Composite target scattering center modeling method and system based on ray tracing

Abstract

The invention provides a ray tracing-based composite target scattering center modeling method and system. The method comprises the following steps of: constructing a nested geometric model of a medium-PEC composite target; the direction of the outer normal direction of the target surface is defined according to the number of layers of the closed surface of the nested geometric model, and a multi-region surface discrete grid model is obtained through surface discretization and component decomposition; acquiring a ray path set containing regional source information and scattering mechanism information, and classifying according to whether the two types of information are the same or not to obtain ray path subsets; screening and acquiring a ray path set of the main contribution area from the acquired ray path subset; according to the corresponding relation between the three-dimensional attribute scattering center model and the geometric structure, a plurality of model parameters are deduced in the forward direction, and a parameterized attribute scattering center model is obtained. The invention provides a dielectric material electromagnetic parameter definition method, and high-frequency electromagnetic modeling of a dielectric-PEC composite target with a higher order and a transmission complex scattering mechanism is realized.

Description

Technical Field

[0001] The present application relates to the technical field of high-frequency electromagnetic scattering modeling of radar targets, and in particular to a composite target scattering center modeling method and system based on ray tracing. Background Art

[0002] With the extensive application of dielectric materials in modern weapons and equipment, many radar targets are composed of a combination of dielectric and PEC materials, such as stealth targets with absorbing dielectric coatings, various aircraft with dielectric and PEC (Perfect Electrical Conductor) hybrid wing designs, and various radomes. Given that radar target characteristic technology plays an important technical support role in target detection, tracking and identification applications, the research on electromagnetic scattering modeling methods and technologies including target scattering center models for dielectric (referring to isotropic uniform lossless dielectric)-ideal conductor hybrid material targets has become a frontier topic in this professional field. In the optical region of radar characteristics, the total field of the target can be regarded as the superposition of coherent scattering from the scattering centers of many independent components on the target. The scattering center model can concisely and completely describe the total scattering field of the target, and provide physical related information such as the amplitude, position, polarization, and structure of the target scattering response, and is therefore widely used in the fields of scattering feature extraction and target identification.

[0003] The traditional inverse method starts from the radar characteristic data obtained from actual measurement or electromagnetic simulation, and extracts the electromagnetic parameters of the scattering center through an inversion approach. In practical applications, the acquisition of multi-angle and multi-frequency radar echo data and the iterative optimization processing are usually very time-consuming; because the electromagnetic wave propagation mechanism and process are not clear in the inverse method, the extracted scattering center model lacks physical meaning and cannot correspond to the target structure.

[0004] On the contrary, the forward method can directly separate the scattering center from the nested geometric model and forwardly infer the electromagnetic parameters of the scattering center by using a high-frequency calculation method with ray field characteristics. The approximate analytical separation method and high-frequency quantitative description make the electromagnetic scattering mechanism of the scattering center model obtained by the forward method clear, closely related to the local structure, and the electromagnetic parameters unique. However, all modeling methods are still limited to PEC targets. In reality, there are a large number of complex targets containing dielectric materials, whose geometric structures and electromagnetic material distributions are more diverse, and the scattering mechanism of electromagnetic waves is more complex.

[0005] As the research deepens, the existing technology also shows many shortcomings: in the multi-layer nested structure containing medium and PEC materials, there is a scattering mechanism of "transmission / ... / reflection / ...transmission" type with multiple transmission couplings. The calculation and separation of its scattering contribution is a huge challenge; the existing scattering center attribute parameter estimation method cannot meet the calculation of the scattering center attribute parameters corresponding to the internal structure existing in the medium-PEC composite target. Summary of the invention

[0006] The present application provides a composite target scattering center modeling method and system based on ray tracing, which can solve the problem in the prior art that in a multi-layer nested structure containing medium and PEC material, there is a "transmission / ... / reflection / ...transmission" type of multiple transmission-coupled scattering mechanism, and the calculation and separation of its scattering contribution is a huge challenge; the existing scattering center attribute parameter inference method cannot meet the technical problem of calculating the scattering center attribute parameters corresponding to the internal structure existing in the medium-PEC composite target.

[0007] In a first aspect, the present application provides a composite target scattering center modeling method based on ray tracing, comprising the following steps:

[0008] According to the known geometric information and material properties of the medium-PEC composite target, a nested geometric model of the medium-PEC composite target is constructed;

[0009] The number of closed surface layers of the nested geometric model is obtained, the outer normal direction of the target surface is defined according to the number of closed surface layers of the nested geometric model, and a multi-region surface discrete grid model is obtained through surface discretization and component decomposition;

[0010] Under the given attitude angle, frequency, polarization mode and number of rays, the ray tracing method is used to trace the paths of each reflected and transmitted ray irradiated on the discrete facet of the multi-region surface discrete grid model, and a set of ray paths containing regional source information and scattering mechanism information is obtained. According to the regional source and scattering mechanism, ray path subsets representing different scattering centers are classified from the ray path set.

[0011] A set of ray paths whose scattering intensity is greater than an intensity threshold is screened from the obtained ray path subset to obtain a set of ray paths in a main contribution area;

[0012] For the ray path set of the main contribution area, multiple model parameters are forward derived according to the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure. The multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters. Based on the derived multiple model parameters, a parameterized attribute scattering center model of the medium-PEC composite target is constructed.

[0013] In combination with the first aspect, in one embodiment, under a given attitude angle, frequency, polarization mode and number of ray actions, a ray tracing method is used to track each reflection and transmission ray path irradiated on a discrete facet of a multi-region surface discrete grid model, to obtain a ray path set containing regional source information and scattering mechanism information, and to classify ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism, specifically including the following steps:

[0014] Under the given attitude angle, frequency, polarization mode and number of rays, the ray tracing method is used to track the path of each reflection and transmission ray irradiated on the discrete facet of the multi-region surface discrete grid model. According to the mechanism information of each point on the ray path in the total set of ray paths and the material electromagnetic parameters of the corresponding space, the propagation of the GO ray field is tracked, the GO electric field information at each point on the ray path is obtained, and the total set of ray paths with regional source and scattering mechanism information is obtained;

[0015] And according to whether the regional sources and scattering mechanism information in the total set of ray paths are the same, the ray paths in the ray path set are identified and classified, and the ray paths with the same identities are grouped together to obtain a subset of multiple-action ray paths representing different scattering sources.

[0016] In combination with the first aspect, in one implementation, the ray paths in the ray path set are identified and classified according to whether the regional sources and scattering mechanism information in the total set of ray paths are the same, ray paths with the same identities are grouped together, and a subset of multiple ray paths representing different scattering sources is obtained, which specifically includes the following steps:

[0017] Marking the identity of each ray path in the total set of one-time action ray paths, grouping ray paths with the same identity, and obtaining multiple one-time action ray path subsets;

[0018] Read the number of elements in the secondary action ray path set. If the number of elements in the secondary action ray path set is not 0, mark each ray path in the total set of secondary action ray paths with an identity, group ray paths with the same identity, and obtain subsets of secondary action ray paths with different scattering sources.

[0019] By analogy, continue to perform identity tagging for each ray path in the total set of subsequent multiple action ray paths, and collect ray paths with the same identity until the number of ray actions reaches the set threshold N. m Or the number of elements in the nth illuminated surface set is 0, and the subset of multiple action ray paths is obtained.

[0020] In combination with the first aspect, in one embodiment, screening a set of ray paths having scattering intensities greater than an intensity threshold from the acquired ray path subsets, and acquiring a set of ray paths that make a major contribution in each ray path subset, specifically comprises the following steps:

[0021] The total scattered field is calculated for each subset of ray paths using the GO-PO algorithm;

[0022] The total scattering fields of all the obtained scattering subsets are sorted from large to small according to the scattering field intensity values, and a set of strong scattering paths whose ray path subset scattering field values ​​are greater than an intensity threshold is obtained;

[0023] The angle between the outgoing direction and the receiving direction of each ray in the strong scattering path set is calculated, and the ray path set with an angle less than ±3 degrees is taken as the ray path set with the main contribution.

[0024] In combination with the first aspect, in one implementation, the calculating the total scattered field of each ray path subset using the GO-PO algorithm specifically includes the following steps:

[0025] For a single-action scattering path, the PO algorithm is used to calculate the far-field scattering intensity excited by each incident ray to obtain the scattering field of the single-action scattering path;

[0026] For multiple-action ray paths, the GO-PO algorithm is used to calculate the PO contribution of each reflection point of the GO ray to the observation point to obtain the scattered field of the multiple-action ray path, where the PO calculation is only applied to the last reflection or transmission of the surface;

[0027] Then, the scattered fields of all ray paths in each ray path subset are added together to obtain the total scattered field of each ray path subset.

[0028] In combination with the first aspect, in one implementation, the forward derivation of the frequency-dependent parameters in the plurality of model parameters specifically includes the following steps:

[0029] According to the corresponding relationship between the frequency dependence factor and the type of geometric structure surface, the frequency dependence factor expressed by multiplication is obtained by tracing the ray field propagation process and determining the type of geometric structure surface.

[0030] In combination with the first aspect, in one implementation, the forward derivation of the position parameter among the plurality of model parameters specifically includes the following steps:

[0031] Firstly, the action point and equivalent action point of each ray path in the ray path set of the main contribution area are determined;

[0032] For single scattering, the ray bounce point is the ray's action point;

[0033] For multiple action ray paths, combined with the principle of equivalent optical path difference, the equivalent action point position of each ray path is determined. Finally, the weighted average of all multiple action ray action points or equivalent action points in the ray path of the main contribution area is the position parameter of the scattering center.

[0034] In combination with the first aspect, in one implementation, the forward derivation of the length parameter among the multiple model parameters specifically includes the following steps:

[0035] The action points or equivalent action points of all ray paths that meet the in-phase condition in the ray path subset are projected in the azimuth direction, and the length parameters of the distributed scattering center are determined by the projection information data.

[0036] In a second aspect, the present application provides a composite target scattering center modeling system based on ray tracing, comprising:

[0037] A geometric model building module, used to build a nested geometric model of a medium-PEC composite target based on known geometric information and material properties of the medium-PEC composite target;

[0038] A multi-region surface discrete grid model acquisition module is connected to the geometric model construction module for acquiring the number of closed surface layers of the nested geometric model, defining the outer normal direction of the target surface according to the number of closed surface layers of the nested geometric model, and obtaining the multi-region surface discrete grid model through surface discretization and component decomposition;

[0039] A ray path subset acquisition module is communicatively connected with the multi-region surface discrete grid model acquisition module, and is used to use a ray tracing method to track each reflection and transmission ray path irradiated on a discrete facet of the multi-region surface discrete grid model under a given attitude angle, frequency, polarization mode and number of rays, to obtain a ray path set containing regional source information and scattering mechanism information, and to classify ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism;

[0040] A main contribution ray set screening module is in communication with the ray path subset acquisition module and is used to screen a set of ray paths with scattering intensities greater than an intensity threshold from the acquired ray path subset to acquire a ray path set of a main contribution area;

[0041] The composite target scattering center model construction module is communicatively connected to the main contribution ray set screening module, and is used to forward derive multiple model parameters for the ray path set of the main contribution area according to the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure. The multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters, and construct a parameterized attribute scattering center model of the medium-PEC composite target based on the derived multiple model parameters.

[0042] In conjunction with the second aspect, in one implementation, the ray path subset acquisition module includes:

[0043] A ray path collection acquisition unit is used to track the reflection and transmission ray paths of each discrete facet of the multi-region surface discrete grid model by using a ray tracing method under the given attitude angle, frequency, polarization mode and number of rays, and to track the propagation of the GO ray field according to the mechanism information of each point on the ray path in the ray path collection and the material electromagnetic parameters of the corresponding space, so as to obtain the GO electric field information at each point on the ray path and obtain the ray path collection with regional source and scattering mechanism information;

[0044] The ray path subset acquisition unit is communicatively connected with the ray path total set acquisition unit, and is used to identify and classify the ray paths in the ray path set according to whether the regional sources and scattering mechanism information in the ray path total set are the same, group the ray paths with the same identities, and obtain multiple action ray path subsets representing different scattering sources.

[0045] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0046] This application proposes a composite target scattering center modeling method based on ray tracing. Compared with the existing technology, its advantage is that it provides a method for defining the electromagnetic parameters of dielectric materials and realizes high-frequency electromagnetic modeling of dielectric-PEC composite targets with higher-order complex scattering mechanisms containing transmission;

[0047] Based on the high-frequency electromagnetic mechanism of complex targets and the principle of equivalent optical path difference, a method for calculating the equivalent points of internal coupling rays is proposed, which solves the problem of forward calculation of the three-dimensional position parameters of the medium-PEC complex target scattering center.

[0048] The entire modeling process is completely based on nested geometric models and material electromagnetic parameters. It has a small amount of calculation and the amount of parameterized model data obtained is small, providing technical support for real-time and rapid identification of radar targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of a process flow of a composite target scattering center modeling method based on ray tracing provided in an embodiment of the present application;

[0050] Figure 2 A nested geometric model diagram of a modified SLICY target provided in an embodiment of the present application;

[0051] Figure 3 A schematic diagram of the target model entity components decomposition provided in the embodiment of the present application;

[0052] Figure 4 Schematic diagram of target surface normal definition provided in the embodiment of the present application;

[0053] Figure 5 Flow chart of the frequency dependent parameter forward estimation algorithm provided in the embodiment of the present application;

[0054] Figure 6 Flow chart of the method for calculating the scattering center position parameters provided in the embodiment of the present application;

[0055] Figure 7 FEKO high frequency algorithm simulation SAR image provided in the embodiment of the present application;

[0056] Figure 8 The scattering center model provided in the embodiment of the present application reconstructs the SAR image. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0059] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0060] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0061] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0062] First, some technical terms in the present application are explained to facilitate those skilled in the art to understand the present application.

[0063] The composite target is a radar detection target of a composite medium including two or more media, namely, an isotropic medium (referring to an isotropic lossless medium) and an ideal conductor.

[0064] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0065] First, please refer to Figure 1 The present application embodiment provides a composite target scattering center modeling method based on ray tracing, comprising the following steps:

[0066] Step S1, constructing a nested geometric model of the medium-PEC composite target based on known geometric information and material properties of the medium-PEC composite target;

[0067] Step S2, obtaining the number of closed surface layers of the nested geometric model, defining the outer normal direction of the target surface according to the number of closed surface layers of the nested geometric model, and obtaining a multi-region surface discrete grid model through surface discretization and component decomposition;

[0068] Step S3, under the condition of given attitude angle, frequency, polarization mode and number of rays, using ray tracing method to trace each reflection and transmission ray path irradiated on the discrete facet of the multi-region surface discrete grid model, to obtain a ray path set containing regional source information and scattering mechanism information, and classify ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism;

[0069] Step S4, screening a set of ray paths whose scattering intensity is greater than an intensity threshold from the acquired ray path subset, and acquiring a ray path set of a main contribution area;

[0070] Step S5, for the ray path set of the main contribution area, based on the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure, multiple model parameters are forward derived, and the multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters. Based on the derived multiple model parameters, a parameterized attribute scattering center model of the medium-PEC composite target is constructed.

[0071] This application proposes a composite target scattering center modeling method based on ray tracing. Compared with the existing technology, its advantage is that it provides a method for defining the electromagnetic parameters of dielectric materials and realizes high-frequency electromagnetic modeling of dielectric-PEC composite targets with higher-order complex scattering mechanisms containing transmission;

[0072] Based on the high-frequency electromagnetic mechanism of complex targets and the principle of equivalent optical path difference, a method for calculating the equivalent points of internal coupling rays is proposed, which solves the problem of forward calculation of the three-dimensional position parameters of the medium-PEC complex target scattering center.

[0073] The entire modeling process is completely based on nested geometric models and material electromagnetic parameters. It has a small amount of calculation and the amount of parameterized model data obtained is small, providing technical support for real-time and rapid identification of radar targets.

[0074] In one embodiment, the step S1, constructing a nested geometric model of the medium-PEC composite target according to known geometric information and material properties of the medium-PEC composite target, specifically includes the following steps:

[0075] According to the known geometric information and material properties of the dielectric-PEC composite radar target, the Workbench module in the commercial software ANSYS is used for geometric modeling to construct a nested geometric model of the dielectric-PEC composite target.

[0076] In a specific embodiment, if Figure 2 As shown in the figure, the nested geometric model of the modified SLICY is formed by placing two cylinders and a triangular device inside a rectangular cavity, made of PEC, to form a nested geometric model with a length × width × height of 3m × 3m × 2m. The shell composed of the rectangular block, two dihedrals and a quarter cylinder has a thickness of about 0.02m and is made of isotropic medium.

[0077] In one embodiment, the step S2, obtaining the number of closed surface layers of the nested geometric model, defining the outer normal direction of the target surface according to the number of closed surface layers of the nested geometric model, and obtaining a multi-region surface discrete grid model by surface discretization and component decomposition, specifically includes the following steps:

[0078] Step S21, obtaining the number of closed surface layers of the nested geometric model;

[0079] Step S22: Find one or more closed surfaces S in the nested geometric model according to the number of closed surface layers of the nested geometric model. 1 ,S 2 ,...,S p , p represents the total number of closed surfaces in the nested geometric model, and the external normal directions of these closed surfaces are defined. The specific definition rules are as follows:

[0080] 1. The normal vectors of the outermost closed surface all point outward to free space;

[0081] 2. The normal vectors of the remaining closed surfaces are reversed in order according to the number of levels enclosed from the outside to the inside;

[0082] 3. The top closed surfaces visible in the same enclosing circle have equal enclosed levels and their normal directions do not affect each other;

[0083] The network model is obtained by fitting the target surface using triangular facets;

[0084] Step S23, decomposing the target surface in the network model into a plurality of electrically large-sized regions, numbering the divided plurality of electrically large-sized regions in sequence, and obtaining a multi-region network model;

[0085] by Figure 2 As an example, the multi-region network model with unified surface normals at all levels and region numbers implemented in step S22 and step S23 is shown in FIG. Figure 4 As shown;

[0086] Step S24, according to the requirements of high-frequency theory on the segmentation size, decompose the target surface of the multi-region network model into a combination of electrically large-sized solid components to obtain a multi-region surface discrete grid model;

[0087] Specifically, Figure 2 Taking the nested geometric model of as an example, steps S23 and S24 are implemented as follows: the surface of the nested geometric model GM of the medium-PEC composite target is divided into 16 electrically large size regions, and the decomposition results of the target CAD model entity parts are as follows: Figure 3 As shown, all electrically large-size areas are numbered in sequence. According to the high-frequency electromagnetic scattering theory, the target surface is decomposed into a combination of electrically large-size solid components. The entire model is discretized into 89,360 triangular face elements.

[0088] Step S25, describing the material parameters of the materials on both sides of the interface of the nested geometric model; specifically, Figure 2 Taking the nested geometric model as an example, the parameters of the material of the composite target are defined. The material statistics on both sides of each interface of the target are as follows:

[0089] The outer side of the shell interface composed of a cuboid, two dihedrals and a quarter cylinder is free space, and the inner side of the interface is an isotropic dielectric body. The electromagnetic parameter ε r =4+j0,μ r =1+j0,ε r , μ r are the relative permittivity and relative magnetic permeability of the medium respectively;

[0090] The internal parts of the nested geometry model include large and small cylinders;

[0091] There is free space outside the trihedral interface, and ideal conductors inside the interface.

[0092] Based on step S21-step S22, the external normal directions of all closed surfaces of the nested geometric model are obtained; based on step S23, the network model of the nested geometric model after being decomposed into components is obtained; based on step S24, the network model after being decomposed into components obtained in step S23 is further surface discretized to obtain the network model of the nested geometric model after surface discretization and component decomposition; based on step S25, the material parameter description information of the nested geometric model is obtained for subsequent ray path subset acquisition and forward derivation of model parameters.

[0093] In one embodiment, step S3, under the condition of given attitude angle, frequency, polarization mode and number of rays, uses a ray tracing method to trace each reflection and transmission ray path irradiated on a discrete facet of a multi-region surface discrete grid model, obtains a ray path set containing regional source information and scattering mechanism information, and classifies ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism, specifically includes the following steps:

[0094] Step S31: Under the condition of the given attitude angle, frequency, polarization mode and number of rays, the ray tracing method is used to track each reflection and transmission ray path irradiated on the discrete surface element of the multi-region surface discrete grid model until the ray escapes from the target surface or the number of ray bounces reaches a preset value, and the propagation of the GO ray field is tracked according to the mechanism information of each point on the ray path in the total set of ray paths and the material electromagnetic parameters of the corresponding space, and the GO electric field information at each point on the ray path is obtained, and the total set of ray paths with regional source and scattering mechanism information is obtained, wherein the number of incident rays is the number of all visible surface elements under the current radar viewing angle;

[0095] Step S32: Based on whether the regional sources and scattering mechanism information in the total set of ray paths are the same, the ray paths in the ray path set are identified and classified, ray paths with the same identities are grouped together, and a subset of multiple-action ray paths representing different scattering sources is obtained.

[0096] In a specific embodiment, the frequency of the radar incident plane wave is set to 10 GHz, and the plane wave is directed parallel to the nested geometric model at a pitch angle of 90° and an azimuth angle of 0°. Each illuminated small triangular face element on the nested geometric model corresponds to an incident ray, and the illuminated point is the midpoint of the face element. Then, based on the ray splitting tracing method, rays satisfying the conditions on the surface and inside of the complex medium target are obtained to form a total set of ray paths. The step S31 is specifically implemented as follows:

[0097] Set the maximum number of action rays to 9, use the Z-Buffer method in OpenGL technology to obtain the initial illuminated surface set, and obtain the first action illuminated surface set;

[0098] The nth ray in the set of ray paths for the first illuminated surface is read in sequence, and the reflection law and refraction law in geometric optics are used to determine the direction of the reflected wave and the direction of the refracted wave on the medium interface at the first illuminated surface by the nth ray, and the surface element illuminated by the reflected wave and the refracted wave is determined according to whether there is a dielectric body, and each ray is tracked and recorded in sequence to obtain the total set of secondary action ray paths;

[0099] The i-th ray r i Each ejection point Q on the propagation path on the surface and inside the model n The number of the area n , put it into the index sequence of the area where the ray acts: [I 1 ,I 2 ,...,I n ,...I N ], I n is the region number of the nth ray, and N is the maximum number of rays. The scattering mechanism J of the ray at the point of action n Put it into the scattering mechanism sequence: [J1 ,J 2 ,...,J n ,...J N ], J n The scattering mechanism of the nth ray at the point of action, including reflected or refracted rays, is represented by R or T.

[0100] Trace each ray in turn to obtain each ray path of the current number of rays, and obtain the total set of ray paths under the action of m rays: U m =[r 1 ,r 2 ,...,r n ,...,r m ],r n Represents the nth ray path.

[0101] In one embodiment, the step S32, based on whether the regional sources and scattering mechanism information in the total set of ray paths are the same, classifying the ray paths in the ray path set, grouping the ray paths with the same identity, and obtaining a subset of multiple action ray paths representing different scattering sources, specifically includes the following steps:

[0102] Step S321, marking the identity of each ray in the set of primary action ray paths, grouping ray paths with the same identity, and obtaining a subset of primary action ray paths of different scattering sources;

[0103] Step S322, reading the number of elements in the secondary action ray path set, if the number of elements in the secondary action ray path set is not 0, marking each ray path in the secondary action ray path set with an identity, grouping ray paths with the same identity, and obtaining a subset of secondary action ray paths of different scattering sources;

[0104] By analogy, step S322 is repeated to continue to mark the identity of each ray path in the subsequent multiple action ray path set, and to group ray paths with the same identity until the number of ray actions reaches the set threshold N. m Or the number of elements in the nth illuminated surface set is 0, and a subset of multiple ray paths representing different scattering sources is obtained.

[0105] In a specific embodiment, step S321 and step S322 and subsequent steps are performed to mark the identity of each ray in the total set of ray paths for each action, collect ray paths with the same identity, and obtain a subset of ray paths that act on the scattering source for a corresponding number of times, which is specifically implemented as follows:

[0106] Take the example of marking the identity of each ray in the total set of ray paths of a single action, grouping ray paths with the same identity, and obtaining a subset of ray paths of a single action with different scattering sources:

[0107] The total set of ray paths for a single action U 1 The first ray R in 1 Identity information P 1 = {I 1 , J 1}marked as 0;

[0108] Read the second ray, if the two sequences representing the identity I 2 with I 1 Same, Q 2 or Q 2 The reverse sequence of Q 1 If they are the same, their identity information P 2 Mark as 0, otherwise mark as 1;

[0109] Read the third ray, and compare its two sequences representing the identity with the first two rays according to the same rules as above, and convert the identity information P 3 Mark the rays with the same number as those that meet the conditions. If they are all different, add 1 in the order of the total number of existing identities, and repeat this process until the identity information of each ray in the total set of ray paths is marked;

[0110] According to the identity information marked on the ray path, the rays with the same identity mark are grouped into the same subset, and the primary action ray path subsets of different scattering sources are classified;

[0111] If the number of elements in the secondary action ray path set is not 0, read each ray in the secondary action ray path set in turn;

[0112] According to the above method, a subset of secondary action ray paths representing different scattering sources is determined;

[0113] By analogy, the classification of different scattering sources in the total set of multiple action ray paths is completed.

[0114] In one embodiment, the step S4, screening a set of ray paths whose scattering intensity is greater than an intensity threshold from the acquired ray path subset to obtain a ray path set of a main contribution area, mainly comprises the following steps:

[0115] Step S41, using the GO-PO algorithm to calculate the total scattered field of each ray path subset;

[0116] Step S42, sorting the total scattering fields of all the acquired scattering subsets from large to small according to the scattering field intensity values, and acquiring a set of strong scattering paths whose ray path subset scattering field values ​​are greater than an intensity threshold;

[0117] Step S43, calculating the angle between the emitting direction and the receiving direction of each ray in the strong scattering path set, and taking the ray path set with an angle less than a preset angle value as the main contributing ray path set; specifically, the preset angle value is ±3 degrees.

[0118] In one embodiment, the step S41, using the GO-PO algorithm to calculate the total scattered field of each ray path subset, specifically includes the following steps:

[0119] According to the scattering mechanism of the last bounce point on each ray path, the GO-PO algorithm is used to calculate the reflection field or transmission field of each ray path; specifically, according to the theory of geometric optics, the amplitude and phase of the scattered field of multiple coupling effects are tracked one by one; the angle between the incident ray at the last bounce point on each path and the normal of the surface element is obtained;

[0120] If the angle is greater than 90°, the physical optics algorithm is used to calculate the reflection field formed by the path on the surface;

[0121] If the angle is less than 90°, the transmission field formed by the path on the surface is calculated using the physical optics algorithm;

[0122] According to the Huygens principle, the scattered field of each ray path in the ray path subset is added according to the acquired reflection field or transmission field to obtain the total scattered field of each ray path subset.

[0123] In one embodiment, step S5, for the ray path set of the main contribution area, based on the correspondence between the three-dimensional attribute scattering center model and the geometric structure, multiple model parameters are forward derived, and the multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters, and three-dimensional position parameters, to obtain the three-dimensional attribute scattering center model in the parameterized attribute scattering center model of the medium-PEC composite target:

[0124]

[0125] The parameters that need to be solved in this three-dimensional attribute scattering center model include the amplitude parameter A i , frequency dependence factor α i , length parameter L i , three-dimensional position parameter. f represents the center frequency of the radar bandwidth, f c represents the sampling frequency, is the central azimuth, Characterizes the imaging azimuth of the distributed scattering center. Contains the length parameter L i The sinc function reflects the spread width of the distributed scattering center and characterizes the dependence of the scattering center on the azimuth angle. i = 0. The dependence of the point scattering center on the azimuth angle is expressed by the decaying exponential function, L i=0,γ i Take something like 10 -10 A very small value, i is the amplitude parameter of the i-th scattering center, α i Describe the frequency dependence, (x i ,y i ,z i ) is the three-dimensional position of the scattering center.

[0126] In one embodiment, the step S5, forward deriving the frequency-dependent parameters among the multiple model parameters, specifically comprises the following steps:

[0127] According to the corresponding relationship between the frequency dependence factor and the type of geometric structure surface, the frequency dependence factor expressed by multiplication is obtained by tracing the ray field propagation process and determining the type of geometric structure surface.

[0128] In one embodiment, the step S5, forwardly deriving the position parameter from the plurality of model parameters, specifically comprises the following steps:

[0129] Firstly, the action point and equivalent action point of each ray path in the main contribution area are determined;

[0130] For a single scattered ray, the ray bounce point is the action point of the ray, and the three-dimensional coordinates of the ray bounce point are used as the position parameters of the scattering center;

[0131] For multiple action ray paths, the equivalent action point position of each ray is determined in combination with the principle of equivalent optical path difference, and finally the weighted average of all equivalent action points in the set is the position parameter of the scattering center.

[0132] In one embodiment, the step S5, forwardly deriving the length parameter from the plurality of model parameters, specifically comprises the following steps:

[0133] All equivalent point positions corresponding to the position parameters of the scattering center are projected in the azimuth direction, and the length parameters of the distributed scattering center are determined by the projection information data.

[0134] In one embodiment, step S5 is specifically implemented as follows:

[0135] According to the different number of ray coupling, scattering centers can be divided into single-action scattering centers and coupled-action scattering centers. Coupled-action scattering centers can be further divided into surface multiple-action scattering centers and internal multiple-action scattering centers.

[0136] A. Amplitude parameter A i The ray path set S of the main contribution area obtained in step S4 is used for calculation k The scattered field intensity is expressed as .

[0137] B. Figure 5 As shown, the frequency dependence factor α i , which describes the effect of frequency on scattering, is calculated as follows:

[0138] The frequency dependence factor α parameters of some typical structures have been obtained through theoretical derivation.

[0139] For the primary scattering center, the frequency dependence factor of the main contributing area is used as the frequency dependence factor of the entire component;

[0140] For the external coupling scattering center, the frequency dependence parameter of the coupling scattering center is obtained by multiplying the frequency dependence factors of the main contribution area of ​​each component;

[0141] For the internal coupling scattering center, the frequency dependence factor of the area where the scattering mechanism in the ray path is reflection is taken as the frequency dependence parameter of the scattering center.

[0142] It should be noted that the scattering center frequency-dependent parameters of the coupling type of single curved surface-single curved surface do not satisfy the above product relationship.

[0143] Weighted average of the ray's action point or equivalent action point:

[0144]

[0145] In the formula, represent Ray Weight J s (Q n ) represents the surface current on the last action surface element, Indicates the optical emission direction of the last surface element on the corresponding ray path.

[0146] C. Figure 6 As shown, the position parameters of the scattering center are:

[0147] (1) Read each ray path in the ray path subset

[0148] (2) Determine the ray r n Is it a primary action ray or a coupled action ray?

[0149] (31) For the scattering center of a primary action ray, the center of each triangular facet in the ray path subset is directly used as the reflection action point.

[0150] (32) For the scattering center of the coupled action ray inside the medium and the scattering center of the coupled action ray on the surface, the action point is selected as the equivalent action point of the coupled scattering center, and the equivalent reflection point of each ray is calculated using the principle of equivalent optical path difference. Specifically, first consider the ray from the medium surface Q a Refracted into the interior, through the Q on the other surface of the medium b Reflection, finally point Q from the surface c The equivalent position of the three-way coupled action ray refracted from the surface of the medium is calculated. In the case of a single station, the equivalent position can be obtained by the principle of equivalent optical path difference.

[0151]

[0152] In the formula, b,c represent the a To Q b , Q b To Q c The light path between.

[0153] The equivalent position of the internal coupling action ray with a higher order action ray can be obtained by modifying the optical path length and the optical path length inside the medium in the above formula.

[0154] (4) Equivalent reflection points for all rays in the ray path subset The weighted average calculation of the equivalent three-dimensional geometric position parameters of the scattering center S

[0155] (5) According to the equivalent three-dimensional geometric position parameters Get the position parameters of the scattering center

[0156] D.L i is the spreading length parameter of the scattering source on the imaging plane, and its calculation method is as follows:

[0157] Project the action points or equivalent action points of all ray paths in the corresponding ray path subset obtained in the process of position parameter estimation onto the imaging plane, and find the two equivalent endpoints (x m ,y m ),(x n ,y n ).

[0158] Use the formula Find the distance Δv between the two equivalent endpoints;

[0159] Determine whether the distance difference Δv is greater than one resolution unit. If the distance difference is greater than one resolution unit, the scattering center is a distributed scattering center, and the length parameter L = Δv;

[0160] Otherwise, the scattering center is a local scattering center, and the length parameter L=0.

[0161] The parameterized attribute scattering center model finally obtained in this application is shown in the following table. The verification results are as follows Figure 7 and Figure 8 As shown, Figure 7 This is a simulated SAR (Synthetic Aperture Radar) image obtained by the FEKO high-frequency algorithm. Figure 8 The SAR image is reconstructed based on the parameterized attribute scattering center model, and the similarity between the two images is 91.3%.

[0162] Table 1 Parameterized attribute scattering center model obtained in this application

[0163]

[0164] In a second aspect, the present application provides a composite target scattering center modeling system based on ray tracing, comprising:

[0165] A geometric model building module, used to build a nested geometric model of a medium-PEC composite target based on known geometric information and material properties of the medium-PEC composite target;

[0166] A multi-region surface discrete grid model acquisition module is connected to the geometric model construction module for acquiring the number of closed surface layers of the nested geometric model, defining the outer normal direction of the target surface according to the number of closed surface layers of the nested geometric model, and obtaining the multi-region surface discrete grid model through surface discretization and component decomposition;

[0167] A ray path subset acquisition module is communicatively connected with the multi-region surface discrete grid model acquisition module, and is used to use a ray tracing method to track each reflection and transmission ray path irradiated on a discrete facet of the multi-region surface discrete grid model under a given attitude angle, frequency, polarization mode and number of rays, to obtain a ray path set containing regional source information and scattering mechanism information, and to classify ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism;

[0168] A main contribution ray set screening module is in communication with the ray path subset acquisition module and is used to screen a set of ray paths with scattering intensities greater than an intensity threshold from the acquired ray path subset to acquire a ray path set of a main contribution area;

[0169] The composite target scattering center model construction module is communicatively connected to the main contribution ray set screening module, and is used to forward derive multiple model parameters for the ray path set of the main contribution area according to the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure. The multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters, and construct a parameterized attribute scattering center model of the medium-PEC composite target based on the derived multiple model parameters.

[0170] In one embodiment, the ray path subset acquisition module includes:

[0171] A ray path collection acquisition unit is used to track the reflection and transmission ray paths of each discrete facet of the multi-region surface discrete grid model by using a ray tracing method under the given attitude angle, frequency, polarization mode and number of rays, and to track the propagation of the GO ray field according to the mechanism information of each point on the ray path in the ray path collection and the material electromagnetic parameters of the corresponding space, so as to obtain the GO electric field information at each point on the ray path and obtain the ray path collection with regional source and scattering mechanism information;

[0172] The ray path subset acquisition unit is communicatively connected with the ray path total set acquisition unit, and is used to identify and classify the ray paths in the ray path set according to whether the regional sources and scattering mechanism information in the ray path total set are the same, group the ray paths with the same identities, and obtain multiple action ray path subsets representing different scattering sources.

[0173] Among them, the functional implementation of each module in the above-mentioned composite target scattering center modeling system based on ray tracing corresponds to the steps in the above-mentioned composite target scattering center modeling method embodiment based on ray tracing, and its functions and implementation processes will not be repeated here one by one.

[0174] In a third aspect, an embodiment of the present application provides a composite target scattering center modeling device based on ray tracing. The composite target scattering center modeling device based on ray tracing can be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0175] In an embodiment of the present application, a composite target scattering center modeling device based on ray tracing may include a processor, a memory, a communication interface, and a communication bus.

[0176] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0177] The communication interface includes an input / output (I / O) interface, a physical interface, and a logical interface, etc., which are used to realize the interconnection of devices inside the composite target scattering center modeling device based on ray tracing, and an interface used to realize the interconnection of the composite target scattering center modeling device based on ray tracing with other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, an optical fiber interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.

[0178] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0179] The processor may be a general-purpose processor, and the general-purpose processor may call the composite target scattering center modeling program based on ray tracing stored in the memory, and execute the composite target scattering center modeling method based on ray tracing provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the composite target scattering center modeling program based on ray tracing is called may refer to the various embodiments of the composite target scattering center modeling method based on ray tracing of the present application, and will not be repeated here.

[0180] In a fourth aspect, an embodiment of the present application also provides a readable storage medium.

[0181] The readable storage medium of the present application stores a composite target scattering center modeling program based on ray tracing, wherein when the composite target scattering center modeling program based on ray tracing is executed by a processor, the steps of the composite target scattering center modeling method based on ray tracing as described above are implemented.

[0182] Among them, the method implemented when the composite target scattering center modeling program based on ray tracing is executed can refer to the various embodiments of the composite target scattering center modeling method based on ray tracing of the present application, and will not be repeated here.

[0183] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0184] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0185] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A composite target scattering center modeling method based on ray tracing, characterized in that: The following steps are involved: According to the known geometric information and material properties of the medium-PEC composite target, a nested geometric model of the medium-PEC composite target is constructed; The number of closed surface layers of the nested geometric model is obtained, the outer normal direction of the target surface is defined according to the number of closed surface layers of the nested geometric model, and a multi-region surface discrete grid model is obtained through surface discretization and component decomposition; Under the given attitude angle, frequency, polarization mode and number of rays, the ray tracing method is used to trace the paths of each reflected and transmitted ray irradiated on the discrete facet of the multi-region surface discrete grid model, and a set of ray paths containing regional source information and scattering mechanism information is obtained. According to the regional source and scattering mechanism, ray path subsets representing different scattering centers are classified from the ray path set. A set of ray paths whose scattering intensity is greater than an intensity threshold is screened from the obtained ray path subset to obtain a set of ray paths in a main contribution area; For the ray path set of the main contribution area, multiple model parameters are forward derived according to the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure. The multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters. Based on the derived multiple model parameters, a parameterized attribute scattering center model of the medium-PEC composite target is constructed.

2. The composite target scattering center modeling method based on ray tracing according to claim 1, characterized in that: The method uses a ray tracing method to trace each reflection and transmission ray path irradiated on a discrete facet of a multi-region surface discrete grid model under a given attitude angle, frequency, polarization mode and number of rays, obtains a ray path set containing regional source information and scattering mechanism information, and classifies ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism, specifically including the following steps: Under the given attitude angle, frequency, polarization mode and number of rays, the ray tracing method is used to track the path of each reflection and transmission ray irradiated on the discrete facet of the multi-region surface discrete grid model. According to the mechanism information of each point on the ray path in the total set of ray paths and the material electromagnetic parameters of the corresponding space, the propagation of the GO ray field is tracked, the GO electric field information at each point on the ray path is obtained, and the total set of ray paths with regional source and scattering mechanism information is obtained; According to whether the regional sources and scattering mechanism information in the total set of ray paths are the same, the ray paths in the ray path set are identified and classified, and the ray paths with the same identities are grouped together to obtain a subset of multiple-action ray paths representing different scattering sources.

3. The composite target scattering center modeling method based on ray tracing according to claim 2, characterized in that: According to whether the regional sources and scattering mechanism information in the total set of ray paths are the same, the ray paths in the ray path set are identified and classified, ray paths with the same identity are grouped together, and a subset of ray paths with multiple effects is obtained, which specifically includes the following steps: Mark each ray path in the set of ray paths of a single action, group ray paths with the same identity, and obtain a ray path subset of the ray of a single action; Read the number of elements in the secondary action ray path set. If the number of elements in the secondary action ray path set is not 0, mark each ray path in the secondary action ray path set with an identity, group ray paths with the same identity, and obtain a subset of secondary action ray paths representing different scattering sources. By analogy, continue to perform identity tagging for each ray path in the total set of subsequent ray action times, and collect ray paths with the same identity until the number of ray actions reaches the set threshold N. m Or the number of elements in the nth illuminated surface set is 0, and a subset of multiple ray paths of different scattering sources is obtained.

4. The composite target scattering center modeling method based on ray tracing according to claim 1, characterized in that: The method of screening a set of ray paths whose scattering intensity is greater than an intensity threshold from the acquired ray path subsets, and acquiring a set of ray paths that make the main contribution in each ray path subset, specifically includes the following steps: The total scattered field is calculated for each subset of ray paths using the GO-PO algorithm; The total scattering fields of all the obtained scattering subsets are sorted from large to small according to the scattering field intensity values, and a set of strong scattering paths whose ray path subset scattering field values ​​are greater than an intensity threshold is obtained; The angle between the outgoing direction and the receiving direction of each ray in the strong scattering path set is calculated, and the ray path set with a value less than the preset angle is taken as the ray path set with the main contribution.

5. The composite target scattering center modeling method based on ray tracing according to claim 4, characterized in that: The method of calculating the total scattered field of each ray path subset using the GO-PO algorithm specifically includes the following steps: For a single-action scattering path, the PO algorithm is used to calculate the far-field scattering intensity excited by each incident ray to obtain the scattering field of the single-action scattering path; For multiple-action ray paths, the GO-PO algorithm is used to calculate the PO contribution of each reflection point of the GO ray to the observation point to obtain the scattered field of the multiple-action ray path, where the PO calculation is only applied to the last reflection or transmission of the surface; Then, the scattered fields of all ray paths in each ray path subset are added together to obtain the total scattered field of each ray path subset.

6. The composite target scattering center modeling method based on ray tracing according to claim 1, characterized in that: The forward derivation of the frequency-dependent parameters among the multiple model parameters specifically comprises the following steps: According to the corresponding relationship between the frequency dependence factor and the type of geometric structure surface, the frequency dependence factor expressed by multiplication is obtained by tracing the ray field propagation process and determining the type of geometric structure surface.

7. The composite target scattering center modeling method based on ray tracing according to claim 1, characterized in that: The forward derivation of the position parameter from the plurality of model parameters specifically comprises the following steps: Firstly, the action point and equivalent action point of each ray path in the ray path set of the main contribution area are determined; For single scattering, the ray bounce point is the ray's action point; For multiple action ray paths, combined with the principle of equivalent optical path difference, the equivalent action point position of each ray path is determined. Finally, the weighted average of all multiple action ray action points or equivalent action points in the ray path of the main contribution area is the position parameter of the scattering center.

8. The composite target scattering center modeling method based on ray tracing according to claim 7, characterized in that: The forward derivation of the length parameter among the multiple model parameters specifically comprises the following steps: The action points or equivalent action points of all ray paths that meet the in-phase condition in the ray path subset are projected in the azimuth direction, and the length parameters of the distributed scattering center are determined by the projection information data.

9. A composite target scattering center modeling system based on ray tracing, characterized in that: include: A geometric model building module, used to build a nested geometric model of a medium-PEC composite target based on known geometric information and material properties of the medium-PEC composite target; A multi-region surface discrete grid model acquisition module is connected to the geometric model construction module for acquiring the number of closed surface layers of the nested geometric model, defining the outer normal direction of the target surface according to the number of closed surface layers of the nested geometric model, and obtaining the multi-region surface discrete grid model through surface discretization and component decomposition; A ray path subset acquisition module is communicatively connected with the multi-region surface discrete grid model acquisition module, and is used to use a ray tracing method to track each reflection and transmission ray path irradiated on a discrete facet of the multi-region surface discrete grid model under a given attitude angle, frequency, polarization mode and number of rays, to obtain a ray path set containing regional source information and scattering mechanism information, and to classify ray path subsets representing different scattering centers from the ray path set according to the regional source and scattering mechanism; A main contribution ray set screening module is in communication with the ray path subset acquisition module and is used to screen a set of ray paths with scattering intensities greater than an intensity threshold from the acquired ray path subset to acquire a ray path set of a main contribution area; The composite target scattering center model construction module is communicatively connected to the main contribution ray set screening module, and is used to forward derive multiple model parameters for the ray path set of the main contribution area according to the correspondence between the three-dimensional attribute scattering center model parameters and the geometric structure. The multiple model parameters include amplitude parameters, frequency-dependent parameters, length parameters and three-dimensional position parameters, and construct a parameterized attribute scattering center model of the medium-PEC composite target based on the derived multiple model parameters.

10. The composite target scattering center modeling system based on ray tracing according to claim 9, characterized in that: The ray path subset acquisition module includes: A ray path collection acquisition unit is used to track the reflection and transmission ray paths of each discrete facet of the multi-region surface discrete grid model by using a ray tracing method under the given attitude angle, frequency, polarization mode and number of rays, and to track the propagation of the GO ray field according to the mechanism information of each point on the ray path in the ray path collection and the material electromagnetic parameters of the corresponding space, so as to obtain the GO electric field information at each point on the ray path and obtain the ray path collection with regional source and scattering mechanism information; The ray path subset acquisition unit is communicatively connected with the ray path total set acquisition unit, and is used to identify and classify the ray paths in the ray path set according to whether the regional sources and scattering mechanism information in the ray path total set are the same, group the ray paths with the same identities, and obtain multiple action ray path subsets representing different scattering sources.

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