CN101839719A - Inertial measurement unit based on gyroscope and geomagnetic sensor - Google Patents

Abstract

The invention discloses an inertial measurement unit based on a gyroscope and geomagnetic sensors. The unit is formed by a three-axis MEMS gyroscope and two film geomagnetic sensors. By using the characteristics that the film geomagnetic sensors do not accumulate errors with flight time, the film geomagnetic sensors and the inertial device, i.e. the three-axis MEMS gyroscope are designed in a combining way. The invention adopts a state estimation method, an attitude determination system takes the high-precision film geomagnetic sensors as attitude measurement references and corrects the drift of the three-axis MEMS gyroscope, and a comparatively accurate extended Kalman filter algorithm is adopted to improve the precision of attitude determination. The invention has the advantages of small volume, light weight and low cost, and can be used in the high-speed rotating missile attitude measurement field.

Description

A kind of inertial measuring unit based on gyro, geomagnetic sensor

One, technical field

The invention belongs to high speed rotating bullet attitude measurement field, be specifically related to a kind of inertial measuring unit based on gyro, geomagnetic sensor.

Two, background technology

In modern war, precision strike is trend of the times, and countries in the world make great efforts to develop new guided munition on the one hand, also making great efforts that the great amount of conventional ammunition is transformed into dexterous ammunition, makes it have precision strike capability on the one hand.High speed rotating is one of the most frequently used stationary mode of conventional ammunition, and the attitude information that obtains the high speed rotating bullet is the only way that it is transformed.Therefore, design is applicable to that the inertial measurement system of high speed rotating, small size just seems particularly important, in the conventional inertia measuring system, often utilizes the acceleration of linear accelerometer Measuring Object, utilizes the angular velocity of gyro to measure object.But since traditional accelerometer exist install complicated, installation accuracy require high, resolve problem such as complexity, given up accelerometer here as inertia device, adopt wide range MEMS gyro.Though gyro is the output angle velocity information continuously, there is drift, prolonged application can produce bigger deviation; And the short-term accuracy of film coil sensor is not as inertia device, but it has the not cumulative errors with the flight time, high precision, high-responsivity, small volume etc., the high plurality of advantages of reliability, be that it becomes the many navigational materials of present research, make up the attitude angle information that to determine flying body exactly with other inertia device, can improve the overall navigation precision and the navigation performance of system.Therefore the present invention adopts the state estimation method, attitude and heading reference system with the output of film coil sensor as attitude reference, output with the film coil sensor is proofreaied and correct gyroscopic drift, and adopt more accurate general Kalman filtering algorithm to improve the precision that attitude is determined, at last its effect has been carried out emulation, analysis.

The present invention proposes a kind of attitude measurement that is applicable to the inertial navigation system of high speed rotating, small size, its purpose is to make full use of the advantage of film coil, gyrosensor, overcome the single method algorithm and resolve the existing weak point of attitude angle, a kind of brand-new 3 d pose measuring method has been proposed, and adopt more accurate general Kalman filtering algorithm to improve the precision that attitude is determined, the present invention satisfies the needs of small size attitude measurement, and the 3 d pose measuring system designed of this method has characteristics such as reliability height, cost be low, easy to operate again.

Three, summary of the invention

The invention provides a kind of inertial measuring unit based on gyro, geomagnetic sensor, solved installation complexity, installation accuracy that the conventional inertia measurement utilizes accelerometer to exist require high, resolve complexity and utilize gyroscope survey to exist precision to be subjected to the influence of gyro angular speed drift separately and utilize the diaphragm type geomagnetic sensor can not continuous three problems of deciding appearance separately, and combine the general Kalman filtering algorithm for estimating on this basis, for the research inertia combined navigation system, improve the significant and actual application value of attitude information of high speed rotating bullet.

The present invention can be achieved through the following technical solutions: a kind of inertial measuring unit based on gyro, geomagnetic sensor, comprise gyro and geomagnetic sensor, and gyro adopts the 3 axis MEMS gyro, and geomagnetic sensor adopts two diaphragm type geomagnetic sensors.The diaphragm type geomagnetic sensor adopts the film coil sensor, and the film coil sensor is the electromagnetic induction diaphragm type coil of a n circle coil.

A kind of inertial measuring unit based on gyro, geomagnetic sensor is located in the metal cylinder of cylindrical non iron material, be provided with the 3 axis MEMS gyro in the metal cylinder, the 3 axis MEMS gyro is made up of gyro face 1, gyro face 3 and gyro face 4, the outer wall of metal cylinder is provided with the diaphragm type geomagnetic sensor, the diaphragm type geomagnetic sensor is made up of film coil sensor 2 and film coil sensor 5, and film coil sensor 2 is perpendicular to film coil sensor 5.

A kind of based on gyro, the attitude parameter calculation method that the inertial measuring unit of geomagnetic sensor is measured adopts general Kalman filtering attitude algorithm for estimating, the output of the diaphragm type geomagnetic sensor that precision is higher is as the attitude measurement benchmark, be used for revising the error of 3 axis MEMS gyro, utilize the 3 axis MEMS gyro to remedy the diaphragm type geomagnetic sensor and decide the shortcoming that there is the real-time difference in appearance, simultaneously for fear of the error of calculation that causes by non-linear and low-angle, adopt the hypercomplex number method to replace common Euler's horn cupping to calculate, obtain this System State Model and observation model by analysis.

The present invention compared with prior art has following beneficial effect:

1, the present invention has given up the practice of traditional inertial navigation system employing accelerometer as inertia device, but adopted the 3 axis MEMS gyro to carry out angular velocity measurement, the 3 axis MEMS gyro is the output angle rate signal continuously, and it has: dynamic range height, reliability height, start-up time advantage such as weak point, low cost.

2, the present invention at first introduces attitude measurement with the diaphragm type geomagnetic sensor, as supplementary means, the output of the diaphragm type geomagnetic sensor that precision is higher is as the attitude measurement benchmark, be used for revising the error of 3 axis MEMS gyro, utilize the 3 axis MEMS gyro to remedy the diaphragm type geomagnetic sensor simultaneously and decide the shortcoming that there is the real-time difference in appearance.The diaphragm type geomagnetic sensor is simple in structure, size is little, can anti high overload and impact, signal deteching circuit is highly sensitive, working stability, reliable, the ratio of performance to price is high.

3, the present invention combines general Kalman filtering attitude algorithm for estimating, under the situation that does not increase hardware cost, improves system accuracy and reliability.

4, this inertial measuring unit that is applicable to high speed rotating, small size of the present invention's proposition has reliability height, low, the convenience operation of cost.

Four, description of drawings

Fig. 1 is a structural representation of the present invention,

Fig. 2 is a high speed rotating bullet attitude and heading reference system shop drawing,

Fig. 3 is the attitude algorithm block diagram.

Five, embodiment

Be described in further detail by embodiment below in conjunction with accompanying drawing.

A kind of inertial measuring unit based on gyro, geomagnetic sensor is located in the metal cylinder of cylindrical aluminium material, be provided with the 3 axis MEMS gyro in the metal cylinder, the 3 axis MEMS gyro is made up of gyro face 1, gyro face 3 and gyro face 4, the outer wall of metal cylinder is provided with the diaphragm type geomagnetic sensor, the diaphragm type geomagnetic sensor is made up of film coil sensor 2 and film coil sensor 5, and film coil sensor 2 is perpendicular to film coil sensor 5.

The 3 axis MEMS gyro is installed on the orthogonal plane of posture testing system, their sensitive axes is orthogonal, the three-dimensional system of coordinate of forming measuring body, as shown in Figure 1, GX, GY, GZ are respectively three sensitive axes of MEMS gyroscope G1, true origin O is positioned at the geometric center of high speed rotating bullet, and the direction that GX, GY, GZ are three and the missile coordinate system of high speed rotating bullet are consistent, and two film coil sensors vertically are attached on two faces of metal cylinder.The speed of measuring body utilizes this system can accurately measure the high speed rotating bullet in each 3 d pose information constantly more than 10r/s.

The angular velocity signal of the 3 axis MEMS gyro of at first sampling output is set up the angular velocity mathematical model according to actual conditions, utilizes the hypercomplex number method to calculate one group of quaternary numerical value; The tach signal of the film coil sensor of sampling then output also converts thereof into angular velocity signal, with the output of film coil sensor as the attitude measurement benchmark, be used for revising the error of 3 axis MEMS gyro, utilize the 3 axis MEMS gyro to remedy the shortcoming that the film coil sensor is decided appearance real-time difference simultaneously, adopt broad sense Kalman attitude algorithm for estimating to the fusion of two groups of quaternary numerical value at last, obtain one group of more accurate quaternary numerical value.The present invention improves system accuracy and reliability, and can also provide the attitude of statistics to determine optimum solution under the situation that does not increase hardware cost, estimates some uncertain factors in reference vector and the measurement vector.

Then by Computer Processing signal of sensor and calculate measurement result, and test macro is carried out emulation, analysis, obtain needed attitude angle at last.

1, gyro to measure equation

Gyroscope claims turn meter can be used for detecting the angular velocity and the angle of rotation again.Utilizing the angular velocity of gyroscope survey carrier rotation, is to measure according to the principle of newton law of inertia.Three axle outputs of gyro obtain the angular velocity information of one group of body with the voltage signal that each axial angle rate variation of body changes.The gyro to measure model is that attitude is determined a major issue in the algorithm modeling, and in deciding the appearance filter design, the gyro to measure model that adopts is as follows usually:

ω _i＝ω+d+b+η _i (1)

ω _iBe the measurement output of gyro, ω _i∈ R _{3 * 1}ω is the coordinate of high speed rotating bullet relative inertness space on body series, ω ∈ R _{3 * 1}, d is the correlation of indices part in the gyroscopic drift, d ∈ R _{3 * 1}B is the gyroscope constant value drift part, b ∈ R _{3 * 1}η _iBe the measurement noise of gyro, η _i∈ R _{3 * 1}, suppose η usually _iBe white noise.

2, film coil sensor measurement equation

It is when rotate with the high speed rotating bullet by the coil (coil plane is along the flying body longitudinal axis) that two plane included angles are installed is θ that the film coil sensor is surveyed appearance, and coil cuts the terrestrial magnetic field magnetic line of force, and magnetic flux changes and produces induction electromotive force.According to the coil initial phase, when flying body departs from datum line, the size and Orientation generating period variation of induction electromotive force, metering circuit is noted each instantaneous induction electromotive force value, by resolving the spatial attitude angle that obtains flying body.According to Faraday's electromagnetic induction law, the induction electromotive force that produces in the coil:

By following formula as can be known, the information of voltage that is recorded by the film coil sensor can obtain the rotating speed and the angular velocity information of high speed rotating bullet.ω=[ω _x, ω _y, ω _z] ^TIt is the rotational angular velocity of film coil sensor relative inertness coordinate system.Utilize the film coil sensor can not continuous three to decide appearance separately, but can utilize orbital motion intermittently to obtain three-axis attitude, but utilize the film coil sensor to decide in the appearance application certain limitation is arranged separately, usually film coil sensor and gyro combination are carried out deciding appearance.The output of the film coil sensor of degree of precision as the attitude measurement benchmark, is used for revising the error of gyro.

3, hypercomplex number differential equation.With step 1,2 the differential equation of substitution hypercomplex number as a result:

When representing high speed rotating bullet attitude with attitude matrix, the Eulerian angle representation is classical attitude description, but will introduce six equation of constraint when finding the solution direction cosine, and calculated amount is bigger, and Euler's angie type needs repeatedly triangulo operation, and with the singular point problem.Therefore the present invention adopts the hypercomplex number method to replace Euler's horn cupping.Euler Parameter in the hypercomplex number method is compared with the direction cosine battle array, only contains four variablees and an equation of constraint; Compare with Euler's axle/angular dimensions formula, the element of attitude matrix does not contain trigonometric function, can be in the hope of realizing the attitude maneuver parameter of attitude to the expectation attitude maneuver, thereby draw the direction and the corner of Euler's axle, can draw more easily original state is tending towards the attitude maneuver hypercomplex number of expecting that attitude is required and the wide-angle singular problem of having avoided Euler's horn cupping to cause.The hypercomplex number differential equation is as follows:

Or

(2)

$\left[\begin{array}{c}{\stackrel{\&CenterDot;}{q}}_0\\ {\stackrel{\&CenterDot;}{q}}_1\\ {\stackrel{\&CenterDot;}{q}}_2\\ {\stackrel{\&CenterDot;}{q}}_3\end{array}\right]=\left[\begin{array}{cccc}0& \frac{-{\mathrm{\&omega;}}_x}{2}& \frac{-{\mathrm{\&omega;}}_y}{2}& \frac{-{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="HSA00000107432500011.png"\; state="\{\{state\}\}">z</figure-callout>}}}{2}\\ \frac{{\mathrm{\&omega;}}_x}{2}& 0& \frac{{\mathrm{\&omega;}}_z}{2}& \frac{-{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HSA00000107432500011.png"\; state="\{\{state\}\}">y</figure-callout>}}}{2}\\ \frac{{\mathrm{\&omega;}}_y}{2}& \frac{-{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="HSA00000107432500011.png"\; state="\{\{state\}\}">z</figure-callout>}}}{2}& 0& \frac{{\mathrm{\&omega;}}_x}{2}\\ \frac{{\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="HSA00000107432500011.png"\; state="\{\{state\}\}">z</figure-callout>}}}{2}& \frac{{\mathrm{\&omega;}}_y}{2}& \frac{-{\mathrm{\&omega;}}_x}{2}& 0\end{array}\right]\left[\begin{array}{c}{q}_0\\ q_1\\ q_2\\ {\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="HSA00000107432500011.png"\; state="\{\{state\}\}">q</figure-callout>}}_3\end{array}\right]$

(3)

q ₀, q ₁, q ₂, q ₃Be four real numbers, utilize finish the card approximatioss and find the solution (3) formula and can obtain rotating hypercomplex number q, with step 1,2 resolve in two groups of angular velocity substitution formula (3) just can in the hope of the value of two groups of hypercomplex numbers.

4, general Kalman filtering carries out information fusion

Kalman filter provides a kind of high efficient and reliable Calculation Method to come the state of estimation procedure, and makes estimation square error minimum.It can estimated signal past and current state, even can estimate state in the future, even and do not know the definite character of model.In high speed rotating bullet attitude was determined, because system equation is non-linear, the nonlinear filtering of state estimation had consequence, and most of attitude is determined algorithm, all is based on the nonlinear filtering thought of state estimation.General Kalman filtering (EKF) is most widely used nonlinear estimation method, by the linearization process to nonlinear state equation and measurement equation, carries out filtering according to the thought of lienarized equation filtering then.

Here with attitude quaternion x=(q ₀, q ₁, q ₂, q ₃) as state variable, will resolve by gyrostatic output angle speed data and get hypercomplex number as state equation, the output angle speed data of film coil sensor is resolved and is got hypercomplex number as observation equation.Utilize the general Kalman filtering equation to carry out information fusion these group data then, resolve and obtain one group of quaternary numerical value more accurately.In the Kalman filtering experiment, because output data largely is subjected to The noise, make the measuring accuracy step-down of data, in order effectively to utilize Kalman filter, it can be got a desired effect, often need state variable is done some processing prior and afterwards, so that utilize the MATLAB Kalman filter better.In this research, employing be to utilize experiment, measure one group of comparatively accurate noise equation, in its stress state equation, the precision of measurement data is improved.

5, attitude angle is found the solution

The quaternary numerical value that utilizes step 4 to try to achieve can obtain attitude matrix T, just can be with the corresponding element substitution formula (4) in the attitude matrix in the hope of attitude angle, and the T in the formula (4) ₃₂, T ₃₁, T ₂₁And T ₁₁Representative be corresponding element value among the attitude matrix T.

$\left\{\begin{array}{c}\mathrm{\&alpha;}={\mathrm{tg}}^{-1}\left(\frac{{-T}_{32}}{T_{33}}\right)\\ \mathrm{\&beta;}={\sin }^{-1}\left(T_{31}\right)\\ \mathrm{\&gamma;}={\mathrm{tg}}^{-1}\left(\frac{-T_{21}}{T_{11}}\right)\end{array}\right.$

Claims (3)

1. the inertial measuring unit based on gyro, geomagnetic sensor is characterized in that: comprise gyro and geomagnetic sensor, gyro employing 3 axis MEMS gyro, two diaphragm type geomagnetic sensors of geomagnetic sensor employing.

2. a kind of inertial measuring unit based on gyro, geomagnetic sensor according to claim 1 is characterized in that: the diaphragm type geomagnetic sensor adopts the film coil sensor, and the film coil sensor is the electromagnetic induction diaphragm type coil of a n circle coil.

3. a kind of inertial measuring unit according to claim 1 and 2 based on gyro, geomagnetic sensor, it is characterized in that: be provided with the 3 axis MEMS gyro in the metal cylinder of a cylindrical non iron material, the 3 axis MEMS gyro is made up of gyro face 1, gyro face 3 and gyro face 4, the outer wall of metal cylinder is provided with the diaphragm type geomagnetic sensor, the diaphragm type geomagnetic sensor is made up of film coil sensor 2 and film coil sensor 5, and film coil sensor 2 is perpendicular to film coil sensor 5.

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