CN101241009B - Magneto- electronic compass error compensation method - Google Patents

Abstract

The invention provides an electronic magnetic compass error compensation method which bases on deformation round distribution and cyclical assumptions. The measurement error caused by around ferromagnetic materials and other factors must be compensated to enhance electronic magnetic compass measurement accuracy. At present, domestic and foreign popular methods of compensation are based on assumptions which relate to the effect of the environmental interference magnetic field causing the magnetic field strength level projection component distribution from round into oval. But because of more and complicated influence factors, in fact the magnetic field strength level projection component distribution can not be guarantee as perfect oval. In view of this situation, the invention provides error compensation algorithmic method which bases on deformation round distribution and cyclical assumptions, the objective is to compensate the measurement error caused by around ferromagnetic materials and other factors, and achieve magnetic azimuth high-precision measurement.

Description

A kind of magneto-electronic compass error compensation method

Technical field

Patent of the present invention relates to the sub-compass of magnetoelectricity that utilizes the terrestrial magnetic field to realize orientating function, has provided the measurement Error Compensation method of the sub-compass of a kind of magnetoelectricity.

Background technology

After the sub-compass of magnetoelectricity was fixed on the carrier, the magnetic azinuth measurement result can be subjected to the influence of ferromagnetic material on every side.Disturbing magnetic field is made up of hard iron magnetic field and soft iron magnetic field two parts.When having disturbing magnetic field on every side, the distribution of magnetic field intensity horizontal projection component no longer is positive circle, and distortion (influence in soft iron magnetic field) has taken place its shape, and skew (influence in hard iron magnetic field) has also taken place its center relative coordinate initial point.The existence of above factor causes the sub-compass of magnetoelectricity measuring error to occur in the magnetic azinuth measuring process.Distribution that the popular backoff algorithm influence that is based on environmental interference magnetic field both at home and abroad causes magnetic field intensity horizontal projection component becomes oval-shaped hypothesis by positive circle.Promptly fit magnetic field intensity horizontal projection component and distribute, ask for relevant coefficient, in use carry out the compensation of magnetic-field measurement value according to relevant coefficient according to ellipse.Above backoff algorithm is supposed the ellipse that is distributed as rule of magnetic field intensity horizontal projection component, and in fact is difficult to guarantee the strictness establishment of this condition owing to the complicacy of concrete condition, thereby has limited the raising of measuring accuracy.

Summary of the invention

The present invention proposes based on being out of shape the Error Compensation Algorithm that circle distributes and periodically supposes, with a kind of method that can be used for the magneto-electronic compass error compensation of caused by factors measuring error such as ferromagnetic material around the compensation.

The present invention is a kind of method that can be used for magneto-electronic compass error compensation, when the sub-compass of magnetoelectricity uniform rotation multi-turn in the environment around, and the azimuth angle alpha of azimuth angle alpha, the not compensated that records so _m, azimuth measurement error Δ α is with the generating period variation, can be expressed as the form of the periodic function of the sub-compass corner of magnetoelectricity β, [0,2 π] in the scope, the form of the function generate convergent series behind periodic extension can be similar to this function with the algebraic sum of finite term, promptly

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In the following formula, j is the finite value positive integer, and a0, an, bn are coefficient, n=1 wherein, and 2,3 ...,

Calibration process comprises following each step:

(1) the no magnetic turntable of sub-compass of magnetoelectricity and caliberating device is equipped with in rotation, makes it point to positive north, determines that this moment, the position angle was 0 degree; (2) according to the actual measurement magnetic field data and as data computation position angle, geomagnetic declination approximate value α _m

(3) the corner data α computer azimuth angle error delta α=α that exports according to caliberating device _m-α;

(4) rotate no magnetic turntable and make the position angle increase a certain angle, repeat second step and the 3rd step, the sub-compass azimuth angle error of the magnetoelectricity when obtaining the respective party parallactic angle.Reach 360 degree (identical) until the position angle with 0 degree;

(5) calculate compensation formula according to azimuth angle error

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In penalty coefficient a0, an, bn, n=1 wherein, 2,3 ...;

During use, the compensation formula coefficient calculations that will obtain according to demarcation more on the occasion of, its step is as follows:

(1) according to the actual measurement magnetic field data and as data computation position angle, geomagnetic declination approximate value α _m

(2) according to compensation formula

Calculate more on the occasion of-Δ α, at first use position angle approximate value α during calculating _mReplace position angle actual value α, then carry out repeatedly iteration as the need degree of precision;

(3) calculate compensation back bearing measured value α '=α _m+ (Δ α).

Advantage of the present invention:

Proposed with caused by factors measuring error such as ferromagnetic materials around the compensation, to realize the high-acruracy survey of magnetic azinuth based on being out of shape the Error Compensation Algorithm that circle distributes and periodically supposes.

Embodiment

Provide an instantiation that adopts patent of the present invention to realize the magneto-electronic compass error compensation below.

In this example, be the magnetic azimuth angle transducer with high performance three magnetic resistance sensors, measure the terrestrial magnetic field component on carrier x axle, y axle, z axle respectively

With the double-axel acceleration sensor is the angle of pitch (θ) and roll angle (γ) survey sensor.The information of comprehensive above a plurality of sensors, the high-acruracy survey of realization magnetic azinuth.

The realization of the magneto-electronic compass error compensation method that patent of the present invention proposes is divided into two stages, i.e. the error compensation stage of the coefficient calculations stage of calibration process and use.In calibration process, calculate the compensation formula coefficient according to measurement error value; In use, utilize compensation formula and relevant coefficient calculations more on the occasion of, realize error compensation.

When the sub-compass of magnetoelectricity uniform rotation multi-turn in the environment around, the azimuth angle alpha of the not compensated that records so _m, azimuth measurement error Δ α is with the generating period variation, can be expressed as the form of the periodic function of azimuth angle alpha, [0,2 π] in the scope, the form of the function generate convergent series behind periodic extension can be similar to this function with the algebraic sum of finite term, promptly

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In the following formula, j is the finite value positive integer, and a0, an, bn are coefficient, n=1 wherein, and 2,3 ...;

Timing signal is installed in the sub-compass of magnetoelectricity on the no magnetic turntable, and the turntable corner is measured by high-precision photoelectric encoder.Calibration process is made up of following steps.

The first step is rotated no magnetic turntable, makes its forward direction refer to north, and the output of the photoelectric encoder that resets determines that the position angle is 0 degree.

Second step is according to measured data computer azimuth angle approximate value.At first, according to following formula calculating magnetic field strength level projection H _x, H _y

In the formula,

For Magnetic Sensor in θ ≠ 0,3 geomagnetic field components that record under γ ≠ 0 state.

Then, according to H _x, H _yCalculate the magnetic azinuth approximate value

${\widetilde{\mathrm{\α}}}_M=\arctan \left(\frac{H_y}{H_x}\right)$

At last, according to the magnetic declination value D computer azimuth angle approximate value of locality

${\mathrm{\α}}_m={\widetilde{\mathrm{\α}}}_M+D$

The 3rd step is according to the corner data α computer azimuth angle error of photoelectric encoder output.

Δα＝α _m-α

The 4th step, rotate no magnetic turntable and make the position angle increase by 15 degree, repeat second step and the 3rd step, the sub-compass azimuth angle error of the magnetoelectricity when obtaining the respective party parallactic angle.Reach 360 degree (identical) until the position angle with 0 degree.

In the 5th step, calculate compensation formula according to azimuth angle error

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In penalty coefficient a0, an, bn, n=1 wherein, 2,3 ....

In the above calibration process, we only need to rotate no magnetic turntable and get final product to respective angles.

During use, the compensation formula coefficient calculations that will obtain according to demarcation more on the occasion of, its step is as follows.

The first step is according to measured data computer azimuth angle approximate value.At first, according to following public affairs

Formula calculating magnetic field strength level projection H _x, H _y

In the formula,

For Magnetic Sensor in θ ≠ 0,3 geomagnetic field components that record under γ ≠ 0 state.

Then, according to H _x, H _yCalculate the magnetic azinuth approximate value

${\widetilde{\mathrm{\α}}}_M=\arctan \left(\frac{H_y}{H_x}\right)$

At last, according to the magnetic declination value D computer azimuth angle approximate value of locality

${\mathrm{\α}}_m={\widetilde{\mathrm{\α}}}_M+D$

Second step is according to compensation formula

Calculate more on the occasion of-Δ α, at first use position angle approximate value α during calculating _mReplace position angle actual value α, then repeatedly change as the need degree of precision.

In the 3rd step, calculate compensation back bearing measured value α '=α _m+ (Δ α).

Claims (2)

1. method that is used for magneto-electronic compass error compensation is characterized in that when the sub-compass of magnetoelectricity uniform rotation multi-turn in the environment around, the azimuth angle alpha of the not compensated that records so _m, azimuth measurement error Δ α is with the generating period variation, all is expressed as the form of the periodic function of azimuth angle alpha, in [0,2 π] scope, the form of the function generate convergent series behind periodic extension is similar to this function with the algebraic sum of finite term, promptly

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In the following formula, j is the finite value positive integer, a ₀, a _n, b _nBe coefficient, n=1 wherein, 2,3 ...; Calibration process comprises following each step:

(1) the no magnetic turntable of sub-compass of magnetoelectricity and caliberating device is equipped with in rotation, makes it point to positive north, determines that this moment, the position angle was 0 degree;

(2) according to the actual measurement magnetic field data and as data computation position angle, geomagnetic declination approximate value α _m

(3) the corner data α computer azimuth angle error delta α=α that exports according to caliberating device _m-α;

(4) rotate no magnetic turntable and make the position angle increase a certain angle, repeat second step and the 3rd step, the sub-compass azimuth angle error of the magnetoelectricity when obtaining the respective party parallactic angle reaches 360 degree until the position angle;

(5) calculate compensation formula according to azimuth angle error

$\mathrm{\Δ\α}=a_0+\underset{n=1}{\overset{j}{\mathrm{\Σ}}}(a_n\cos \mathrm{n\α}+b_n\sin \mathrm{n\α})$

In penalty coefficient a ₀, a _n, b _n, n=1 wherein, 2,3 ...;

During use, the compensation formula coefficient calculations that will obtain according to demarcation more on the occasion of, its step is as follows:

(1) according to the actual measurement magnetic field data and as data computation position angle, geomagnetic declination approximate value α _m

(2) according to compensation formula

Calculate more on the occasion of-Δ α, at first use position angle approximate value α during calculating _mReplace position angle actual value α, then carry out repeatedly iteration as the need degree of precision;

(3) calculate compensation back bearing measured value α '=α _m+ (Δ α).

2. a kind of method that is used for the magneto-electronic compass error compensation according to claim 1 is characterized in that the sub-compass of described magnetoelectricity is based on the measuring sensor of fluxgate technology or anisotropic magnetoresistance technology or giant magnetoresistance technology or giant magnetic impedance technology.