CN104567932A

CN104567932A - High-precision fiber-optic gyroscope inertial measurement device calibration method

Info

Publication number: CN104567932A
Application number: CN201510024279.1A
Authority: CN
Inventors: 张峰; 向政; 邢向明; 孟祥涛; 邢辉; 韩英杰; 郑极石; 刘玲
Original assignee: Beijing Aerospace Times Optical Electronic Technology Co Ltd
Current assignee: Beijing Aerospace Times Optical Electronic Technology Co Ltd
Priority date: 2015-01-16
Filing date: 2015-01-16
Publication date: 2015-04-29
Also published as: DE102016100618A1; WO2016112571A1; JP6613236B2; JP2018508007A

Abstract

The invention discloses a high-precision fiber-optic gyroscope inertial measurement device calibration method which comprises the following steps: S1, respectively forwards turning a fiber-optic gyroscope inertial measurement device by 90 degrees, 180 degrees and 270 degrees for three times according to three axes of oi shaft (i refers to X, Y and Z), reversely rotating the device by 90 degrees, 180 degrees and 270 degrees for three times, and returning to an initial position; and S2, totally moving by 19 positions comprising the previous 18 turning positions and the initial position, fully exciting the error of the instrument under static and dynamic conditions, and performing optimal estimation by utilizing a parameter estimation method. According to the method disclosed by the invention, repeated electrification and power failure are not needed, the device is only turned according to a certain sequence, the parameters can be identified, and the influence caused by inconsistent reference in the repeated electrification and calibration process is avoided.

Description

High-precision fiber optic gyroscope inertial measurement device calibration method

Technical Field

The invention relates to the field of fiber-optic gyroscope inertia measurement devices, in particular to a calibration method of a high-precision fiber-optic gyroscope inertia measurement device.

Background

The satellite is used as a mark for high-tech development and plays an extremely important role in national defense and economic construction in China. The attitude determination precision is the premise that a satellite stably and effectively acquires information, the satellite attitude control system is one of important systems for ensuring the satellite attitude precision, and the inertial device is an extremely key sensor in the satellite attitude control system and directly influences the precision and the performance of the attitude control system.

The optical fiber gyroscope is an all-solid-state inertial instrument and has the advantages which are not possessed by the traditional electromechanical instrument. The gyroscope is a closed-loop system consisting of an optical device and an electronic device, and determines the angular velocity of the gyroscope by detecting the phase difference of two beams of light, so the gyroscope is structurally a completely solid gyroscope without any moving part. The optical fiber gyroscope has the advantages in principle and structure, so that the optical fiber gyroscope has obvious advantages in many application fields, and particularly has the following main characteristics on a spacecraft with high requirements on product reliability and service life: (1) all solid state: the components of the optical fiber gyroscope are all solid, and have the characteristics of vacuum resistance, vibration resistance and impact resistance; (2) long service life: the key optical devices used by the optical fiber gyroscope can meet the long-life requirement of 15 years of space application; (3) high reliability: the optical fiber gyroscope has flexible structural design and relatively simple production process, can be conveniently subjected to redundant design of a circuit, or adopts a redundant gyroscope to form an inertial measurement system, so that the reliability of the system can be improved.

The existing calibration technology for the fiber optic gyroscope inertia measurement device is obtained through different test items, wherein zero offset is obtained through averaging at a plurality of positions, scale factors are obtained through fitting by rotating a plurality of angular velocities in the positive and negative directions, and installation errors are obtained through rotating the positive and negative directions for a full circle at a large angular velocity. The calibration process inevitably generates multiple power-on and power-off operations, and has the problem of inconsistent reference, so that a large amount of human errors are introduced into the calibration result. And the calibration process is long in time, and the calibration time is several hours. The existing calibration methods calculate parameters under the working conditions of static state (including static position and uniform motion of a turntable), and do not consider the error of an instrument in the dynamic process.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for quickly and accurately calibrating the high-precision fiber-optic gyroscope inertial measurement device is provided, and the problems of large human error and long process time in the calibration method in the prior art are solved.

The technical scheme of the invention is as follows:

a calibration method of a high-precision fiber-optic gyroscope inertial measurement device comprises the following steps of S1, turning the fiber-optic gyroscope inertial measurement device by 90 degrees, 180 degrees and 270 degrees in the forward direction and then reversely rotating by 90 degrees, 180 degrees and 270 degrees for three times according to three axes of an oi axis (i is X, Y, Z), returning to an initial position, and turning the position for 18 times in total; s2, adding 19 positions in the initial position together with 18 times of position overturning, setting a coordinate system b of the fiber optic gyroscope inertial measurement device body, and establishing an error model relation of a gyroscope and an accelerometer as follows:

wherein:

for the measurement error of three gyroscopes,

D = [\begin{matrix} D_{x} \\ D_{y} \\ D_{z} \end{matrix}]

is the zero-bias of the gyroscope,

M = [\begin{matrix} M_{xx} & M_{xy} & M_{xz} \\ M_{yx} & M_{yy} & M_{yz} \\ M_{zx} & M_{zy} & M_{zz} \end{matrix}]

is the coupling coefficient of the gyroscope,

is the output value of the gyroscope,

for the measurement error of three accelerometers,

B = [\begin{matrix} B_{x} \\ B_{y} \\ B_{z} \end{matrix}]

for the zero-offset of the accelerometer,

K = [\begin{matrix} K_{xx} & 0 & 0 \\ K_{yx} & K_{yy} & 0 \\ K_{zx} & K_{zy} & K_{zz} \end{matrix}]

for the coupling coefficient of the accelerometer,

f^{b} = [\begin{matrix} f_{x}^{b} \\ f_{y}^{b} \\ f_{z}^{b} \end{matrix}]

the accelerometer output value.

Further, the method comprises the following step, S3, setting the navigation coordinate system as n, and establishing the simplified velocity error equation and the simplified attitude error equation as follows:

wherein:

is the error in the acceleration of the three axes,

is the attitude angular acceleration error of the three axes,

is the error in the attitude of the three axes,

f^{n} = [\begin{matrix} f_{x}^{n} \\ f_{y}^{n} \\ f_{z}^{n} \end{matrix}]

for the output of the accelerometer in the navigation coordinate system n,

is the projection value of the ground speed component in the navigation coordinate system,

for the measurement error of the accelerometer in the navigation coordinate system n,

the measurement error of the gyroscope in the navigation coordinate system n.

Further, three process calculations including initial alignment, position flipping and static navigation are included; wherein,

an initial alignment process: attitude conversion obtained by initial alignment of fiber optic gyroscope inertial measurement unit at 0 th position (initial position)0 is:

in the mth position, the measurement error of the accelerometer in the navigation coordinate system is:

the calculated speed error is then:

the initial alignment process is carried out by a single alignment process,namely:

then the initial value of the error angle phi at the m-th position can be calculated_x0、φ_y0And phi_z0；

And (3) a position overturning process: the initial alignment completion moment of the fiber-optic gyroscope inertia measurement device at the mth position is recorded as t₀When the vehicle is turned to the (m +1) th position around a certain axis oi (i ═ X, Y, Z), the turning angular velocity is The turning angle is 90 degrees, and the turning finishing moment is t_bNeglecting the sum of the constant drifts of the gyroscopesInfluence of (2), the attitude error angleThe approximation is:

wherein:the results are as follows:

at (t)₀,t_b) In time, the resulting attitude angle error is:

<math> <mrow> <mi>Δφ</mi> <mo>=</mo> <mo>-</mo> <msubsup> <mo>&Integral;</mo> <msub> <mi>t</mi> <mn>0</mn> </msub> <msub> <mi>t</mi> <mi>b</mi> </msub> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>C</mi> <msub> <mi>b</mi> <mn>0</mn> </msub> <mi>n</mi> </msubsup> <mo>·</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>C</mi> <msub> <mi>b</mi> <mn>0</mn> </msub> <msub> <mi>b</mi> <mi>m</mi> </msub> </msubsup> <mo>)</mo> </mrow> <mi>T</mi> </msup> <mo>·</mo> <msubsup> <mi>δω</mi> <msub> <mi>ib</mi> <mi>m</mi> </msub> <msub> <mi>b</mi> <mi>m</mi> </msub> </msubsup> <mo>)</mo> </mrow> <mi>dt</mi> <mo>;</mo> </mrow> </math>

and (3) static navigation process: after the material is turned to the (m +1) th position in the position turning process, the turning completion time is t_bStarting static navigation, the navigation end time is t_eThe error equation is calibrated for the system at (t)_b,t_e) Integrating the time period to obtain the speed error V in the time periodⁿAnd attitude angle φ:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msup> <mi>δV</mi> <mi>n</mi> </msup> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <msub> <mi>t</mi> <mi>b</mi> </msub> <msub> <mi>t</mi> <mi>e</mi> </msub> </msubsup> <mrow> <mo>(</mo> <msup> <mi>f</mi> <mi>n</mi> </msup> <mo>×</mo> <mi>φ</mi> <mo>+</mo> <msup> <mi>δf</mi> <mi>n</mi> </msup> <mo>)</mo> </mrow> <mi>dt</mi> </mtd> </mtr> <mtr> <mtd> <mi>φ</mi> <mo>=</mo> <mo>-</mo> <msubsup> <mo>&Integral;</mo> <msub> <mi>t</mi> <mi>b</mi> </msub> <msub> <mi>t</mi> <mi>e</mi> </msub> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>ω</mi> <mi>ie</mi> <mi>n</mi> </msubsup> <mo>×</mo> <mi>φ</mi> <mo>+</mo> <msubsup> <mi>δω</mi> <mi>ib</mi> <mi>n</mi> </msubsup> <mo>)</mo> </mrow> <mi>dt</mi> </mtd> </mtr> </mtable> </mfenced> </math>

writing the speed error equation in the static navigation process into the following form:

wherein:is t_bError value of time velocity, V_Dx、V_DyAnd V_DzThe error amount after the integration of the three-axis velocity is shown,the three directional speed error primary term coefficients and the three directional speed error secondary term coefficients are respectively;

writing an attitude error equation in the static navigation process into the following form:

wherein:

where u represents the attitude error equation first order coefficient.

Further, M is identified by adopting a least square method_xx、M_yy、M_zz、M_xy、M_xz、M_yx、M_yz、M_zx、M_zy、D_x、D_y、D_z、K_xx、K_yy、K_zz、K_yx、K_zx、K_zy、B_x、B_y、B_zThe total number of the parameters is 21.

Further, establishingThe measurement equation of (a) is:

Z_i＝H_i·X_i+V_i(i＝x,y,z)

wherein:

estimation of a state vector X using a least squares method_iThe calculation is as follows:

compared with the prior art, the invention has the advantages that:

(1) under the same reference condition, the identification of the parameters can be completed only by turning over the fiber-optic gyroscope inertia measurement device according to a certain sequence without repeatedly powering on and off, and the influence caused by inconsistent reference in the repeated powering on and calibrating processes is avoided.

(2) The method fully excites the error of the instrument under static and dynamic working conditions, and utilizes a parameter estimation method to carry out optimal estimation so as to realize system-level optimization.

(3) Compared with other types of fiber optic gyroscope inertia measurement device test methods, the method is a rapid calibration method, is simple and feasible, does not exceed half an hour in the whole calibration process, improves the calibration efficiency, and saves manpower and material resources.

(4) Compared with other types of fiber optic gyroscope inertial measurement unit test methods, the method does not need to distinguish scale factors and installation errors, and avoids calculation errors caused by small calculation and installation errors.

Drawings

FIG. 1 is a flow chart of an implementation of the calibration method of the present invention;

fig. 2 is a schematic view of the measurement position of the calibration method of the present invention.

Detailed Description

Aiming at the problems in the prior art, the invention provides a calibration method of a high-precision fiber-optic gyroscope inertial measurement device, which is carried out under the same working condition without replacing a tool, ensures the consistency of a reference surface, only completes one test item and is simple in test operation; the calibration method has short test time, and only needs about half an hour. The method fully excites the error of the instrument under static and dynamic working conditions, and utilizes a parameter estimation method to carry out optimal estimation; compared with other types of fiber optic gyroscope inertia measurement device test methods, the method is simple and easy to implement, the calibration efficiency is improved, and manpower and material resources are saved.

The technical scheme of the invention is as follows:

the high-precision fiber optic gyroscope inertial measurement device is installed in a hexahedral tool, wherein an X axis, a Y axis and a Z axis are respectively turned over for 90 degrees, 180 degrees and 270 degrees in the forward direction according to three axes of an oi axis (i is X, Y, Z) and then are turned over for 90 degrees, 180 degrees and 270 degrees in the reverse direction for three times to return to an initial position, 18 times of position turning is carried out in total, and the initial position comprises 19 positions. For example: taking 19 positions of north heaven, south earth east, north earth east, south earth east, north west heaven, south west south earth, south west earth, north west earth, south west earth, north west earth and north earth east for calibration.

According to the relation among the 19 positions, parameters such as scale factors, coupling errors and zero positions of the gyroscope and the accelerometer can be obtained by using a navigation error equation under each position.

One specific embodiment is as follows:

as shown in fig. 1, the calibration method of the fiber-optic gyroscope inertial measurement unit (inertial measurement unit) includes the following steps:

(1) the X-axis, the Y-axis and the Z-axis of the high-precision fiber-optic gyroscope inertial measurement device are respectively turned by 90 degrees, 180 degrees and 270 degrees in the forward direction according to an oi-axis (i is X, Y, Z), then are reversely rotated by 90 degrees, 180 degrees and 270 degrees, return to the initial position, are subjected to 18-time position turning, and totally comprise 19 positions. For example, 19 positions of north heaven, south heaven, north west heaven, south west earth, north west earth, south west earth, north west earth and north heaven are used for calibration.

(2) Setting a body coordinate system b of the high-precision fiber optic gyroscope inertial measurement device, and establishing an error model relation between a gyroscope and an accelerometer as follows:

wherein:

for the measurement error of three gyroscopes,

D = [\begin{matrix} D_{x} \\ D_{y} \\ D_{z} \end{matrix}]

is the zero-bias of the gyroscope,

M = [\begin{matrix} M_{xx} & M_{xy} & M_{xz} \\ M_{yx} & M_{yy} & M_{yz} \\ M_{zx} & M_{zy} & M_{zz} \end{matrix}]

is the coupling coefficient of the gyroscope,

is the output value of the gyroscope,

for the measurement error of three accelerometers,

B = [\begin{matrix} B_{x} \\ B_{y} \\ B_{z} \end{matrix}]

for the zero-offset of the accelerometer,

K = [\begin{matrix} K_{xx} & 0 & 0 \\ K_{yx} & K_{yy} & 0 \\ K_{zx} & K_{zy} & K_{zz} \end{matrix}]

for the coupling coefficient of the accelerometer,

f^{b} = [\begin{matrix} f_{x}^{b} \\ f_{y}^{b} \\ f_{z}^{b} \end{matrix}]

the accelerometer output value.

Setting a navigation coordinate system as n, and establishing a speed error equation and an attitude error equation as follows:

considering V in the calibration processⁿIs 0, easy to knowNeglecting the acceleration involvedThe above equation reduces to:

wherein:

is the error in the speed of the three axes,

attitude error for three axes，

f^{n} = [\begin{matrix} f_{x}^{n} \\ f_{y}^{n} \\ f_{z}^{n} \end{matrix}]

For the output of the accelerometer in the navigation coordinate system n,

the measurement error of the gyroscope in the navigation coordinate system n.

(3) Attitude conversion obtained by initial alignment of fiber optic gyroscope inertial measurement unit at 0 th position (initial position)Comprises the following steps:

in the above formulaAnd (3) representing the posture conversion matrix of the mth relative initial position, and calculating the speed error as follows:

the initial alignment process is carried out by a single alignment process,then the initial value of the horizontal attitude error angle phi at the m-th position can be calculated_x0And phi_z0。

(4) The initial alignment completion moment of the high-precision fiber-optic gyroscope inertia measurement device at the mth (m is more than or equal to 1 and less than or equal to 18) position is recorded as t₀When the vehicle is turned to the (m +1) th position around a certain axis oi (i ═ X, Y, Z), the turning angular velocity is The turning angle is 90 degrees, and the turning finishing moment is t_bConsider a shorter roll-over process time and a lower constant drift (typically 10) for a high-precision gyroscope^-3In the order of deg/h), ignoring the sum of the constant drifts of the gyroscopeInfluence of (2), the attitude error angleThe approximation is:

in the above formulaRepresenting the component of the angular velocity of rotation of the earth relative to an inertial frame;the gyroscope body system measures the error of the navigation coordinate system n relative to the inertial coordinate system;representing the measurement error of the gyroscope at the mth position. Wherein:the results are as follows:

at (t)₀,t_b) In time, the resulting attitude angle error is:

(5) after the step (4) is turned to the (m +1) th position, the turning completion time is t_bStarting static navigation, the navigation end time is t_eThe error equation is calibrated for the system at (t)_b,t_e) Integrating the time period to obtain the time periodSpeed error VⁿAnd attitude error Δ φ:

writing a speed error equation and an attitude error in the static navigation process into the following forms:

wherein:is t_bError value of time velocity, V_Dx、V_DyAnd V_DzThe error amount after the integration of the three-axis velocity is shown,the three directional speed error first-order coefficient and second-order coefficient are respectively.

wherein:

u represents only the first order error parameter of the above equation. EstablishingThe measurement equation of (a) is:

Z_i＝H_i·X_i+V_i(i＝x,y,z)

wherein:

(6) obtained in step (7) during 18 times of turning positions And (3) related equations, wherein 90 equations in total can be obtained from 18 equation sets, and measurement equations of all error parameters of the instrument are established:

Z＝H·X+V

X = {[\begin{matrix} M_{xx} & M_{yy} & M_{zz} & M_{xy} & M_{xz} & M_{yx} & M_{yz} & M_{zx} & M_{zy} & D_{x} & D_{y} & D_{z} & K_{xx} & K_{yy} & K_{zz} & K_{yx} & K_{zx} & K_{zy} & B_{x} & B_{y} & B_{z} \end{matrix}]}^{T}

the state vector X is estimated using the least squares method, as follows:

table 1 shows a summary of 19 positions of the invention, as follows.

TABLE 1

Claims

1. A calibration method of a high-precision fiber-optic gyroscope inertial measurement device is characterized by comprising the following steps,

s1, the fiber optic gyroscope inertial measurement device is turned over by 90 degrees, 180 degrees and 270 degrees in the forward direction and then reversely rotated by 90 degrees, 180 degrees and 270 degrees by three times according to three axes of oi axis (i is X, Y, Z), the fiber optic gyroscope inertial measurement device returns to the initial position by three times, and the position turning is carried out for 18 times in total;

s2, adding 19 positions in the initial position together with 18 times of position overturning, setting a coordinate system b of the fiber optic gyroscope inertial measurement device body, and establishing an error model relation of a gyroscope and an accelerometer as follows:

wherein:for the measurement error of three gyroscopes,is the zero-bias of the gyroscope,is the coupling coefficient of the gyroscope,is the output value of the gyroscope,

for the measurement error of three accelerometers,for the zero-offset of the accelerometer,for the coupling coefficient of the accelerometer,the accelerometer output value.

2. The calibration method of the high-precision fiber-optic gyroscope inertial measurement unit according to claim 1, characterized by comprising the following steps,

s3, setting a navigation coordinate system as n, and establishing a simplified speed error equation and an attitude error equation as follows:

wherein:is the error in the acceleration of the three axes,is the attitude angular acceleration error of the three axes,is the error in the attitude of the three axes,for the output of the accelerometer in the navigation coordinate system n,is the projection value of the ground speed component in the navigation coordinate system,for the measurement error of the accelerometer in the navigation coordinate system n,the measurement error of the gyroscope in the navigation coordinate system n.

3. The calibration method of the high-precision fiber-optic gyroscope inertial measurement unit according to claim 1, characterized by comprising three process calculations of initial alignment, position overturning and static navigation; wherein,

an initial alignment process: the fiber optic gyroscope inertial measurement unit performs attitude conversion obtained by initial alignment at the 0 th position (initial position)Comprises the following steps:

the calculated speed error is then:

And (3) a position overturning process: the initial alignment completion moment of the fiber optic gyroscope inertia measurement device at the mth position is recorded as t₀When the vehicle is turned to the (m +1) th position around a certain axis oi (i ═ X, Y, Z), the turning angular velocity is The turning angle is 90 degrees, and the turning finishing moment is t_bNeglecting the sum of the constant drifts of the gyroscopesInfluence of (2), the attitude error angleThe approximation is:

wherein:the results are as follows:

at (t)₀,t_b) In time, the resulting attitude angle error is:

wherein:

u represents the attitude error equation first order coefficient.

4. The method for calibrating the inertial measurement unit of the high-precision fiber-optic gyroscope of claim 3, wherein M is identified by using a least square method_xx、M_yy、M_zz、M_xy、M_xz、M_yx、M_yz、M_zx、M_zy、D_x、D_y、D_z、K_xx、K_yy、K_zz、K_yx、K_zx、K_zy、B_x、B_y、B_zThe total number of the parameters is 21.

5. The method for calibrating the high-precision fiber-optic gyroscope inertial measurement unit according to claim 4,

establishingThe measurement equation of (a) is:

Z_i＝H_i·X_i+V_i(i＝x,y,z)

wherein:

。