CN103267531A - Method for high-precision compensation of fiber-optic gyroscope random error - Google Patents

Abstract

The invention provides a method for high-precision compensation of a fiber-optic gyroscope random error. The method comprises the following steps of building a fiber-optic gyroscope measure model, building a fiber-optic gyroscope state noise covariance array model, carrying out a fiber-optic gyroscope high-precision rotary table test, calculating a fiber-optic gyroscope angle random walk coefficient and a fiber-optic gyroscope angular velocity random walk coefficient, carrying out fiber-optic gyroscope angle increment error compensation, and acquiring a fiber-optic gyroscope high-precision angular velocity. The method is designed based on a gyro inertial technology principle, adopts a random process theory, builds a fiber-optic gyroscope measure error model based on the fiber-optic gyroscope output signal characteristics, and carries out real-time dynamic compensation of fiber-optic gyroscope output by the analysis formula of angular velocity measure errors. A ground test proves that through the method, the fiber-optic gyroscope measure error compensation rate is more than 80%; a fiber-optic gyroscope measure precision is greatly improved; and an aircraft inertial navigation capability is improved.

Description

A kind of high-accuracy compensation method of optical fiber gyro random error

Technical field

The present invention relates to fields such as photoelectric technology, inertial technology, stochastic process principle, signal processing technology, particularly a kind of high-accuracy compensation method of satellite-borne optical fiber gyroscope stochastic error.Analysis result can be used for fields such as spacecraft control design, inertial navigation.

Background technology

Along with the development of spationautics, the measuring accuracy of spacecraft attitude benchmark is required more and more higher, this has promoted that greatly the development of development, especially inertial sensor of attitude sensor technology is more rapid.Compare with traditional mechanical gyro, optical fibre gyro have movement-less part, precision broad covered area, dynamic range big, start advantages such as fast, long-life, in light weight and digitizing, have wide development and application prospect at civil areas such as military field such as Aeronautics and Astronautics, navigation and weapons and geology, petroleum prospectings.

Optical fibre gyro precision at short notice is very high, but because factors such as self structure and light source cause the constantly accumulation in time of its error, precise decreasing is very fast when working long hours.Therefore, usually be that the information such as high-precision attitude, navigation that provide of using are provided for gyro and other attitude sensors on aircraft.But, if aircraft carries out in large angle maneuver or the inertial navigation system, other attitude sensor errors can't be used or not configuration, can only rely on gyro to obtain the attitude of flight vehicle benchmark, the back attitude reference precise decreasing that works long hours is very fast, and work makes a big impact to aircraft.

100 p optical fiber gyro output error mainly comprises constant value drift, random drift and measurement noise three parts.Generally, can only utilize other attitude sensors that constant value drift is carried out correction-compensation, be difficult to the random drift of optical fibre gyro is carried out correction-compensation with the error that measurement noise equal error causes.And in fact, by random drift with to measure the error that noise causes very big to the influence of optical fibre gyro precision, if manage its modeling and compensate, will improve the attitude reference measuring accuracy of optical fibre gyro greatly.

Summary of the invention

Be to improve the optical fibre gyro precision, to the random drift of optical fibre gyro with measure noise error and carry out correction-compensation, the present invention proposes a kind of Dynamic High-accuracy compensation method of optical fiber gyro random error.This method is set up random error model towards engineering reality from the Optical Fiber Gyroscope characteristic, obtains the dynamic compensation model, and the angular error that can cause random drift and the measurement noise of optical fibre gyro is carried out real-time dynamic compensation.Through ground experiment checking, utilize this method the measurement Error Compensation of optical fibre gyro more than 80%, can have been improved the measuring accuracy of optical fibre gyro greatly, further improved aircraft inertial navigation ability.

Main thought of the present invention is: set about from optical fibre gyro angular velocity measurement model, carry out the discretize processing to measuring equation, obtain the model of optical fibre gyro state-noise covariance matrix, and then obtain the angular error model that optic fiber gyroscope random drift and noise cause, calculate key parameter in the angular error model by the turntable test data, and then the angle step error that causes of compensated optical fiber Gyro Random error, obtain optical fibre gyro high precision magnitude of angular velocity at last.

For solving the problems of the technologies described above, the high-accuracy compensation method of a kind of optical fiber gyro random error of the present invention comprises the steps:

Step 1: the optical fibre gyro measurement model is carried out modeling, set out according to the random drift of optical fibre gyro and the characteristic of noise, try to achieve the variance that state-noise changes, as the input of optical fibre gyro state-noise covariance matrix model.As among Fig. 1 1. shown in.

Step 2: the optical fibre gyro measurement model in the step 1 is carried out discretize, calculate noisiness after the discretize, obtain the model of optical fibre gyro state-noise covariance matrix.As among Fig. 1 2. shown in.

Step 3: utilize test table measuring fiber gyro test in time T ₁Interior angle speed drift variable quantity and time T ₂The variation of interior integration output angle.As among Fig. 1 3. shown in.

Step 4: utilize special-purpose test table test result in the model of optical fibre gyro state-noise covariance matrix in the step 2 and the step 3, try to achieve optical fibre gyro angle random migration coefficient and angular velocity random walk coefficient.As among Fig. 1 4. shown in.

Step 5: utilize the result of step 4 to calculate the angle step drift value of any adjacent moment optical fibre gyro, because of the angle step error that the optical fibre gyro measurement brings, obtain the optical fibre gyro angle step value after any time compensates with this drift value compensation in the sampling time.As among Fig. 1 5. shown in.

Step 6: optical fibre gyro angle step after the compensation that obtains by step 5, handle through the differential in the sampling time again and obtain the output of optical fibre gyro high precision angular velocity.As among Fig. 1 6. shown in.

Preferably, time T ₁Be not less than 4 hours.

Preferably, time T ₂It is 0.5～1 hour.

Preferably, also comprise the steps:

Step 7: will export to aircraft subsequent control system and inertial navigation system by the optical fibre gyro high precision angular velocity that step 6 obtains, to realize high-precision attitude control and High Accuracy Inertial benchmark.

Description of drawings

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is the high-accuracy compensation principle schematic of optical fiber gyro random error.

Embodiment

The present invention is described in detail below in conjunction with specific embodiment.Following examples will help those skilled in the art further to understand the present invention, but not limit the present invention in any form.Should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

As shown in Figure 1, for rotatable parts of the present invention the flexible satellite kinetic effect is analyzed synoptic diagram.Analyze content and comprise 6 parts, be respectively: the modeling of optical fibre gyro measurement model, optical fibre gyro state-noise covariance matrix model, optical fibre gyro turntable high precision measurement, the calculating of optical fibre gyro angle random migration coefficient and angular velocity random walk coefficient, optical fibre gyro angle step error compensation, the calculating of optical fibre gyro high precision angular velocity.

1. optical fibre gyro measurement model modeling

The optical fibre gyro measurement model is as follows:

$\left\{\begin{array}{c}\mathrm{\ω}={\mathrm{\ω}}_g-b-n_v\\ \stackrel{\·}{b}=n_u\end{array}\right.---\left(1\right)$

In the formula, ω is the true angular speed of aircraft, ω _gAngular velocity measurement value for optical fibre gyro output; B is the optical fibre gyro drift value, comprises constant value drift and random drift, and the random drift part is driven by the angular speed random walk and produces among the b; n _uLong term drift speed for optical fibre gyro; n _vBe optical fibre gyro angular rate measurement noise, be assumed to be the zero-mean white noise, satisfy:

$E\left[n_v\left(t\right)n_v\left(\mathrm{\τ}\right)\right]={\mathrm{\σ}}_v^2\mathrm{\δ}(t-\mathrm{\τ})=\left\{\begin{array}{cc}{\mathrm{\σ}}_v^2& t=\mathrm{\τ}\\ 0& t\≠\mathrm{\τ}\end{array}\right.---\left(\text{2}\right)$

Wherein, E[n _v(t) n _v(τ)] be stochastic variable n _v(t) and n _vCovariance (τ), σ _vBe the angle random migration coefficient of optical fibre gyro, δ (t) is dirac (Dirac) function, is also referred to as impulse function, satisfies $\left\{\begin{array}{cc}\mathrm{\δ}\left(t\right)=0& t\≠0\\ \mathrm{\δ}\left(t\right)=\∞& t=0\end{array}\right.,$ And ${\∫}_{-\∞}^{+\∞}\mathrm{\δ}\left(t\right)\mathrm{dt}=1.$

Optical fibre gyro drift b satisfies:

n _uShow as the long term drift speed of random walk, have standard deviation sigma _uThe integration white-noise process.n _uAverage is 0, and its variance satisfies:

$E\left[n_u\left(t\right)n_u\left(\mathrm{\τ}\right)\right]={\mathrm{\σ}}_u^2\mathrm{\δ}(t-\mathrm{\τ})=\left\{\begin{array}{cc}{\mathrm{\σ}}_u^2& t=\mathrm{\τ}\\ 0& t\≠\mathrm{\τ}\end{array}\right.---\left(\text{3}\right)$

In the formula, σ _uSpeed random walk coefficient for optical fibre gyro.

2. optical fibre gyro state-noise covariance matrix model

Choose optical fibre gyro angular velocity integrated value θ and optical fibre gyro drift value b is new state variable, form new state equation, again the state equation discretize is handled, obtain the discretization equation of state variable θ and b.The covariance matrix Q that calculates state-noise in the discretization equation is:

$Q=\left[\begin{array}{cc}{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">v</figure-callout>}}^2\mathrm{\&Delta;t}+\frac{1}{3}{\mathrm{\&sigma;}}_u^2\mathrm{\&Delta;}{t}^3& -\frac{1}{2}{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">v</figure-callout>}}^2\mathrm{\&Delta;}{t}^2\\ -\frac{1}{2}{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">v</figure-callout>}}^2{\mathrm{\&Delta;<figure-callout\; id="2"\; label="t"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">t</figure-callout>}}^2& {\mathrm{\&sigma;}}_u^2\mathrm{\&Delta;t}\end{array}\right]---\left(4\right)$

Wherein,

Be the long term drift speed n that has described optical fibre gyro _uΔ t(is the discrete sampling time in time) in the angular speed drift that causes; Be to have reacted Gyro Random drift b and measured noise n _vThe common integral error angle of Δ t in time.

3. optical fibre gyro turntable high precision measurement

Utilize the special high-accuracy turntable that optical fibre gyro is tested, test it in time T ₁(T ₁Be not less than 4 hours) interior angle speed drift variation delta ω (1 σ), in time T ₂The changes delta θ of (0.5～1 hour) interior integration output angle _m(1 σ).

4. optical fibre gyro angle random migration factor sigma _vWith speed random walk factor sigma _uCalculating

Utilize the turntable test result, calculate the angle random migration factor sigma of optical fibre gyro again according to formula (4) _vWith speed random walk factor sigma _u:

$\left\{\begin{array}{c}{\mathrm{\&sigma;}}_u^2{T}_1\mathrm{\&Delta;}{\mathrm{\&omega;}}^2\\ {\mathrm{\&sigma;}}_v^2{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">T</figure-callout>}}_2+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}^3{\mathrm{\&Delta;\&theta;}}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">m</figure-callout>}}^2\end{array}\right.\&DoubleRightArrow;\left\{\begin{array}{c}{\mathrm{\&sigma;}}_u=\frac{\mathrm{\&Delta;\&omega;}}{\sqrt{T_1}}\\ {\mathrm{\&sigma;}}_v=\sqrt{\frac{{\mathrm{\&Delta;\&theta;}}_m^2-\frac{{{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="HDA00003091299800011.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}^3}{3T_1}{\mathrm{\&Delta;\&omega;}}^2}{T_2}}\end{array}\right.---\left(5\right)$

In the formula, T ₁Be the time of turntable measuring fiber gyro angular velocity drift variable quantity, T ₂Be the time of turntable measuring fiber gyro integration output angle variation.

5. optical fibre gyro angle step error compensation

The angle random migration factor sigma of the optical fibre gyro that is obtained by step 4 _vWith speed random walk factor sigma _u, again according to the physical significance of the state covariance matrix Q in the step 2, obtain the angular error σ that any t moment optic fiber gyroscope random drift and noise produce _θ(t) be:

${\mathrm{\&sigma;}}_{\mathrm{\&theta;}}\left(t\right)=\sqrt{{\mathrm{\&sigma;}}_v^{2}t+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{t}^3}---\left(6\right)$

So, any adjacent time t _I+1And t _iThe angle step that optical fiber gyro random error and noise produce is:

$\mathrm{\&Delta;}{\mathrm{\&sigma;}}_{\mathrm{\&theta;}}\left(\mathrm{\&Delta;T}\right)=\sqrt{{\mathrm{\&sigma;}}_v^2{t}_{i+1}+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{t}_{i+1}^3}-\sqrt{{\mathrm{\&sigma;}}_v^2{t}_i+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{t}_i^3}(\mathrm{\&Delta;T}=t_{i+1}-t_i)---\left(7\right)$

In addition, because the output of optical fibre gyro is t _I+1The angle step value Δ θ (3 σ) in the sampling time Δ T constantly, wherein Δ θ has comprised optical fibre gyro the angle changes delta θ that the true angular velocity of carrier causes has been installed ₁, the angle changes delta θ that causes of optical fibre gyro measuring error ₂Two parts.We expect to use Δ σ _θThe angle changing value Δ θ that is caused by measuring error is fallen in (Δ T) compensation ₂, obtain the angle step Δ θ after the compensation in the Δ T time _BchFor:

${\mathrm{\&Delta;\&theta;}}_{\mathrm{bch}}=\mathrm{\&Delta;\&theta;}-3{\mathrm{\&Delta;\&sigma;}}_{\mathrm{\&theta;}}\left(\mathrm{\&Delta;T}\right)=\mathrm{\&Delta;\&theta;}-3(\sqrt{{\mathrm{\&sigma;}}_v^2{t}_{i+1}+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{t}_{i+1}^3}-\sqrt{{\mathrm{\&sigma;}}_v^2{t}_i+\frac{1}{3}{\mathrm{\&sigma;}}_u^2{t}_i^3})---\left(\text{8}\right)$

6. optical fibre gyro high precision angular speed calculation

Because optical fibre gyro output is angle step, also need to carry out the differential processing for obtaining angular velocity.Therefore, after the compensated optical fiber Gyro Random error, can obtain the high precision angular velocity omega of aircraft:

$\mathrm{\&omega;}=\frac{{\mathrm{\&Delta;\&theta;}}_{\mathrm{bch}}}{\mathrm{\&Delta;T}}---\left(9\right)$

It more than is the step explanation to optical fiber gyro random error modeling of the present invention and compensation method, after obtaining high-precision attitude angular velocity by method of the present invention, in aircraft subsequent control system and inertial navigation system design, realize high-precision attitude control and High Accuracy Inertial benchmark thus.

More than specific embodiments of the invention are described.It will be appreciated that the present invention is not limited to above-mentioned specific implementations, those skilled in the art can make various distortion or modification within the scope of the claims, and this does not influence flesh and blood of the present invention.

Claims (4)

1. the high-accuracy compensation method of an optical fiber gyro random error is characterized in that, comprises the steps:

Step 1: the optical fibre gyro measurement model is carried out modeling, according to the random drift of optical fibre gyro and the characteristic of noise, try to achieve the variance that state-noise changes, as the input of optical fibre gyro state-noise covariance matrix model;

Step 2: the optical fibre gyro measurement model in the step 1 is carried out discretize, calculate noisiness after the discretize, obtain the model of optical fibre gyro state-noise covariance matrix;

Step 3: utilize test table measuring fiber gyro, test is in time T ₁Interior angle speed drift variable quantity and time T ₂The variation of interior integration output angle;

Step 4: utilize test table test result in the model of optical fibre gyro state-noise covariance matrix in the step 2 and the step 3, try to achieve angle random migration coefficient and the angular velocity random walk coefficient of optical fibre gyro;

Step 5: the optical fibre gyro angle random migration coefficient and the angular velocity random walk coefficient that utilize step 4 to obtain, calculate the angle step drift value of any adjacent moment optical fibre gyro, because of the angle step error that the optical fibre gyro measurement brings, obtain the optical fibre gyro angle step value after any time compensates with this drift value compensation in the sampling time;

Step 6: optical fibre gyro angle step after the compensation that obtains by step 5, handle through the differential in the sampling time again and obtain the output of optical fibre gyro high precision angular velocity.

2. the high-accuracy compensation method of optical fiber gyro random error according to claim 1 is characterized in that time T ₁Be not less than 4 hours.

3. the high-accuracy compensation method of optical fiber gyro random error according to claim 1 is characterized in that time T ₂It is 0.5～1 hour.

4. the high-accuracy compensation method of optical fiber gyro random error according to claim 1 is characterized in that, also comprises the steps:

Step 7: will export to aircraft subsequent control system and inertial navigation system by the optical fibre gyro high precision angular velocity that step 6 obtains, to realize high-precision attitude control and High Accuracy Inertial benchmark.

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