CN1687707A - Engineering implementation method for quick starting inertial measurement unit of optical fiber gyroscope and guaranteeing precision - Google Patents

Abstract

The invention is the project realizing method of fiber top inertia measuring device fast starting and precision guarantee, which adopts the temperature demarcating system to detect the temperature mode; found the module of the affirming parts of the fiber top and the quartz accelerator and effectively reduce the zero-bias brought by the temperature; implement small-wave transforming procession to the fiber top noises and make the stability of the zero-bias be better than 0.5 Deg./h and the zero-bias error be smaller than 10 to power 4 g. The invention effectively reduces the zero temperature floating and noises and improves the performance of the system.

Description

The engineering implementation method of quick starting inertial measurement unit of optical fiber gyroscope and accuracy guarantee

Technical field

The present invention relates to the engineering implementation method of a kind of quick starting inertial measurement unit of optical fiber gyroscope and accuracy guarantee.

Background technology

Traditional electromechanical inertial measuring unit (hereinafter to be referred as IMU) energising back motor needs the lock in time of second surplus in the of ten, also needs temperature control to guarantee precision, is difficult to realize starting fast.Optical fibre gyro IMU can instantaneous starting in-40 ℃～65 ℃ temperature ranges, but zero exist bigger drift partially, and noise is also bigger, and foreign literature is not seen the report of relevant test and compensation method, and this has limited the application of optical fibre gyro to a certain extent.Simultaneously, compare with the electromechanical gyro, the optical fibre gyro output noise is bigger.Random walk coefficients R WC is a technical indicator that characterizes white noise size in the optical fibre gyro, introduces the course angle error with the square root growth of working time t in system ${\mathrm{\σ}}_{\mathrm{\θ}}=\mathrm{RWC}\·\sqrt{t},$ This uncertainty of course angle has weakened the performance of inertial measurement system, therefore, need manage to reduce optical fibre gyro random walk coefficient.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, the engineering implementation method of quick startup of a kind of optical fiber gyro inertial measurement device and accuracy guarantee is provided, adopt this method can reduce the zero-bit temperature drift and the noise of optical fiber gyroscope inertial measurement system effectively, improve its quick-reaction capability (QRC).

Technical solution of the present invention: the engineering implementation method of quick startup of a kind of optical fiber gyro inertial measurement device and accuracy guarantee, its characteristics are to comprise the following steps:

(1) in total temperature scope-40～+ 65 ℃, obtains optical fibre gyro and the temperature variant output data of accelerometer under each temperature spot by the temperature calibration system;

(2), after picking wild value, weighted, adopt mean point method to obtain K according to the temperature data that draws in the step (1) _F0Be the zero degree item coefficient of optical fibre gyro zero offset compensation, K _F1Be an once coefficient of optical fibre gyro zero offset compensation, K _AT0Be the zero degree item coefficient of accelerometer bias compensation, K _AT1Be an once coefficient of accelerometer bias compensation, K _AT2For the quadratic term coefficient of accelerometer bias compensation, set up the zero bias temperature compensation model, wherein zero of optical fibre gyro is the linear function of temperature partially

K _f0(T)＝K _fT0+K _fT1T (1)

Quartz accelerometer zero bias temperature model is the quadratic function of temperature

K _a0(T)＝K _aT0+K _aT1T+K _aT2T ² (2)

(3) with above-mentioned each penalty coefficient K that obtains _FT0, K _FT1, K _AT0, K _AT1, K _AT2, write computer system, when IMU works, according to temperature sensor output temperature T ₀, calculate corresponding compensation rate K _F0(T ₀), K _A0(T ₀), deduction from output;

(4) carry out above-mentioned zero offset compensation after, adopt wavelet transform filtering again, the compensation residual error of optical fibre gyro is carried out exporting after the filtering, to reduce noise.

The advantage that the present invention compares with prior art is: the present invention partly adopts the weighted mean method of selected points to carry out modeling to determinacy in optical fibre gyro and the quartz accelerometer output, reduce temperature effectively and cause that zero changes partially, the mean point method of weighting has higher engineering using value, its method is simple, test volume is little, especially to independent variable---the measuring accuracy of temperature is less demanding, the temperature model of setting up has the stability higher than least square method, and can reduce the match residual error in important temperature interval by different reconnaissance modes; Noise under the high low temperature of optical fibre gyro is carried out wavelet transform process, and according to different wavelet basis filter effects, the filtering method of having taked suitable engineering to use makes the zero stability partially of optical fibre gyro be better than 0.5 °/h, and accelerometer compensation back zero inclined to one side error is less than 10 ^-4G has reduced the zero-bit temperature drift and the noise of optical fiber gyro inertial measurement device effectively, has improved the performance of system, has reduced the requirement to the optical fibre gyro precision, has alleviated the contradiction of precision and cost to a certain extent.

Description of drawings

Fig. 1 is the formation synoptic diagram of temperature calibration coefficient of the present invention;

Output result when Fig. 2 does not add zero offset compensation for optical fibre gyro;

Fig. 3 adopts the output result of method compensation of the present invention for optical fibre gyro;

Output result when Fig. 4 does not add zero offset compensation for accelerometer;

Fig. 5 is the output result after accelerometer the adopts method of the present invention compensation;

Fig. 6 is the effect before optical fibre gyro of the present invention is adopted the Db4 wavelet filtering;

Fig. 7 is the effect after optical fibre gyro of the present invention is adopted the Db4 wavelet filtering.

Embodiment

As shown in Figure 1, demarcation testing apparatus of the present invention is made up of high-precision temperature opertaing device TD-500 and single shaft precision rotating platform 3TS-320B, partly covers temperature control device TD-500 at panoramic table testpieces installing mechanism, and measured piece is carried out temperature control.Because panoramic table is installed on the vibro-damping mount, temperature control device work vibrations and personnel walk about and can not have influence on IMU, guarantee the reliability of test data.

IMU is installed in the panoramic table installed surface, tested angular speed input shaft level.Panoramic table is operated in rate mode, can carry out speed to gyro and demarcate, and mode position is set panoramic table and worked in digital grating dividing head mode, and accelerometer is carried out ± the interior linearity test of 1g scope.Demarcate IMU at the temperature spot of setting, obtain the partially zero of instrument.

Adopt above-mentioned temperature calibration system, in total temperature scope-40～+ 65 ℃, choose 8 temperature spots-40 ,-20 ,-10,0,10,20,40,65 ℃, i.e. T ₁～T ₈, fully the insulation back was tested 3 minutes on each temperature spot, and output data is rejected wild some rear weight, and weights are got α respectively ₁～α _j, satisfy

$\underset{1}{\overset{j}{\mathrm{\Σ}}}{\mathrm{\α}}_i=1---\left(3\right)$

And α ₁＜α ₂＜...＜α _j, i.e. the bigger weight of data after leaning under each temperature spot.

The basic thought of mean point method is: the Total Test point is divided into two groups, first half n ₁The point of individual testing site is that the coordinate at center is:

$\stackrel{\‾}{X_1}=\frac{1}{n_1}\underset{i=1}{\overset{n_1}{\mathrm{\Σ}}}{X}_i$

$\stackrel{\‾}{Y_1}=\frac{1}{n_1}\underset{i=1}{\overset{n_1}{\mathrm{\Σ}}}{Y}_i---\left(4\right)$

Latter half of n ₂The point of individual testing site is that the coordinate at center is:

$\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}=\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\underset{i=n_1+1}{\overset{n}{\mathrm{\&Sigma;}}}{X}_i$

$\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">Y</figure-callout>}}_2}=\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">n</figure-callout>}}_2}\underset{i=n_1+1}{\overset{n}{\mathrm{\&Sigma;}}}{Y}_i---\left(5\right)$

By these two points is the center

Straight line, promptly the slope of regression straight line is

$\hat{b}=\frac{\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">Y</figure-callout>}}_2}-\stackrel{\&OverBar;}{Y_1}}{\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="A20051007485500081.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}-\stackrel{\&OverBar;}{X_1}}---\left(6\right)$

Its intercept on Y-axis

$\hat{a}=\stackrel{\&OverBar;}{Y_1}-\hat{b}\stackrel{\&OverBar;}{X_1}---\left(7\right)$

Regression beeline equation is:

Y＝+x (8)

It promptly is the compensation model of the optical fibre gyro in the formula (1) among the present invention.

For the polynomial expression of the accelerometer meter of formula (2), the disposal route of mean point method is:

${y=a}_0+a_{1}x+a_2{x}^2=\underset{j=0}{\overset{2}{\mathrm{\&Sigma;}}}{a}_j{x}^j---\left(9\right)$

For (the x more arbitrarily in the test figure ₀, y ₀) have:

y ₀＝a ₀+a ₁x ₀+a ₂x ₀ ² (10)

y-y ₀＝[a ₁+a ₂(x+x ₀)](x-x ₀)

$\frac{y-y_0}{x-x_0}=a_1+a_2{x}_0+a_{2}x---\left(11\right)$

Order $\frac{y-y_0}{x-x_0}=z,$ a ₁+ a ₂x ₀=b, then following formula becomes straight-line equation

z＝b+a ₂x (12)

Utilize mean point method to obtain the coefficient b and a of this straight-line equation ₂, and then can obtain a ₀And a ₁, can determine the compensation model of accelerometer.

The temperature test data adopt mean point method to obtain K through after picking wild value, weighted among the present invention _FT0, K _FT1, K _AT0, K _AT1, K _AT2, set up the compensation model of formula (1) and (2), shown in Fig. 2,4, simultaneously above-mentioned each coefficient is write computer system.When IMU works, according to temperature sensor output temperature T ₀, calculate corresponding compensation rate K _F0(T ₀), K _A0(T ₀), deduction from output is shown in Fig. 3,5, by Fig. 2 and Fig. 3, Fig. 4 and Fig. 5 are compared as can be seen, effect is different fully before and after the compensation of optical fibre gyro and accelerometer, through zero compensation of the present invention, has eliminated the partially zero of optical fibre gyro and acceleration.

After carrying out above-mentioned zero offset compensation, adopt the wavelet transform filtering method again, the compensation residual error of optical fibre gyro is carried out exporting after the filtering, to eliminate noise.Small echo has the local time-frequency ruled area energy good to signal, when removing most of noise, and the transient state characteristic of stick signal.According to filter effect, select vanishing moment be 2 Db4 small echo to the compensation residual filtering, reduce the noise of optical fibre gyro.The scaling function that is adopted is

Wavelet function is

A wave filter based on the Mallat algorithm that constitutes, its filter coefficient satisfies

h ₀＝0.683，h ₁＝1.183，h ₂＝0.317，h ₃＝-0.183

Utilize above-mentioned wave filter, greatly reduce optical fibre gyro output white noise, filter effect as shown in Figure 7, and is more obvious than the effect as Fig. 6 before the filtering.

More than be compensation and the filtering on direction of optical fibre gyro and accelerometer such as the directions X, the compensation of other direction such as Y direction and Z direction is identical therewith with filtering.

The present invention is on the basis of substantive test test, and optical fibre gyro that the method compensation temperature of employing Temperature Modeling causes and quartz accelerometer zero change partially, and it is zero partially to the sensitivity of temperature to eliminate IMU, has improved the service precision of system.Simultaneously, adopt the method for wavelet filtering, reduce the noise of optical fibre gyro, guaranteed that optical fibre gyro IMU starts and operating accuracy fast in-40 ℃～65 ℃ scopes.

Claims (2)

1, the engineering implementation method of a kind of quick starting inertial measurement unit of optical fiber gyroscope and accuracy guarantee is characterized in that comprising the following steps:

(1) in temperature range-40～+ 65 ℃, obtains optical fibre gyro and the temperature variant output data of accelerometer under each temperature spot by the temperature calibration system;

(2), after picking wild value, weighted, adopt mean point method to obtain K according to the temperature data that draws in the step (1) _F0Be the zero degree item coefficient of optical fibre gyro zero offset compensation, K _F1Be an once coefficient of optical fibre gyro zero offset compensation, K _AT0Be the zero degree item coefficient of accelerometer bias compensation, K _AT1Be an once coefficient of accelerometer bias compensation, K _AT2For the quadratic term coefficient of accelerometer bias compensation, set up the zero bias temperature compensation model, wherein zero of optical fibre gyro is the linear function of temperature partially

K _f0(T)＝K _fT0+K _fT1T (1)

Quartz accelerometer zero bias temperature model is the quadratic function of temperature

K _a0(T)＝K _aT0+K _aT1T+K _aT2T ² (2)

(3) with above-mentioned each penalty coefficient K that obtains _FT0, K _FT1, K _AT0, K _AT1, K _AT2, write computer system, when IMU works, according to temperature sensor output temperature T ₀, calculate corresponding compensation rate K _F0(T ₀), K _A0(T ₀), deduction from output;

(4) carry out above-mentioned zero offset compensation after, adopt the wavelet transform filtering method again, the compensation residual error of optical fibre gyro is carried out exporting after the filtering, to reduce noise.

2, the engineering implementation method of quick starting inertial measurement unit of optical fiber gyroscope according to claim 1 and accuracy guarantee is characterized in that: the wavelet transformation employing vanishing moment in the described step (4) is 2 Db4 small echo.

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