CN106199743A - Magnetic anomaly signal detecting method - Google Patents

Abstract

The invention provides a kind of magnetic anomaly signal detecting method, the method includes: build the model of the magnetic anomaly signal produced relative to magnetic sensor along the objective body that parabolic path moves；It is one group of orthogonal basis function by the model decomposition of described magnetic anomaly signal；Based on described one group of orthogonal basis function, detection signal is carried out matched filtering, to obtain detecting the energy signal of signal；And the energy signal according to detection signal, the existence of detection magnetic anomaly signal.

Description

Magnetic anomaly signal detecting method

Technical field

The present invention relates to geophysics's technical field, particularly relate to a kind of orthogonal basis based on objective body parabolic path The magnetic anomaly signal detecting method of function (Orthonormal Basis Function, OBF).

Background technology

Magnetic anomaly detection (Magnetic Abnormal Detection, the MAD) several years are always for detecting magnet mesh Mark, this makes MAD for detection of concealed target and becomes attractive.MAD is commonly used to search system, such as to carry out Detecting under water, wrack detection, mine detect, bury detection etc., and warning system, such as to carry out invasive noise, Virtual protection (infrastructure protection), anti-ask controls (passenger accesses control, inlet point monitors), medical applications, Industry Control, Ball physics-EQ prediction etc..MAD method is generally divided into two kinds, and one is that another kind is based on noise based on mesh object detection method Detection method.

Based in mesh object detection method, prior art assumes that magnetic target is linearly relative to the track of Magnetic Sensor Motion, magnetic target produces magnetic field B.This magnetic field B is modeled, and is decomposed into one group of orthogonal basis function.Then by by real Border detection signal carries out matched filtering with orthogonal basis function, detects the existence of magnetic target.The clean magnetic field that Magnetic Sensor measurement is arrived Including target induced magnetic fields, magnetic field of the earth and magnetic noise.This magnetic noise includes instrument vibrations noise, earth magnetism fluctuation (earth's magnetic field Change), the noise that introduces of the noise that introduces of motion and surge, thus cause the situation of actually detected data low signal-to-noise ratio, I.e. signal is submerged in the middle of noise.Low signal-to-noise ratio would generally limit the discovery of engineering detecting abnormal object, be one formidable Problem.For the magnetic signal test problems under straight path low signal-to-noise ratio, some scholar proposes based on straight path orthogonal basis The method decomposed, but its be limited in that can only the magnetic anomaly signal of detection of straight lines track.

It is thus desirable to one is obviously improved signal to noise ratio, magnetic anomaly can be detected under the low signal-to-noise ratio of-15dB white noise The detection method of signal.

Summary of the invention

(1) to solve the technical problem that

In view of above-mentioned technical problem, the invention provides a kind of orthogonal basis magnetic anomaly signal detection based on parabolic path Method, can detect magnetic anomaly signal under the low signal-to-noise ratio of-15dB white noise, thus be obviously improved signal to noise ratio,

(2) technical scheme

According to an aspect of the invention, it is provided a kind of magnetic anomaly signal detecting method, including:

Build the model of the magnetic anomaly signal produced relative to magnetic sensor along the objective body that parabolic path moves；

It is one group of orthogonal basis function by the model decomposition of described magnetic anomaly signal；

Based on described one group of orthogonal basis function, detection signal is carried out matched filtering, to obtain detecting the energy letter of signal Number；And

According to the energy signal of detection signal, the existence of detection magnetic anomaly signal.

Preferably, it is that one group of orthogonal basis includes by the model decomposition of described magnetic anomaly signal:

The model of described magnetic anomaly signal is performed sliding-model control, to obtain the discrete model of described magnetic anomaly signal；

According to described discrete model, it is thus achieved that one group of Line independent basic function；

Calculate the Wronskian of described one group of Line independent basic function；And

Gram Schmidt orthogonalization process is used described Wronskian to be carried out orthonomalization, to obtain State one group of orthogonal basis function.

Preferably, detection signal is carried out matched filtering to include:

Based on described one group of orthogonal basis function, it is thus achieved that one group of matched filtering function, and to described one group of matched filtering function Invert；

One group of matched filtering function after detection signal and reversion is carried out convolution；And

Squared to convolution results, to obtain detecting the energy signal of signal.

Preferably, the model of described magnetic anomaly signal is:

And

u₀For the pcrmeability in air, m is the magnetic torque of objective body, v₀For the initial velocity of objective body horizontal direction, a is The acceleration of objective body vertical direction,And

Preferably, u=at/v is made₀, w=v₀ ²/ a, λ=a/v₀, described discrete model is:

$\stackrel{\→}{B}\left(n\right)=\frac{u_0}{4\mathrm{\π}}\left\{\begin{array}{c}\frac{-m_{x}w-3m_y{w}^2\mathrm{\λ}n-m_x(w-12w^2){\left(\mathrm{\λ}n\right)}^2+3m_y{w}^2{\left(\mathrm{\λ}n\right)}^3}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{\frac{1}{2}{m}_{y}w-6m_x{w}^2\mathrm{\λ}n-w{\left(\mathrm{\λ}n\right)}^2+6m_x{w}^2{\left(\mathrm{\λ}n\right)}^3+\frac{3}{2}{m}_{y}w{\left(\mathrm{\λ}n\right)}^4}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{-m_{z}w-m_{z}w{\left(\mathrm{\λ}n\right)}^2}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\end{array}\right\}$

Wherein, w and u is respectively the curvature of parabolic path.

Preferably, described one group of Line independent basic function is:

$\left\{\begin{array}{c}{\mathrm{\Φ}}_1\left(u\right)=\frac{1}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_2\left(u\right)=\frac{u}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_3\left(u\right)=\frac{u^2}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_4\left(u\right)=\frac{u^3}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_5\left(u\right)=\frac{u^4}{{(u^2+1)}^5}\end{array}\right..$

Preferably, described Wronskian is:

$\left|\begin{array}{ccccc}{\mathrm{\Φ}}_1& {\mathrm{\Φ}}_2& {\mathrm{\Φ}}_3& {\mathrm{\Φ}}_4& {\mathrm{\Φ}}_5\\ \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}\\ \frac{d^2{\mathrm{\Φ}}_1}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_2}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_3}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_4}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_5}{{\mathrm{du}}^2}\\ \frac{d^3{\mathrm{\Φ}}_1}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_2}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_3}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_4}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_5}{{\mathrm{du}}^3}\\ \frac{d^4{\mathrm{\Φ}}_1}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_2}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_3}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_4}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_5}{{\mathrm{du}}^4}\end{array}\right|=\frac{288}{{(u^2+1)}^{25}}\≠0.$

Preferably, described one group of orthogonal basis function is:

$\left\{\begin{array}{c}{g}_1\left(u\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{(u^2+1)}^5}\\ g_2\left(u\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{u}{{(u^2+1)}^5}\\ g_3\left(u\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{u^2}{{(u^2+1)}^5}-\frac{\frac{1}{17}}{{(u^2+1)}^5})\\ g_4\left(u\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{u^3}{{(u^2+1)}^5}-\frac{\frac{1}{5}u}{{(u^2+1)}^5})\\ g_5\left(u\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{u^4}{{(u^2+1)}^5}+\frac{\frac{1}{65}}{{(u^2+1)}^5}-\frac{6}{13}\frac{u^2}{{(u^2+1)}^5})\end{array}\right..$

Preferably, described one group of matched filtering device function is:

$\left\{\begin{array}{c}{g}_1\left(n\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_2\left(n\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_3\left(n\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{17}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_4\left(n\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{{\mathrm{\λ}}^3{n}^3}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{5}\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_5\left(n\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{{\mathrm{\λ}}^4{n}^4}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{6}{13}\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}+\frac{\frac{1}{65}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\end{array}\right..$

Preferably, the existence of detection magnetic anomaly signal includes:

If the peak value in the energy signal of detection signal is more than predetermined threshold, then judge to there is objective body, wherein, described Predetermined threshold is the 90% of the gross energy of energy signal.

(3) beneficial effect

From technique scheme it can be seen that parabolic path orthogonal basis magnetic anomaly signal detecting method of the present invention have with Lower beneficial effect:

(1) parabolic path is obtained according to the magnetic induction expression formula of the magnetic dipole along parabolic path set up Under matched filtering function；And

(2) compared to other magnetic anomaly signal detecting method, it is obviously improved signal to noise ratio, can be at-15dB white noise Magnetic anomaly signal is detected under low signal-to-noise ratio.

Accompanying drawing explanation

Fig. 1 shows the schematic diagram that objective body moves along parabolic path relative to Magnetic Sensor；

Fig. 2 is the orthogonal basis magnetic anomaly signal detection side based on parabolic path according to the present invention the first example embodiment The flow chart of method；

Fig. 3 is the orthogonal basis magnetic anomaly signal detection side based on parabolic path according to the present invention the second example embodiment The flow chart of method；

Fig. 4 is the orthogonal basis magnetic anomaly signal detection side based on parabolic path according to the present invention the 3rd example embodiment The flow chart of method；

Fig. 5 shows the time-domain diagram of not magnetic anomaly signal by noise jamming；

Fig. 6 shows the time-domain diagram of the magnetic anomaly signal by noise interferences；

Fig. 7 shows orthogonal basis magnetic anomaly signal detecting method based on parabolic path according to embodiments of the present invention Testing result.

Detailed description of the invention

The present invention proposes a kind of orthogonal basis magnetic anomaly signal detecting method based on parabolic path, to parabolic path The magnetic signal of magnetic anomaly target of motion is modeled, it is thus achieved that one group of matched filtering function, to carry out the signal detected Join filtering, the most squared and obtain signal detecting result, thus it is obviously improved signal to noise ratio.

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference Accompanying drawing, the present invention is described in more detail.

Fig. 1 shows the schematic diagram that objective body moves along parabolic path relative to Magnetic Sensor；Fig. 2 is according to the present invention The flow chart of the orthogonal basis magnetic anomaly signal detecting method based on parabolic path of the first example embodiment.

As shown in Figure 1, it is considered to magnetic signal detecting system includes magnetic sensor, Magnetic Sensor can be but not limited to, Flux-gate magnetometer, coil, optical pumping magnetometer etc. can measure the instrument of magnetic field data.Magnetic target produces magnetic fieldAt magnetic In the case of minimum distance R0 between sensor and magnetic target exceedes magnetic target maximum size, it is generally recognized that magnetic field is by a magnetic couple Extremely son produces.It is assumed herein that magnetic target is moved along parabolic path (as shown in phantom in fig. 1) relative to Magnetic Sensor.At figure In 1, M is the magnetic moment (component in three directions is respectively Mx, My and Mz) of magnetic target, and a is adding of the magnetic target vertical direction of motion Speed, v is the speed of the magnetic target level direction of motion.

With reference to Fig. 2, the magnetic anomaly signal detection of orthogonal basis based on parabolic path according to a first embodiment of the present invention Method 200 includes:

In step 201, build the magnetic anomaly produced relative to magnetic sensor along the magnetic target that parabolic path moves The model of signal, i.e. builds the magnetic induction of the magnetic dipole moved along parabolic pathExpression formula；

In step 202, it is one group of orthogonal basis function by the model decomposition of magnetic anomaly signal；

In step 203, based on described one group of orthogonal basis function, detection signal is carried out matched filtering, to obtain detection letter Number energy signal；And

In step 204, according to the energy signal of detection signal, the existence of detection magnetic anomaly signal.

Fig. 3 is the orthogonal basis magnetic anomaly signal detection side based on parabolic path according to the present invention the second example embodiment The flow chart of method.As it is shown on figure 3, the step 202 in Fig. 2 includes:

In step 2021, the model of magnetic anomaly signal is performed sliding-model control, with obtain described magnetic anomaly signal from Dissipate model；

In step 2022, according to discrete model, it is thus achieved that one group of Line independent basic function；

In step 2023, calculate the Wronskian of this group of Line independent basic function；And

In step 2024, use Gram Schmidt orthogonalization process that Wronskian is carried out orthonomalization, with Obtain one group of orthogonal basis function.

It addition, the step 203 in Fig. 2 includes:

In step 2031, based on this group orthogonal basis function, it is thus achieved that one group of matched filtering function, and to this group one group coupling filter Wave function inverts；

In step 2032, one group of matched filtering function after detection signal and reversion is carried out convolution；And

In step 2033, squared to convolution results, to obtain detecting the energy signal of signal.

In embodiments of the present invention, the magnetic signal of the magnetic anomaly target by moving parabolic path is modeled, and obtains One group of matched filtering function the signal detected to be carried out matched filtering, the most squared and obtain signal detecting result, Thus it is obviously improved signal to noise ratio.

Referring to Fig. 4, to the orthogonal basis magnetic anomaly based on parabolic path according to the present invention the 3rd example embodiment The flow chart of signal detecting method is described in detail.Assume that magnetic target is transported along parabolic path as shown in phantom in Figure 1 Dynamic, Magnetic Sensor is positioned at the position of its focal point.

First, the model of the magnetic anomaly signal that magnetic target produces can be expressed as:

$\stackrel{\→}{B}\left(t\right)=\frac{u_0}{4\mathrm{\π}}\[\frac{3*(m_x{v}_{0}t+m_{y}q)*(v_{0}t,q,0)}{p^5}-\frac{(m_{x}p,m_{y}p,m_{z}p)}{p^5}\]---\left(1\right)$

Wherein, u₀For the pcrmeability in air, m is the magnetic torque of magnetic target, v₀Initial speed for magnetic target level direction Degree, a is the acceleration in magnetic target vertical direction,And

Then, u=at/v is made₀, w=v₀ ²/ a obtains:

$\stackrel{\→}{B}\left(t\right)=\frac{u_0}{4\mathrm{\π}}\left\{\begin{array}{c}\frac{-m_{x}w-3m_y{w}^{2}u-m_x(w-12w^2)u^2+3m_y{w}^2{u}^3}{w^5{(1+u^2)}^5}\\ \frac{\frac{1}{2}{m}_{y}w-6m_x{w}^{2}u-{\mathrm{wu}}^2+6m_x{w}^2{u}^3+\frac{3}{2}{m}_y{\mathrm{wu}}^4}{w^5{(1+u^2)}^5}\\ \frac{-m_{z}w-m_z{\mathrm{wu}}^2}{w^5{(1+u^2)}^5}\end{array}\right\}---\left(2\right)$

Then, for the magnetic anomaly signal model in formula (2)Carried out sliding-model control to obtain

$\stackrel{\→}{B}\left(n\right)=\frac{u_0}{4\mathrm{\π}}\left\{\begin{array}{c}\frac{-m_{x}w-3m_y{w}^2\mathrm{\λ}n-m_x(w-12w^2){\left(\mathrm{\λ}n\right)}^2+3m_y{w}^2{\left(\mathrm{\λ}n\right)}^3}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{\frac{1}{2}{m}_{y}w-6m_x{w}^2\mathrm{\λ}n-w{\left(\mathrm{\λ}n\right)}^2+6m_x{w}^2{\left(\mathrm{\λ}n\right)}^3+\frac{3}{2}{m}_{y}w{\left(\mathrm{\λ}n\right)}^4}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{-m_{z}w-m_{z}w{\left(\mathrm{\λ}n\right)}^2}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\end{array}\right\}---\left(3\right)$

Wherein, λ=a/v₀, w and u is respectively the curvature of parabolic path.

Then, owing in formula (3), high-order term is the biquadratic item of n, and successively decrease by its power, therefore obtain 5 Line independent basic function:

$\left\{\begin{array}{c}{\mathrm{\Φ}}_1\left(u\right)=\frac{1}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_2\left(u\right)=\frac{u}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_3\left(u\right)=\frac{u^2}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_4\left(u\right)=\frac{u^3}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_5\left(u\right)=\frac{u^4}{{(u^2+1)}^5}\end{array}\right.---\left(4\right)$

Then, calculating the Wronskian of 5 Line independent basic functions, calculated Wronskian is:

$\left|\begin{array}{ccccc}{\mathrm{\Φ}}_1& {\mathrm{\Φ}}_2& {\mathrm{\Φ}}_3& {\mathrm{\Φ}}_4& {\mathrm{\Φ}}_5\\ \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}\\ \frac{d^2{\mathrm{\Φ}}_1}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_2}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_3}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_4}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_5}{{\mathrm{du}}^2}\\ \frac{d^3{\mathrm{\Φ}}_1}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_2}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_3}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_4}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_5}{{\mathrm{du}}^3}\\ \frac{d^4{\mathrm{\Φ}}_1}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_2}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_3}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_4}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_5}{{\mathrm{du}}^4}\end{array}\right|=\frac{288}{{(u^2+1)}^{25}}\≠0---\left(5\right)$

Gram Schmidt orthogonalization process is used formula (5) to be carried out orthonomalization, to obtain one group of orthogonal basis letter Number is:

$\left\{\begin{array}{c}{g}_1\left(u\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{(u^2+1)}^5}\\ g_2\left(u\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{u}{{(u^2+1)}^5}\\ g_3\left(u\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{u^2}{{(u^2+1)}^5}-\frac{\frac{1}{17}}{{(u^2+1)}^5})\\ g_4\left(u\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{u^3}{{(u^2+1)}^5}-\frac{\frac{1}{5}u}{{(u^2+1)}^5})\\ g_5\left(u\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{u^4}{{(u^2+1)}^5}+\frac{\frac{1}{65}}{{(u^2+1)}^5}-\frac{6}{13}\frac{u^2}{{(u^2+1)}^5})\end{array}\right.---\left(6\right)$

Then, u is made²=λ²n², and substitute in formula (6), to obtain matched filtering function:

$\left\{\begin{array}{c}{g}_1\left(n\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_2\left(n\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_3\left(n\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{17}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_4\left(n\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{{\mathrm{\λ}}^3{n}^3}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{5}\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_5\left(n\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{{\mathrm{\λ}}^4{n}^4}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{6}{13}\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}+\frac{\frac{1}{65}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\end{array}\right.---\left(7\right)$

Being different from other kinds of matched filtering function, this matched filtering function more meets magnetic target detection reality should With, therefore, utilize this matched filtering function that magnetic anomaly signal carries out noise suppression effect during matched filtering good, signal to noise ratio is notable Improve.

Then, matched filtering function is inverted, and the matched filtering function g after signal x (n) and reversion will be detected_i (-n), i=1,2,3,4,5 make convolution (that is, detection signal being carried out matched filtering), draw convolution results h_i(n), i=1,2, 3,4,5.

Then, convolution results h_i(n), i=1,2,3,4,5 squared and, obtain detect signal energy:

$E\left(n\right)=\underset{i=1}{\overset{5}{\Σ}}{h_i}^2\left(n\right)---\left(8\right)$

Finally, utilize whether E (n) detection magnetic anomaly target exists.Specifically, if in the energy signal of detection signal Peak value is more than predetermined threshold, then judge to there is magnetic anomaly target.In the exemplary embodiment, predetermined threshold is the total energy of energy signal The 90% of amount.

For the ease of comparing, Fig. 5 shows the time-domain diagram of not magnetic anomaly signal by noise jamming；Fig. 6 shows and is made an uproar The time-domain diagram of the magnetic anomaly signal of sound interference signal；And Fig. 7 show according to embodiments of the present invention based on parabolic path The testing result of orthogonal basis magnetic anomaly signal detecting method.With reference to Fig. 7, the method using the present embodiment, compared to other Magnetic anomaly signal detecting method, can be obviously improved signal to noise ratio, it is possible to magnetic anomaly detected under-15dB white noise low signal-to-noise ratio Signal.

So far, already in connection with accompanying drawing, the present embodiment has been described in detail.According to above description, those skilled in the art The present invention should use parabolic path magnetic anomaly detection method had clearly recognize.

In sum, the present invention utilizes the parabolic path that magnetic anomaly target Equivalent is magnetic dipole to be modeled, and tries to achieve The model of magnetic anomaly signal under parabolic path, and on the basis of orthogonal basis decomposes, obtain matched filtering function, utilizing should Matched filtering function carries out matched filtering to magnetic anomaly signal, the most squared and obtain signal detecting result, can significantly carry Rise signal to noise ratio, the advantage with good stability.The present invention is especially suitable for the commonly used of engineering, and for other noises Technology for eliminating has good reference.

Particular embodiments described above, has been carried out the purpose of the present invention, technical scheme and beneficial effect the most in detail Describe in detail bright, be it should be understood that and the foregoing is only the specific embodiment of the present invention and oneself, be not limited to the present invention, all Within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. done, should be included in the guarantor of the present invention Within the scope of protecting.

Claims (10)

1. a magnetic anomaly signal detecting method, including:

Build the model of the magnetic anomaly signal produced relative to magnetic sensor along the objective body that parabolic path moves；

It is one group of orthogonal basis function by the model decomposition of described magnetic anomaly signal；

Based on described one group of orthogonal basis function, detection signal is carried out matched filtering, to obtain detecting the energy signal of signal；With And

According to the energy signal of detection signal, the existence of detection magnetic anomaly signal.

Method the most according to claim 1, wherein, is one group of orthogonal basis bag by the model decomposition of described magnetic anomaly signal Include:

The model of described magnetic anomaly signal is performed sliding-model control, to obtain the discrete model of described magnetic anomaly signal；

According to described discrete model, it is thus achieved that one group of Line independent basic function；

Calculate the Wronskian of described one group of Line independent basic function；And

Gram Schmidt orthogonalization process is used described Wronskian to be carried out orthonomalization, to obtain described one Group orthogonal basis function.

Method the most according to claim 2, wherein, carries out matched filtering to detection signal and includes:

Based on described one group of orthogonal basis function, it is thus achieved that one group of matched filtering function, and described one group of matched filtering function is carried out Reversion；

One group of matched filtering function after detection signal and reversion is carried out convolution；And

Squared to convolution results, to obtain detecting the energy signal of signal.

Method the most according to claim 3, wherein, the model of described magnetic anomaly signal is:

And

u₀For the pcrmeability in air, m is the magnetic torque of objective body, v₀For the initial velocity of objective body horizontal direction, a is target The acceleration of body vertical direction,And

Method the most according to claim 4, wherein, makes u=at/v₀, w=v₀ ²/ a, λ=a/v₀, described discrete model is:

$\stackrel{\‾}{B}\left(n\right)=\frac{u_0}{4\mathrm{\π}}\left\{\begin{array}{c}\frac{-m_{x}w-3m_y{w}^2\mathrm{\λ}n-m_x(w-12w^2){\left(\mathrm{\λ}n\right)}^2+3m_y{w}^2{\left(\mathrm{\λ}n\right)}^3}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{\frac{1}{2}{m}_{y}w-6m_x{w}^2\mathrm{\λ}n-w{\left(\mathrm{\λ}n\right)}^2+6m_x{w}^2{\left(\mathrm{\λ}n\right)}^3+\frac{3}{2}{m}_{y}w{\left(\mathrm{\λ}n\right)}^4}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\\ \frac{-m_{z}w-m_{z}w{\left(\mathrm{\λ}n\right)}^2}{w^5{(1+{\left(\mathrm{\λ}n\right)}^2)}^5}\end{array}\right\}$

Wherein, w and u is respectively the curvature of parabolic path.

Method the most according to claim 5, wherein, described one group of Line independent basic function is:

$\left\{\begin{array}{c}{\mathrm{\Φ}}_1\left(u\right)=\frac{1}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_2\left(u\right)=\frac{u}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_3\left(u\right)=\frac{u^2}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_4\left(u\right)=\frac{u^3}{{(u^2+1)}^5}\\ {\mathrm{\Φ}}_5\left(u\right)=\frac{u^4}{{(u^2+1)}^5}\end{array}\right..$

Method the most according to claim 6, wherein, described Wronskian is:

$\left|\begin{array}{ccccc}{\mathrm{\Φ}}_1& {\mathrm{\Φ}}_2& {\mathrm{\Φ}}_3& {\mathrm{\Φ}}_4& {\mathrm{\Φ}}_5\\ \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}& \frac{{\mathrm{d\Φ}}_1}{du}\\ \frac{d^2{\mathrm{\Φ}}_1}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_2}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_3}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_4}{{\mathrm{du}}^2}& \frac{d^2{\mathrm{\Φ}}_5}{{\mathrm{du}}^2}\\ \frac{d^3{\mathrm{\Φ}}_1}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_2}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_3}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_4}{{\mathrm{du}}^3}& \frac{d^3{\mathrm{\Φ}}_5}{{\mathrm{du}}^3}\\ \frac{d^4{\mathrm{\Φ}}_1}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_2}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_3}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_4}{{\mathrm{du}}^4}& \frac{d^4{\mathrm{\Φ}}_5}{{\mathrm{du}}^4}\end{array}\right|=\frac{288}{{(u^2+1)}^{25}}\≠0.$

Method the most according to claim 7, wherein, described one group of orthogonal basis function is:

$\left\{\begin{array}{c}{g}_1\left(u\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{(u^2+1)}^5}\\ g_2\left(u\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{u}{{(u^2+1)}^5}\\ g_3\left(u\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{u^2}{{(u^2+1)}^5}-\frac{\frac{1}{17}}{{(u^2+1)}^5})\\ g_4\left(u\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{u^3}{{(u^2+1)}^5}-\frac{\frac{1}{5}u}{{(u^2+1)}^5})\\ g_5\left(u\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{u^4}{{(u^2+1)}^5}+\frac{\frac{1}{65}}{{(u^2+1)}^5}-\frac{6}{13}\frac{u^2}{{(u^2+1)}^5})\end{array}\right..$

Method the most according to claim 8, wherein, described one group of matched filtering device function is:

$\left\{\begin{array}{c}{g}_1\left(n\right)=\sqrt{\frac{65536}{12155\mathrm{\π}}}\frac{1}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_2\left(n\right)=\sqrt{\frac{65536}{715\mathrm{\π}}}\frac{\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5}\\ g_3\left(n\right)=\sqrt{\frac{278528}{429\mathrm{\π}}}(\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{17}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_4\left(n\right)=\sqrt{\frac{81920}{33\mathrm{\π}}}(\frac{{\mathrm{\λ}}^3{n}^3}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{\frac{1}{5}\mathrm{\λ}n}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\\ g_5\left(n\right)=\sqrt{\frac{16640}{3\mathrm{\π}}}(\frac{{\mathrm{\λ}}^4{n}^4}{{({\mathrm{\λ}}^2{n}^2+1)}^5}-\frac{6}{13}\frac{{\mathrm{\λ}}^2{n}^2}{{({\mathrm{\λ}}^2{n}^2+1)}^5}+\frac{\frac{1}{65}}{{({\mathrm{\λ}}^2{n}^2+1)}^5})\end{array}\right..$

Method the most according to claim 1, wherein, the existence of detection magnetic anomaly signal includes: if the energy of detection signal Peak value in amount signal more than predetermined threshold, then judges to there is objective body, and wherein, described predetermined threshold is the total energy of energy signal The 90% of amount.