CN102288170B - Correction method of electronic compass in underwater vehicle - Google Patents

Abstract

The invention discloses a correction method of an electronic compass in an underwater vehicle, which comprises the following steps of: inquiring magnetic declination, and carrying out corrected navigation on the water surface of the vehicle; recording navigation data by a navigation sensor; exporting correction navigation data from a communication module; searching a hard magnetic interference parameter, solving the error surface plot between a correction track and a reference track under the condition of (2N+1)<2> disperse hard magnetic interference parameters, wherein the minimum point corresponding to the surface plot is the search result; according to the set correction precision requirement, repeating and reducing the search range and grid, and re-searching to obtain a more precise hard magnetic interference parameter evaluation value; and finally, applying the searched magnetic parameter evaluation value in the navigation of the underwater vehicle. The method disclosed by the invention has the advantages that the operation is simple, the influence of the outer magnetic interference to the electronic compass in the underwater vehicle can be effectively eliminated and thus, the corrected electronic compass can return back to the corrected attitude angle.

Description

A kind of bearing calibration of electronic compass in underwater vehicle

Technical field

The invention belongs to the correction of instrument, relate in particular to a kind of extraneous hard magnetic of electronic compass is disturbed and carry out reasonable compensation, thereby minimize the external magnetic field interference to the method for calibrating electronic compass of the impact of submarine navigation device navigation accuracy, can be applicable to the technical fields such as navigation, location and sonar, radar system motion compensation.

Background technology

Submarine navigation device is one of focus of oceanographic engineering area research in recent years, environmental monitoring under water, offshore oil engineer operation, search under water obtain to use more and more widely with military fields such as mapping and region of war warnings in real time, its normal structure that adopts as shown in Figure 1, the internal module relation is as shown in Figure 2.

The underwater navigation technology is to realize the key of the autonomous navigation of submarine navigation device, but is different from conventional navigation systems, and the underwater navigation technology has that marine environment complexity, retrievable external information are few, disguised high, has great challenge.Underwater navigation sensor commonly used has Doppler log, electronic compass, inertia measurement equipment, depth transducer etc., and wherein Doppler log is the equipment of carrier translational speed of measuring according to the Doppler shift principle; Electronic compass is built-in with magnetometric sensor, measures course angle and the attitude angle of submarine navigation device by calculating compass axle and the angle of ground magnet-wire; Inertia measurement equipment is built-in with accelerometer and gyroscope, can measure translational acceleration and the angular velocity of carrier; Depth transducer is extrapolated the degree of depth at place by the size of measuring hydraulic pressure.

Present most autonomous Underwater Vehicle Navigation System all is based on dead reckoning, and the precision of dead reckoning depends on the course angle precision that electronic compass is measured more.But in actual tests, the electronic compass that is loaded into submarine navigation device inside often is subject to the interference of external magnetic field, course angle and the attitude angle of the submarine navigation device that measures without the electronic compass of over-compensation have larger deviation, the error of the course angle of generally returning is greater than 5 °, thereby the electronic compass error that the calibration magnetic interference causes is of crucial importance to realizing the navigation of submarine navigation device high precision.

For the plane electronics compass of measuring the horizontal course angle, it has two orthogonal axles, is respectively OX axle and OY axle, as shown in Figure 3.Along diaxon, 2 Magnetic Sensor SX and SY that measure component are installed respectively.If ON is the magnetic north direction, the angle that definition turns over clockwise from magnetic north direction ON to the OX axle is magnetic azimuth, represents with θ.If the horizontal component of terrestrial magnetic field is H ₀, the magnetic-field component measured of magnetometric sensor SX and SY is:

H _x＝H ₀·cosθ，

H _y＝-H ₀·sinθ；

In formula

But in fact north geographic pole and magnetic north direction ON are not same directions, and the angle between them is called magnetic declination, uses θ _{The geomagnetic declination}Expression.The electronic compass measured value will just can obtain by the compensation of magnetic declination the angle between OX axle and north geographic pole, so real course angle should be θ _Real=θ+θ _{The geomagnetic declination}

Discussed above is in ideal conditions, the error that actual electronic compass returns navigation angle can exist various factors to cause.It comprises that magnetic declination, error of fixed angles, hard magnetic material cause error and soft magnetic material to cause error.Magnetic declination, error of fixed angles can find out it is fixed value in suitable scope.Magnetic declination be the actual magnetic north to and the north geographic pole direction between the angle that exists; And the error of fixed angles that error of fixed angles is compass to be existed in installation process, most of electronic compasss all carry the established angle compensate function.Soft magnetic material is relevant with the mutual alignment to the direction that compass produces acting force, size and the proportional relation of excitation field; And retentive material is permanent, and its size and Orientation is fixed.

Under the desirable condition without the outer room magnetic interference, as shown in Figure 4, electronic compass only is subject to the effect of terrestrial magnetic field and refers to magnetic north, and in actual conditions electronic compass because the impact that is subject to carrier magnetic field can produce deviation.Magnetic interference can be divided into hard iron interference and soft iron interference two classes.

Hard iron is the permanent magnet on carrier, and its size and Orientation is fixed, and on carrier, the source of hard iron mainly contains DC current, permanent magnet and motor etc.Having increased a definite value on the output valve of compass, made the center of circle of compass output curve diagram be offset (seeing Fig. 5), is the impact (seeing Fig. 6) of one-period on the impact in course.

Itself does not have magnetic soft iron, and it obtains magnetic after by the magnetization of terrestrial magnetic field and external magnetic field, and magnetic changes along with the variation of the size of terrestrial magnetic field and external magnetic field and relative direction.Its annoyance level relevant with the direction of compass (seeing Fig. 7), when generally being subject to soft magnetism and disturbing, the error in compass output course as shown in Figure 8.

When electronics was subject to hard magnetic material and soft magnetic material interference, the upper magnetic-field component of the Magnetic Sensor SX of 2 directions and SY should be:

${\hat{H}}_x=(1+{\mathrm{\&alpha;}}_x)(H_0\&CenterDot;\cos \mathrm{\&theta;}+{\mathrm{\&delta;H}}_x),$

${\hat{H}}_y=-(1+{\mathrm{\&alpha;}}_y)(H_0\&CenterDot;\sin \mathrm{\&theta;}+{\mathrm{\&delta;H}}_y);$

Existing electronic compass compensation technique all needs to calibrate before the aircraft test under water.A kind of possible method is after mounted submarine navigation device is powered on, to be placed on the platform of level; At interval of fixing angle

Flatly rotate submarine navigation device, read rreturn value after the electronic compass rreturn value is stable

Then the electronic compass error is set up mathematical model, comprise unknown hard magnetic interference parameter in model; At last will The error model equation of substitution electronic compass is obtained the approximate value of unknown parameter in the error model equation with least square method.

The weak point of said method is: the first, and during operation, external condition is had relatively high expectations, and needs the rotatable platform of extra production technique; The second, the difficulty that operates is higher, and the general volume of submarine navigation device is larger, and weight reaches kilograms up to a hundred, horizontally rotates submarine navigation device not too convenient and actual; The 3rd, calibrate consuming time manyly, lengthened time and the financial cost of submarine navigation device test.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, a kind of bearing calibration of being convenient to the electronic compass in underwater vehicle of practical operation is provided.

The objective of the invention is to be achieved through the following technical solutions: a kind of bearing calibration of electronic compass in underwater vehicle, the method are used for the electronic compass that is arranged on submarine navigation device is calibrated, thereby improve the precision of submarine navigation device independent navigation.Submarine navigation device has navigation sensor module, Central Control Module, battery module, propulsion die, GPS receiver module and communication module etc., and Doppler log is installed, and all modules are all powered by battery module.The method comprises the following steps:

(1) the inquiry geomagnetic declination, set the correction accuracy requirement;

(2) the aircraft water surface is done the calibration navigation, records respectively position, course angle and the translational speed of submarine navigation device by GPS receiver module, electronic compass and Doppler log, obtains calibration navigation navigation data;

(3) set (2N+1) ²Individual discrete hard magnetic interference parameter initial ranging collection

$\{({\mathrm{\&delta;H}}_x^{\left(i\right)},{\mathrm{\&delta;H}}_y^{\left(j\right)}),i,j=\mathrm{0,1},...2N+1\};$

Calculate (2N+1) ²Error W between calibration track and reference locus under individual discrete hard magnetic interference parameter condition ^{(i, j)}Surface chart, search error surface chart minimum value, the corresponding parameter set of error smallest point

It is namely the approximate value of hard magnetic interference parameter;

(4) according to the correction accuracy requirement of setting, repeat to dwindle hunting zone and grid, search again obtains more accurate hard magnetic interference parameter estimation value

Error in above-mentioned steps (3) is calculated and is comprised following substep:

(A) calculate hypothesis X, on the Y-axis magnetometric sensor, hard magnetic disturbs and causes the error of zero to be

Situation under,

Corresponding electronic compass calibration course angle

Measure course angle θ with electronic compass _mBetween corresponding relation

(B) according to the navigation angle after calibration Adopt the dead reckoning calculating parameter

Corresponding submarine navigation device movement locus

Dead reckoning is specific as follows, with the submarine navigation device translational speed V of Doppler log collection _DVLDecompose under terrestrial coordinate system, resolve into the speed of North and South direction and the speed of east-west direction, be expressed as respectively With

Wherein,

Expression t North and South direction speed component constantly,

Expression t is the speed component of east-west direction constantly;

Speed after decomposing be multiply by the time interval add up, just can obtain the position of the submarine navigation device in each sampled point moment that dead reckoning estimates, mathematical notation is:

$x_{N,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{N,t}\&CenterDot;\mathrm{dT}+x_{N,0}^{\mathrm{GPS}},$

$x_{E,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{E,t}\&CenterDot;\mathrm{dT}+x_{E,0}^{\mathrm{GPS}};$

Wherein,

Represent respectively hard magnetic interference parameter group

Corresponding to the coordinate of t aircraft constantly at North and South direction and east-west direction; DT is the time interval,

The expression accumulating operation;

Represent respectively the North and South direction of the submarine navigation device that the GPS receiver module gathers and the t=0 moment initial position of east-west direction; Derive like this

Corresponding submarine navigation device is estimated track

$P_{1:L}^{(i,j)}=\left\{(x_{N,t}^{(i,j)},x_{E,t}^{(i,j)})|t=1,...,L\right\};$

(C) calculate

Corresponding calibration submarine navigation device track

With field survey or reference locus that the GPS receiver module returns

Between navigation error, wherein

The k that expression GPS returns is the North and South direction position constantly,

The k that expression GPS returns is the east-west direction position constantly, and navigation error is expressed as:

$W^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^L{(x_{N,k}^{(i,j)}-x_{N,k}^{\&prime;\mathrm{GPS}})}^2+{\mathrm{\&Sigma;}}_{k=1}^L{(x_{E,k}^{(i,j)}-x_{E,k}^{\&prime;\mathrm{GPS}})}^2;$

Wherein, W ^{(i, j)}Expression hard magnetic interference parameter

Corresponding calibration track and the error between reference locus.

Error surface chart minimum value searching method in above-mentioned steps (3) can be exhaustive search, relatively ask for the error minimum value by pointwise, can be also by asking for the error minimum value based on the local search algorithm of gradient, can be also to ask for the error minimum value by global optimization approach, typical global optimization approach comprises simulated annealing, genetic algorithm, particle group optimizing etc.

Calibration navigation navigation data in above-mentioned steps (2) can export to submarine navigation device inter-process equipment by communication module, the processing of completing steps (3) and (4), also can export to water surface treatment facility by communication module, the processing of completing steps (3) and (4).

Hard magnetic interference parameter in above-mentioned steps (3) is replaceable is the set of soft magnetism interference parameter or hard magnetic interference parameter and soft magnetism interference parameter, proofreaies and correct by same processing.

After the method is completed the electronic compass calibration according to above-mentioned steps (1) to (5), the magnetic parameter estimated value that search is obtained is applied in the submarine navigation device navigation: the magnetic interference estimates of parameters that obtains after search outputs in the submarine navigation device Central Control Module by communication module, and is stored in the storage medium of Central Control Module; When submarine navigation device re-starts conventional navigation, the course angle θ from the actual measurement of navigation sensor module return electron compass _mAnd after the magnetic interference estimates of parameters was transferred to Central Control Module, Central Control Module calculated the course angle after calibration

In conjunction with other navigation sensor module data, complete dead reckoning.

The invention has the beneficial effects as follows: method of the present invention is simple to operate, can effectively eliminate the impact of the extraneous magnetic interference that electronic compass in underwater vehicle is subject to, thereby make the electronic compass after calibration return to correct attitude angle, and be convenient to multi-purpose computer or embedded system realizes automatically, have very strong practical value.

Description of drawings

Fig. 1 is the structural representation of general submarine navigation device;

Fig. 2 is the graph of a relation of each intermodule of submarine navigation device;

Fig. 3 is the structural representation of plane electronics lining;

Fig. 4 is that under noiseless condition, electronic compass is placed on XY axle magnetometric sensor Output rusults figure on surface level;

Fig. 5 is under the environment of hard magnetic interference, XY axle magnetometric sensor Output rusults figure;

Fig. 6 is under the environment of hard magnetic interference, and hard magnetic disturbs the periodicity impact figure on the electronic compass output angle;

Fig. 7 is under the environment of soft magnetism interference, XY axle magnetometric sensor Output rusults figure;

Fig. 8 is under the environment of soft magnetism interference, and soft magnetism is disturbed the periodicity impact figure on the electronic compass output angle;

Fig. 9 is a kind of schematic flow sheet of embodiment;

Figure 10 is navigation path error sum of squares surface chart after calibration;

Figure 11 is that submarine navigation device GPS receiver module returns to track, not the navigation path figure of dead reckoning navigation path and the rear dead reckoning of calibration before the calibration;

Figure 12 is that rear navigation relative error-time chart is not calibrated and calibrated to electronic compass.

Embodiment

The present invention is used for the electronic compass that is arranged on submarine navigation device is calibrated, thereby improves the precision of submarine navigation device independent navigation.

General submarine navigation device structure such as Fig. 1, the aircraft length of using in enforcement is about 3 meters, 30 centimetres of diameters.Device in the cylinder storehouse roughly can be divided into: navigation sensor module, Central Control Module, battery module, afterbody are push module; The aircraft shell upper is equipped with the ethernet module interface, and wireless station and GPS receiver module are installed on tail fin; The aircraft bottom is equipped with Doppler log.All modules are all by being arranged on the battery module power supply at middle part.What each module was detailed is described below:

The navigation sensor module mainly gathers aircraft physical motion information by various navigation sensors: as speed, acceleration, attitude angle and the degree of depth etc.; Utilize navigation algorithm to estimate the position of aircraft self, thereby realize the independent navigation of submarine navigation device.The electronic compass that the present invention relates to is arranged in this module.

Central Control Module is the core of submarine navigation device, is used for controlling aircraft navigation, task operating, coordinates communication and the power supply of each intermodule, and the motor in the push module of aircraft afterbody is also by this module controls.

Battery module is the energy source of aircraft, and the electric energy part of battery is used for the afterbody propulsion electric machine and rotates; Another part electric energy is used for keeping the normal operation of other circuit blocks and sensor.

Mainly comprise diving rudder and vertical rudder that propulsion electric machine, motor control box and navigation attitude are controlled in push module, motor connects the screw propeller that is positioned at the aircraft tail end, and the expulsive force of working direction is provided for submarine navigation device.

Wireless station is mainly used in the radio communication of submarine navigation device and shore command terminal, and operating personnel can be by receiving the aircraft wireless station information such as the battery allowance of understanding aircraft, motor speed, each module duty, gps data that send a message back; The operating personnel of same shore command terminal also can send instruction control aircraft and navigate by water by track and the mode of operation of appointment.

Global Positioning System (GPS) (Global Positioning System, be called for short GPS) receiver module aircraft tail fin under water emerges in situation, by aircraft latitude and longitude information under the calculated signals water outlet that receives position location satellite.The longitude and latitude of submarine navigation device can be shared by the operating personnel of wireless station and test base after being converted into position under terrestrial coordinate system.

Also comprise an ethernet module interface in aircraft, be the network communication module under the IEEE ICP/IP protocol.When submarine navigation device returned to the test base at shore command terminal place, connecting by netting twine the Ethernet interface that is arranged in tool water-tight function on the aircraft shell can will be stored in the navigation data of submarine navigation device hard disk and other data transmission ashore on the computer of command terminal.

Doppler log is the sensor of measuring the submarine navigation device translational speed, is arranged on bottom submarine navigation device, sends the sound wave of fixed frequency during work to the bottom.According to the principle of Doppler shift, the movement of carrier can cause the variation that receives signal frequency.Doppler log returns to the frequency of sound wave by measurement, and calculates the carrier translational speed by the relation of frequency between reception and transmitted signal.

Fig. 2 represents the relation of each intermodule.In actual mechanical process, the operating personnel of shore command end send navigation beginning by wireless station control signal is to the wireless station on aircraft tail fin under water, and then signal is delivered to Central Control Module.Central Control Module sends to control information other three large modules subsequently.When wherein battery module powers on power delivery to navigation sensor module, Central Control Module and push module.The motor of the push module screw propeller that rear drive is connected that powers on, Central Control Module just can be controlled the aircraft pace by controlling current of electric.In the navigation process, the navigation sensor module gathers motion and the navigation information in operational process, and sends the data to Central Control Module by the RS232 serial ports, finally is stored in the hard disk of Central Control Module.Under aircraft emerged situation under water, the wireless station on the aircraft tail fin can keep and the shore command terminal communication, and the information such as motor speed, headway, navigation attitude angle are sent to the shore command terminal; Simultaneously also can receive the steering order that the shore command terminal is sent, then carry out work according to navigation route and the mode of operation of appointment.After navigational duty was completed, submarine navigation device turned back to test base, shore command terminal place, submarine navigation device can by netting twine connect the ethernet module interface with the navigation sensor data upload to the computer of shore command terminal or other equipment with network interface card.

Because the submarine navigation device navigation accuracy is subject to the course angle precision that electronic compass is measured, the below is introduced electronic compass error compensation principle of the present invention.

In the situation that without magnetic interference, when carrier was in level, the output valve quadratic sum of X and Y-axis magnetometric sensor was certain value, this pass ties up in the rectangular coordinate system that X, Y-axis output valve are coordinate axis and is expressed as circle, sees Fig. 4, and the Z axis magnetometric sensor is output as normal value.And the hard magnetic interference could make this circle off-centring, causes the error of zero, sees Fig. 5 mistake! Do not find Reference source.The soft magnetism interference can make this circle distortion for oval, causes sensitivity error, sees Fig. 7, and therefore, under the acting in conjunction that hard soft magnetism disturbs, the output of the Magnetic Sensor of both direction will be mapped as the described off-centring elliptical area of following formula in the space:

${\left(\frac{{\hat{H}}_x^b-{\mathrm{\&delta;H}}_x}{1+{\mathrm{sf}}_x}\right)}^2+{\left(\frac{{\hat{H}}_y^b-{\mathrm{\&delta;<figure-callout\; id="1"\; label="H\; y"\; filenames="110714161519.png"\; state="\{\{state\}\}">H</figure-callout>}}_y}{1+{\mathrm{sf}}_y}\right)}^2=H_0^2;$

Wherein

Expression X, Y-axis magnetometric sensor SX, SY output valve, H ₀Be earth magnetic field intensity.δ H _x, δ H _yBe the SX that the Hard Magnetic mushing error causes, the error of zero of SY axle output valve, 1+sf _x, 1+sf _yDisturb the SX that causes, SY axle output valve sensitivity error for soft magnetism.

Experimental data shows that in submarine navigation device, the electronic compass magnetic interference overwhelming majority comes from the hard magnetic interference, purpose of the present invention mainly is to proofread and correct hard magnetic and disturbs the error that causes, proofread and correct soft magnetism and disturb the error that causes and proofread and correct hard, soft magnetism and disturb the error that causes simultaneously yet the method that the following describes can extend to easily, centered by the off-centring disc is remapped at the disc of initial point.

Take the Hard Magnetic interference compensation as example, the present invention is used for being loaded into the calibration of submarine navigation device electronic compass, comprises the following steps:

Step 1: inquire about the geomagnetic declination, set the correction accuracy requirement.

In fact there are angle in magnetic north and north geographic pole direction, and the magnetic north direction of earth surface any point is called the geomagnetic declination with meridianal angle.On the earth, different regions are not identical in the different time geomagnetic declination, can inquire about by pertinent literature obtaining, and can be sent in the submarine navigation device correlation module by wireless station.Accuracy requirement can be for course angle, also can be for trajectory error.

Step 2: Autonomous Underwater Vehicle is done the calibration navigation at the water surface, records respectively position, course angle and the translational speed of submarine navigation device by GPS receiver module, electronic compass and Doppler log.

Send the navigation instruction of starting working by the shore command terminal, control submarine navigation device and calibrate navigation in the water surface.Submarine navigation device gathers by the GPS receiver module that is arranged on the tail fin position latitude and longitude information that aircraft should be in the time period; Gather each course angle constantly of aircraft by electronic compass; Gather by Doppler log the speed that aircraft moves; The raw data of navigation sensor module collection is delivered to Central Control Module, and is stored in wherein hard disk.The operator of test base transmits control signal by the shore command platform, and the operation submarine navigation device is done the navigation campaign of ' S ' shape track or round track, makes submarine navigation device turn over angle more than all to fixed-direction as far as possible; The time of submarine navigation device surface navigation is longer and angle that turn over is more, and the effect of this calibration steps is better.

After the calibration finished voyage, submarine navigation device returns to the test base, connect Ethernet interface and shore command terminal on the submarine navigation device shell with netting twine, the navigation data that will calibrate navigation by netting twine communication is transferred on the shore command terminal, and the shore command terminal can be the computing machine with network interface card.Because different navigation sensor such as GPS receiver module, electronic compass and Doppler log etc., their image data frequencies are different, and the form of data storage is different, need to read and be transformed into unified physics unit by the frequency format of correspondence.

Step 3: search hard magnetic interference parameter on a large scale.

Fig. 9 has provided the detailed flow process of this step.The core concept of this step is the rational hunting zone of setting hard magnetic interference parameter, respectively to the parameters discretize, form the uniform parameter combinations in some intervals, then the parameters combination is used for proofreading and correct the navigation path of calibration navigation, wherein returning to parameter corresponding to the most close track of track with GPS is exactly the optimum estimate parameter.

At first in larger Reasonable Parameters scope, the hard magnetic interference parameter is carried out discretize process.If in the hunting zone, the discrete set of possible hard magnetic interference parameter is:

$\left\{(\frac{-N+i}{N}{H}_x^{\max },\frac{-N+j}{N}{H}_y^{\max })\right|i=\mathrm{0,1},...,2N;j=\mathrm{0,1},...,2N\};$

Wherein,

Be the search upper limit of hard magnetic interference on the X-axis magnetometric sensor,

Be the search upper limit that Y-axis magnetometric sensor hard magnetic disturbs, N is the skip number of positive dirction (or negative direction) search,

With

The search precision that represents respectively two parameters, the precision of the larger expression search of N is higher.From i=0, j=0 begins to i=2N, j=2N search all (2N+1) ²Individual possibility parameter combinations.If:

${\mathrm{\&delta;H}}_x^{\left(i\right)}=\frac{-N+i}{N}{H}_x^{\max },$ ${\mathrm{\&delta;H}}_y^{\left(j\right)}=\frac{-N+j}{N}{H}_j^{\max };$

For any one group of parameter combinations wherein

Calculate the navigation path that this parameter combinations is used for proofreading and correct the calibration navigation

And calculating and GPS receiver module return to track

Between error, parameter corresponding to the minimum track of error wherein

Be the optimal estimation value of hard magnetic interference parameter in this search.Concrete steps are as follows:

3.1 calculate hypothesis X, Y-axis magnetometric sensor hard magnetic disturbs and causes the error of zero to be

Situation under, parameter

Corresponding electronic compass calibration course angle Measure course angle θ with electronic compass _mBetween corresponding relation

Wherein

The inquiry of expression step 1 obtains the geomagnetic declination, The expression hard magnetic disturbs the error of zero that causes to be

The time course angle after corresponding calibration.

3.2 according to the navigation angle after calibration

Adopt dead reckoning to calculate corresponding submarine navigation device movement locus

The dead reckoning concrete steps are as follows: with the submarine navigation device translational speed V of Doppler log collection _DVLDecompose under terrestrial coordinate system, resolve into the speed of North and South direction and the speed of east-west direction, be expressed as respectively,

$v_{N,t}^{(i,j)}=v_{\mathrm{DVL},t}\&CenterDot;\cos \left({\mathrm{\&theta;}}_{\mathrm{clb},t}^{(i,j)}\right),$ $v_{E,t}^{(i,j)}=v_{\mathrm{DVL},t}\&CenterDot;\sin \left({\mathrm{\&theta;}}_{\mathrm{clb},t}^{(i,j)}\right);$

Wherein

Expression t is the speed of North and South direction constantly,

Expression t is the speed of east-west direction constantly.

Both direction speed after decomposing be multiply by the time interval then add up, just can obtain the position of the submarine navigation device in each sampled point moment that dead reckoning estimates, mathematical notation is:

$x_{N,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{N,t}^{(i,j)}\&CenterDot;\mathrm{dT}+x_{N,0}^{\mathrm{GPS}},$

$x_{E,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{E,t}^{(i,j)}\&CenterDot;\mathrm{dT}+x_{E,0}^{\mathrm{GPS}};$

Wherein

Represent respectively hard magnetic interference parameter group

Corresponding to the coordinate of t aircraft constantly at North and South direction and east-west direction, dT is the time interval,

The expression accumulating operation,

Represent respectively the North and South direction of the submarine navigation device that the GPS receiver module gathers and the t=0 moment initial position of east-west direction.Derive like this

Corresponding submarine navigation device track

3.3 calculate Be used for proofreading and correct calibration navigation navigation path

The reference locus that returns with the GPS receiver module

Between trajectory error.Because in identical hours underway, the sampling number K of GPS receiver module is not identical with the sampling number L of electronic compass and Doppler log, usually L is far longer than K, for the convenient error of calculating between reference locus and calibration track, and be to the reference locus of GPS receiver module collection Carry out interpolation, have identical sampling number L after interpolation, be expressed as Then calculate parameter

Corresponding navigation path and GPS return to the cumulative errors W between track ^{(i, j)}

In hard magnetic interference parameter hunting zone (2N+1) ²Individual discrete hard magnetic interference parameter collection Error W between corresponding calibration track and GPS reference locus ^{(i, j)}After calculating, individual with (2N+1)

Be the X-axis coordinate, individual with (2N+1)

For the Y-axis coordinate, with W ^{(i, j)}Be expressed as the Z axis coordinate, use curved surface $W^{(i,j)}=h({\mathrm{\&delta;H}}_x^{\left(i\right)},{\mathrm{\&delta;H}}_y^{\left(j\right)})$ Expression is as shown in 10.

So far can obtain curved surface

Smallest point.Because hard magnetic interference parameter hunting zone is limited discrete point: $\left\{(\frac{-N+i}{N}{H}_x^{\max },\frac{-N+j}{N}{H}_y^{\max })\right|i=\mathrm{0,1},...,2N;j=\mathrm{0,1},...,2N\},$ When the time direct search (2N+1) that is not very large of search total sample number ²Individual W ^{(i, j)}When the search sample is larger, can search for gradient descent method (2N+1) ²Minimum value in individual sample.Minimum W wherein ^{(i, j)}Corresponding

Be namely hard magnetic interference parameter optimal parameter estimated value in this hunting zone, be designated as

Step 4: according to the correction accuracy requirement of setting, dwindle the hunting zone, search, obtain more accurate hard magnetic interference parameter estimation value again.

Dwindle the hunting zone that hard magnetic disturbs the error of zero that causes, be made as:

$\left\{({\mathrm{\&delta;H}}_x^{\mathrm{opt}1}+\frac{-N+i}{N}{\tilde{H}}_x^{\max },{\mathrm{\&delta;H}}_y^{\mathrm{opt}1}+\frac{-M+j}{N}{\tilde{H}}_y^{\max })\right|i=\mathrm{0,1},...,2M;j=\mathrm{0,1},...,2M\};$

Be the search upper limit that on new X-axis magnetometric sensor, hard magnetic disturbs, be made as the former X-axis hard magnetic interference parameter search upper limit

Namely

Be the search upper limit that new Y-axis magnetometric sensor hard magnetic disturbs, be made as the former Y-axis hard magnetic interference parameter search upper limit

Namely With Be two search precisions that parameter is new, M is the new positive dirction scouting interval, and the precision of the larger expression search of M is higher.Following formula is illustrated in the hard magnetic interference parameter approximate value that obtains in step 3

Near again the search, obtain more accurate hard magnetic interference parameter From parameter i=0, j=0 begins to i=2M, j=2M search all (2M+1) ²Individual possibility parameter combinations.

Correction accuracy requirement according to setting can repeat the zone that dwindles is carried out the search of more refinement.The hard magnetic of obtaining further optimization disturbs the estimated value of the error of zero parameter that causes, and is designated as

Obtain the estimated value of high-precision hard magnetic interference parameter after completing optimum hard magnetic interference parameter search

Can pass through the ethernet module interface will

Send in submarine navigation device, and be stored in the hard disk of Central Control Module.

When submarine navigation device re-starts conventional sea trial, the course angle θ with the hard magnetic interference that electronic compass returns _mAfter being transferred to Central Control Module, Central Control Module utilizes formula

Calculate the course angle after calibrating

Course angle after the experiment results proved calibration

With true course angle θ _RealError

Much smaller than unregulated course angle error | θ _m-θ _Real|.When after the submarine navigation device dive or GPS receiver module when failing to accept positioning satellite signal, submarine navigation device can be calibrated course angle by employing like this

Headway v with the Doppler log measurement _DVLExtrapolate the position of aircraft self.Aircraft in the position of North and South direction and east-west direction is:

$x_{N,t}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{\mathrm{DVL},k}\&CenterDot;\cos \left({\mathrm{\&theta;}}_{\mathrm{clb},k}^{\mathrm{opt}2}\right)\&CenterDot;\mathrm{dT}+x_{N,0}^{\mathrm{GPS}},$

$x_{E,t}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{\mathrm{DVL},k}\&CenterDot;\sin \left({\mathrm{\&theta;}}_{\mathrm{clb},k}^{\mathrm{opt}2}\right)\&CenterDot;\mathrm{dT}+x_{E,0}^{\mathrm{GPS}};$

Wherein dT is the time interval of location estimation, x _{N, t}, x _{E, t}The position that represents respectively t moment aircraft North and South direction and east-west direction,

v _{DVL, k}The headway that returns that represents respectively electronic compass navigation angle that k calibrates constantly and Doppler log,

Aircraft initial position for North and South direction and east-west direction.Before and after the electronic compass calibration, submarine navigation device independent navigation examples of traces as shown in figure 11, what wherein solid line represented is the aircraft track that GPS receiver module return data is calculated, dotted line represents the unregulated navigation path of electronic compass, and dotted line represents is navigation path after the electronic compass calibration.The actual tests proof adopts the navigation results of the rear course angle of calibration with respect to adopting the navigation results site error of not calibrating course angle from being reduced to more than 15% in 1%, sees Figure 12.

Claims (5)

1. the bearing calibration of an electronic compass in underwater vehicle, the method are used for the electronic compass that is arranged on submarine navigation device is calibrated, thereby improve the precision of submarine navigation device independent navigation; Submarine navigation device has navigation sensor module, Central Control Module, battery module, propulsion die, GPS receiver module and communication module, and Doppler log is installed, and all modules are all powered by battery module; The method comprises the following steps:

(1) the inquiry geomagnetic declination, set the correction accuracy requirement;

(2) the aircraft water surface is done the calibration navigation, records respectively position, course angle and the translational speed of submarine navigation device by GPS receiver module, electronic compass and Doppler log, obtains calibration navigation navigation data;

(3) set (2N+1) ²Individual discrete hard magnetic interference parameter initial ranging collection:

$\{({\mathrm{\&theta;H}}_x^{\left(i\right)},{\mathrm{\&delta;}}_y^{\left(j\right)}),i,j=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;2N+1\};$

Calculate (2N+1) ²Error W between calibration track and reference locus under individual discrete hard magnetic interference parameter condition ^{(i, j)}Surface chart, search error surface chart minimum value, the corresponding parameter set of error smallest point

Namely the approximate value of hard magnetic interference parameter, δ H _x, δ H _yBe the SX that the Hard Magnetic mushing error causes, the error of zero of SY axle output valve;

(4) according to the correction accuracy requirement of setting, repeat to dwindle hunting zone and grid, search again obtains more accurate hard magnetic interference parameter estimation value

Error in described step (3) is calculated and is comprised the following steps:

(3.1) calculate hypothesis X, on the Y-axis magnetometric sensor, hard magnetic disturbs and causes the error of zero to be

Situation under, Corresponding electronic compass calibration course angle

Measure course angle θ with electronic compass _mBetween corresponding relation θ _{The geomagnetic declination}Inquire about the geomagnetic declination that obtains for step (1);

(3.2) according to the navigation angle after calibration

Adopt the dead reckoning calculating parameter

Corresponding submarine navigation device movement locus

Dead reckoning is specific as follows, with the submarine navigation device translational speed V of Doppler log collection _DVLDecompose under terrestrial coordinate system, resolve into the speed of North and South direction and the speed of east-west direction, be expressed as respectively

With Wherein,

Expression t North and South direction speed component constantly,

Expression t is the speed component of east-west direction constantly;

Speed after decomposing be multiply by the time interval add up, obtain the position of each sampled point submarine navigation device constantly that dead reckoning estimates, mathematical notation is:

$x_{N,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{N,t}\&CenterDot;\mathrm{dT}+x_{N,0}^{\mathrm{GPS}},$

$x_{E,t}^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^t{v}_{E,t}\&CenterDot;\mathrm{dT}+x_{E,0}^{\mathrm{GPS}};$

Wherein,

Represent respectively hard magnetic interference parameter group

Corresponding to the coordinate of t aircraft constantly at North and South direction and east-west direction; DT is the time interval,

The expression accumulating operation;

Represent respectively the North and South direction of the submarine navigation device that the GPS receiver module gathers and the t=0 moment initial position of east-west direction; Derive like this

Corresponding submarine navigation device is estimated track

$P_{1:L}^{(i,j)}=\left\{(x_{N,t}^{(i,j)},x_{E,t}^{(i,j)})\right|t=1,...,L\};$

(3.3) calculate

Corresponding calibration submarine navigation device track

With field survey or reference locus that the GPS receiver module returns

Between navigation error, wherein

The k that expression GPS returns is the North and South direction position constantly,

The k that expression GPS returns is the east-west direction position constantly, and navigation error is expressed as:

$W^{(i,j)}={\mathrm{\&Sigma;}}_{k=1}^L{(x_{N,k}^{(i,j)}-x_{N,k}^{\&prime;\mathrm{GPS}})}^2+{\mathrm{\&Sigma;}}_{k=1}^L{(x_{E,k}^{(i,j)}-x_{E,k}^{\&prime;\mathrm{GPS}})}^2;$

Wherein, W ^{(i, j)}Expression hard magnetic interference parameter Corresponding calibration track and the error between reference locus.

2. the bearing calibration of electronic compass in underwater vehicle according to claim 1, it is characterized in that, error surface chart minimum value searching method in described step (3) is exhaustive search, relatively ask for the error minimum value by pointwise, or by asking for the error minimum value based on the local search algorithm of gradient, or ask for the error minimum value by global optimization approach; Described global optimization approach comprises simulated annealing, genetic algorithm and particle group optimizing.

3. the bearing calibration of electronic compass in underwater vehicle according to claim 1, it is characterized in that, calibration navigation navigation data in described step (2) exports to submarine navigation device inter-process equipment by communication module, the processing of completing steps (3) and (4), perhaps export to water surface treatment facility by communication module, the processing of completing steps (3) and (4).

4. the bearing calibration of electronic compass in underwater vehicle according to claim 1, is characterized in that, the hard magnetic interference parameter in described step (3) replaces with the set of soft magnetism interference parameter or hard magnetic interference parameter and soft magnetism interference parameter.

5. the submarine navigation device air navigation aid of a having electronic compass compensation, after the method is completed the electronic compass calibration according to the bearing calibration of any one in claim 1 to 4, the magnetic interference estimates of parameters that search is obtained is applied in the submarine navigation device navigation: the magnetic interference estimates of parameters that obtains after search outputs in the submarine navigation device Central Control Module by communication module, and is stored in the storage medium of Central Control Module; When submarine navigation device re-starts conventional navigation, the course angle θ from the actual measurement of navigation sensor module return electron compass _mAnd after the magnetic interference estimates of parameters was transferred to Central Control Module, Central Control Module calculated the course angle after calibration In conjunction with other navigation sensor module data, complete dead reckoning.

Images