Three-shaped fluxgate parallel matrix array for measuring flight speed of target and method of three-shaped fluxgate parallel matrix array

Abstract

The invention belongs to the technical field of magnetic field detection, and discloses a three-shaped fluxgate parallel matrix array for measuring the flight speed of a target and a method of the three-shaped fluxgate parallel matrix array. The three-shaped fluxgate parallel matrix array comprises three parallel mounting racks, and a plurality of sensors are respectively clamped on each mounting rack through sliding chutes; a probe of each sensor vertically faces a target; the three-shaped fluxgate parallel matrix array can be expanded along the line, and the baseline distance can be adjusted; the measurement method comprises the following steps: measuring a magnetic induction intensity vector matrix; measuring a second-order magnetic gradient tensor matrix; calculating normalized magnetic source intensity; and calculating the average speed of the target. The method is simple, a second-order magnetic gradient tensor matrix is sequentially calculated through observation points along a middle column sensor, the normalized magnetic source intensity at each observation point is calculated according to the second-order magnetic gradient tensor matrix, and compared with traditional speed measurement methods such as photoelectric detection and radar detection, the method is not influenced by a plasma sheath around a high-speed target and is not influenced by shielding of media such as fire light and smoke. The engineering practical value is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic field detection, and particularly relates to a three-letter type magnetic flux gate parallel matrix array for measuring the flying speed of a target and a method thereof. BACKGROUND

[0002] The measurement of the magnetic gradient tensor has a wide range of applications in the fields of geophysical exploration, marine magnetic detection, and military target positioning. Traditional magnetic field detection devices can only measure the magnetic induction intensity at a single point (i.e., the first-order magnetic gradient), and cannot accurately measure higher-order gradients of the magnetic field (such as the second-order magnetic gradient and the third-order magnetic gradient). The magnetic gradient tensor can provide more spatial information of the target, such as the magnetic moment distribution and the position characteristics of the target.

[0003] When a target is flying at a high speed, the aerodynamic optical effect and the plasma flow field effect will seriously affect the optical and radar detection process, especially the target capture, trajectory generation, and accurate positioning process. When phenomena such as self-luminous, refraction, and wake shock occur, the use of conventional optical detection means such as light curtain detection control instruments and photoelectric detectors for target speed measurement becomes unstable, and problems such as false triggering, reduced speed measurement accuracy, and speed measurement failure may occur. Moreover, the plasma sheath generated around the high-speed target can cause the black barrier effect, and the radar scattering characteristics are severely affected by the plasma, which strongly interferes with the radar speed measurement process.

[0004] Magnetic detection technology is a passive detection technology that captures targets by measuring the magnetic field and the change in the magnetic field around a ferromagnetic target. Using magnetic detection technology to measure the speed of a flying target is not affected by plasma and light smoke, and the magnetic force line can penetrate any object without ferromagnetic components, achieving a wall detection capability. Using magnetic detection technology, the change in the near-point magnetic field when the target flies by can be captured, thereby determining the accurate time when the target approaches, and achieving target speed measurement.

[0005] According to the magnetic dipole magnetic field vector and the forward and inverse formula of the magnetic gradient tensor, the change in the waveform of the magnetic field signal is affected by the distance and the order of the magnetic field. For example, when measuring the first-order and lower magnetic gradient tensor (such as the total magnetic field and the magnetic field vector), the measurement value decays with the third power of the target distance. When measuring the second-order magnetic gradient tensor and calculating the normalized magnetic source strength, the measurement value decays with the fourth power of the target distance. During the translational flight of the target, the change in the third power decay process curve of the first-order magnetic tensor caused by the change in the target distance is relatively flat, making it difficult to accurately capture the nearest point and the passing point time of the target path and the observation point. By estimating the magnetic gradient tensor components through the difference calculation between the sensor arrays, the normalized magnetic source strength of the target can be measured, and a more steep passing point waveform and a more accurate passing point time can be obtained.

[0006] Traditional magnetic gradient tensor measurement devices usually adopt fixed baseline distance design and fixed sensor layout, which is difficult to adapt to the distance and magnetic moment size changes of different measured targets, and has the problems of poor adaptability or limited measurement accuracy. Once the measurement accuracy and sensitivity of the magnetic measurement equipment are fixed, the application range and environmental adaptability will be greatly limited, especially for various free flight tests in the ballistic target chamber, the speed, size and magnetic moment strength of the target are quite different, and the single fixed baseline distance sensor array structure cannot effectively capture the test scene of the frequently changing properties of the magnetic moment, position and size of various target groups.

[0007] Currently, it is urgent to develop a three-letter magnetic flux gate parallel matrix array for measuring target flight speed and a method thereof. SUMMARY

[0008] One of the technical problems to be solved by the present application is to provide a three-letter magnetic flux gate parallel matrix array for measuring target flight speed, and another technical problem to be solved by the present application is to provide a target flight speed measurement method based on the three-letter magnetic flux gate parallel matrix array, to overcome the defects of the prior art.

[0009] The three-letter magnetic flux gate parallel matrix array for measuring target flight speed and the method thereof of the present application capture and calculate the magnetic induction intensity vector matrix of the target in the passing point area and the normalized magnetic source intensity calculated by the second-order magnetic gradient tensor matrix, accurately obtain the speed of the target at each sensor measurement point position and the passing point time, and monitor the flight speed of the target in the sensor array route throughout the journey.

[0010] The three-letter magnetic flux gate parallel matrix array for measuring target flight speed of the present application comprises three parallel mounting racks, each mounting rack is provided with a straight sliding groove, a plurality of sensors are arranged on each sliding groove, the spacing between adjacent sensors on the same sliding groove is adjusted by the sliding groove; all the sensors are arranged in a matrix array, the spacing between each sensor and the adjacent sensors in the four directions of up, down, left and right is equal, and the probe of each sensor is vertically directed to the target. d ​From top to bottom, the sensors of the first chute, from front to back, are labeled in turn: transducer (1, 1), transducer (1, 2), transducer (1, 3), transducer (1, 4), … transducer (1, n), … transducer (1, m), …; the sensors of the middle chute, from front to back, are labeled in turn: transducer (2, 1), transducer (2, 2), transducer (2, 3), transducer (2, 4), … transducer (2, n), … transducer (2, m), …; the sensors of the third chute, from front to back, are labeled in turn: transducer (3, 1), transducer (3, 2), transducer (3, 3), transducer (3, 4), … transducer (3, n), … transducer (3, m), …; The target flies along the flight path parallel to the chute from front to back.

[0011] Further, the three-letter magnetic flux gate parallel matrix array is horizontally expanded according to test requirements, and the baseline distances in the horizontal and vertical directions are adjusted; the baseline distances in the horizontal and vertical directions are equal to the spacing between the sensors d . The number of sensors on each chute and the length of the chute are adjusted according to test requirements to change the horizontal baseline distance of the flight path; the spacing between the mounting racks is adjusted according to test requirements to change the vertical baseline distance of the flight path; for weak magnetic targets, reducing the baseline distance improves the detection sensitivity, but also brings higher measurement noise; for strong magnetic targets, increasing the baseline distance improves the detection distance and maintains the detection sensitivity that meets the measurement requirements.

[0012] Further, the sensors are three-axis magnetic flux gate sensors, the mounting racks are non-magnetic materials, and the target is a ferromagnetic target.

[0013] Further, the magnetic induction intensity vector components measured by each sensor are b x , b y and b z , obtaining a magnetic induction intensity vector matrix; for the middle chute, in addition to the first and last two sensors, the adjacent three sensors and the sensors corresponding to the first and third chutes form several cross-shaped tensor measurement units; the front-to-back labels of each cross-shaped tensor measurement unit are 1, 2, 3, …. i , …. j ; each cross-shaped tensor measurement unit is named in turn as sensor 1, sensor 2, sensor 3, and sensor 4 in the counterclockwise direction starting from the 12 o'clock direction, and the sensor at the center is named sensor 5; the object coordinate system on each sensor from sensor 1 to sensor 5 is a spatial orthogonal coordinate system, and the three axes of the spatial orthogonal coordinate system are respectively x axis 1, axis 2, and axis 3.y axis and z axis; The magnetic induction intensity vector measured by sensor 4 is subjected to differential calculation to obtain the second-order magnetic gradient tensor matrix and part of the third-order magnetic gradient tensor components at the observation position of sensor 5; the central region magnetic induction intensity vector measured by sensor 5 is taken as a supplementary measurement value; The second-order magnetic gradient tensor matrix is obtained by differential instead of partial differential; two sensors symmetrical to sensor 5 are symmetrically placed at the two ends of the measuring line in the f axis direction, and according to the definition of the magnetic gradient tensor, the change rate of the e axis ( e = x , y , z ) component of the magnetic induction intensity vector in the f axis ( f = x , y , z ) direction is recorded as the second-order magnetic gradient tensor component ; the second-order magnetic gradient tensor component is represented by the difference between the readings of the e axis components of the two sensors: (without i , j , to avoid repeated use of the same symbol) ; wherein, is the distance between the two ends of the measuring line in the f axis direction, i.e. twice the baseline distance; b e is the e axis component of the magnetic induction intensity vector at the observation position of sensor 5; is the difference between the readings of the e axis components of the magnetic induction intensity vectors of the two sensors; formula (1) is the standard formula for differential measurement of the magnetic gradient tensor; Therefore, at the observation position of sensor 5, the second-order magnetic gradient tensor matrix G m is obtained by using the corresponding cross-shaped tensor measurement unit: ; wherein, b i j represents the reading of sensor i in the j axis direction, i =1,2,3,4,5, j = x , y ,z ; λ 1. λ 2 and λ 3 is the second-order magnetic gradient tensor matrix G m The eigenvalues ​​of λ 3 is the second-order magnetic gradient tensor matrix G m The intermediate eigenvalue of λ 1 and λ 2 are the minimum eigenvalue and the maximum eigenvalue respectively; the corresponding eigenvectors are v 1. v 2 and v 3. Through sensors ~ sensor 5, 6 independent components of the 27 third-order magnetic gradient tensor components of the observation position of sensor 5 are obtained, namely: ; in, is part of the third-order magnetic gradient tensor component; the second-order magnetic gradient tensor matrix is ​​used to measure the normalized magnetic source intensity, and part of the third-order magnetic gradient tensor component is used to understand the spatial position and physical property information of the magnetic source target; Normalized magnetic source intensity Through the second-order magnetic gradient tensor matrix G m Eigenvalue calculation, normalized magnetic source intensity for: ; in, m is the magnetic moment vector, r is the position vector, μ 0 is the vacuum permeability, , ; The target flight speed measurement method based on the three-shaped fluxgate parallel matrix array of the present invention comprises the following steps: S10. Measure the magnetic induction intensity vector matrix; When the target is observed flying along the flight path, each sensor synchronously collects the magnetic induction intensity vector signal to obtain the magnetic induction intensity vector matrix of the three-shaped fluxgate parallel matrix array; S20. Measure the second-order magnetic gradient tensor matrix; For each sensor in the middle chute except the first and last two sensors, the second-order magnetic gradient tensor matrix is ​​calculated using formula (2): G m1、 G m2、 G m3 …; S30. Calculate normalized magnetic source intensity ; By second-order magnetic gradient tensor matrix G m1、 G m2、 G m3 …, calculate each normalized magnetic source strength , and record each normalized magnetic source strength The corresponding peak moment t 1, t 2, t 3…; S40. Calculate the average speed of the target; Calculate the average speed of the target of the adjacent cross-shaped tensor measurement unit v 1, v 2, v 3…, as follows: ; At the same time, using any two cross-shaped tensor measurement units, the average speed of the target is calculated v i,j , wherein i and j are the serial numbers of the two cross-shaped tensor measurement units, and j > i , as follows: .

[0014] The three-letter magnetic flux gate parallel matrix array for measuring the flight speed of the target and the method thereof have the following characteristics: a. Adopting variable baseline distance design: the baseline distance between the four sensors of any cross-shaped tensor measurement unit in the matrix array can be adjusted, which can optimize the detection according to different target characteristics, and has strong adaptability; b. Can continuously measure rich magnetic field information on the flight path: b1. Simultaneously measure the magnetic total field and the magnetic field vector at each sensor observation point of the matrix array; b2. Calculate the second-order magnetic gradient tensor matrix for the observation points along the line of the middle column sensor in sequence, obtain a row of observation point connecting lines, and continuously observe the normalized magnetic source strength value of the target passing through the observation points; b3. For any cross-shaped tensor measurement unit in the matrix array, 5 total field data, 15 component field data, 10 total field gradient data, a second-order magnetic gradient tensor matrix at the center observation point (9 components, including 5 independent components), and 6 independent third-order magnetic gradient tensor components at the center point (27 components, only 7 independent components) can be obtained; b4. Any number of sensors in the three-letter type magnetic flux gate parallel matrix array can be combined to realize the synchronous observation of the second-order and above magnetic gradient tensor component signals at different points in the target flight path direction and different baseline distances (multiples of the minimum baseline distance); c. Can adapt to the application of the tank target chamber and the outer target field: the three-letter type matrix array structure is very suitable for the spatial layout of the long-scale tank target chamber, such as the free flight trajectory target, the outer target field and other large-scale test equipment, and realizes the speed measurement task of tracking the flying target throughout the journey.

[0015] The three-letter type magnetic flux gate parallel matrix array and the method for measuring the flight speed of the target of the application can flexibly adjust the variable baseline distance between the sensors in the array, optimize the sensor layout, use the differential calculation of the second-order magnetic gradient tensor along the path direction, and calculate the normalized magnetic source intensity at each observation point of the three-letter type magnetic flux gate parallel matrix array. Compared with directly measuring the total field intensity value, the range of capturing the target passing point area can be reduced, the target passing point time when the target passes through the tangent line of the shortest distance to the path can be more accurately captured, and the target passing point time and speed can be continuously observed and calculated by the parallel array. Finally, the flight speed of the target in the path direction can be efficiently and reliably observed.

[0016] The three-letter type magnetic flux gate parallel matrix array and the method for measuring the flight speed of the target of the application can be applied to the free flight trajectory target chamber, and by laying the three-letter type magnetic flux gate tensor matrix array, the speed of the free flight target after the muzzle in the flight and target hitting process can be observed throughout the journey, and the change of the rich magnetic field information throughout the process can be observed. It can also be applied to the outer target field test, and by laying the three-letter type magnetic flux gate parallel matrix array in the atmospheric open test section, the speed of the target in the flight process can be observed throughout the journey, and the signal rising edge trigger instruction can be provided for other test equipment.

[0017] In short, the three-letter type magnetic flux gate parallel matrix array for measuring the flight speed of the target of the application can be expanded along the line and the baseline distance can be adjusted. The measurement method is simple, the second-order magnetic gradient tensor matrix is calculated in sequence through the observation points along the line of the middle column sensors, and the normalized magnetic source intensity at each observation point position is calculated. Compared with the traditional photoelectric detection and radar detection speed measurement method, it is not affected by the plasma sheath around the high-speed target and is not affected by the medium shielding such as fire smoke, and has engineering practical value. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structure diagram of the three-letter type magnetic flux gate parallel matrix array for measuring the flight speed of the target of the application; Figure 2 The structure diagram of the cross-shaped tensor measurement unit in the three-letter type magnetic flux gate parallel matrix array for measuring the flight speed of the target of the application.

[0019] In the figure, 1. sensor; 2. slide; 3. mounting stand.

[0020] In the figure, the sensor is referred to as the sensor; x 、 y 、 z are the coordinate axes of the object coordinate system. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0022] Example 1: Figure 1 As shown, the three-shaped fluxgate parallel matrix array for measuring the target flight speed of this embodiment includes three parallel mounting platforms 3, each mounting platform 3 is provided with a straight slide 2, and each slide 2 is respectively mounted with a plurality of sensors 1. The spacing between adjacent sensors 1 on the same slide 2 is adjusted by the slide 2; all sensors 1 are arranged in a matrix array, and the spacing between each sensor 1 and the adjacent sensors 1 in the four directions of up, down, left, and right is adjusted. d Equally, the probe of each sensor 1 is perpendicular to the target; From top to bottom, the sensors 1 of the first chute 2 are numbered from front to back as follows: transmission (1, 1), transmission (1, 2), transmission (1, 3), transmission (1, 4), ... transmission (1, n), ... transmission (1, m), ...; the sensors 1 of the middle chute 2 are numbered from front to back as follows: transmission (2, 1), transmission (2, 2), transmission (2, 3), transmission (2, 4), ... transmission (2, n), ... transmission (2, m), ...; the sensors 1 of the third chute 2 are numbered from front to back as follows: transmission (3, 1), transmission (3, 2), transmission (3, 3), transmission (3, 4), ... transmission (3, n), ... transmission (3, m), ...; The target flies from front to back along a flight path parallel to chute 2.

[0023] Furthermore, the three-shaped fluxgate parallel matrix array is horizontally expanded according to the test requirements, and the baseline distance in the horizontal and vertical directions is adjusted; the baseline distance in the horizontal and vertical directions is adjusted to the spacing between the sensor 1. d equal; The number of sensors 1 on each chute 2 and the length of the chute 2 are adjusted according to the test requirements to change the horizontal baseline distance of the flight path; the spacing between the mounting platforms 3 is adjusted according to the test requirements to change the vertical baseline distance of the flight path; for weakly magnetic targets, the baseline distance is reduced to improve the detection sensitivity, but at the same time it brings higher measurement noise; for strongly magnetic targets, the baseline distance is increased to improve the detection distance while maintaining the detection sensitivity that meets the measurement requirements.

[0024] Further, the sensor 1 is a three-axis fluxgate sensor, the installation platform 3 is made of non-magnetic material, and the target is a ferromagnetic target.

[0025] Further, as shown in the figure, the magnetic induction intensity vector component measured by each sensor 1 is Figure 1 x b y b z , and a magnetic induction intensity vector matrix is obtained; as shown in the figure, for the middle chute 2, except for the first and last two sensors 1, the adjacent three sensors 1 and the sensors 1 corresponding to the first chute 2 and the sensors 1 corresponding to the third chute 2 form several cross-shaped tensor measurement units; the labels of the cross-shaped tensor measurement units from front to back are 1, 2, 3, …. b Figure 2 i j Each cross-shaped tensor measurement unit is named sensor 1, sensor 2, sensor 3, and sensor 4 in the counterclockwise direction from the 12 o'clock direction, and the sensor located at the center is named sensor 5. The object coordinate system on each of the sensors 1 to 5 is a spatial orthogonal coordinate system, and the three axes of the spatial orthogonal coordinate system are respectively x axis, y axis, and z axis; The magnetic induction intensity vectors measured by the sensors 1 to 4 are subjected to difference calculation to obtain a second-order magnetic gradient tensor matrix and part of third-order magnetic gradient tensor components at the observation position of the sensor 5; the central region magnetic induction intensity vector measured by the sensor 5 is used as a supplementary measurement value; The second-order magnetic gradient tensor matrix is obtained by difference instead of partial differentiation; two sensors 1 symmetric to the sensor 5 are symmetrically placed at the two ends of the measurement line in the f axis direction, according to the definition of the magnetic gradient tensor, the change rate of the e axis ( e = x , y , z ) component of the magnetic induction intensity vector in the f axis ( f = x , y , z ) direction is recorded as the second-order magnetic gradient tensor component ; the second-order magnetic gradient tensor component is represented by the difference between the readings of the e axis components of the two sensors 1: (without i , j , to avoid repeated use of the same symbol)​​​​​ ; wherein, is the distance between the two ends of the survey line in the direction of the axis, i.e. twice the baseline distance; f b e is the magnetic induction intensity vector observed by the sensor 5 at the observation position; e axis component; is the difference between the magnetic induction intensity vector component readings of the two sensors 1; e Equation (1) is the standard formula for differential measurement of the magnetic gradient tensor; then at the observation position of the sensor 5, the second-order magnetic gradient tensor matrix G m is: ; wherein, b i j denotes the reading of the sensor i in the direction of the axis, j =1,2,3,4,5, i = j , x , y , z ; λ 1, λ 2 and λ 3 are the eigenvalues of the second-order magnetic gradient tensor matrix G m , λ 3 is the intermediate eigenvalue of the second-order magnetic gradient tensor matrix G m , λ 1 and λ 2 are the minimum eigenvalue and the maximum eigenvalue, respectively; the corresponding eigenvectors are v 1, v 2 and v 3; through the sensors 1-5, 6 independent components among the 27 third-order magnetic gradient tensor components at the observation position of the sensor 5 are obtained, i.e. ; wherein, is a partial third-order magnetic gradient tensor component; the second-order magnetic gradient tensor matrix is used to measure the normalized magnetic source intensity, and the partial third-order magnetic gradient tensor component is used to understand the spatial position and physical property information of the magnetic source target; the normalized magnetic source intensity is calculated through the eigenvalues of the second-order magnetic gradient tensor matrix G m , and the normalized magnetic source intensity​ for: ; in, m is the magnetic moment vector, r is the position vector, μ 0 is the vacuum permeability, , ; It can be seen that the normalized magnetic source intensity It is less affected by the magnetization direction of the magnetic target and is almost only related to the target distance. The closer the distance to the target, the larger the value. In addition, the normalized magnetic source intensity It decays with the fourth power of the relative distance between the observation position and the target and is sensitive to the relative distance. It can not only effectively filter out weak magnetic interference targets in a multi-magnetic target area, but also make the signal waveform formed by the target flying over steeper, which is beneficial to improving the accuracy of obtaining the peak moment and also beneficial to improving the observation bit density of continuous observation of target speed.

[0026] The target flight speed measurement method based on the three-shaped fluxgate parallel matrix array of this embodiment includes the following steps: S10. Measure the magnetic induction intensity vector matrix; When the target is observed flying along the flight path, each sensor 1 synchronously collects the magnetic induction intensity vector signal to obtain the magnetic induction intensity vector matrix of the three-shaped fluxgate parallel matrix array; S20. Measure the second-order magnetic gradient tensor matrix; For each sensor 1 in the middle chute 2 except the first and last two sensors 1, the second-order magnetic gradient tensor matrix is ​​calculated using formula (2): G m1、 G m2、 G m3 …; S30. Calculate normalized magnetic source intensity ; Through the second-order magnetic gradient tensor matrix G m1、 G m2、 G m3 ..., calculate the normalized magnetic source intensity , and record the normalized magnetic source intensity The corresponding peak time t 1, t 2, t 3…; S40. Calculate the average speed of the target; Computing the average velocity of a target using adjacent cross-tau measurement units v 1, v 2, v 3…, as follows: ; Simultaneously, the average velocity of the target is computed using any two cross-tau measurement units v i,j wherein i and j are the indices of the two cross-tau measurement units, respectively, and j i as follows: .

[0027] While embodiments of the application have been disclosed in connection with the above specification, it should be understood that it is not intended to limit the application to the particular details so far set forth, and that the scope of the application is to be determined by the appended claims, unless the specification clearly dictates to the contrary. Thus, any modification and variations that come within the scope of the claimed application are to be considered covered by the present application as set forth in the following claims.​

Claims

1. A three-shaped fluxgate parallel matrix array for measuring target flight speed, characterized in that: The three-shaped fluxgate parallel matrix array comprises three parallel mounting racks (3), each mounting rack (3) is provided with a straight slide groove (2), each slide groove (2) is respectively mounted with a plurality of sensors (1), and the spacing between adjacent sensors (1) on the same slide groove (2) is adjusted by the slide groove (2); all sensors (1) are arranged in a matrix array, and the spacing between each sensor (1) and the adjacent sensors (1) in the four directions of up, down, left, and right is adjusted. d Equally, the probe of each sensor (1) is perpendicular to the target; From top to bottom, the sensors (1) of the first chute (2) are numbered from front to back as follows: transmission (1, 1), transmission (1, 2), transmission (1, 3), transmission (1, 4), ... transmission (1, n), ... transmission (1, m), ...; the sensors (1) of the middle chute (2) are numbered from front to back as follows: transmission (2, 1), transmission (2, 2), transmission (2, 3), transmission (2, 4), ... transmission (2, n), ... transmission (2, m), ...; the sensors (1) of the third chute (2) are numbered from front to back as follows: transmission (3, 1), transmission (3, 2), transmission (3, 3), transmission (3, 4), ... transmission (3, n), ... transmission (3, m), ...; The target flies from front to back along a flight path parallel to the chute (2).

2. The three-shaped fluxgate parallel matrix array for measuring target flight speed according to claim 1, characterized in that: The three-shaped fluxgate parallel matrix array is horizontally expanded according to the test requirements, and the baseline distance in the horizontal and vertical directions is adjusted; the baseline distance in the horizontal and vertical directions is adjusted to the spacing between the sensor (1) d equal; The number of sensors (1) on each chute (2) and the length of the chute (2) are adjusted according to the test requirements to change the horizontal baseline distance of the flight path; the spacing between the mounting platforms (3) is adjusted according to the test requirements to change the vertical baseline distance of the flight path; for weak magnetic targets, the baseline distance is reduced to improve the detection sensitivity, but at the same time brings higher measurement noise; for strong magnetic targets, the baseline distance is increased to improve the detection distance and maintain the detection sensitivity that meets the measurement requirements.

3. The three-shaped fluxgate parallel matrix array for measuring target flight speed according to claim 2, characterized in that: The sensor (1) is a three-axis fluxgate sensor, the mounting stand (3) is made of non-magnetic material, and the target is a ferromagnetic target.

4. The three-shaped fluxgate parallel matrix array for measuring target flight speed according to claim 3, characterized in that: The magnetic induction intensity vector components measured by each sensor (1) are: b x 、 b y and b z , obtaining the magnetic induction intensity vector matrix; for the middle chute (2), except for the first and last two sensors (1), the adjacent three sensors (1) and the sensor (1) corresponding to the first chute (2) and the sensor (1) corresponding to the third chute (2) constitute a number of cross-shaped tensor measurement units; the numbers of the cross-shaped tensor measurement units from front to back are 1, 2, 3, ... i 、…… j , ...; Each cross-shaped tensor measurement unit is named sensor 1, sensor 2, sensor 3 and sensor 4 in the counterclockwise direction starting from the 12 o'clock direction. The sensor at the center is named sensor 5. The object coordinate system on each sensor from sensor 1 to sensor 5 is a spatial orthogonal coordinate system. The three axes of the spatial orthogonal coordinate system are respectively recorded as x axis, y Axis and z axis; The magnetic induction intensity vectors measured by sensors 1 to 4 are differentially calculated to obtain the second-order magnetic gradient tensor matrix and some third-order magnetic gradient tensor components at the observation position of sensor 5; The magnetic induction intensity vector of the central area measured by sensor 5 is used as a supplementary measurement value; The second-order magnetic gradient tensor matrix is ​​obtained by replacing partial differentials with differences; two sensors (1) symmetrical to sensor 5 are placed symmetrically. f At both ends of the measuring line in the axial direction, the magnetic induction intensity vector is e axis( e = x , y , z ) f axis( f = x , y , z ) is recorded as the second-order magnetic gradient tensor component ; then the second-order magnetic gradient tensor component With two sensors (1) e The difference between the readings of the axis components is expressed as follows: (without i 、 j , to avoid reusing the same symbol) ； in, For two sensors (1) in f The distance between the two ends of the measuring line in the axial direction is twice the baseline distance; b e is the magnetic induction intensity vector at the observation position of sensor 5 e Axis component; is the magnetic induction intensity vector of the two sensors (1) e The difference between the component readings; Equation (1) is the standard formula for differential measurement of the magnetic gradient tensor; Then, at the observation position of sensor 5, the corresponding cross-shaped tensor measurement unit is used to obtain the second-order magnetic gradient tensor matrix G m for: ； in, b i j Indicates sensor i exist j Readings in the axis direction, i =1,2,3,4,5, j = x , y , z ; λ 1. λ 2 and λ 3 is the second-order magnetic gradient tensor matrix G m The eigenvalues ​​of λ 3 is the second-order magnetic gradient tensor matrix G m The intermediate eigenvalue of λ 1 and λ 2 are the minimum eigenvalue and the maximum eigenvalue respectively; the corresponding eigenvectors are v 1. v 2 and v 3. Through sensors 1 to 5, 6 independent components of the 27 third-order magnetic gradient tensor components of the observation position of sensor 5 are obtained, namely: ； in, is part of the third-order magnetic gradient tensor component; the second-order magnetic gradient tensor matrix is ​​used to measure the normalized magnetic source intensity, and part of the third-order magnetic gradient tensor component is used to understand the spatial position and physical property information of the magnetic source target; Normalized magnetic source intensity Through the second-order magnetic gradient tensor matrix G m Eigenvalue calculation, normalized magnetic source intensity for: ； in, m is the magnetic moment vector, r is the position vector, μ 0 is the vacuum permeability, , .

5. A method for measuring target flight speed based on a three-shaped fluxgate parallel matrix array, which is based on the three-shaped fluxgate parallel matrix array for measuring target flight speed according to claim 4, characterized in that: The following steps are involved: S10. Measure the magnetic induction intensity vector matrix; When the target is observed to fly along the flight path, each sensor (1) synchronously collects magnetic induction intensity vector signals to obtain a magnetic induction intensity vector matrix of a three-shaped fluxgate parallel matrix array; S20. Measure the second-order magnetic gradient tensor matrix; For each sensor (1) in the middle chute (2) except the first and last two sensors (1), the second-order magnetic gradient tensor matrix is ​​calculated using formula (2): G m1、 G m2、 G m3 …; S30. Calculate normalized magnetic source intensity ; Through the second-order magnetic gradient tensor matrix G m1、 G m2、 G m3 ..., calculate the normalized magnetic source intensity , and record the normalized magnetic source intensity The corresponding peak time t 1, t 2, t 3…; S40. Calculate the average speed of the target; Calculate the average velocity of the target of adjacent cross-shaped tensor measurement units v 1, v 2, v 3…, as follows: ； At the same time, the average speed of the target is calculated using any two cross-shaped tensor measurement units. v i,j ,in i and j are the serial numbers of the two cross-shaped tensor measurement units, and j > i ,as follows: 。

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