CN108152799A - The radar cross section quick calculation method of superelevation velocity of sound aircraft - Google Patents
The radar cross section quick calculation method of superelevation velocity of sound aircraft Download PDFInfo
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Abstract
The present invention proposes a kind of radar cross section quick calculation method of superelevation velocity of sound aircraft, it includes：S1, based on plasma distribution characteristics around it under aircraft motion state, extraction obtains physics field parameters be distributed based on plasma stream field data, which includes plasma electron density, collision frequency；S2, mesh generation is carried out to zoning, the plasma stream field data distributed intelligence based on discretization obtains spectral function distributed model corresponding under corresponding sports situation state；S3, the physics field parameters based on the distribution of plasma stream field data carry out corresponding radar cross section solution；S4, setting incidence angles degree obtain the radar cross section of different orientations according to the gridding information delimited.Its advantage is：Provide a kind of simple and quick equivalent electromagnetic radar scattering section method for solving.
Description
Technical field
The present invention relates to radar cross section solution technique fields, and in particular to a kind of radar of superelevation velocity of sound aircraft dissipates
Penetrate section quick calculation method.
Background technology
Reenter or the hypersonic stealthy aircraft of near space be in atmosphere during flight, can be formed plasma stream and
Tail will seriously affect the Electromagnetic Scattering Characteristics of aircraft so that near space hypersonic aircraft show with greatly
Conventional aircraft and above-atmosphere trajectory aircraft are significantly different on Electromagnetic Scattering Characteristics in gas-bearing formation, the spy to aircraft
It surveys, track band carrys out new challenge (A.H.Richard.The application of light gas gun facilities
for hyper-velocity aerophysics research[R].AIAA92-98.).When super speed vehicle near space
During flight, the air of surrounding generates infra-red radiation by drastically intense attrition, surface are heated between compression, aircraft and air
With visible optical radiation, body surface forms plasma sheath, aircraft downstream forms ionized trail, greatly changes aircraft
Electromagnetic property (happy Jiangling, high ferro lock, the manned physics of [M] of once learning military affairs, Beijing：National Defense Industry Press, 2005. Zhang Zhis into,
Pneumatic physical [M] Beijing：National Defense Industry Press, 20 (3), 2013).It is previous research shows that, people again in space atmospheric
The turbulent plasma field of its tail of object or the electromagnetic scattering main source of superelevation velocity of sound stealthy aircraft
(G.F.Pippert.On the structure of wake turbulence deduced from field radar
measurements[R].AIAA Paper 630-640,1963)。
In general, ionization flow field is streamed in super speed vehicle head body portion is typically in laminar condition.And tail flow field is a part of
Be laminar flow, a part it is turbulent flow.The electromagnetic scattering of laminar flow is usually specular scattering, the ratio very little of back scattering.Turbulent flow phase
For the electromagnetic wavelength of exposure, it is divided into overstocked turbulent flow and Ya Mi turbulent flows, overstocked turbulent flow is face diffusing scattering, and sub- close turbulent flow is body
Scattering, the intensity of the electromagnetic scattering of sub- close turbulent flow are usually more much bigger than overstocked turbulent flow.Therefore, the radar of sub- close turbulent wake is special
Property is one of main research of defensive radar target identification, is analyzed it with important practical significance.
Super speed vehicle and radar cross section (RCS, Radar Cross Section) the simulated behavior side streamed
Face, analysis method can substantially be divided into three classes.Exact Analytic Method, high-frequency approximation and Method for Numerical (Yu Zhefeng, Liu Jiaqi,
Liu Lianyuan etc..Near space hypersonic aircraft RCS characteristic researchs, aerospace journal, 2014,35 (6), 713-717).Three kinds
Method respectively has advantage and disadvantage, and accurate analytic method is most accurate, but limited shape can only be solved.Approximate solution is transported
It is fast to calculate speed, can solve the problems, such as electrically large sizes, but computational accuracy is limited, there is also problems for the processing of complex appearance
(in detail etc., aircraft plasma sheath and electromagnetic wave interaction prediction method, sky is closed in Beijing by Su Hansheng, Zhang Zuoyi, Liu Xiu
Between vehicle system engineering research institute, the patent No.：CN106611083A,2017.5)；Method for Numerical such as Fdtd Method side
Method etc., quick multimachine subalgorithm and finite element algorithm etc., computational accuracy are high, it may be convenient to calculate shape and the flight of medium complexity
The RCS of device, shortcoming are to be difficult to solve the problems, such as electrically large sizes (Chen Rushan, fourth high aim, Fan Zhenhong etc., the conformal sub- grid electricity of aircraft
The emulation mode of magnetic scattering specificity analysis, Institutes Of Technology Of Nanjing, the patent No.：CN105653747A, 2014.6).In addition, also have logical
It crosses test method and obtains radar cross section (Xie Kai, Zhao Liang, Qin Yongqiang, Li Xiaoping, plasma that plasma surrounds target
The radar reflection characteristic measuring device and method of covering material, Xian Electronics Science and Technology University, the patent No.：CN102809577A,
2012.12)。
On the whole, the sub- close turbulent wake RCS characteristics similarity rules research of hypersonic aircraft is one extremely difficult
The problem of, the country not yet specially carried out the research of this respect, and also without ready-made theory in the external document published
It can use for reference.
Invention content
The purpose of the present invention is to provide a kind of radar cross section quick calculation method of superelevation velocity of sound aircraft, bases
Plasma distribution characteristics around it, is obtained by extracting its plasma stream field data under superelevation velocity of sound aircraft motion state
Spectral function feature distribution model is taken, is a kind of simple and quick equivalent electromagnetic radar so as to carry out radar cross section solution
Scattering section method for solving.
In order to achieve the above object, the invention is realized by the following technical scheme：
A kind of radar cross section quick calculation method of superelevation velocity of sound aircraft, it is characterized in that, comprising：
S1, based on plasma distribution characteristics around it under aircraft motion state, extraction is obtained based on plasma stream
The physics field parameters of field data distribution, the physics field parameters include plasma electron density, collision frequency；
S2, mesh generation is carried out to zoning, the plasma stream field data distributed intelligence based on discretization obtains phase
Meet the tendency of spectral function distributed model corresponding under emotionally shape state；
S3, the physics field parameters based on the distribution of plasma stream field data carry out corresponding radar cross section solution；
S4, setting incidence angles degree obtain the radar cross section of different orientations according to the gridding information delimited.
The radar cross section quick calculation method of above-mentioned superelevation velocity of sound aircraft, wherein, the step S2 is specifically wrapped
Contain：
S21, input aircraft geometrical model structure, establish corresponding model, and input superelevation velocity of sound aircraft in residing fortune
Physics field parameters around under dynamic state, obtain under different motion state aircraft based on the distribution of discretization number grid around
Plasma is distributed, and data correspond to the plasma draw physical parameter of corresponding region on each grid；
S22, for sub- close turbulent wake Electromagnetic Scattering Characteristics, the distortion that form is corrected using single order Born approximation methods is near
Sihe transport theory, and consider the refraction effect of plasma in the case of electromagnetic wave incident, solve the electromagnetism of plasma target
Scattering properties；
S23, the close turbulent wake Electromagnetic Scattering Characteristics for aircraft, the plasma mesh that will be solved in step S22
Target Electromagnetic Scattering Characteristics are distributed, and are brought into Shkarofsky spectrum of turbulence function expressions, solve aircraft certain high
Isotropism spectral function distribution expression formula under degree and state of flight；
Plasma geometric areas around S24, discretization aircraft, according to zoning about along direction of motion axis pair
Claim the characteristic of structure, and higher according to head plasma geometric areas density, along caudal directions, plasma density distribution is non-
Plasma geometric areas, is divided into several circular annular regions by uniform smaller feature along the direction of motion, it is ensured that each circle
Ring approximation corresponds to a plasma geometric areas with uniform physical properties；For each circular annular region, using pair
The method that the electromagnetic scattering distributed data of discretization obtained in step S23 is averaged solves plasma and surrounds
Isotropic spectral function distribution on aircraft corresponding to each annulus.
The radar cross section quick calculation method of above-mentioned superelevation velocity of sound aircraft, wherein, the step S3 is specific
Comprising：
It is distributed according to the discretization Sharofsky spectral functions solved, single order Born approximation methods correct the distortion of form
The approximate sub- close turbulent wake radar cross section solution formulas of Born corresponding to approximate and transport theory, obtain and are transported along aircraft
The radar cross section distribution of discretization on direction is moved, and the radar cross section is distributed, volume point is carried out, solves along winged
Total radar cross section size on line direction.The radar cross section quick calculation method of above-mentioned superelevation velocity of sound aircraft,
Wherein, plasma geometric areas is by being based on plasma density around the discretization aircraft in the step S24
The geometric areas feature of distribution carries out mesh generation, thus discretization heating region property distribution, specifically：To plasma
Body region carries out mesh generation, and the geometric areas of model is to tail region and in y directions and z from top area in the z-direction
Direction is axisymmetricly distributed, and maximum value is the diameter of tail portion, and entire space is asked using the division methods of regular hexahedron grid
Solve the mesh generation that region carries out enough accuracy；The radar cross section quick calculation method of above-mentioned superelevation velocity of sound aircraft,
Wherein, in the step S23, the electromagnetic scattering distribution of the discretization solved is brought into Shkarofsky turbulent flow spectral functions
In expression formula, aircraft isotropism spectral function distribution expression formula under certain altitude and state of flight is solved, it is specific
Process includes：
The radar cross section of the model plasma is calculated, takes and grid stroke is carried out to entire zoning model
Respectively in corresponding incident direction, it is average close that the corresponding plasma in the incident direction is calculated in the method divided
Degree；
Discrete Fourier transform is carried out to the plasma average electron density of corresponding grid, obtains corresponding electron density
Corresponding frequency spectrum：
In formula, vector x contains n non-uniform sampled points, and i is imaginary part unit, ω=e-2πi/nFor its in entire space
In a complex root, j and k are represented respectively to be calculated from 0 to n-1 point；
According to the spectrum distribution of electron density, it is updated in Sharofsky spectrum of turbulence function expressions, so as to solve
Go out the spectral function expression formula of isotropic turbulence.
And then the sub- close turbulent wake radar cross section solution formula of Born approximation is combined, show that corresponding radar scattering is cut
Face.
The radar cross section quick calculation method of above-mentioned superelevation velocity of sound aircraft, wherein, the step S24 is specific
Comprising：
Plasma parameter attribute file carries out data extraction first, to the grid divided, carries out each respectively
Average physical parametric solution on grid；
For arbitrary a branch of electromagnetic wave, it is solved along paths traversed under straightline propagation situation, the path is counted and is passed through
The regular hexahedron grid gone through, so as to which the electromagnetic wave for obtaining corresponding frequencies is believed along the path undergone under linear transmission situation
Breath；
Discretization record is carried out to these grids, with the corresponding coordinate information of the central point record of each grid；It is right
In the grid that Electromagnetic Wave Propagation is passed through, as a reference point nearest from path of corresponding grid central point is obtained；Based on these strokes
The grid divided, it can be approximately point-blank to undergo grid element center point；
Radar cross section solution is carried out using Sharofsky spectral functions formula, so as to obtain corresponding cline frequency electromagnetism
Wave radar cross section.
Compared with the prior art, the present invention has the following advantages：
1st, it being directed under electromagnetic wave and superelevation velocity of sound plasma sheath operative condition, plasma parameter is difficult to obtain,
And lacking the problems such as effective electromagnetic wave is explained with action of plasma Physical Mechanism, this method can solve electromagnetic wave dynamic
The scattering problems propagated in state plasma sheath, so as to avoid using equivalent Jie based on plasma physics parameter distribution
Matter Mathematical Modeling Methods or the complicated calculations method based on Monte Carlo reduce calculation amount and promotion computation rate to reach
Purpose；
2nd, according to theory deduction, the method calculated using approximate formula, to carry out the solution of radar cross section, so as to generation
For the method for traditional massive values computation.This method has certain universality, although being directed to complex geometry model
Precise results can not be provided, but in terms of practical operation, there is actual application value；
3rd, this method is based on full-scale quick calculation method.The problem of due to calculation amount, current most of researchs
It is the radar cross section based on theoretical calculation small size target, then the method using contracting ratio, carries out large scale target radar and dissipate
Penetrate section derivation；
4th, using the method that full-scale mesh generation is carried out to zoning, the spectral characteristic side based on plasma density
Method carries out radar cross section solution.
Description of the drawings
Fig. 1 is flow chart of the method for the present invention；
Fig. 2 is by aircraft tail upper half-space area distribution geometrical model and size in the embodiment of the present invention and adopts
Mesh generation schematic diagram；
Fig. 3 is divided by the embodiment of the present invention plasma area grid and incident electromagnetic wave undergoes grid element center
The selection figure of coordinate points；
Fig. 4 be angle in the coordinate calculated in the embodiment of the present invention on regional space corresponding to any one grid and
Each region average physical attribute computing method figure；
Fig. 5 solves flow chart for plasma tail of embodiment of the present invention radar cross section；
Fig. 6 is 10Ma speed in the embodiment of the present invention, and 65km height, in the case of χ=45 °, required solution spectral function variation is bent
Line and Ya Mi turbulent wake RCS one-dimensional range profiles.
Specific embodiment
Below in conjunction with attached drawing, by the way that a preferable specific embodiment is described in detail, the present invention is further elaborated.
For superelevation velocity of sound stealthy aircraft, the plasma being wrapped in around aircraft target can be formed in flight course
Body sheath.Under usual situation, the distribution of plasma is sufficiently complex.Its physical attribute is distributed and height, the fortune where aircraft
Dynamic state and ambient enviroment are closely related.Traditional computational methods usually can not accurately obtain plasma properties distribution,
So as to can not accurately obtain radar cross section using numerical computation method.In institute, the present invention provides one kind using approximation method
Adaptability is good, the high superelevation velocity of sound aircraft radars scattering section computational methods with plasma encirclement of computational efficiency, should
Method substitutes traditional method by accurate numerical computations, speed is calculated so as to greatly improve by approximately calculating means
Rate.
As shown in Figure 1, 2, the present invention proposes a kind of radar cross section quick calculation method of superelevation velocity of sound aircraft,
It includes：
S1, based on plasma distribution characteristics around it under aircraft motion state, extraction is obtained based on plasma stream
The physics field parameters of field data distribution, the physics field parameters include plasma electron density, collision frequency；
In the present embodiment, the specific implementation process of step S1 is：According to the aerodynamic configuration of aircraft, state of flight and
Height residing for aircraft carries out its dynamics simulation using FD-FASTRAN softwares, obtains plasma around corresponding aircraft
Volume density, collision frequency distributed intelligence, so as to define physical field information of the electromagnetic wave in the substance of space, ambient condition information,
And plasma properties.
S2, mesh generation is carried out to zoning, preferably using regular hexahedron mesh generation, the grade based on discretization from
Daughter flow field Data distribution information obtains spectral function distributed model corresponding under aircraft corresponding state；That is, to obtain etc.
Ion body region carries out mesh generation, and so as to make plasma physics property distribution discretization, the numerical solution for next step is done
Prepare, this step defines plasma there are section, so as to define electromagnetic wave and action of plasma section；
Specifically, plasma parameter attribute file carries out data extraction first.For arbitrary a branch of electromagnetic wave, solve
It counts the regular hexahedron gridding information that the path is lived through along paths traversed under straightline propagation situation.So as to obtain
The electromagnetic wave of corresponding frequencies is along the routing information undergone under linear transmission situation.
The grid of model split as shown in Figure 2, carries out the average physical parametric solution on each grid, example respectively
Such as average electron density, collision frequency.
S3, the physics field parameters based on the distribution of plasma stream field data carry out corresponding radar cross section solution；
S4, setting incidence angles degree obtain the radar cross section of different orientations according to the gridding information delimited.
In the present embodiment, the step S2 is specifically included：
S21, input aircraft geometrical model structure, establish corresponding model, and input aircraft under residing motion state
Around physics field parameters, obtain different motion state under aircraft based on discretization number grid distribution around plasma
It is distributed, data correspond to the plasma draw physical parameter of corresponding region on each grid；
S22, for sub- close turbulent wake Electromagnetic Scattering Characteristics, form is corrected using single order Born (Bonn) approximation method
Distortion approximation and transport theory, and consider the refraction effect of plasma in the case of electromagnetic wave incident, solve plasma target
Electromagnetic Scattering Characteristics；
S23, the close turbulent wake Electromagnetic Scattering Characteristics for aircraft, the plasma mesh that will be solved in step S22
The distribution of target Electromagnetic Scattering Characteristics is brought into Shkarofsky spectrum of turbulence function expressions, solves aircraft in certain altitude
And isotropism spectral function distribution expression formula under state of flight；
Plasma geometric areas around S24, discretization aircraft, according to zoning about along direction of motion axis pair
Claim the characteristic of structure, and higher according to head plasma geometric areas density, along caudal directions, plasma density distribution is non-
Plasma geometric areas, is divided into several circular annular regions by uniform smaller feature along the direction of motion, it is ensured that each circle
Ring approximation corresponds to a plasma geometric areas with uniform physical properties；For each circular annular region, using pair
The method that the electromagnetic scattering distributed data of discretization obtained in step S23 is averaged solves plasma and surrounds
Isotropic spectral function distribution on aircraft corresponding to each annulus, to track corresponding incoming electromagnetic propagation path direction
On plasma properties information.
In the present embodiment, the step S3 is specifically included：
It is distributed according to the discretization Sharofsky spectral functions solved, single order Born approximation methods correct the distortion of form
The approximate sub- close turbulent wake radar cross section solution formulas of Born corresponding to approximate and transport theory, obtain and are transported along aircraft
The radar cross section distribution of discretization on direction is moved, and the radar cross section is distributed, volume point is carried out, solves along winged
Total radar cross section size on line direction.
Plasma geometric areas is close by being based on plasma around discretization aircraft in the step S24
The geometric areas feature of degree distribution carries out mesh generation, is specifically wrapped so as to the process of discretization heating region property distribution
Contain：
Plasma region carries out mesh generation, and the geometric areas of model is from top area to tailer in the z-direction
It domain and is axisymmetricly distributed in y directions and z directions, maximum value is the diameter of tail portion, using the division of regular hexahedron grid
Method carries out entire space domain the mesh generation of enough accuracy；
Plasma electron density information according to corresponding to these grids carries out discrete Fourier transform, so as to complete pair
Plasma electron density on each section, collision frequency, plasma electron density root mean square etc. and other physics
The statistics of parameter.In this way, the physical parameter attribute of each thin column can be obtained.And then it is approximate to can be applied to Born
During radar cross section formula calculates.So based on above analysis, for different electromagnetic wave incident directions, have different
The thin circular cross-section of plasma also just corresponds to different one-dimensional range profile radar cross section.As shown in figure 4, it is given in the figure
Gone out based on the annulus dividing mode under the incident electromagnetic wave situation of azimuth, so as to the annulus divided based on these, according to from
The corresponding physical field information of dispersion grid carries out average plasma physical attribute statistics and radar cross section solves；
Corresponding regular hexahedron grid on the path undergone according to every a branch of electromagnetic wave, correspondingly, obtain these positive six
The central point of face volume mesh, the yz planes at place and the section of heating region, as shown in Figure 4, each section is in x-axis
Length be regular hexahedron grid length, in this way, each correspondence grid physical parameter information carry out file reading, obtain
Electron density is obtained, collision frequency respectively in information such as x, y, the coordinates in z directions, chooses vertical with incident electromagnetic wave direction put down
Face, and the section for intersecting acquisition with heating region is acquired, then carry out the average physical parameter acquiring on each section,
And plasma electron root mean square Statistics of Density, these physical parameters are united both from the data of each grid on section
Meter.Here, the section parallel with incident electromagnetic wave normal direction is the thin column that thickness is Gridding length.
As shown in Figure 5,6, it gives plasma wake radar cross section and solves flow chart, and give concrete model
Result of calculation.Show upper half-space model in the model, geometric areas be in the z-direction from [- 0.23,1.81], along x and
For y directional spredings with z-axis axial symmetry, region is [- 0.83,0.83].For incident electromagnetic wave, incident angle θ andAccording to
Plasma x/y plane central point for reference point, θ and360 ° are changed to from 0 ° hence for arbitrary random angles electricity
The incidence of magnetic wave can obtain comprehensive electromagnetic wave incident information so that under electromagnetic wave incident situation, can be scattered
Electromagnetic wave solves, and obtains corresponding frequency spectrum and radar cross section.The case provided as shown in Figure 6, the result of calculation are given
Go out in above-mentioned model, spectral function of the aircraft target in the case of 10Ma flying speeds, 65km altitudes has been changed bent
Line and Ya Mi turbulent wake RCS one-dimensional range profiles.
For the electromagnetic wave of any angle incidence, with θ andIt represents.
In the present embodiment, superelevation is calculated based on the method for Sharofsky functions and Spectrum Conversion in the step S23
The process of the radar cross section of velocity of sound plasma specifically includes：
Based on plasma density, the spectral function of plasma is obtained using the method for discrete Fourier transform：
In formula, vector x contains n non-uniform sampled points, and i is imaginary part unit, ω=e-2πi/nFor its in entire space
In a complex root, j and k are represented respectively to be calculated from 0 to n-1 point；
The radar cross section of the model plasma is calculated, takes and grid stroke is carried out to entire zoning model
Respectively in corresponding incident direction, it is average close that the corresponding plasma in the incident direction is calculated in the method divided
Degree；
Discrete Fourier transform is carried out to the plasma average electron density of corresponding grid, obtains corresponding frequency spectrum,
And then the sub- close turbulent wake radar cross section solution formula of Born approximation of application Sharofsky spectral function distributions, obtain phase
The radar scattering interface answered.
In the present embodiment, the step S24 is specifically included：
Plasma parameter attribute file carries out data extraction first, to the grid divided, carries out each respectively
Average physical parametric solution on grid；
For arbitrary a branch of electromagnetic wave, it is solved along paths traversed under straightline propagation situation, the path is counted and is passed through
The regular hexahedron grid gone through, so as to which the electromagnetic wave for obtaining corresponding frequencies is believed along the path undergone under linear transmission situation
Breath；
Discretization record is carried out to these grids, with the corresponding coordinate information of the central point record of each grid；It is right
In the grid that Electromagnetic Wave Propagation is passed through, as a reference point nearest from path of corresponding grid central point is obtained；Based on these strokes
The grid divided, it is noted that the grid of division should be sufficiently small so that it can be approximately at one to undergo grid element center point
On straight line；
Radar cross section solution is carried out using Sharofsky spectral functions formula, so as to obtain corresponding cline frequency electromagnetism
Wave radar cross section.
In conclusion the present invention is compared with conventional radar scattering section computational methods, do not need to carry out based on grid division
The full-wave simulation numerical computation method of corresponding physical attribute, so as to save a large amount of computing resources and time.The present invention is to pass through
It carries out carrying out mesh generation to interested region, the spectrum of target is obtained using the Sharofsky spectral function distribution formulas of discretization
Function is distributed, and average physical statistics of attributes is carried out on electromagnetic wave incident direction, then with the approximate sub- close turbulent wake thunders of Born
Up to scattering section equations.So the radar scattering interface of the especially suitable electrically large sizes plasma target of this method is quick
It solves.
Although present disclosure is discussed in detail by above preferred embodiment, but it should be appreciated that above-mentioned
Description is not considered as limitation of the present invention.After those skilled in the art have read the above, for the present invention's
A variety of modifications and substitutions all will be apparent.Therefore, protection scope of the present invention should be limited to the appended claims.
Claims (6)
1. a kind of radar cross section quick calculation method of superelevation velocity of sound aircraft, which is characterized in that include：
S1, based on plasma distribution characteristics around it under aircraft motion state, extraction is obtained based on plasma stream number of fields
According to the physics field parameters of distribution, which includes plasma electron density, collision frequency；
S2, mesh generation, the plasma stream field data distributed intelligence based on discretization are carried out to zoning, acquisition is mutually met the tendency of
Emotionally spectral function distributed model corresponding under shape state；
S3, the physics field parameters based on the distribution of plasma stream field data carry out corresponding radar cross section solution；
S4, setting incidence angles degree obtain the radar cross section of different orientations according to the gridding information delimited.
2. the radar cross section quick calculation method of superelevation velocity of sound aircraft as described in claim 1, which is characterized in that institute
Step S2 is stated specifically to include：
S21, input aircraft geometrical model structure, establish corresponding model, and input superelevation velocity of sound aircraft in residing movement shape
Under state around physics field parameters, obtain different motion state under aircraft based on discretization number grid distribution around grade from
Daughter is distributed, and data correspond to the plasma draw physical parameter of corresponding region on each grid；
S22, for sub- close turbulent wake Electromagnetic Scattering Characteristics, using single order Born approximation methods correct form distortion approximation and
Transport theory, and consider the refraction effect of plasma in the case of electromagnetic wave incident, solve the electromagnetic scattering of plasma target
Characteristic；
S23, the close turbulent wake Electromagnetic Scattering Characteristics for aircraft, by the plasma target solved in step S22
Electromagnetic Scattering Characteristics be distributed, be brought into Shkarofsky spectrum of turbulence function expressions, solve aircraft certain altitude with
And isotropism spectral function distribution expression formula under state of flight；
Plasma geometric areas around S24, discretization aircraft, according to zoning about along direction of motion axial symmetry knot
The characteristic of structure, and it is higher according to head plasma geometric areas density, and along caudal directions, plasma density distribution is non-homogeneous
Plasma geometric areas is divided into several circular annular regions, it is ensured that each annulus is near by smaller feature along the direction of motion
Like a corresponding plasma geometric areas with uniform physical properties；For each circular annular region, using to step
The method that the electromagnetic scattering distributed data of discretization obtained in S23 is averaged solves plasma and surrounds flight
Isotropic spectral function distribution on device corresponding to each annulus.
3. the radar cross section quick calculation method of superelevation velocity of sound aircraft as claimed in claim 2, which is characterized in that institute
The step S3 stated is specifically included：
It is distributed according to the discretization Sharofsky spectral functions solved, the distortion that single order Born approximation methods correct form is approximate
The approximate sub- close turbulent wake radar cross section solution formulas of Born with corresponding to transport theory, obtain along the aircraft side of moving
The radar cross section distribution of upward discretization, and the radar cross section is distributed, volume point is carried out, is solved along flight side
Total radar cross section size upwards.
4. the radar cross section quick calculation method of superelevation velocity of sound aircraft as claimed in claim 2, which is characterized in that institute
Plasma geometric areas is by based on the several of plasma density distribution around discretization aircraft in the step S24 stated
What provincial characteristics carries out mesh generation, thus discretization heating region property distribution, specifically：
Plasma region carries out mesh generation, the geometric areas of model be in the z-direction from top area to tail region, with
And be axisymmetricly distributed in y directions and z directions, maximum value is the diameter of tail portion, using the division methods of regular hexahedron grid
The mesh generation of enough accuracy is carried out to entire space domain.
5. the radar cross section quick calculation method of superelevation velocity of sound aircraft as claimed in claim 4, which is characterized in that institute
In the step S23 stated, the electromagnetic scattering distribution of the discretization solved is brought into Shkarofsky spectrum of turbulence function expressions
In, solve aircraft isotropism spectral function distribution expression formula under certain altitude and state of flight, detailed process packet
It includes：
The radar cross section of the model plasma is calculated, takes and mesh generation is carried out to entire zoning model
Respectively in corresponding incident direction, the corresponding plasma averag density in the incident direction is calculated in method；
Discrete Fourier transform is carried out to the plasma average electron density of corresponding grid, it is right to obtain corresponding electron density institute
The frequency spectrum answered：
In formula, vector x contains n non-uniform sampled points, and i is imaginary part unit, ω=e-2πi/nFor wherein one in entire space
A complex root, j and k are represented respectively to be calculated from 0 to n-1 point；
According to the spectrum distribution of electron density, it is updated in Sharofsky spectrum of turbulence function expressions, it is each so as to solve
To the spectral function expression formula of same sex turbulent flow.
And then the sub- close turbulent wake radar cross section solution formula of Born approximation is combined, obtain corresponding radar cross section.
6. the radar cross section quick calculation method of superelevation velocity of sound aircraft as claimed in claim 5, which is characterized in that institute
The step S24 stated is specifically included：
Plasma parameter attribute file carries out data extraction first, to the grid divided, carries out each grid respectively
On average physical parametric solution；
For arbitrary a branch of electromagnetic wave, it is solved along paths traversed under straightline propagation situation, the path is counted and is lived through
Regular hexahedron grid, so as to obtain the electromagnetic waves of corresponding frequencies along the routing information undergone under linear transmission situation；
Discretization record is carried out to these grids, with the corresponding coordinate information of the central point record of each grid；For electricity
The grid that electromagnetic wave propagation is passed through obtains as a reference point nearest from path of corresponding grid central point；Based on these divisions
Grid, it can be approximately point-blank to undergo grid element center point；
Radar cross section solution is carried out using Sharofsky spectral functions formula, so as to obtain corresponding cline frequency electromagnetic wave thunder
Up to scattering section.
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| CN201711260743.2A CN108152799B (en) | 2017-12-04 | 2017-12-04 | Method for rapidly calculating radar scattering cross section of hypersonic aircraft |
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| CN112257350A (en) * | 2020-09-30 | 2021-01-22 | 北京空间飞行器总体设计部 | Aircraft electromagnetic characteristic modeling method in high-speed flight state |
| CN112611921A (en) * | 2020-12-09 | 2021-04-06 | 上海无线电设备研究所 | Atmospheric sound field simulation device and electromagnetic scattering characteristic test method thereof |
| CN113124999A (en) * | 2021-04-13 | 2021-07-16 | 常州工学院 | Method and device for acquiring scattering sound pressure based on three-dimensional scanning and Fourier transform |
| CN114167883A (en) * | 2022-02-11 | 2022-03-11 | 中国空气动力研究与发展中心计算空气动力研究所 | Method for controlling attitude of high-altitude aircraft by jet flow |
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| CN110531331A (en) * | 2019-03-31 | 2019-12-03 | 西安电子科技大学 | Plasma coats target radar returns modeling and simulating method |
| CN110276109A (en) * | 2019-05-31 | 2019-09-24 | 南京理工大学 | A kind of emulation mode of hypersonic aircraft plasma sheath electromagnetic property |
| CN110276109B (en) * | 2019-05-31 | 2020-08-11 | 南京理工大学 | Simulation method for electromagnetic property of plasma sheath of hypersonic aircraft |
| CN112257350A (en) * | 2020-09-30 | 2021-01-22 | 北京空间飞行器总体设计部 | Aircraft electromagnetic characteristic modeling method in high-speed flight state |
| CN112257350B (en) * | 2020-09-30 | 2023-06-06 | 北京空间飞行器总体设计部 | Aircraft electromagnetic characteristic modeling method under high-speed flight state |
| CN112611921A (en) * | 2020-12-09 | 2021-04-06 | 上海无线电设备研究所 | Atmospheric sound field simulation device and electromagnetic scattering characteristic test method thereof |
| CN113124999A (en) * | 2021-04-13 | 2021-07-16 | 常州工学院 | Method and device for acquiring scattering sound pressure based on three-dimensional scanning and Fourier transform |
| CN113124999B (en) * | 2021-04-13 | 2023-09-22 | 常州工学院 | Method and device for acquiring scattering sound pressure based on three-dimensional scanning and Fourier transformation |
| CN114167883A (en) * | 2022-02-11 | 2022-03-11 | 中国空气动力研究与发展中心计算空气动力研究所 | Method for controlling attitude of high-altitude aircraft by jet flow |
| CN114167883B (en) * | 2022-02-11 | 2022-04-15 | 中国空气动力研究与发展中心计算空气动力研究所 | Method for controlling attitude of high-altitude aircraft by jet flow |
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