angle difference when the roll is in the positive direction, δ γ- Indicates the output angle difference when the roll is in the negative direction, δ φ+ Indicates the output angle difference when the heading is in positive motion, δ φ- Indicates the output angle difference when the heading is in negative direction, and n is the number of rotations.

[0132] Among them, the above corrections should meet the debugging indicators in Table 2:

[0133] Table 2

[0134]

[0135] S104: Adjust the ambient temperature of the turntable to a preset range, adjust the body axis position to multiple preset directions, and use corresponding preset formulas to calculate the gyro drift values, accelerometer zero correction values, and accelerometer scale factor correction values ​​corresponding to the X, Y, and Z axes, and perform fitting compensation;

[0136] In this embodiment, the system is turned on after being kept warm for 2 hours at a temperature range of -50°C. When the temperature rises to 75°C, the system is turned off. The temperature drift rotation scheme is shown in Table 3:

[0137] Table 3

[0138]

[0139] Exemplarily, the corresponding preset formulas are used to calculate the gyro drift values, accelerometer zero correction values, and accelerometer scale factor correction values ​​corresponding to the X, Y, and Z axes, including:

[0140] After adjusting the body axis to WSU, rotate the turntable 180° to WNU. After the turntable is in place, measure H, Dy, and Dz 20 seconds later, and calculate Dx and

[0141] Dx=sign(sin((H avg +45)*π / 180*(HH avg ) / 4.6))

[0142]

[0143] Among them, H is the heading value, Havg is the average heading value of this drift test, is the acceleration error in the east and north directions, is the accelerometer zero correction;

[0144] After adjusting the coordinate system to DES, test γ, H2, Rotate the turntable 180° around E to the UWN position, and test after the turntable stabilizes for 20 seconds.

[0145]

[0146] Among them, γ and H2 are the roll angle and heading angle after navigation, is the X-axis scale factor correction, is the north acceleration error, is the error of the celestial acceleration corresponding to the X-axis pointing to the ground, is the error of the celestial acceleration corresponding to the X-axis pointing upward;

[0147] Adjust the coordinate system to WUN and test Then rotate the turntable 180° around E to the WDS position and wait for the turntable to stabilize for 20 seconds before testing. and

[0148]

[0149] in, is the Y-axis scale factor correction value, is the error of the celestial acceleration corresponding to the Y-axis pointing upward, The error of the Y-axis celestial acceleration corresponding to the ground;

[0150] After adjusting the coordinate system to WND, test Then rotate the turntable 180° around E to the WSU position and wait for the turntable to stabilize for 20 seconds before testing. and

[0151]

[0152] in, is the Z-axis scale factor correction, is the error of the celestial acceleration corresponding to the Z axis pointing to the ground, It is the error of the celestial acceleration corresponding to the Z-axis pointing upward.

[0153] Exemplarily, in one implementation, performing fitting compensation on the gyro drift value, the accelerometer zero correction value, and the accelerometer scale factor correction value includes:

[0154] Use the gyro drift value fitting formula to fit the compensation:

[0155]

[0156] Use the accelerometer zero correction fitting formula to fit the compensation:

[0157]

[0158] Use the calibration coefficient correction fitting formula to fit the compensation:

[0159]

[0160] Among them, T_G X _nn(N) is the new x-axis gyro drift temperature compensation coefficient, T_G X _nn(O) is the original x-axis gyro drift temperature compensation coefficient, T_A X _nn(N) is the new x-axis accelerometer zero temperature compensation coefficient, T_A X _nn(O) is the original x-axis accelerometer zero temperature compensation coefficient, T_KA x _nn(N) is the new x-axis accelerometer scale factor, T_KA x _nn(O) is the original x-axis accelerometer scale factor.

[0161] After completing the above calculations, the system parameters are compensated. After the compensation is completed, the above process is calibrated. For example, the inertial navigation component is placed on a calibrated two-axis turntable and calibrated according to the rotation scheme in Table 4. The rotation angular velocity should be stable.

[0162] Table 4

[0163]

[0164]

[0165] The calibration test is used to determine the validity of the correction parameters. If the correction parameters do not meet the requirements, another calibration is performed. If the correction parameters meet the requirements, the system compensates for the corresponding parameters.

[0166] This application utilizes hardware resources such as a turntable and temperature control to simulate the operating conditions and signal output of an optical strapdown inertial navigation system in a real-world operating environment. Furthermore, it takes into account errors caused by calibration equipment, temperature variations, and polarity of sensitive components, based on conventional calibration. Furthermore, it compensates for each calibration parameter while individually correcting key calibration parameters, achieving high-precision calibration. This method can significantly improve the accuracy of optical strapdown inertial navigation systems and has broad application prospects in the field of calibration methods.

[0167] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0168] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and inventive concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.

Claims

1. A method for calibrating the main parameters of an optical strapdown inertial navigation system, characterized in that: include: Mounting the inertial navigation component on a dual-axis turntable and performing multi-directional reference adjustment on the turntable position; Adjust the body axis to the WSU direction, switch to the navigation state for 20 seconds, rotate the turntable azimuth axis 180°, calculate the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes, and correct them; adjust the body axis to the DES direction, switch to the navigation state for 20 seconds, rotate the turntable azimuth axis 180° around the W direction, calculate the second north acceleration error, and the accelerometer zero constant of the Z axis, and correct them; Adjust the body axis to the WSU direction, calculate the gyro drift values ​​of the Y and Z axes, adjust the body axis to the NWU direction, calculate the gyro drift value of the X axis, and based on the gyro drift values ​​of the X, Y, and Z axes, correct the gyro scale coefficients of the corresponding axes; The turntable ambient temperature is adjusted to a preset range, the body axis position is adjusted to multiple preset directions, and the corresponding preset formulas are used to calculate the gyro drift value, accelerometer zero correction value, and accelerometer scale factor correction value corresponding to the X, Y, and Z axes, and perform fitting compensation; Among them, WSUEND are west, south, sky, east, north, and earth directions respectively, and the azimuth axis is the axis pointing to the U direction.

2. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 1, wherein: The calculating and correcting the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes, includes: calculating the east acceleration error and the first north acceleration error, as well as the accelerometer zero constants of the X and Y axes and correcting them using a first target formula, wherein the first target formula includes: in, Represent the acceleration errors in the east and north directions, V e2 、V e1 Represents the eastward velocity 10 seconds before and after; V n2 、V n1 They represent the northward velocity 10 seconds before and after respectively; according to Calculate the accelerometer zero constant δ for the X and Y axes respectively x , δ y : Calculate δ based on the actual number of tests x , δ y Average value And correct the corresponding zero constant: The calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis includes: calculating and correcting the second north acceleration error and the accelerometer zero constant of the Z axis using a second target formula, wherein the second target formula includes: in, Indicates the second north acceleration error, V n2 、V n1 Represents the northward speed 10 seconds before and after, according to Calculate the Z accelerometer constant zero position δ respectively z And make compensation: Calculate δ based on the actual number of tests z Average value And correct the corresponding zero constant: Among them, delta_x0 is the X-axis gyro drift constant, delta_y0 is the X-axis gyro drift constant, and delta_z0 is the X-axis gyro drift constant.

3. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 1, wherein: The calculation of the gyro drift values ​​of the Y and Z axes and the calculation of the gyro drift value of the X axis includes: When the body axis is adjusted to the WSU direction, record the gyro drift value D y 、D z , calculate D according to the actual number of tests y 、D z Average value And correct the corresponding gyro drift constant value: When the body axis is adjusted to the NWU direction, record the gyro drift value D X , calculate D according to the actual number of tests X Average value And correct the corresponding gyro drift constant value: Where drift_y0 is the y-axis gyro drift constant, drift_z0 is the z-axis gyro drift constant, and drift_x0 is the x-axis gyro drift constant.

4. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 3, wherein: The method of correcting the gyro scale coefficients of the corresponding axes based on the gyro drift values ​​of the X, Y, and Z axes includes: After adjusting the inertial guidance component body axis to WSU, rotate the inertial guidance component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ θ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ θ- , calculate and correct K_gxz and K_gxf according to the following formula: After adjusting the inertial navigation component body axis to NWU, rotate the inertial navigation component around W at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ γ+ , rotate the inertial navigation component around E at an angular velocity ω for n times and then calculate δ γ- , calculate and correct K_gyz and K_gyf according to the following formula: After adjusting the inertial navigation component body axis to WSU, rotate the inertial navigation component around U at an angular velocity ω (20° / h≤ω≤200° / h) for n (10≤ω≤30) circles to calculate δ φ+ , rotate the inertial navigation component around D at an angular velocity ω for n times to calculate δ φ- , calculate and correct K_gzz, K_gzf according to the following formula: Among them, K_gxz is the positive scale coefficient of the X-axis gyro, K_gxf is the negative scale coefficient of the X-axis gyro, K_gyz is the positive scale coefficient of the Y-axis gyro, K_gyf is the negative scale coefficient of the Y-axis gyro, K_gzz is the positive scale coefficient of the Z-axis gyro, K_gzf is the negative scale coefficient of the Z-axis gyro, δ θ+ Indicates the output angle difference when the pitch is in the positive direction, δ θ- Indicates the output angle difference when the pitch is in the negative direction, δ γ+ Indicates the output angle difference when the roll is in the positive direction, δ γ- Indicates the output angle difference when the roll is in the negative direction, δ φ+ Indicates the output angle difference when the heading is in positive motion, δ φ- Indicates the output angle difference when the heading is in negative direction, and n is the number of rotations.

5. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 4, wherein: The corresponding preset formula is used to calculate the gyro drift value, accelerometer zero correction value, and accelerometer scale factor correction value corresponding to the X, Y, and Z axes, including: After adjusting the body axis to WSU, rotate the turntable 180° to WNU. After the turntable is in place, measure H, Dy, and Dz 20 seconds later, and calculate Dx and Dx=sign(sin((H avg +45)*π / 180*(H-H avg ) / 14.6)) Among them, H is the heading value, H avg is the average heading value of this drift test, is the acceleration error in the east and north directions, is the accelerometer zero correction; After adjusting the coordinate system to DES, test γ, H2, Rotate the turntable 180° around E to the UWN position, and test after the turntable stabilizes for 20 seconds. Among them, γ and H2 are the roll angle and heading angle after navigation, is the X-axis scale factor correction, is the north acceleration error, is the error of the celestial acceleration corresponding to the X-axis pointing to the ground, is the error of the celestial acceleration corresponding to the X-axis pointing upward; Adjust the coordinate system to WUN and test Then rotate the turntable 180° around E to the WDS position and wait for the turntable to stabilize for 20 seconds before testing. and in, is the Y-axis scale factor correction value, is the error of the celestial acceleration corresponding to the Y-axis pointing upward, The error of the Y-axis celestial acceleration corresponding to the ground; After adjusting the coordinate system to WND, test Then rotate the turntable 180° around E to the WSU position and wait for the turntable to stabilize for 20 seconds before testing. and in, is the Z-axis scale factor correction value, is the error of the celestial acceleration corresponding to the Z axis pointing to the ground, It is the error of the celestial acceleration corresponding to the Z-axis pointing upward.

6. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 5, wherein: The fitting compensation for gyro drift value, accelerometer zero correction value, and accelerometer scale factor correction value includes: Use the gyro drift value fitting formula to fit the compensation: Use the accelerometer zero correction fitting formula to fit the compensation: Use the calibration coefficient correction fitting formula to fit the compensation: Among them, T_G X _nn(N) is the new x-axis gyro drift temperature compensation coefficient, T_G X _nn(O) is the original x-axis gyro drift temperature compensation coefficient, T_A X _nn(N) is the new x-axis accelerometer zero temperature compensation coefficient, T_A X _nn(O) is the original x-axis accelerometer zero temperature compensation coefficient, T_KA x _nn(N) is the new x-axis accelerometer scale factor, T_KA x _nn(O) is the original x-axis accelerometer scale factor.

7. The method for calibrating the main parameters of an optical strapdown inertial navigation system according to claim 5, wherein: The inertial navigation component is mounted on a dual-axis turntable, and the turntable position is adjusted in multiple directions, including: Mount the inertial navigation component on a dual-axis turntable and turn the body axis toward ENU. Calculate the average pulse number N of the Y accelerometer over 30 seconds. Y1 The turntable rotates 180° around the U axis to the WSU position, and the average pulse number N of the Y accelerometer in 30 seconds is calculated again. Y2 , calculate the horizontal deflection angle δ1 of the turntable, and correct the zero position parameters of the pitch axis turntable according to δ1: δ1=(N Y2 -N Y1 ) / 2*(ka*0.1 / 9.8)*57.3*3600 =(N Y2 -N Y1 ) / 2*0.6″ Where: Ka = 3 × 10 -4 m / s / n, repeat this step until δ1≤1'; Point the body axis toward EDN and calculate the average pulse number N of the X accelerometer for 30 seconds. X1 , rotate 180° around the turntable azimuth axis to the WUN position, and calculate the average pulse number N of the X accelerometer for 30 seconds again X2 , calculate the azimuth deflection angle δ2 of the X accelerometer sensitive axis, and adjust the turntable spindle zero position correction parameters according to δ2: δ2=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600 =(N X2 -N X1 ) / 2*0.6″ Among them: Ka=3×10 -4 m / s / n; After the reference position adjustment is completed, the initial position is set as ENU, and other positions are determined based on it; Adjust the turntable to a horizontal position with the body axis pointing to ENU, and calculate the average number of pulses N for X plus 30s. X1 , the turntable azimuth axis rotates 180° to the WSU position, and calculates X again plus the average pulse number N for 30 seconds X2 , calculate the eastward horizontal δ3 of the turntable: δ3=(N X2 -N X1 ) / 2*(ka*0.1 / 9.8)*57.3*3600 =(N X2 -N X1 ) / 2*0.6″ Among them: Ka=3×10 -4 m / s / n,δ3≤1'.

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