CN103198227B - The Analysis of Electromagnetic Scattering method of hypervelocity flight target - Google Patents

Abstract

The invention discloses a kind of Analysis of Electromagnetic Scattering method of hypervelocity flight target.For being wrapped in the nonuniformity of plasma around hypervelocity flight target, have employed dignity integral Equation Methods to be analyzed, plasma equivalent relative dielectric constant processes close to the part of 1 as air, the region that equivalent relative dielectric constant is bigger uses Adaptive refinement to process, in order to reach required solving precision.Relative to the traditional method using uniform grid body subdivision plasma valve jacket, method in the present invention can greatly save calculating resource, simultaneously because the Green's function used in dignity integral equation is the Green's function in vacuum, the quick multistage sub-technology of multilamellar is used to further speed up and solves so that the present invention needs less calculating internal memory and calculating time for solving hypervelocity flight target scattering problem.

Description

The Analysis of Electromagnetic Scattering method of hypervelocity flight target

Technical field

The invention belongs to the quick computing technique of electromagnetic characteristic of scattering, particularly one and be applied to hypervelocity flight mesh Target Analysis of Electromagnetic Scattering method.

Background technology

Hypervelocity flight target is owing to having flight speed (more than 3 Mach) quickly and higher flying height (more than 20Km), can produce the Aerodynamic Heating of thousand of degrees Celsius so that it is surrounding air is due to ionization with windage during its flight Exist in ionic condition.When ionization degree reaches to a certain degree, ionized gas has plasma properties.Now at airbound target The cladding flow field of near surface is commonly called plasma cladding flow field, reenters plasma or plasma valve jacket, now Be equivalent to airbound target by plasma cover (normal rain. supersonic speed/hypersonic plasma Field Flow Numerical Simulation and electricity thereof Magnetic characteristic research, National University of Defense technology's thesis for the doctorate, 2009).

It is ionized the inhomogeneities of the plasma relative dielectric constant of formation due to air, causes using numerical method to divide The electromagnetic scattering problems of analysis airbound target has certain difficulty.Found by research, be positioned at the grade of aircraft tip portion from Daughter valve jacket has bigger equivalent relative dielectric constant, and gas ions valve jacket other parts dielectric permittivity is close to air. For this metallic plasma mixed structure, metal part is normally used as perfect electronic conductor (PEC) and processes, and easily Quilt cover integral Equation Methods (SIE) carrys out analysis and solution, wherein RWG basic function (Rao M, Wilton D and Glisson A.Electromagnetic scattering by surfaces of arbitrary shape.IEEE Transaction On Antennas and Propagation, 1982,30 (3): 409 418.) generally it is used as due to its motility Launch the basic function of unknown current.Media fraction, generally uses volume integral equations method (Schaubert D, Wilton D and Glisson A.A tetrahedral modeling method for electromagnetic scattering by arbitrarily shaped inhomogeneous dielectric bodies.IEEE Transaction on Antennas and Propagation, 1984,32 (1): 77 85.) it is analyzed.And processing with dignity integral equation Time, it may be considered that the most airlike part is saved, thus is greatly saved unknown quantity, saves the consumption of internal memory.Due to right Plasma valve jacket part uses body subdivision to cause unknown quantity huge, even if taking the relative dielectric constant portion close to 1 Dividing and process as air, still faced one calculates the problem that resource consumption is high.

Summary of the invention

It is an object of the invention to provide a kind of Analysis of Electromagnetic Scattering method of hypervelocity flight target, thus realize quickly Obtain the Electromagnetic Scattering Characteristics parameter of hypervelocity flight target.

The technical solution realizing the object of the invention is: a kind of Analysis of Electromagnetic Scattering method of hypervelocity flight target, Step is as follows:

The first step, sets up hypervelocity flight target plasma valve jacket model, according to the flying height of airbound target, the angle of attack and Flight Mach number parameter, carries out pneumatic analog calculating to hypervelocity flight target, obtain the electron number densitiy of target, temperature and Pressure information data, thus obtains plasma characteristics frequency and collision frequency, then is obtained by the following formula plasma valve jacket The equivalent relative dielectric constant of each locus,

${\mathrm{\ϵ}}_r=1-\frac{{{\mathrm{\ω}}^2}_{\mathrm{pe}}}{{\mathrm{\ω}}^2+v^2}-j\frac{v}{\mathrm{\ω}}\frac{{{\mathrm{\ω}}^2}_{\mathrm{pe}}}{{\mathrm{\ω}}^2+v^2}---\left(1\right)$

Wherein ω_peFor plasma characteristics frequency, ω is wave frequency, and v is plasma collision frequency；

Second step, uses triangle subdivision to airbound target metal part, and plasma valve jacket equivalent relative dielectric constant connects Being bordering on the part of 1 as air, it is not necessary to carry out mesh generation, plasma valve jacket non-air region part uses tetrahedron to cut open Point, and use Adaptive refinement to process in the region that equivalent relative dielectric constant is bigger；

3rd step, according to the scattering properties of parcel plasma valve jacket high hypervelocity airbound target structure, uses moment method basis Theory, obtains dignity integral equation, and its matrix form equation is:

$\left[\begin{array}{cc}{Z}_{\mathrm{mn}}^{\mathrm{DD}}& Z_{\mathrm{mn}}^{\mathrm{MD}}\\ Z_{\mathrm{mn}}^{\mathrm{DM}}& Z_{\mathrm{mn}}^{\mathrm{MM}}\end{array}\right]\left[\begin{array}{c}{D}_n\\ I_n\end{array}\right]=\left[\begin{array}{c}{v}_m^V\\ v_m^S\end{array}\right]---\left(2\right)$

Z^DDRepresent the medium effect to medium, Z^DMRepresent the medium effect to metal, Z^MDAll represent the phase of medium and metal Interaction part, Z^MMRepresent the effect of metal to metal, D_nAnd I_nIt is unknowm coefficient to be asked,WithIt it is the right vector excitation；

4th step, to the free space Green's function in the 3rd stepLaunch according to addition theorem, and provide dignity Body polymerizing factor, transfer factor and the expression of the configuration factor in integral equation；

5th step, solution matrix equation (2), obtain current coefficient, calculated electromagnetism further according to reciprocal theorem by current coefficient Scattering parameters.

Formula 3 is used to judge that whether plasma part is as air:

||εr|-1|≤δ (3)

Wherein, ε_rFor plasma equivalent relative dielectric constant, δ determines that whether plasma part is as air-treatment.

In described step 3 matrix equation to embody form as follows:

$Z^{\mathrm{DD}}=\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·\frac{\stackrel{\→}{D}\left({\stackrel{\→}{r}}^{\′}\right)}{\widehat{\mathrm{\ϵ}}\left({\stackrel{\→}{r}}^{\′}\right)}d\stackrel{\→}{r}+\mathrm{j\ω}\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}$

(4)

$-\underset{V_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}+\underset{{\mathrm{\Ω}}_m}{\∫}(\stackrel{\→}{n}\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}$

$Z^{\mathrm{MD}}=\mathrm{j\ω}\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{V_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}+\underset{{\mathrm{\Ω}}_m}{\∫}(\stackrel{\→}{n}\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(5\right)$

$Z^{\mathrm{DM}}=\mathrm{j\ω}\underset{S_m}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{S_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(6\right)$

$Z^{\mathrm{MM}}=\mathrm{j\ω}\underset{S_m}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{S_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(7\right)$

Wherein,WithRepresenting body dough-making powder test basic function respectively, ω is electromagnetic wave angular frequency,WithIt is respectively WithThe electric flux representing to be asked is close Degree and metal covering electric current density,It it is the Green's function of free space；

In above formula, the right vector is produced by plane wave, can be write as

$v_m^V=\underset{V}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{E}}^{i}d\stackrel{\→}{r}---\left(8\right)$

$v_m^S=\underset{V}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{E}}^{i}d\stackrel{\→}{r}---\left(9\right)$

It it is incident electric fields.

The body polymerizing factor, transfer factor and the configuration factor that are given in described step 4 in dignity integral equation embody The step of formula is as follows:

Step 4.1, two the some r being positioned in different group m and n in same layer_iAnd r_j, it is assumed that r_iIt it is the observation in m group Point, r_jIt is the source point in n group, r_mAnd r_nRepresenting point of observation and the group switching centre at source point place, the vector of point of observation to source point is r_ij= r_i-r_j=r_im+r_mn+r_njIf m and n is the most misaligned the most non-conterminous for group, then | r_im+r_nj| ＜ | r_mn|, scalar Green's function is used Vector addition theorem is unfolded as follows:

Wherein,

$T_L(\hat{k}\·\hat{r})=\underset{l=0}{\overset{L}{\mathrm{\Σ}}}{(-j)}^l(2l+1)h_l^{\left(2\right)}\left(\mathrm{kr}\right)P_l(\hat{k}\·\hat{r})---\left(12\right)$

For transfer factor, L be infinite summation block item number,For Equations of The Second Kind ball Hankel function, P_l (), for Legendre function,Represent the double integral in angular spectrum space, it usually needs K_L=2 (L+1)²Individual point, L= Kd+ α log (π+kd), and the size that d is group；

Step 4.2, provides Z^DD、Z^MD、Z^DMAnd Z^MMPolymerizing factor, the expression of transfer factor and the configuration factor is respectively For:

The present invention compared with prior art, its remarkable advantage: 1. unknown quantity is few.Due to equivalent relative dielectric constant close to The plasma area of 1 is as air-treatment, it is not necessary to carries out mesh generation, decreases unknown quantity, simultaneously because to relative equivalent The plasma area that power saving parameter is big have employed adaptive refinement, under conditions of not affecting precision, further decreases not The amount of knowing.2. solving speed is fast.Owing to have employed dignity integration equation analysis hypervelocity flight target and being wrapped in ultrahigh speed and fly Non-homogeneous plasma outside row target, Green's function used is the Green's function of free space, facilitates the quick multistage son of multilamellar The introducing of technology, accelerates Matrix Solving.

Accompanying drawing explanation

Fig. 1 is a segmentation point segmentation schematic diagram, and a is initialization figure, and b is segmentation schematic diagram, and c is each four sides after segmentation Body.

Fig. 2 is two segmentation point segmentation schematic diagrams, and a is initialization figure, and b is final polyhedron hull schematic diagram, and c is segmentation signal Figure, d is each tetrahedron after segmentation.

Fig. 3 is three segmentation point segmentation schematic diagrams, and a is initialization figure, and b is final polyhedron hull schematic diagram, and c is segmentation signal Figure, d is each tetrahedron after segmentation.

Fig. 4 is the signal of blunted cone two-dimensional structure and dimensional drawing.

Fig. 5 is relative dielectric constant distribution.

Fig. 6 is two kinds of results contrast of VSIE.

Fig. 7 is blunted cone model dual station RCS figure.

Detailed description of the invention

The Analysis of Electromagnetic Scattering method of hypervelocity flight target of the present invention, step is as follows:

The first step, sets up high-speed flight target and the electromagnetic parameter mould of plasma valve jacket model, mainly plasma valve jacket The determination of type, it is relevant with the flight environment of vehicle of high-speed flight target, as big around flying height, flight speed and airbound target Air pressure is strong and temperature etc..

Second step, grid processes.Triangle subdivision is used for metal part, four sides is used for plasma valve jacket part Body subdivision.

3rd step, sets up dignity integral equation.According to the scattering properties of mixed structure, the incidence that the resultant field in target is equal to Field and all of scattered field sum, incident electric fields is known excitation, and uniform plane wave is usually used to as incident electric fields, scattering Electric field can represent by electric flux density to be asked and induced current density.

4th step, launches Green's function in free space based on addition theorem, the expression formula of coalition Line Integral equation, Provide the polymerizing factor of far-field portion, transfer factor and the configuration factor embodies form.

5th step, matrix equation solves and the calculating of electromagnetic scattering parameter.

Below in conjunction with the accompanying drawings the present invention is described in further detail.

The first step, sets up hypervelocity flight target and plasma valve jacket model, the mainly electromagnetic parameter of plasma valve jacket The determination of model, it is relevant with the flight environment of vehicle of hypervelocity flight target, such as flying height, flight speed and airbound target week Enclose atmospheric pressure and temperature etc..By the flying height of airbound target, the angle of attack and flight Mach number parameter, object module is carried out gas Dynamic model intend calculate, obtain the electron number densitiy of target, temperature, pressure information data, thus obtain plasma characteristics frequency with And collision frequency, then it is obtained by the following formula the equivalent relative dielectric constant of plasma valve jacket,

${\mathrm{\ϵ}}_r=1-\frac{{{\mathrm{\ω}}^2}_{\mathrm{pe}}}{{\mathrm{\ω}}^2+v^2}-j\frac{v}{\mathrm{\ω}}\frac{{{\mathrm{\ω}}^2}_{\mathrm{pe}}}{{\mathrm{\ω}}^2+v^2}---\left(1\right)$

Wherein ω_peFor plasma characteristics frequency, ω is wave frequency, and v is plasma collision frequency.

Second step, uses triangle subdivision for metal part, uses Tetrahedron subdivision for plasma valve jacket part.Pin To difference require computational accuracy can use different threshold values δ to determine plasma part whether as air-treatment, i.e. It is made without mesh generation.Basis for estimation is as follows

||ε_r|-1|≤δ (2)

Wherein, ε_rFor plasma equivalent relative dielectric constant.The region that equivalent relative dielectric constant is bigger then needs to use Adaptive refinement processes；Three-dimensional adaptive grid is owing to being encrypted by node self-adapting, therefore tetrahedron divides owing to contained need adds The difference of close node number is divided into four kinds of modes.

Tetrahedron comprises only the situation of a segmentation point as it is shown in figure 1, being numbered the point of 7 is segmentation point, former tetrahedron quilt It is divided into four parts: 4567,2675,1752 and 1237.

Tetrahedron element comprises two refined grid situations as in figure 2 it is shown, tetrahedron is subdivided into 7 tetrahedrons: 1567, 4789,5678,6789,2568,2689 and 2369.

Tetrahedron element comprises three refined grid situations as it is shown on figure 3, tetrahedron is subdivided into 7 tetrahedrons: 1578, 5789,2569,5679,3671,6791,4891 and 7891.

3rd step, according to the scattering properties of parcel plasma valve jacket high hypervelocity airbound target structure, uses moment method basis Theory, obtains dignity integral equation, and its matrix form equation is:

$\left[\begin{array}{cc}{Z}_{\mathrm{mn}}^{\mathrm{DD}}& Z_{\mathrm{mn}}^{\mathrm{MD}}\\ Z_{\mathrm{mn}}^{\mathrm{DM}}& Z_{\mathrm{mn}}^{\mathrm{MM}}\end{array}\right]\left[\begin{array}{c}{D}_n\\ I_n\end{array}\right]=\left[\begin{array}{c}{v}_m^V\\ v_m^S\end{array}\right]---\left(3\right)$

Wherein:

$Z^{\mathrm{DD}}=\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·\frac{\stackrel{\→}{D}\left({\stackrel{\→}{r}}^{\′}\right)}{\widehat{\mathrm{\ϵ}}\left({\stackrel{\→}{r}}^{\′}\right)}d\stackrel{\→}{r}+\mathrm{j\ω}\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}$

(4)

$-\underset{V_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}+\underset{{\mathrm{\Ω}}_m}{\∫}(\stackrel{\→}{n}\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}$

$Z^{\mathrm{MD}}=\mathrm{j\ω}\underset{V_m}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{V_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}+\underset{{\mathrm{\Ω}}_m}{\∫}(\stackrel{\→}{n}\·{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(5\right)$

$Z^{\mathrm{DM}}=\mathrm{j\ω}\underset{S_m}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{S_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_V\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(6\right)$

$Z^{\mathrm{MM}}=\mathrm{j\ω}\underset{S_m}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{A}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}-\underset{S_m}{\∫}(\▿\·{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)){\mathrm{\Φ}}_S\left({\stackrel{\→}{r}}^{\′}\right)d\stackrel{\→}{r}---\left(7\right)$

Wherein,WithRepresenting body dough-making powder test basic function respectively, ω is electromagnetic wave angular frequency,WithIt is respectively WithThe electric flux representing to be asked is close Degree and metal covering electric current density,It it is the Green's function of free space.

In above formula, the right vector is produced by plane wave, can be write as

$v_m^V=\underset{V}{\∫}{\stackrel{\→}{f}}_m^V\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{E}}^{i}d\stackrel{\→}{r}---\left(8\right)$

$v_m^S=\underset{V}{\∫}{\stackrel{\→}{f}}_m^S\left(\stackrel{\→}{r}\right)\·{\stackrel{\→}{E}}^{i}d\stackrel{\→}{r}---\left(9\right)$

It it is incident electric fields.

Z^DDRepresent the medium effect to medium, Z^DMRepresent the medium effect to metal, Z^MDAll represent the phase of medium and metal Interaction part, Z^MMRepresent the effect of metal to metal；

4th step, launches according to addition theorem the Green's function of free space, and provides the body polymerization in dignity integration The factor, transfer factor and the expression of the configuration factor.In Fast multipole implementation process, it is contemplated that same layer In the point being positioned in two different groups.Assuming that r_iIt is the point of observation in m group, r_jIt it is the source point in n group.If we use r_mWith r_nRepresent point of observation and the group switching centre at source point place, then the vector of point of observation to source point is r_ij=r_i-r_j=r_im+r_mn+r_nj。 If m and n is the most misaligned the most non-conterminous for group, then | r_im+r_nj| ＜ | r_mn|.So the scalar Green's function of three-dimensional problem is permissible It is unfolded as follows by vector addition theorem:

$T_L(\hat{k}\·\hat{r})=\underset{l=0}{\overset{L}{\mathrm{\Σ}}}{(-j)}^l(2l+1)h_l^{\left(2\right)}\left(\mathrm{kr}\right)P_l(\hat{k}\·\hat{r})---\left(12\right)$

In above formula,For transfer factor, L be infinite summation block item number,For Equations of The Second Kind ball Hunk that Function, P_l() is Legendre function.Represent the double integral in angular spectrum space, it usually needs K_L=2 (L+1)²Individual integration Point.General L=kd+ α log (π+kd), and the size that d is group.

Provide Z^DD、Z^MD、Z^DMAnd Z^MMPolymerizing factor, the expression of transfer factor and the configuration factor is respectively as follows:

5th step, solution matrix equation, obtain current coefficient, calculated electromagnetic scattering further according to reciprocal theorem by current coefficient Parameter.

For efficiency and the precision of verification method, shown below is the example of the electromagnetic scattering of hypervelocity flight target, figure Table can be seen that the property of the method.

Blunted cone model, two-dimensional structure is as it is shown in figure 1, electromagnetic parameter model is as in figure 2 it is shown, left figure is equivalence dielectric ginseng relatively Number value of real part, right figure is equivalence dielectric parameter imaginary values relatively.After mesh generation, total unknown quantity is that 686230+8379(is situated between Matter triangle+inner edge), ensureing in the range of computational accuracy, if by equivalent relative dielectric constant modulus value 0.95～1.05 (δ= 0.5) plasma portion between treats as air-treatment, and final unknown quantity sum is 133399+8379, if equivalence being relatively situated between Electric constant modulus value plasma in the range of 0.9～1.1 (δ=1) as air portion divisional processing, the most final unknown quantity sum is 72469+8379, uses three layers of Fast Multiple Method to calculate.Calculate under LINUX translation and compiling environment, call 32 task parallelisms and calculate, Using MUMPS fore condition, angle of incidence isFrequency is 2GHz, two kinds of different threshold values select in the case of double The RCS that stands compares, as shown in Figure 3.Fig. 4 be then the inventive method result of calculation (relative dielectric constant modulus value 0.9～ In the range of 1.1) and the comparison of FEBI method result of calculation.

Table 1 blunted cone model example comparison of computational results table.

Claims (4)

1. the Analysis of Electromagnetic Scattering method of a hypervelocity flight target, it is characterised in that step is as follows:

The first step, sets up hypervelocity flight target plasma valve jacket model, according to flying height, the angle of attack and the flight of airbound target Mach number parameter, carries out pneumatic analog calculating to hypervelocity flight target, obtains the electron number densitiy of target, temperature and pressure letter Breath data, thus obtain plasma characteristics frequency and collision frequency, then are obtained by the following formula each space of plasma valve jacket The equivalent relative dielectric constant of position,

Wherein ω_peFor plasma characteristics frequency, ω is wave frequency, and v is plasma collision frequency；

Second step, uses triangle subdivision to airbound target metal part, and plasma valve jacket equivalent relative dielectric constant is close to 1 Part as air, it is not necessary to carrying out mesh generation, plasma valve jacket non-air region part uses Tetrahedron subdivision, and right The region that equivalent relative dielectric constant is bigger uses Adaptive refinement to process；

3rd step, according to the scattering properties of parcel plasma valve jacket high hypervelocity airbound target structure, uses moment method rationale, Obtaining dignity integral equation, its matrix form equation is:

Z^DDRepresent the medium effect to medium, Z^DMRepresent the medium effect to metal, Z^MDAll represent the phase interaction of medium and metal With part, Z^MMRepresent the effect of metal to metal, D_nAnd I_nIt is unknowm coefficient to be asked,WithIt it is the right vector excitation；

4th step, to free space Green's functionLaunch according to addition theorem, and provide the body in dignity integral equation Polymerizing factor, transfer factor and the expression of the configuration factor；

5th step, solution matrix equation (2), obtain current coefficient, calculated electromagnetic scattering further according to reciprocal theorem by current coefficient Parameter.

The Analysis of Electromagnetic Scattering method of hypervelocity flight target the most according to claim 1, it is characterised in that use formula 3 judge that whether plasma part is as air:

||ε_r|-1|≤δ (3)

Wherein, ε_rFor plasma equivalent relative dielectric constant, δ determines that whether plasma part is as air-treatment.

The Analysis of Electromagnetic Scattering method of hypervelocity flight target the most according to claim 1, it is characterised in that described In three steps matrix equation to embody form as follows:

Wherein,WithRepresenting body dough-making powder test basic function respectively, ω is electromagnetic wave angular frequency,WithRespectively For WithRepresent dielectric (flux) density to be asked and metal Surface current density,It it is the Green's function of free space；

In formula (2), the right vector is produced by plane wave, can be write as

It it is incident electric fields.

The Analysis of Electromagnetic Scattering method of hypervelocity flight target the most according to claim 1, it is characterised in that the described 4th Step provides the step of body polymerizing factor, transfer factor and configuration factor expression in dignity integral equation as follows:

Step 4.1, two the some r being positioned in different group m and n in same layer_iAnd r_j, it is assumed that r_iIt is the point of observation in m group, r_jIt is Source point in n group, r_mAnd r_nRepresenting point of observation and the group switching centre at source point place, the vector of point of observation to source point is r_ij=r_i-r_j= r_im+r_mn+r_njIf m and n is the most misaligned the most non-conterminous for group, then | r_im+r_nj| ＜ | r_mn|, scalar Green's function vector adds Method theorem is unfolded as follows:

Wherein,

For transfer factor, L be infinite summation block item number,For Equations of The Second Kind ball Hankel function, P_l() is Legendre function,Represent the double integral in angular spectrum space, it usually needs K_L=2 (L+1)²Individual point, L=kd+ α log (π+kd), and the size that d is group；

Step 4.2, provides Z^DD、Z^MD、Z^DMAnd Z^MMPolymerizing factor, the expression of transfer factor and the configuration factor is respectively as follows:

。