CN105091880A - Method for tracking and positioning underwater long-distance magnetic object based on scalar sensor array - Google Patents

Abstract

The invention relates to a method for tracking and positioning an underwater long-distance magnetic object based on a scalar sensor array According to the method, five magnetic sensors are utilized to form a cross-shaped array on water surface or under water, the sensor optical axis orientation is basically parallel to the earth magnetic field vector T0 direction, and one edge of the cross-shaped sensor array is aligned to the earth-magnetic-field north magnetic pole direction. Each sensor is processed according to the following formula, T1-Ti, wherein i is not equal to 1, and thus the position coordinate (x,y,z) of the magnetic object relative to the first sensor and the object magnetic moment |P<right arrow>| are obtained. According to the method, through the position relationship of the sensors in the array, the quasi gradient of the total earth magnetic field is obtained, and thus three-dimension tracking positioning on the magnetic object is realized, and influence of earth magnetic field variation along with time and influence of space environment magnetic field distribution on magnetic positioning are eliminated.

Description

The method of a kind of tracing and positioning based on scalar sensors array remote magnetic target under water

Technical field

The present invention relates to the method for a kind of tracing and positioning based on scalar sensors array remote magnetic target under water.

Background technology

Terrestrial magnetic field is the natural physical field of of the earth, and it has various different origin, is formed by stacking by the magnetic field components of different Changing Pattern.Divide according to location of source, terrestrial magnetic field can be divided into internal field and external field.If consider terrestrial magnetic field feature over time, becoming the variation magnetic field of the earth by changing terrestrial magnetic field faster in time, changing the stabilizing magnetic field that slower or substantially constant terrestrial magnetic field becomes the earth in time.Side by side magnetic field is one of important physical amount of the processes such as reflection universe differentiation, Earth evolution, geologic structure differentiation and seismic activity.Research on geomagnetic field achievement has extensive and important application in the fields such as navigation, Aeronautics and Astronautics, energy minerals, safety, archaeology.

In various application fields, determining that the position of object is a top priority, is the prerequisite of carrying out follow-up work.The goods rescue, the removal of mines, the monitoring of seabeach rescue work, yard craft, antisubmarine application etc. of the sinking ship carried out as military affairs need, all need to carry out accurately and fast locating to underwater object.China's Huanghai Sea mean depth of the sea 50 meters, the East Sea mostly is the continental platform of 200 meters, and in such a case, sea situation and target noise are the biggest factors determining sonar contact distance.Then these factors need not be considered based on detection of magnetic field.Due to the existence of magnetic target, its induced field produced can cause the change of Distribution of Magnetic Field spatially, thus produces magnetic anomaly within this space.Therefore magnetic survey technology is very effective side, and people by the inverting to magnetic anomaly, can obtain some information (e.g., geometric parameter, location parameter etc.) of this target object.

Terrestrial magnetic field is vector field, implements vector measurement and can more fully describe and grasp magnetic element and Geomagnetism Information.Present stage generally selects the vector sensor can measuring more than 3 magnetic elements.When using vector sensor, it installs and uses all very complicated, and during installation, attitude orientation must critical alignment, still wants the impact of real-Time Compensation attitude and Orientation differences in carrier movement process, and correction attitude orientation also will use other high-accuracy position systems.Simultaneously due to the time dependent impact in terrestrial magnetic field, the measuring distance based on the method for vector sensor can not be oversize.

Compared to vector sensing, the scalar sensors optically pumped magnetometer of detection geomagnetic total field has highly reliable high-precision feature, and highest resolution can reach fT magnitude simultaneously.Therefore, the limit detection distance of the sensor array under fT magnitude is more than 10km.Owing to measuring geomagnetic total field, resultant field optically pumped magnetometer is installed and used does not need attitude orientation to calibrate, very convenient.

Summary of the invention

The object of the present invention is to provide a kind of can eliminate terrestrial magnetic field space distribution impact and the method for the remote magnetic target under water of the tracing and positioning based on scalar sensors array of time dependent impact.

The object of the present invention is achieved like this:

(1) at the water surface or utilize five Magnetic Sensors to be arranged in " ten " font array under water, the distance between adjacent sensors is L, and array plane direction is general parallel with the direction of surface level, wherein first sensor T ₁position be set to true origin (0,0,0), second sensor T ₂be positioned over (L, 0,0) position in x-axis, the 3rd sensor T ₃be positioned over (-L, 0, D) position in x-axis, the 4th sensor T ₄be positioned over (0, L, 0) position in y plane, the 5th sensor T ₅be positioned over (0 ,-L, 0) position in y plane; Sensor direction of optic axis and geomagnetic fieldvector T ₀the basic keeping parallelism in direction, the simultaneously alignedly magnetic north pole direction, a limit of " ten " font sensor array;

(2) each sensor is processed as follows: T ₁-T _ii ≠ 1; Draw the position coordinates relative to first sensor (x, y, z) and the target magnetic moment of magnetic target

$\left\{\begin{array}{c}{T}_1-T_2={\mathrm{\&Delta;T}}_{12}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_2(x,y,z\left)\right)\\ T_1-T_3={\mathrm{\&Delta;T}}_{13}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_3(x,y,z\left)\right)\\ T_1-T_4={\mathrm{\&Delta;T}}_{14}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_4(x,y,z\left)\right)\\ T_1-T_5={\mathrm{\&Delta;T}}_{15}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_5(x,y,z\left)\right)\end{array}\right.$

Wherein, (x, y, z) represents the position coordinates of magnetic target relative to first sensor, r _irepresent the distance of magnetic target to sensor i, Δ T _ijrepresent the difference of the earth magnetism static field of sensor i and sensor j; After sensor array is fixing, Δ T _ijcan being obtained by measurement, can known quantity be considered as when calculating;

Solve magnetic target relative to the position coordinates (x, y, z) of first sensor and magnetic target magnetic moment

Beneficial effect of the present invention is:

Above-mentioned localization method is the tracing and positioning realizing magnetic target by detecting the single scalar of geomagnetic total field.And owing to measuring resultant field, magnetometer is installed and used does not need attitude orientation to calibrate, very convenient.By the position relationship between sensor array, obtain the accurate gradient of corresponding geomagnetic total field, thus realize the three-dimensional tracing and positioning to magnetic target, can exclusively magnetic field time the impact that becomes and space environment Distribution of Magnetic Field on the impact of magnetic orientation.The magnetic moment calculated value tentatively can judge the yardstick of target.

Accompanying drawing explanation

Fig. 1 Magnetic Field positioning analysis schematic diagram.

The sensor array schematic diagram of Fig. 2 three-dimensional magnetic target localization.

The movement locus of Fig. 3 magnetic target.

The tracing and positioning result (X, Y, the relative error in Z-direction) of Fig. 4 target.

Embodiment

The present invention is to provide the method for a kind of tracing and positioning based on scalar sensors array remote magnetic target under water.By the corresponding relation between sensor array, obtain the accurate gradient information of corresponding terrestrial magnetic field, thus according to accurate gradient information, obtain the three dimensional local information of magnetic target under water.The proposed by the invention accurate gradient protocol utilizing geomagnetic sensor array to obtain exclusively can change the impact on magnetic survey location in magnetic field in time, laying of scalar sensors has nothing to do with orientation simultaneously, therefore this detection method is implemented simple, and positioning precision is high, and orientation distance is far away.

Due to the time dependent impact in terrestrial magnetic field, the detection range based on the detection method of the magnetic target under water of geomagnetic total field gradient is shorter.In the method, array based on five scalar sensors can effectively eliminate terrestrial magnetic field change in time on measure impact, improve measuring distance, it is characterized in that: by the position relationship between sensor array, obtain corresponding geomagnetic total field gradient, thus realize the three-dimensional tracing and positioning to magnetic target.

Utilize the array of scalar sensors and the algorithm realization of correspondence to the high accuracy remote of magnetic target enforcement under water tracing and positioning.It is characterized in that: five scalar sensors are arranged in " ten " font array, with reference to accompanying drawing 1.

The object of the invention is to carry out high-precision tracing and positioning to remote magnetic target under water.The geomagnetic total field data that the sensor array utilizing five scalar sensors to form obtains, the accurate gradient of earth magnetism is obtained by the relativeness between sensor, far field theory according to magnetic target magnetic dipole is deduced and algorithm design through strict physical concept, draw the position coordinates of magnetic target relative to sensor, realize the accurate location to target

2.1, oriented array is formed and algorithm design

When magnetic target is greater than itself size to the distance of sensor, this magnetic target can be equivalent to a magnetic dipole.The magnetic field that magnetic dipole produces can be expressed as:

$\stackrel{\&RightArrow;}{B}\left(\stackrel{\&RightArrow;}{r}\right)=\frac{\mathrm{\&mu;}}{4\mathrm{\&pi;}}(\frac{3(\stackrel{\&RightArrow;}{P}\&CenterDot;\stackrel{\&RightArrow;}{r})\stackrel{\&RightArrow;}{r}}{r^5}-\frac{\stackrel{\&RightArrow;}{P}}{r^3})---\left(1\right)$

Wherein, represent the distance of magnetic dipole to sensor, $\stackrel{\&RightArrow;}{P}$ Represent the magnetic moment of magnetic dipole, μ represents magnetic permeability.

The scalar expression that magnetic dipole produces magnetic field is:

$\left|\stackrel{\&RightArrow;}{B}\left(\stackrel{\&RightArrow;}{r}\right)\right|=\frac{\mathrm{\&mu;}}{4\mathrm{\&pi;}}\frac{\left|\stackrel{\&RightArrow;}{P}\right|}{\left|\right|r^3\left|\right|}\sqrt{3{\cos }^2\mathrm{\&beta;}+1}---\left(2\right)$

Wherein, be scalar value, β represents with between angle.In measuring process, the magnetic field measured comprises: the magnetic field that terrestrial magnetic field and magnetic dipole produce, and magnetic field expression formula is as follows:

$\stackrel{\&RightArrow;}{T}\left(\stackrel{\&RightArrow;}{r}\right)={\stackrel{\&RightArrow;}{T}}_0+\stackrel{\&RightArrow;}{B}\left(\stackrel{\&RightArrow;}{r}\right)---\left(3\right)$

Wherein, represent the terrestrial magnetic field at sensor place.

From formula 3, we can obtain:

$T^2=T_0^2+B^2+2\left|{\stackrel{\&RightArrow;}{T}}_0\right|\left|\stackrel{\&RightArrow;}{B}\right|cos\mathrm{\&alpha;}---\left(4\right)$

Wherein, α represents with between angle.Because α and β exists corresponding relation, its relation is as follows:

$tan\mathrm{\&alpha;}=\frac{3sin\mathrm{\&beta;}cos\mathrm{\&beta;}}{3{\cos }^2\mathrm{\&beta;}-1}---\left(5\right)$

By formula (4) and (5), we can obtain:

$T=T_0+\frac{\mathrm{\&mu;}}{4\mathrm{\&pi;}}\frac{\left|\stackrel{\&RightArrow;}{P}\right|}{\left|\right|r^3\left|\right|}3{\cos }^2\mathrm{\&beta;}-1---\left(6\right)$

β can be expressed as:

Wherein, be expressed as geomagnetic declination, θ is expressed as earth's magnetic dip angle.(x, y, z) represents the position coordinates of magnetic dipole relative to sensor.

Finally, we obtain the Scalar Expression form of earth magnetism:

By the above analysis to a scalar sensors, we have proposed a kind of method of the tracing and positioning to distant object based on five scalar sensors arrays.L represents the distance of adjacent sensors.We can obtain the geomagnetic field information about 5 sensors:

Wherein, r _irepresent the distance of magnetic dipole to sensor i, (x, y, z) represents the position of magnetic dipole relative to the 1st sensor.

In order to eliminate the time dependent impact in terrestrial magnetic field, we process as follows to each sensor: T ₁-T _i(i ≠ 1), finally obtains:

$\left\{\begin{array}{c}{T}_1-T_2={\mathrm{\&Delta;T}}_{12}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_2(x,y,z\left)\right)\\ T_1-T_3={\mathrm{\&Delta;T}}_{13}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_3(x,y,z\left)\right)\\ T_1-T_4={\mathrm{\&Delta;T}}_{14}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_4(x,y,z\left)\right)\\ T_1-T_5={\mathrm{\&Delta;T}}_{15}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_5(x,y,z\left)\right)\end{array}\right.---\left(9\right)$

Wherein, Δ T _ijrepresent the difference of the earth magnetism static field of sensor i and sensor j.After sensor array is fixing, Δ T _ijcan being obtained by measurement, can known quantity be considered as when calculating.Therefore, by above-mentioned process, the time dependent impact in terrestrial magnetic field has been eliminated.

Magnetic target can be solved relative to the position coordinates (x, y, z) of sensor 1 and magnetic target magnetic moment by (9) formula

2.2, array forms simple and easy installing and measuring conveniently

Above-mentioned localization method is by detecting the single scalar realize target location of geomagnetic total field.And owing to measuring resultant field, magnetometer is installed and used does not need attitude orientation to calibrate, very convenient.

2.3, not by the impact of ground magnetic temporal variation

By the position relationship between sensor array, obtain the accurate gradient of corresponding geomagnetic total field, thus realize the three-dimensional tracing and positioning to magnetic target, can exclusively magnetic field time the impact that becomes and space environment Distribution of Magnetic Field on the impact of magnetic orientation.

In sensor array, the geomagnetic data of five sensors carries out T ₁-T _i(i ≠ 1) processes, and eliminates the time dependent impact of impact and magnetic field of spatial magnetic field.Wherein, T ₁represent the geomagnetic data of sensor 1, T _irepresent the geomagnetic data of sensor i.

The method adopts modified particle swarm optiziation to achieve quick calculating, can realize real-time tracing location to mobile magnetic target.

Without the need to carrying out attitude orientation calibration to sensor array when the installation of " ten " font sensor array in the method and detection.

It is a kind of based on scalar array of magnetic sensors that involved in the present invention is, utilizes terrestrial magnetic field resultant field data to carry out the method for three-dimensional tracing and positioning to magnetic target under water.The geomagnetic total field data that the sensor array specifically utilizing five scalar magnetometers to form obtains, geomagnetic total field gradient is obtained by the relativeness between sensor, far field theory according to magnetic target magnetic dipole is deduced and algorithm design through strict physical concept, draw the position coordinates of magnetic target, realize pinpoint method, owing to adopting the accurate gradient of earth magnetism, the impact of terrestrial magnetic field space distribution and time dependent impact can be eliminated.Energy mineral reserve exploration under water, various pipeline maintenance monitoring under water, Geological Hazards Monitoring, under water archaeology, wreck surveying, clearance are antisubmarine etc., and there is important application in field.

The object of the invention is to carry out high-precision tracking and location to remote magnetic target under water.The geomagnetic total field data that the sensor array utilizing five scalar magnetometers to form obtains, the accurate gradient of earth magnetism is obtained by the relativeness between sensor, far field theory according to magnetic target magnetic dipole is deduced and algorithm design through strict physical concept, draw the position coordinates of target, realize the accurate location to target.

Particular content of the present invention comprises:

1, array is formed

1. array geometry

As accompanying drawing 1, at the water surface or utilize five Magnetic Sensors to be arranged in " ten " font array under water, the distance between adjacent sensors is L, and with reference to accompanying drawing 1, array plane direction is general parallel with the direction of surface level, one of them sensor T ₁position be set to true origin (0,0,0), second sensor T ₂be positioned over (L, 0,0) position in x-axis, the 3rd sensor T ₃be positioned over (-L, 0, D) position in x-axis, the 4th sensor T ₄be positioned over (0, L, 0) position in y plane, the 5th sensor T ₅be positioned over (0 ,-L, 0) position in y plane.

2. sensor cloth set direction

When adopting optical pumping Magnetic Sensor, sensor direction of optic axis and geomagnetic fieldvector T ₀the basic keeping parallelism in direction, the simultaneously alignedly magnetic north pole direction, a limit of " ten " font sensor array.

3. the principle of foursquare length of side L is determined:

First when various objective condition allows, the distance L between adjacent sensors is larger, and the positioning precision of array is higher.

Length of side L can not exceed the effective range of sensor, and this is determined by the resolution of forming array sensor.

Length of side L does not hinder the motor-driven navigation of array, and this is determined by the load-carrying ability and headway of loading or pulling array carrier.

2, algorithm design

In sensor array, the geomagnetic field information of five sensors is as (1) formula, and in order to eliminate the time dependent impact in terrestrial magnetic field, we process as follows to each sensor: T ₁-T _i(i ≠ 1), obtains (2) formula, can be drawn the position coordinates relative to sensor 1 (x, y, z) and the target magnetic moment of magnetic target by (2) formula

$\left\{\begin{array}{c}{T}_1-T_2={\mathrm{\&Delta;T}}_{12}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_2(x,y,z\left)\right)\\ T_1-T_3={\mathrm{\&Delta;T}}_{13}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_3(x,y,z\left)\right)\\ T_1-T_4={\mathrm{\&Delta;T}}_{14}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_4(x,y,z\left)\right)\\ T_1-T_5={\mathrm{\&Delta;T}}_{15}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\right(x,y,z)-f_5(x,y,z\left)\right)\end{array}\right.---\left(2\right)$

Wherein, (x, y, z) represents the position coordinates of magnetic target relative to sensor 1, r _irepresent the distance of magnetic target to sensor i, Δ T _ijrepresent the difference of the earth magnetism static field of sensor i and sensor j.After sensor array is fixing, Δ T _ijcan being obtained by measurement, can known quantity be considered as when calculating.

Magnetic target can be solved relative to the position coordinates (x, y, z) of sensor 1 and magnetic target magnetic moment by (2) formula

Build scalar array of magnetic sensors with Fig. 2 structure, the transducer spacing L=3m in array, Magnetic Sensor employing sensitivity is the CS-L optically pumped magnetometer of 0.6pT.Sensor array is placed along the parallel direction with magnetic north.Magnetic target moves in surface level, and translational speed is in the x direction 5m/s, and translational speed is in the Y direction 10m/s.Sampling interval is 2s.Magnetic target moves to B point along the flight path of planning from A point, as shown in Figure 3.Fig. 3 is the result of the tracing and positioning adopting this method.Fig. 3 gives the situation of the relative error of each point.Relative error in X and Y-direction is less than 2%, and the relative error in Z-direction is about 5%.Remove outside indivedual obvious errors point, magnetic target is to the distance of sensor 1 average relative error be 1.3%.The visible program can carry out high-precision tracking and location to magnetic target.The magnetic target magnetic moment simultaneously calculated is P=5 × 10 ⁶am ².

Claims (1)

1., based on a method for the tracing and positioning remote magnetic target under water of scalar sensors array, it is characterized in that, comprise the steps:

(1) at the water surface or utilize five Magnetic Sensors to be arranged in " ten " font array under water, the distance between adjacent sensors is L, and array plane direction is general parallel with the direction of surface level, wherein first sensor T ₁position be set to true origin (0,0,0), second sensor T ₂be positioned over (L, 0,0) position in x-axis, the 3rd sensor T ₃be positioned over (-L, 0, D) position in x-axis, the 4th sensor T ₄be positioned over (0, L, 0) position in y plane, the 5th sensor T ₅be positioned over (0 ,-L, 0) position in y plane; Sensor direction of optic axis and geomagnetic fieldvector T ₀the basic keeping parallelism in direction, the simultaneously alignedly magnetic north pole direction, a limit of " ten " font sensor array;

(2) each sensor is processed as follows: T ₁-T _ii ≠ 1; Draw the position coordinates relative to first sensor (x, y, z) and the target magnetic moment of magnetic target

$\left\{\begin{array}{c}{T}_1-T_2={\mathrm{\&Delta;T}}_{12}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\left(x,y,z\right)-f_2\left(x,y,x\right)\right)\\ T_1-T_3={\mathrm{\&Delta;T}}_{13}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\left(x,y,z\right)-f_3\left(x,y,x\right)\right)\\ T_1-T_4={\mathrm{\&Delta;T}}_{14}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\left(x,y,z\right)-f_4\left(x,y,x\right)\right)\\ T_1-T_5={\mathrm{\&Delta;T}}_{15}+\frac{\mathrm{\&mu;}\left|\stackrel{\&RightArrow;}{P}\right|}{4\mathrm{\&pi;}}\left(f_1\left(x,y,z\right)-f_5\left(x,y,x\right)\right)\end{array}\right.$

Wherein, (x, y, z) represents the position coordinates of magnetic target relative to first sensor, r _irepresent the distance of magnetic target to sensor i, Δ T _ijrepresent the difference of the earth magnetism static field of sensor i and sensor j; After sensor array is fixing, Δ T _ijcan being obtained by measurement, can known quantity be considered as when calculating;

Solve magnetic target relative to the position coordinates (x, y, z) of first sensor and magnetic target magnetic moment