Method for correcting unparallelism of shafting based on fiber-optic gyroscope measurement

Abstract

The invention provides a method for correcting the unparallelism of a shaft system based on fiber-optic gyroscope measurement, relates to a method for measuring the unparallelism of a shaft system of a rotary table, and aims to solve the problem that the unparallelism exists between an output shaft of a fiber-optic gyroscope and a rotary shaft of the rotary table in the prior art. Therefore, errors can be caused when the output value of the fiber-optic gyroscope is used for carrying out closed-loop operation on the non-perpendicularity of the shafting, and the technical problem that the non-parallelism of the shafting cannot be measured in real time in the prior art is solved. According to the method, the output speed of the fiber-optic gyroscope and the output angle of the rotary table of the photoelectric theodolite are obtained, the ratio of two output signals is solved, the non-parallelism between the output shaft of the fiber-optic gyroscope and the corresponding rotary shaft of the rotary table of the photoelectric theodolite is calculated, and the output value of the fiber-optic gyroscope is measured and corrected by taking the non-parallelism as a reference. The method has the advantages of simplifying the measurement process, reducing the calculation complexity and improving the measurement precision.

Description

Technical Field

[0001] The invention relates to a method for measuring the non-parallelism of a turntable shaft system, in particular to a method for correcting the non-parallelism of the shaft system based on fiber optic gyroscope measurement. Background Art

[0002] The azimuth axis and elevation axis of the photoelectric theodolite turntable are completely perpendicular in theory. However, in actual use, due to the limitations of installation and manufacturing processes, the azimuth axis and elevation axis cannot be completely perpendicular. The non-perpendicularity of the two axes will have a greater impact when the photoelectric theodolite turntable is used for high-precision tracking and aiming. Therefore, it is necessary to measure the non-perpendicularity of the two axes. The traditional measurement method is to use external tools such as photoelectric autocollimators and plane reflectors for measurement. This method not only requires the use of external high-precision measurement equipment, but also has complex calculations, and cannot perform real-time measurement of the non-perpendicularity of the axis system that may change.

[0003] With the increasing requirements for pointing and tracking accuracy of the photoelectric theodolite turntable, the existing high-precision photoelectric theodolite turntable is generally equipped with a high-precision fiber optic gyroscope for speed measurement and high-precision speed tracking. The high-precision fiber optic gyroscope is not only light in weight, but also has high measurement accuracy with speed. However, due to the limitations of manufacturing and installation factors, the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable cannot be completely parallel, and there is a deviation, which causes the output axis of the fiber optic gyroscope to be unable to represent the speed of the photoelectric theodolite turntable. When the output value of the fiber optic gyroscope is used to perform closed-loop calculations on the non-perpendicularity of the axis system, errors will be caused. Therefore, it is necessary to know the non-parallelism between the output axis of the gyroscope and the corresponding rotation axis of the turntable, and then correct the measurement value of the fiber optic gyroscope. Summary of the invention

[0004] The main purpose of the present invention is to solve the technical problem that there is non-parallelism between the output axis of the fiber optic gyroscope and the rotating axis of the turntable in the prior art, which causes errors when the fiber optic gyroscope output value is used to perform closed calculations on the axis non-perpendicularity, and the technical problem that the prior art cannot achieve real-time measurement of the axis non-parallelism, and proposes a method for correcting the axis non-parallelism based on fiber optic gyroscope measurement.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The method for correcting the non-parallelism of the axis system based on the fiber optic gyro measurement is special in that it includes the following steps:

[0007] 1) Install the fiber optic gyro on the horizontal plane and the elevation plane of the photoelectric theodolite turntable respectively, and the output axis of the fiber optic gyro should coincide with the corresponding rotation axis of the photoelectric theodolite turntable;

[0008] 2) The fiber optic gyroscope is made to be stationary, and the stationary speed ω1 of the fiber optic gyroscope is collected for multiple times, and the average value ω0 of the stationary speed of the fiber optic gyroscope is calculated by using ω1;

[0009] 3) Send the same PPS signal to the fiber optic gyro and the photoelectric theodolite turntable respectively, and synchronously collect the output speed ω of the fiber optic gyro and the output angle θ of the photoelectric theodolite turntable;

[0010] 4) rotating the photoelectric theodolite turntable for n sinusoidal cycles, collecting the output speed ω of the fiber optic gyroscope and the output angle θ of the photoelectric theodolite turntable in each sinusoidal cycle; wherein n≥9;

[0011] 5) Calculate the average angular velocity of the photoelectric theodolite turntable according to the output angle θ of all cycles or part of the intermediate cycles of the photoelectric theodolite turntable collected in step 4 According to the output speed ω of the fiber optic gyroscope collected in the same period and the average output speed ω0 of the fiber optic gyroscope calculated in step 2, the average speed ω of the fiber optic gyroscope is calculated. i ;

[0012] 6) Calculate the average angular velocity of the photoelectric theodolite turntable in step 5 The average speed of the fiber optic gyroscope ω i The non-parallelism γ between the output axis of the fiber optic gyro and the corresponding rotation axis of the photoelectric theodolite turntable is calculated based on the ratio A;

[0013] 7) According to the average speed ω of the fiber optic gyroscope in step 5 i As well as the non-parallelism γ in step 6, the non-parallelism of the axis system is corrected according to the following formula to obtain the corrected angular rate of the fiber optic gyroscope

[0014]

[0015] Furthermore, the step 5 comprises the following steps:

[0016] 5.1) Differentiate the output angle θ of the photoelectric theodolite turntable in each sine cycle and calculate the angular velocity of the photoelectric theodolite turntable in each sine cycle

[0017] 5.2) Angular velocity Perform fitting, and select the middle 6 to 7 sinusoidal cycles after fitting as 6 to 7 calculation cycles;

[0018] 5.3) Average angular velocity Including the maximum average angular velocity and the minimum average angular velocity Take the angular velocity in each calculation cycle The maximum value of the 6-7 angular velocities The maximum value of the average is obtained to obtain the maximum average value of the angular velocity Select the angular velocity in each calculation cycle The minimum value of the angular velocity The absolute value of the minimum value is averaged to obtain the minimum average angular velocity

[0019] 5.4) Average speed of fiber optic gyroscope ω i Including the maximum average speed ω imax and the minimum average speed ω imin , take the maximum value of the output speed ω of the fiber optic gyroscope in each calculation cycle max ,ω max Subtract the average value of the fiber optic gyro output speed ω0, and max -ω0 to find the average, and get the maximum average speed ω of the fiber optic gyroscope imax ; Take the minimum value of the output speed ω of the fiber optic gyroscope in each calculation cycle, subtract the average value ω0 of the output speed of the fiber optic gyroscope, and average the absolute value of ω-ω0 to obtain the minimum average speed ω of the fiber optic gyroscope imin .

[0020] Furthermore, step 6 comprises the following steps:

[0021] 6.1) Non-parallelism γ includes the first angle γ max and the second angle γ min ; Calculate θ in step 5.3 max Same as in step 5.4 imax The ratio of max , for the first ratio A max The first angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable can be obtained by calculating the inverse cosine. max ;

[0022] 6.2) Calculate step 5.3 Same as in step 5.4 imin The ratio of the second ratio A min , for the second ratio A min The inverse cosine can be used to obtain the second angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable. min .

[0023] Furthermore, the step 7 comprises the following steps:

[0024] 7.1) According to the maximum average speed ω of the fiber optic gyroscope imax and the first angle γ max , calculate the maximum corrected angular velocity of the corrected fiber optic gyroscope as follows:

[0025]

[0026] According to the minimum average speed ω of the fiber optic gyroscope imin and the second angle γ min , calculate the minimum corrected angular velocity of the corrected fiber optic gyroscope as follows:

[0027]

[0028] 7.2) Maximum Correction Angular Rate of Fiber Optic Gyroscope and the minimum corrected angular rate Take the average and get the transmission correction angular rate of the fiber optic gyroscope

[0029] Furthermore, the step 2 comprises the following steps:

[0030] 2.1) Keep the fiber optic gyroscope still for 3 to 5 minutes, continuously collect the static speed ω1 of the fiber optic gyroscope, and calculate the average value ω1 of the static speed ω1 of the fiber optic gyroscope;

[0031] 2.2) Repeat step 2.1 k times, and calculate the average value of the static speed of the fiber optic gyroscope from ω1 to ω k ; Wherein, k = 3-5;

[0032] 2.3) For ω1 to ω k Find the average value and obtain the average value ω0 of the static speed of the fiber optic gyroscope.

[0033] Furthermore, a sinusoidal period in step 4 is a position sinusoid of 5*sin(1*t), 1*sin(1*t), 0.5*sin(1*t) and 0.05*sin(1*t), where t is time.

[0034] Furthermore, in step 3, the output speed ω of the fiber optic gyroscope and the output angle θ of the photoelectric theodolite turntable are collected by the main control software, and the output speed ω and the output angle θ are synchronized at the ns level.

[0035] Furthermore, in step 1, the photoelectric theodolite turntable can be replaced by a stable platform.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The method of the present invention utilizes the existing fiber optic gyroscope on the high-precision photoelectric theodolite turntable, obtains the output speed of the fiber optic gyroscope and the output angle of the photoelectric theodolite turntable, obtains the ratio of the two output signals, calculates the non-parallelism γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the photoelectric theodolite turntable, and corrects the output value of the fiber optic gyroscope with the non-parallelism γ as a reference to obtain the corrected angular velocity of the fiber optic gyroscope. There is no need to use external equipment such as a photoelectric autocollimator and a plane reflector for measurement and solution, further avoiding errors in the measurement and correction process, simplifying the measurement process, effectively reducing the calculation complexity, and improving the measurement accuracy.

[0038] 2. The measurement and correction accuracy of the method of the present invention depends on the accuracy of the fiber optic gyroscope and the accuracy of the angle measuring sensor used on the turntable of the photoelectric theodolite, so it can achieve the effect of highly matching the measurement and correction accuracy with the equipment accuracy.

[0039] 3. The method of the present invention uses the main control software to collect the output value of the fiber optic gyroscope and the output value of the photoelectric theodolite turntable, and the main control software can measure and correct the non-parallelism of the axis system in real time, thereby improving the calculation reliability, reducing the operation difficulty and operation cost, and improving the practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention is a flow chart of a method for correcting non-parallelism of an axis system based on fiber optic gyroscope measurement; DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be further described below in conjunction with the embodiments and drawings of the present invention. Figure 1 As shown, the following steps are included:

[0042] 1) A high-precision fiber optic gyroscope is installed on the horizontal plane and the elevation plane of the photoelectric theodolite turntable respectively. The output axis of the fiber optic gyroscope on the horizontal plane is required to completely coincide with the azimuth axis of the photoelectric theodolite turntable in theory, and the output axis of the fiber optic gyroscope on the elevation plane is required to completely coincide with the elevation axis of the photoelectric theodolite turntable in theory;

[0043] 2) The fiber optic gyro itself has zero bias. In order to obtain the accurate value of the output speed of the fiber optic gyro, it is necessary to make the fiber optic gyro stationary before measuring the output speed of the photoelectric theodolite turntable when it rotates. The stationary speed ω1 of the fiber optic gyro is collected multiple times, and ω1 is used to calculate the average value of the fiber optic falling stationary speed, which is specifically:

[0044] 2.1) Keep the fiber optic gyroscope still for 3 to 5 minutes, continuously collect the static speed ω1 of the fiber optic gyroscope, and calculate the average value ω1 of the static speed ω1 of the fiber optic gyroscope;

[0045] 2.2) Repeat step 2.1 k (k = 3-5) times, and calculate the average value of the static speed of the fiber optic gyroscope from ω1 to ω k ;

[0046] 2.3) For ω1 to ω k Find the average value and obtain the average value ω0 of the static speed of the fiber optic gyroscope.

[0047] 3) The output speed ω of the fiber optic gyroscope is collected through the main control software, and the angle output by the encoder on the photoelectric theodolite turntable is collected at the same time as the output angle θ of the photoelectric theodolite turntable; the main control software sends the same PPS (pulse per second) signal to the fiber optic gyroscope and the angle sensor on the photoelectric theodolite turntable respectively, so as to achieve high-precision synchronization between the speed signal and the angle signal, which can reach ns-level synchronization.

[0048] 4) The position sine of the photoelectric theodolite turntable moves 5*sin(1*t), 1*sin(1*t), 0.5*sin(1*t) and 0.05*sin(1*t) respectively as one sine cycle, and repeats 10 sine cycles to collect the output speed ω of the fiber optic gyroscope and the output angle θ of the photoelectric theodolite turntable in each sine cycle;

[0049] 5) According to the intermediate period output angle θ of the photoelectric theodolite turntable collected in step 4, the average angular velocity of the photoelectric theodolite turntable is calculated According to the output speed ω of the fiber optic gyroscope collected in the same period and the average output speed ω0 of the fiber optic gyroscope calculated in step 2, the average speed ω of the fiber optic gyroscope is calculated. i ; Specifically include the following steps:

[0050] 5.1) Differentiate the output angle θ of the photoelectric theodolite turntable in each sine cycle and calculate the angular velocity of the photoelectric theodolite turntable in each sine cycle

[0051] 5.2) Angular velocity Fitting is performed. The differential of the output result of the angle sensor can also be fitted to obtain a speed with very little noise. The middle 6 sine cycles after fitting are selected as 6 calculation cycles.

[0052] 5.3) Average angular velocity Including the maximum average angular velocity and the minimum average angular velocity Take the angular velocity in each calculation cycle The maximum value of the 6 angular velocities The maximum value of the average is obtained to obtain the maximum average value of the angular velocity Take the angular velocity in each calculation cycle The minimum value of the angular velocity The absolute value of the minimum value is averaged to obtain the minimum average angular velocity

[0053] 5.4) Average speed of fiber optic gyroscope ω i Including the maximum average speed ω imax and the minimum average speed ω imin , take the maximum value of the output speed ω of the fiber optic gyroscope in each calculation cycle max ,ω max Subtract the average value of the fiber optic gyro output speed ω0, and max -ω0) to obtain the maximum average speed ω of the fiber optic gyroscope imax ; Take the minimum value of the output speed ω of the fiber optic gyroscope in each calculation cycle, subtract the average value of the output speed ω0 of the fiber optic gyroscope, and average the absolute value of (ω-ω0) to obtain the minimum average speed ω of the fiber optic gyroscope imin ;

[0054] 6) Calculate the average angular velocity of the photoelectric theodolite turntable in step 5 The average speed of the fiber optic gyroscope ω i The non-parallelism γ between the sensitive axis of the fiber optic gyro and the axis system of the photoelectric theodolite turntable is calculated based on the ratio A. The non-parallelism γ includes the first angle γ max and the second angle γ min If the sensitive axis of the fiber optic gyroscope is completely parallel to the rotation axis of the photoelectric theodolite turntable, and the sensitive axis of the angle sensor is completely parallel to the rotation axis of the photoelectric theodolite turntable, then the angular velocity of the photoelectric theodolite turntable is and the average velocity ω of the fiber optic gyroscope i The speed values ​​should be exactly the same; if there is an angle between the sensitive axis of the fiber optic gyroscope and the sensitive axis of the angle sensor, that is, there is non-parallelism, the measured speed values ​​will be different; specifically, the following steps are included:

[0055] 6.1) Calculate step 5.3 With ω imax The ratio of max , for the first ratio A max The first angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable can be obtained by calculating the inverse cosine. max ;

[0056] 6.2) Calculate step 5.3 With ω imin The ratio of the second ratio A min , for the second ratio A min The inverse cosine can be used to obtain the second angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable.min ; The first ratio A max and the second ratio A min Theoretically, they are the same value, but due to measurement errors and other reasons, the first ratio A max and the second ratio A min There are minor differences and they won't be exactly the same.

[0057] 7) According to the average speed ω of the fiber optic gyroscope in step 5 i As well as the non-parallelism γ in step 6, the non-parallelism of the axis system is corrected according to the following formula to obtain the corrected angular rate of the fiber optic gyroscope

[0058] 7.1) According to the maximum average speed ω of the fiber optic gyroscope imax and the first angle γ max , calculate the maximum corrected angular velocity of the fiber optic gyroscope as follows:

[0059]

[0060] According to the minimum average speed ω of the fiber optic gyroscope imin and the second angle γ min , calculate the minimum corrected angular velocity of the fiber optic gyroscope as follows:

[0061]

[0062] 7.2) Maximum Correction Angular Rate of Fiber Optic Gyroscope and the minimum corrected angular rate Take the average and get the corrected angular rate of the fiber optic gyroscope

[0063] The fiber optic gyroscope is a high-precision sensitive inertial measurement element. The fiber optic gyroscope is installed on the reference surface of the turntable. The speed measured by the fiber optic gyroscope's sensitive axis is the speed of the photoelectric theodolite turntable's rotating axis perpendicular to the installation surface. Due to the limitations of the manufacturing and assembly process, the output axis of the fiber optic gyroscope and the axis system of the photoelectric theodolite turntable cannot be completely parallel, which results in the output speed of the fiber optic gyroscope not being completely equal to the speed of the corresponding rotating axis of the photoelectric theodolite turntable. The encoder is installed on the structural axis of the photoelectric theodolite turntable. Due to the influence of assembly and other reasons, there will be a certain error between the encoder's sensitive axis and the photoelectric theodolite turntable's axis system.

[0064] When using the photoelectric theodolite turntable for precise tracking or pointing, a fiber optic gyroscope is used as a speed sensor and an encoder is used as an angle sensor. When implementing the control algorithm, it is assumed that both the speed sensor and the angle sensor are completely aligned with the photoelectric theodolite turntable. In fact, both the speed sensor and the angle sensor are not parallel to the axis system of the photoelectric theodolite turntable, resulting in errors. Therefore, before using the speed of the fiber optic gyroscope to represent the speed of the corresponding rotating axis of the photoelectric theodolite turntable, the speed of the fiber optic gyroscope needs to be corrected. The method of the present invention corrects the non-parallelism of the sensitive axis of the speed sensor and the sensitive axis of the angle sensor, and corrects the sensitive axis of the speed sensor to the sensitive axis of the angle sensor.

[0065] Similarly, the present invention can also use a two-axis or three-axis gyroscope to measure the two-axis and three-axis non-parallelism of the photoelectric theodolite turntable or stable platform. The three-axis non-parallelism of the fiber optic gyroscope has been calibrated at the factory. The two-axis or three-axis output value of the fiber optic gyroscope is obtained, and the two-axis or three-axis output value of the photoelectric theodolite turntable or stable platform is obtained. By comparing the two output values, and then using the two-axis or three-axis non-parallelism of the fiber optic gyroscope as a reference, the two-axis or three-axis non-parallelism of the turntable or stable platform can be calculated.

Claims

1. A method for correcting axis non-parallelism based on fiber optic gyroscope measurement, characterized in that: The following steps are involved: 1) Install the fiber optic gyro on the horizontal plane and the elevation plane of the photoelectric theodolite turntable respectively, and the output axis of the fiber optic gyro should coincide with the corresponding rotation axis of the photoelectric theodolite turntable; 2) The fiber optic gyroscope is made to be stationary, and the stationary speed ω1 of the fiber optic gyroscope is collected for multiple times, and the average value ω0 of the stationary speed of the fiber optic gyroscope is calculated by using ω1; 3) Send the same PPS signal to the fiber optic gyro and the photoelectric theodolite turntable respectively, and synchronously collect the output speed ω of the fiber optic gyro and the output angle θ of the photoelectric theodolite turntable; 4) rotating the photoelectric theodolite turntable for n sinusoidal cycles, collecting the output speed ω of the fiber optic gyroscope and the output angle θ of the photoelectric theodolite turntable in each sinusoidal cycle; wherein n≥9; 5) Calculate the average angular velocity of the photoelectric theodolite turntable according to the output angle θ of all cycles or part of the intermediate cycles of the photoelectric theodolite turntable collected in step 4 According to the output speed ω of the fiber optic gyroscope collected in the same period and the average output speed ω0 of the fiber optic gyroscope calculated in step 2, the average speed ω of the fiber optic gyroscope is calculated. i ; 6) Calculate the average angular velocity of the photoelectric theodolite turntable in step 5 The average speed of the fiber optic gyroscope ω i The non-parallelism γ between the output axis of the fiber optic gyro and the corresponding rotation axis of the photoelectric theodolite turntable is calculated based on the ratio A; 7) According to the average speed ω of the fiber optic gyroscope in step 5 i As well as the non-parallelism γ in step 6, the non-parallelism of the axis system is corrected according to the following formula to obtain the corrected angular velocity of the fiber optic gyroscope 2. The method for correcting axis non-parallelism based on fiber optic gyroscope measurement according to claim 1, characterized in that: The step 5 comprises the following steps: 5.1) Differentiate the output angle θ of the photoelectric theodolite turntable in each sine cycle and calculate the angular velocity of the photoelectric theodolite turntable in each sine cycle 5.2) Angular velocity Perform fitting, and select the middle 6 to 7 sinusoidal cycles after fitting as 6 to 7 calculation cycles; 5.3) Average angular velocity Including the maximum average angular velocity and the minimum average angular velocity Take the angular velocity in each calculation cycle The maximum value of the 6-7 angular velocities The maximum value of the average is obtained to obtain the maximum average value of the angular velocity Select the angular velocity in each calculation cycle The minimum value of the angular velocity The absolute value of the minimum value is averaged to obtain the minimum average angular velocity 5.4) Average speed of fiber optic gyroscope ω i Including the maximum average speed ω imax and the minimum average speed ω imin , take the maximum value of the output speed ω of the fiber optic gyroscope in each calculation cycle max ,ω max Subtract the average value of the fiber optic gyro output speed ω0, and max -ω0 to find the average, and get the maximum average speed ω of the fiber optic gyroscope imax ; Take the minimum value of the output speed ω of the fiber optic gyroscope in each calculation cycle, subtract the average value ω0 of the output speed of the fiber optic gyroscope, and average the absolute value of ω-ω0 to obtain the minimum average speed ω of the fiber optic gyroscope imin .

3. The method for correcting axis non-parallelism based on fiber optic gyroscope measurement according to claim 2, characterized in that: The step 6 comprises the following steps: 6.1) Non-parallelism γ includes the first angle γ max and the second angle γ min ; Calculation step 5.3 Same as in step 5.4 imax The ratio of the first ratio A max , for the first ratio A max The first angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable can be obtained by calculating the inverse cosine. max ; 6.2) Calculate step 5.3 Same as in step 5.4 imin The ratio of the second ratio A min , for the second ratio A min The inverse cosine can be used to obtain the second angle γ between the output axis of the fiber optic gyroscope and the corresponding rotation axis of the turntable. min .

4. The method for correcting axis non-parallelism based on fiber optic gyro measurement according to claim 3, characterized in that: The step 7 comprises the following steps: 7.1) According to the maximum average speed ω of the fiber optic gyroscope imax and the first angle γ max , calculate the maximum corrected angular velocity of the corrected fiber optic gyroscope as follows: According to the minimum average speed ω of the fiber optic gyroscope imin and the second angle γ min , calculate the minimum corrected angular velocity of the corrected fiber optic gyroscope as follows: 7.2) Maximum Correction Angular Rate of Fiber Optic Gyroscope and the minimum corrected angular rate Take the average and get the transmission correction angular rate of the fiber optic gyroscope 5. The method for correcting axis non-parallelism based on fiber optic gyro measurement according to any one of claims 1 to 4, characterized in that: The step 2 comprises the following steps: 2.1) Keep the fiber optic gyroscope still for 3 to 5 minutes, continuously collect the static speed ω1 of the fiber optic gyroscope, and calculate the average value ω1 of the static speed ω1 of the fiber optic gyroscope; 2.2) Repeat step 2.1 k times, and calculate the average value of the static speed of the fiber optic gyroscope from ω1 to ω k ; Wherein, k = 3-5; 2.3) For ω1 to ω k Find the average value and obtain the average value ω0 of the static speed of the fiber optic gyroscope.

6. The method for correcting axis non-parallelism based on fiber optic gyroscope measurement according to claim 5, characterized in that: One sinusoidal period in step 4 is a position sinusoid of 5*sin(1*t), 1*sin(1*t), 0.5*sin(1*t) and 0.05*sin(1*t), where t is time.

7. The method for correcting axis non-parallelism based on fiber optic gyro measurement according to claim 6, characterized in that: In step 3, the output speed ω of the fiber optic gyroscope and the output angle θ of the photoelectric theodolite turntable are collected by the main control software, and the output speed ω and the output angle θ are synchronized at the ns level.

8. The method for correcting axis non-parallelism based on fiber optic gyroscope measurement according to claim 7, characterized in that: In step 1, the photoelectric theodolite turntable can be replaced by a stable platform.

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