CN103674000B

CN103674000B - Electronic compass real time calibration algorithm

Info

Publication number: CN103674000B
Application number: CN201310531661.2A
Authority: CN
Inventors: 王志鹏
Original assignee: WUHAN LIESUN TECHNOLOGY Co Ltd
Current assignee: WUHAN LIESUN TECHNOLOGY Co Ltd
Priority date: 2013-11-01
Filing date: 2013-11-01
Publication date: 2015-10-21
Anticipated expiration: 2033-11-01
Also published as: CN103674000A

Abstract

The invention belongs to the correlative technology field of aviation aircraft, be specially a kind of electronic compass real time calibration algorithm.The present invention can make aviation aircraft constantly carry out real time calibration to electronic compass when not affecting normal use, thus is user-friendly to, improves the environmental suitability of electronic compass and meet the little requirement of algorithm calculated amount.

Description

Electronic compass real time calibration algorithm

Technical field

The invention belongs to the correlative technology field of aviation aircraft, be specially a kind of electronic compass real time calibration algorithm.

Background technology

At present, aviation aircraft obtains self direction, and the parameter generally all relying on electronic compass to provide carrys out identification.

Electronic compass, also referred to as three axle magnetic resistance meters, can be obtained the field strength value of x, y, z three axles in theory, thus extrapolate geomagnetic field intensity and the direction of environment residing for electronic compass by the magnetometer read value of its three axles.But owing to not calibrating zero point by the reading of magnetic resistance meter, using the reasons such as the magnetic interference of the aviation aircraft internal current generation of electronic compass, if its electronic compass three axle reading is directly used in calculate direction, terrestrial magnetic field, be there is huge deviation in the direction, terrestrial magnetic field making to calculate.

It causes the reason of deviation can be divided into three major types principle: the interference of zero deviation, Hard Magnetic and soft magnetism interference.Wherein, zero deviation is droop, is determined by electronic compass self individual difference; Hard Magnetic interference is affected by environment, and under same environmental baseline, this deviation is relatively fixing; Soft magnetism interference causes primarily of the ferromagnetic type objects near electronic compass, both can substantially avoid this to disturb as long as avoid being arranged on by the part having soft magnetism effect near electronic compass.

Summary of the invention

The object of the invention is to overcome above-mentioned deficiency, a kind of electronic compass calibration algorithm is provided, aviation aircraft can be made constantly to carry out real time calibration to electronic compass when not affecting normal use, thus be user-friendly to, improve the environmental suitability of electronic compass and meet the little requirement of algorithm calculated amount.

For realizing above-mentioned technical purpose, scheme provided by the invention is: a kind of electronic compass real time calibration algorithm, comprises the steps.

Step one, setting offset vector F, reads configuration information, obtains to run last gained last time and offset to value and give F, and some f is the corresponding point of vectorial F, and f equals initial point and adds vectorial F.

Step 2, reads the value of real time readouts as vectorial A of the first moment electronic compass, and some a is the corresponding point of vectorial A, and a equals initial point and adds vectorial A.

Step 3, reads the value of real time readouts as vectorial B of the second moment electronic compass, and some b is the corresponding point of vectorial B, and b equals initial point and adds vectorial B.

Step 4, if | A-B| is less than the mould of the surface level projection vector of earth-magnetic field vector, then return step 3; If | A-B| is greater than the mould of the surface level projection vector of earth-magnetic field vector, then enter next step.

Step 5, makes plane D, and D is perpendicular to the straight line C through a, b 2, and D is through the mid point c of a, b 2.

Step 6, some f is to D vertical projection, and obtain some e, initial point is E to the vector of e.

Step 7, makes vectorial F equal vectorial E, makes vectorial A equal vectorial B.

Step 8, skips to step 3, circulation above-mentioned steps.

And described earth-magnetic field vector is that the vector that electronic compass reading is corresponding deducts vectorial F gained.

The present invention can make aviation aircraft constantly carry out real time calibration to electronic compass when not affecting normal use, thus is user-friendly to, improves the environmental suitability of electronic compass and meet the little requirement of algorithm calculated amount.

Embodiment

Below in conjunction with embodiment, the invention will be further described.

The present embodiment provides a kind of electronic compass real time calibration algorithm, if the vector value of zero deviation is M, Hard Magnetic interference vector value is N, and earth-magnetic field vector is T.Vector M can not change substantially, vector N only has the Shi Caihui that change such as the inner airborne equipment of aviation aircraft to change, direction the changing towards with attitudes vibration with aviation aircraft of vector T, the modulus of vector T then changes with latitude and longitude coordinates change residing for aircraft, electronic compass reading R=M+N+T can be established according to this, have | R-M-N|=|T|, that is: all electronic compass readings are all at a periphery, this circle home position is M+N, and radius is | T|.There is this to obtain, to obtain correct magnetic direction, then needing the numerical value (i.e. the position in the circle center of circle) first obtaining M+N.

Appoint and get two electronic compass readings and have R1, R2, there is plane, this plane orthogonal is in R1R2 connecting line, and this plane is through R1R2 mid point, and this plane is through the center of circle of circle.Now establish arbitrfary point, space A1, make A1 perpendicular to this plane projection, obtain the some A2 in plane, the distance that can obtain A2 and the circle center of circle is less than or equal to the distance of A1 to the circle center of circle, that is: Equation f (a, b, c) has A2=f(A1, R1, R2).This is had to obtain, M+N=0 can be established temporarily when value the unknown of M+N, Equation f (a is together substituted into as a and the electronic compass reading newly obtained, b, c), the result of acquisition together brings f(a into as a and the electronic compass reading newly obtained again, b, c), in, continuous iteration and so forth, the result obtained will constantly approach the actual value of M+N.Even if change appears in the value of M+N, after several iterative computation, the result that obtains will constantly approach M+N actual value again.

The concrete scheme that the present embodiment provides comprises the steps.

First need to do following setting.

1. set electronic compass zero deviation and suffered Hard Magnetic to disturb the actual value of sum as vector , wherein , , for constant.

2. set electronic compass zero deviation and suffered Hard Magnetic to disturb the calculated value of sum as vector , wherein , , for variable.

3. set aircraft latitude and longitude real time readouts as , .

4. known tables, record all parts of the world geomagnetic field intensity and angle between direction, terrestrial magnetic field and surface level, so can establish function , wherein for earth-magnetic field vector to surface level projection gained vector field homoemorphism, for latitude, for longitude.

5. set electronic compass real time readouts as , two reading buffer memorys are respectively with .

Step one, reads configuration information, obtains and runs last gained and offset to value last time, for assignment.

Step 2, obtains the real time readouts of the first moment electronic compass , order .

Step 3, obtains the real time readouts of the second moment electronic compass , order .

Step 4, if , then step 3 is returned.

Step 5, makes plane, perpendicular to vector , and through point

，

Can plane equation be obtained thus:

。

Step 6, does straight line, the plane of this linear vertical in step 5, and through point , can straight-line equation be obtained

, the intersection point of this straight line and step 5 midplane can be asked according to this, by straight-line equation and plane equation simultaneous, have

Namely have

, by gained the intersection point that value substitution straight-line equation can obtain both is

。

Step 7, can obtain newly according to content in step 6 , , value be

, order , , , , , .

Step 8, skips to step 3, circulation above-mentioned steps.

Constantly circulated by above flow process, can make infinitely approach , then just can obtain earth-magnetic field vector value accurately , thus obtain geomagnetic field intensity and azimuth information.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvement or distortion, these improve or distortion also should be considered as protection scope of the present invention.

Claims

1. an electronic compass real time calibration algorithm, comprises the steps:

Step one, setting offset vector F, reads configuration information, obtains to run last gained last time and offset to value and give F, and some f is the corresponding point of vectorial F, and f equals initial point and adds vectorial F;

Step 2, reads the value of real time readouts as vectorial A of the first moment electronic compass, and some a is the corresponding point of vectorial A, and a equals initial point and adds vectorial A;

Step 3, reads the value of real time readouts as vectorial B of the second moment electronic compass, and some b is the corresponding point of vectorial B, and b equals initial point and adds vectorial B;

Step 4, if | A-B| is less than the mould of the surface level projection vector of earth-magnetic field vector, then return step 3; If | A-B| is greater than the mould of the surface level projection vector of earth-magnetic field vector, then enter next step;

Step 5, makes plane D, and D is perpendicular to the straight line C through a, b 2, and D is through the mid point c of a, b 2;

Step 6, some f is to D vertical projection, and obtain some e, initial point to the vector of e is E;

Step 7, makes vectorial F equal vectorial E, makes vectorial A equal vectorial B;

Step 8, skips to step 3, circulation above-mentioned steps.

2. a kind of electronic compass real time calibration algorithm according to claim 1, is characterized in that: described earth-magnetic field vector is that the vector that electronic compass reading is corresponding deducts vectorial F gained.