291 results about "Em scattering" patented technology

The invention relates to the technical field of defect detection, and discloses a pipeline repairing method and system based on defect detection. The method comprises the following steps: performing acoustic detection on a pipeline based on a multi-frequency sound wave signal to obtain pipeline sound field data; carrying out electromagnetic wave scattering detection on the pipeline to obtain electromagnetic scattering data; constructing a sound field distribution diagram in the pipeline and an electromagnetic property distribution diagram on the surface of the pipeline; performing feature extraction on the sound field distribution diagram to obtain a first detection feature set, and performing feature extraction on the electromagnetic characteristic distribution diagram to obtain a second detection feature set; inputting the first detection feature set and the second detection feature set into a space-time diagram convolutional network model for pipeline defect diagnosis to obtain a defect position and a defect type; and performing causal reasoning and repair scheme matching on the pipeline according to the defect position and the defect type to obtain a target pipeline repair scheme, thereby improving the accuracy of pipeline defect detection, thereby improving the accuracy of pipeline repair.

The invention provides a multi-means fusion unmanned aerial vehicle countering method and system, and the method comprises the steps: obtaining three-dimensional topographic data, atmospheric turbulence features and electromagnetic spectrum features in real time through deploying a distributed sensing array in a target region, constructing a multi-layer virtual signal barrier boundary, and generating a frequency band interference parameter set; when it is detected that the unmanned aerial vehicle passes through the barrier boundary, the cooperative interference module is triggered to generate an initial interference signal weight, polarization direction distribution and power density distribution are dynamically corrected in combination with electromagnetic scattering characteristics fed back by the unmanned aerial vehicle in real time, and the initial interference signal weight serves as flight path modeling input and is used for generating a three-dimensional dynamic flight path model; according to the method, the azimuth angle correction, the elevation angle compensation coefficient and the energy gradient parameter of the ground interception equipment are calculated, and then the dynamic interception strategy is generated through the dynamic strategy fuser, so that the interference and interception efficiency of the unmanned aerial vehicle is improved through fusion and dynamic closed-loop control of excessive means, and the full-link closed loop from environmental perception to interception control is realized.

The invention provides a control method for optimizing operation of high-power short-pulse microwave equipment, and aims to improve the accuracy of microwave interference signals, the energy utilization efficiency and the system adaptability. The method comprises the following steps: firstly, acquiring position information, motion trail data, electromagnetic scattering characteristics and environmental electromagnetic parameters of a target object; and then, according to the target position prediction data, the electromagnetic scattering characteristics and the environmental electromagnetic parameters, generating a microwave pulse waveform control instruction. And controlling the phased-array antenna array to generate a directional microwave beam based on the control instruction and the target position prediction data. And collecting real-time response data of the target, dynamically updating the target motion trend prediction model according to the real-time response data, and recalculating microwave pulse signal parameters. And finally, according to the updated signal parameters and the target position prediction data, adjusting the transmitting power, the working time sequence and the beam direction of the phased-array antenna array so as to maintain the optimal interference effect, reduce unnecessary energy consumption and improve the stability and adaptability of the system.

The invention belongs to the technical field of electromagnetic modeling of a target in a layered medium, particularly provides a planar multilayer medium electromagnetic scattering modeling method based on a layered medium Green function, and is used for solving the problems that the number of unknown quantities of a system is large and the calculation efficiency is low when electromagnetic scattering characteristics of the target are analyzed in the layered medium. The method comprises the following steps: firstly, carrying out mesh generation on a medium target in a planar multilayer medium; then, a layered medium Green function is calculated based on a space list and an interpolation method, a surface integral equation of the target is solved by adopting a moment method, and a matrix equation of target current and magnetic current is constructed; and finally, solving a matrix equation by applying an improved laminated off-diagonal low-rank matrix, and calculating a target scattering field. According to the method, a direct solving calculation method is adopted, and the problem that an ill-conditioned matrix is difficult to converge in a conventional iteration method is effectively solved; especially for a multi-port excitation problem, repeated calculation is not needed, the solving efficiency of a large-scale problem is improved, and calculation resource consumption is reduced.

The invention relates to a method for rapidly calculating the RCS of a coated unmanned aerial vehicle under a complex background, and belongs to the field of stealth target electromagnetic scattering calculation. Comprising the following steps: determining reflection coefficients of a single-layer wave-absorbing material with a PEC substrate at different incident angles according to an equivalent transmission line theory; calculating induced current generated by incident electromagnetic waves on the surface of the target coated with the single-layer wave-absorbing material according to the reflection coefficient; based on the induced current, utilizing physical optics and physical diffraction theories to calculate scattered fields of all the illuminated surface elements, and superposing all the calculated scattered fields; the scattering field of each surface element on the sea surface model at a fixed angle is obtained through vector superposition of the scattering fields obtained through an EPO'field and a TSM; and finally, superposing all the scattered fields, and calculating the total field RCS of the complex sea background and unmanned aerial vehicle composite model based on the superposed total scattered field. According to the method, the RCS of the coating unmanned aerial vehicle under the complex background can be quickly calculated.

The invention discloses a multi-scale sea surface electromagnetic scattering calculation method and device based on marine environment elements and a storage medium, and belongs to the technical field of marine detection and physical remote sensing. The method comprises the following steps: calculating a tension wave sea spectrum according to an Elfouhail sea spectrum in combination with a Longuet-Higgins directional spectrum; a JONSWAP sea spectrum is combined with a Longuet-Higgins directional spectrum to calculate a gravity wave sea spectrum; superposing the tension wave on the gravity wave according to the slope by using a linear superposition method, and calculating a self-adaptive cut-off wave number; the contribution of small-scale waves to scattering is calculated by adopting an integral equation method, mirror scattering of large-scale waves is counted by adopting a Kirchhoff approximation method, and statistics and fusion are carried out on each scale wave according to the self-adaptive cut-off wave number, so that an electromagnetic scattering value is obtained. According to the method, a sea surface geometric calculation method based on real marine environment element driving is adopted, and accurate calculation is performed aiming at sea surface scattering characteristics under different sea conditions in combination with an integral equation method-Kirchhoff approximation electromagnetic scattering calculation model of an adaptive cut-off wave number, so that the calculation precision of scattering intensity is improved.

The invention provides a sparse approximate inverse Shenwei parallel preprocessing method and system for electromagnetic scattering, and relates to the technical field of processor parallel computing, and the method comprises the steps: carrying out the performance hotspot analysis of a sparse approximate inverse preprocessor in an electromagnetic scattering simulation process, and determining a hotspot function of the sparse approximate inverse preprocessor; extracting a sparse matrix vector multiplication operation of a hotspot function, performing master-slave core parallel calculation on the sparse matrix vector multiplication operation, migrating the sparse matrix vector multiplication operation to slave core calculation, and accelerating hotspot calculation by using a heterogeneous parallel sparse approximate inverse algorithm; parallel computing of master-slave core intensive numerical computing tasks is achieved; in the parallel computing process, the slave cores communicate with the master core in a direct memory access mode, and during the period, the master core is in a waiting state to ensure data consistency and communication synchronization until all the slave cores compute distributed tasks.

The invention relates to a physical constraint fused graph structure UNet neural network for long-time time domain difference optical simulation method and system, and the method comprises the steps: 1, randomly constructing a device parameter data set through an FDTD method, obtaining FDTD uniform grid data, and carrying out the data preprocessing; 2, constructing a graph structure Unet model; 3, inputting the device parameter data set into the graph structure Unet model for end-to-end training; 4, predicting electromagnetic field scattering after a long-time light source encountering period is carried out on given device parameters and initial electromagnetic field distribution; and 5, comparing the electromagnetic field distribution of different device shapes, which is predicted for a long time, with the electromagnetic field value calculated by FDTD, and further judging the prediction accuracy of the graph structure Unet network model. According to the method, one-time long-time sequence prediction of electromagnetic scattering is completed by using the graph structure Unet model.

The invention discloses an SAR image generation method based on guidance of a physical scattering model. The SAR image generation method comprises physically guided feature modulation, attribute scattering center feature constraint and generative network training. According to the physically-guided feature modulation, pitch angle parameterized coding and multi-scale convolution are fused by designing a multi-scale attention module PMA, key scattering features are dynamically enhanced, edge attenuation caused by pitch angle changes is compensated, and geometric continuity of linear scattering is kept. According to the attribute scattering center feature constraint, an ASC loss function is provided based on an attribute scattering center model, multi-scale Gaussian filtering is carried out on frequency domain amplitude spectrums and phase spectrums of generated and real images, and the consistency of the position, the strength and the type of a scattering center is constrained through an L1 distance, so that the generated image is ensured to conform to an electromagnetic scattering physical law. And a CycleGAN generative adversarial network embedded with a PMA module is constructed by generative network training, and cross-angle high-quality SAR image generation is realized by combining end-to-end optimization of adversarial loss, cyclic consistency loss and ASC loss. The method provides a high-precision and physically interpretable solution for SAR image generation and target identification.

The invention relates to an insect type identification method based on a multi-dimensional radar electromagnetic scattering feature sequence, and aims to accurately identify insect types through electromagnetic scattering features of radar echo signals in combination with a deep learning technology. According to the invention, a multi-dimensional feature sequence is constructed based on a fully-polarized radar scattering matrix, and feature learning is carried out by using an insect identification neural network. And the insect identification neural network extracts spatial features of different scales through multi-scale convolution, updates a time dependency relationship in an effective capture feature sequence through a state input based on a time sequence, and finally identifies insect types based on the multi-scale spatial features and the time dependency thereof. According to the technical scheme, the accuracy and robustness of insect type identification are effectively improved, the average accurate identification rate of nine kinds of migratory flying pests in China can reach 98.1%, and the method has wide application prospects and is particularly suitable for the fields of insect migratory flying monitoring, agricultural pest control and ecological research.

The invention provides an echo intensifier based on a cylindrical conformal metasurface structure and a design method of the echo intensifier. The echo intensifier comprises a metal cylinder and a plurality of metasurface units, wherein the metasurface units are periodically arranged on the side face of the metal cylinder, and the metasurface units are used for regulating and controlling the electromagnetic scattering characteristic of the metal cylinder. According to the scheme, when the structure design of the echo intensifier is carried out, cylindrical conformal array design is carried out on the metasurface unit on the side face of the metal cylinder by combining a geometric partitioning method and a phase gradient theory, and meanwhile, the size parameters of the metal patches in the metasurface unit are optimized by utilizing an optimization algorithm; and the optimized metal patches with different sizes form an array and are arranged on the side surface of the metal cylinder so as to meet electromagnetic regulation and control. Therefore, backward echo enhancement can be effectively realized on the cylindrical curved surface carrier, and a solution is provided for echo enhancement of a curved surface structure in a certain angular domain.

Aiming at the detection and identification problems of an underwater target, the invention discloses an electromagnetic scattering field calculation method for an underwater cylindrical metal small target, which comprises the following steps of: 1, carrying out geometric and physical modeling on the underwater cylindrical metal small target to be detected, carrying out numerical discretization preprocessing, calculating information of network nodes of geometric and physical models, and calculating the electromagnetic scattering field of the underwater cylindrical metal small target to be detected; constructing a grid model of the underwater cylindrical metal small target; 2, an electromagnetic scattering field of the grid model is calculated through an improved moment method, and electromagnetic scattering field curves of the underwater cylindrical metal small target in different scenes are obtained; 3, an electromagnetic scattering field of the grid model is calculated through an equivalent surface current method, and electromagnetic scattering field curves of the underwater cylindrical metal small target in different scenes are obtained; and 4, comparing the electromagnetic scattering field curves in the two steps, verifying that the shapes and the amplitudes of the two curves are basically consistent in an allowable error range, and detecting and identifying the underwater metal small target according to the action distance and the intersection situation of the target.

The invention belongs to an electromagnetic simulation technology, and particularly provides an electromagnetic scattering simulation method based on a skeleton decomposition precondition, which is used for completing electromagnetic scattering simulation calculation of an electrically large complex target, improving the ill-conditioned problem of a complex target generation impedance matrix while ensuring the simulation calculation precision, and improving the convergence and reliability of an iteration method. According to the method, firstly, a bone element primary function is selected by using an interpolation decomposition technology and a proxy surface method, and an approximate inverse matrix of an impedance matrix is obtained by using a skeleton decomposition method; then, the approximate inverse matrix is adopted as a pre-processor, a current coefficient is obtained through a Krylov subspace iteration method, and finally electromagnetic scattering of the metal target is obtained through calculation according to the current coefficient. The invention creatively provides a brand-new pre-processor, and compared with the traditional pre-processor, the pre-processor can further improve the matrix behavior, greatly reduce the iteration time and improve the convergence.

The invention relates to an incident wave loading method for simulating ground electromagnetic scattering based on FDTD. The incident wave loading method comprises the steps of solving an attenuation factor at a certain depth of a PML, arranging the side face and the bottom face of a connection boundary CB on the PML, establishing a ground electromagnetic scattering model, connecting the boundary to load an incident wave, and solving an electric field value and a magnetic field value of the loaded incident wave. According to the method, the four side faces and the bottom face of the connecting boundary CB are completely arranged on the PML, incident waves penetrate through the CB to enter the PML in a non-reflection mode, the edge effect generated by truncation of the periphery of the ground is effectively reduced, and the precision of ground electromagnetic scattering calculation is improved. The truncated ground is limited in a CB boundary area, and calculation of a reflection field and a transmission field is avoided. The method does not depend on ground parameters, and electromagnetic scattering calculation of rough ground and layered ground can be achieved.

The invention discloses an arbitrary structure fast electromagnetic scattering analysis method based on time domain finite difference, and the method comprises the steps: obtaining the triangular patch data of a scatterer model, generating an extended bounding box, and improving the adaptability of a complex structure; an initial grid point set is generated by adopting an interpolation method based on a preset grid side length, and grid data is screened and optimized, so that grid division is more accurate, and calculation redundancy is effectively reduced; the optimized grid data is mapped into a three-dimensional array, and a material type and electromagnetic parameter distribution are defined, so that efficient modeling of a complex target is realized; the electromagnetic scattering characteristics are calculated based on time domain finite difference iterative calculation in combination with the surface equivalence principle and the Poynting theorem, the calculation precision and stability are improved, meanwhile, the calculation process is optimized to reduce the storage requirement and the calculation time, and therefore efficient and accurate electromagnetic scattering analysis of any structure is achieved, the calculation efficiency is improved, and the engineering application requirement is met.

The invention relates to the technical field of electromagnetic scattering, in particular to a frequency domain response calculation method and device of an electromagnetic field, equipment and a storage medium. Performing recursive transformation on the time domain basic system equation according to the discrete time domain set and a backward Euler method to obtain a time domain transformation equation and an algebraic matrix equation; carrying out back substitution solving operation on the algebraic matrix equation according to a time domain stepping method and a time domain transformation equation; performing full-time-domain response calculation on the time-domain finite element solution based on a time-domain finite element method to obtain a time-domain base solution; calculating the time domain base solution according to a preset linear superposition principle to obtain a frequency domain response; a continuous problem is dispersed through a backward Euler method, rapid back substitution solution is carried out after factorization for one time, and redundant calculation is reduced; based on a linear superposition principle, phase weighting is carried out to synthesize a time domain base solution, frequency domain response of any frequency is rapidly obtained, frequency-by-frequency repeated calculation is avoided, efficiency is improved, and the method is suitable for broadband high-precision electromagnetic field analysis and has remarkable application value.

The invention discloses a microwave photon radar strong maneuvering target identification method based on small sample incremental learning, and belongs to the field of microwave photon radar maneuvering target identification. Time-frequency dynamic, polarization space and geometric topological features are extracted through a deep learning model, and multi-dimensional joint characterization is realized in combination with a cross-domain attention mechanism; designing a polarization-time frequency adversarial generative network, generating synthetic data conforming to an electromagnetic scattering rule under the physical constraint of a Maxwell equation, and constructing a prototype feature support set through meta learning; a dynamic knowledge distillation framework is introduced, physical consistency loss is utilized to align motion parameters and classification probability distribution of the teacher model and the student model, and lightweight increment updating is realized in combination with gradient importance masks. According to the method, the recognition precision and real-time performance of the strong maneuvering target in a complex electromagnetic environment are remarkably improved, and the method is suitable for high and overspeed maneuvering target recognition.

The invention discloses a three-dimensional target electromagnetic scattering calculation method and system based on point cloud and machine learning, and relates to the technical field of electromagnetic scattering calculation. The method comprises the following specific steps: photographing a three-dimensional target to obtain two-dimensional image data; performing three-dimensional reconstruction on the two-dimensional image data by combining a point cloud technology with a deep learning technology to obtain a three-dimensional point cloud model; converting the three-dimensional point cloud model into a grid model based on a greedy triangulation algorithm; establishing an integral equation of a three-dimensional target according to the grid model in combination with an electromagnetic principle; solving the integral equation to obtain the surface induction current of the three-dimensional target; and calculating a scattering field based on the surface induction current of the three-dimensional target, and completing electromagnetic scattering characteristic calculation of the unknown three-dimensional target. According to the method, the point cloud technology and deep learning are combined for model generation, a two-dimensional image dimension raising method is used for replacing traditional CAD modeling and laser radar scanning, and the three-dimensional target electromagnetic scattering modeling efficiency is improved.

The invention provides a low-scattering carrier for darkroom background level evaluation test, and relates to the technical field of target far-field electromagnetic scattering characteristic test, the low-scattering carrier is a hollow structure formed by seamless connection of an upper surface and a lower surface; the upper surface comprises a plurality of smooth curved surfaces with continuous curvatures, and the lower surface is a smooth plane; the forward direction of the low-scattering carrier is a sharp needle-shaped tip; and the lower surface is provided with a circular truncated cone hole for embedding a two-dimensional rotating top at the top end of the metal bracket and a connecting structure for connecting and fixing the two-dimensional rotating top. The forward direction of the low-scattering carrier provided by the invention is a sharp needle-shaped tip, so that the low-scattering carrier can be ensured to have a low-scattering characteristic in a relatively wide angular domain range in the forward direction, strong RCS scattering of the two-dimensional rotating top can be shielded, the RCS of the metal bracket can be measured more accurately, and a more accurate darkroom background level can be further obtained.

The invention discloses an internal and external solving method for obtaining electromagnetic scattering characteristics of a cavity-containing target, and relates to the technical field of electromagnetic fields and microwaves, and the method comprises the following steps: decomposing a cavity-containing structure into a cavity internal part and a cavity external part, and building a Huygens equivalent surface on the aperture surface of the boundary between the cavity internal part and the cavity external part; the consistency of electromagnetic modeling solutions before and after internal and external partitioning is ensured by utilizing continuity conditions of current and an electromagnetic field; different solving methods are selected in the inner structure and the outer structure respectively, the interior of the cavity is calculated by combining a cascade method with a rapid direct solving technology, the exterior of the cavity is calculated by adopting a parallel multilayer rapid multi-pole algorithm, and finally, iterative solving of the inner region and the outer region is carried out by utilizing an iterative algorithm, so that the RCS scattering characteristic of the whole cavity-containing structure meeting the calculation requirement is obtained. According to the method, the flexibility of electromagnetic scattering modeling of the target with the cavity is improved, the problem of internal resonance caused by a cavity structure is solved, and the electromagnetic scattering solving capability of the target with the cavity is remarkably improved.

The invention relates to the technical field of electromagnetic scattering, in particular to a low-scattering processing method and device for a rigid support rotary table. The embodiment of the invention provides a low-scattering processing method for a rigid support rotary table, and the method comprises the steps: carrying out the electromagnetic scattering test of a target disposed on the rigid support rotary table, and obtaining test data; performing one-dimensional / two-dimensional imaging processing on the test data at different angles to obtain strong scattering point distribution data; judging a target position where the strong scattering point data is generated according to an electromagnetic wave propagation path and a target erection height; and arranging a shielding device under the target position to reduce the influence of ground scattering on test data. The embodiment of the invention provides a low-scattering processing method and device for a rigid support rotary table. The influence of ground reflection on measurement data can be reduced.

The invention discloses an electromagnetic scattering calculation method based on deep learning under the condition that the shape and electrical parameters of a scatterer are not completely known. The electromagnetic scattering calculation method comprises the following steps: step 1, inputting electrical parameters of a known part of the scatterer, such as relative dielectric constant and magnetic conductivity, an incident field, a small amount of scattered field (observation / measurement) data and position coordinates of a to-be-solved scattered field; 2, solving an internal total field under the condition that only the known part of the scatterer exists and the unknown part does not exist by adopting a moment method; 3, inputting a small amount of scattered field (observation / measurement) data, an internal total field under the condition that only the known part of the scatterer exists and the unknown part does not exist, and the electrical parameters of the known part of the scatterer into a deep learning neural network, and obtaining the electrical parameters of the unknown part of the scatterer through the network, such as a relative dielectric constant and magnetic conductivity; 4, inputting the internal total field under the condition that only the known part of the scatterer exists and the unknown part does not exist, the electrical parameters of the unknown part of the scatterer and the electrical parameters of the known part of the scatterer into another neural network, and obtaining the internal total field of the complete scatterer through the network; and 5, calculating a total field or a scattering field at any position according to a moment method. According to the method, prediction of the scattering characteristics of the scatterer of which the shape and the electrical parameters are not completely known can be completed under the condition that only a very small amount of scattering field (observation / measurement) data is needed.

The invention relates to the technical field of underwater target detection, in particular to a single-transmitting multi-receiving underwater metal small target electromagnetic induction detection method, which comprises the following steps: planning a detection route below an underwater metal small target to be detected according to different operating distances and different intersection angles; a single-transmitting multi-receiving antenna system composed of a transmitting antenna and a plurality of receiving sensors is fixed on an underwater vehicle to form an underwater detection device; an underwater detection device is controlled to pass through the lower part of the underwater metal small target according to a detection route, a transmitting antenna continuously radiates low-frequency electromagnetic waves to the outside, and a plurality of receiving sensors receive signals; performing data processing on the signals received by the receiving sensors to obtain electromagnetic scattering field information of the underwater metal small target, and performing visualization processing to obtain a target passing characteristic curve; and performing imaging operation to obtain a three-dimensional contour image of the underwater small metal target, thereby efficiently, accurately and reliably identifying the shape of the underwater small metal target.

The invention provides a metasurface structure and a metasurface structure preparation method, and relates to the technical field of electromagnetic wave regulation and control. The metasurface structure comprises a frequency selection layer, an isolation layer and a reconfigurable gradient impedance layer, the frequency selection layer is located above the isolation layer; wherein the frequency selection layer is used for receiving a first electromagnetic wave incident at a first angle and inhibiting the echo intensity of scattering of the first electromagnetic wave; the reconfigurable gradient impedance layer is located below the isolation layer; wherein the reconfigurable gradient impedance layer is used for receiving a second electromagnetic wave incident at a second angle and inhibiting the echo intensity of scattering of the second electromagnetic wave; wherein the first angle is smaller than the second angle. According to the application, the echo intensity of mirror scattering is suppressed through the frequency selection layer, and the echo intensity of non-mirror scattering is suppressed through the reconfigurable gradient impedance layer, so that electromagnetic scattering suppression of a wide angular domain is realized.

The invention discloses a large-scale cluster target electromagnetic scattering analysis method and system based on a parallel equivalence principle, and the method specifically comprises the steps: carrying out the geometric modeling and equivalent surface construction of each target unit in a cluster target, and generating discrete surface element information; starting a parallel computing process, and distributing a target-equivalent face by adopting a greedy algorithm; a calculation process group corresponding to each sub-domain is partitioned according to a two-dimensional Cartesian coordinate grid, a transfer operator matrix between the sub-domains is partitioned according to the same two-dimensional calculation process grid, global parallel iterative solution circulation is carried out, and the equivalent surface flow of the sub-domain is updated; and the converged equivalent surface flow of each sub-domain is used as an equivalent source, and the radar cross section RCS of the whole cluster target in the specified observation direction is synthesized through far-field radiation integration. The method has good parallel expandability and calculation efficiency, is suitable for complex and diverse cluster target scenes, reduces memory requirements and calculation time overhead, improves calculation efficiency, and is high in engineering practicability.

The invention discloses a method for improving the solving speed of a rotating sphere non-singularity electromagnetic scattering field, and belongs to the field of electromagnetic engineering. Aiming at the electromagnetic scattering problem of a rotating structural body in the field of practical engineering, the invention provides a method for improving the non-singularity electromagnetic scattering field solving speed of a rotating body, and effective analysis of the rotating body is realized based on a moment method. A rotating structure body has important application value in electromagnetic radiation and scattering research due to geometric symmetry, but under the condition of long wavelength, a traditional surface integration method often has the problem of singularity, and numerical stability and precision are affected. Therefore, a method for effectively eliminating singular integrality and converting a dense matrix needing to be solved into a sparse matrix is designed, the calculation efficiency is remarkably improved, and the memory consumption is reduced. A non-singularity surface integral equation is obtained through derivation, simulation and numerical simulation are carried out through a specific electromagnetic rotating body device model, an efficient numerical solution is provided for the electromagnetic scattering problem, and the method has wide engineering application prospects.

The invention provides a ship detection-oriented multi-source remote sensing image fusion method, a ship detection-oriented multi-source remote sensing image fusion medium and a ship detection-oriented multi-source remote sensing image fusion system, and belongs to the technical field of remote sensing images. Constructing an electromagnetic scattering constraint model based on physical optical approximation and a geometric diffraction theory to calculate a predicted value of the backscattering cross section of the target, introducing a fusion cost function, generating a fusion weight matrix by adopting an adaptive feature weighting model, and performing multi-scale fusion on the image through hypercomplex wavelet transform; and iteratively optimizing the fusion result by using an information diffusion heat conduction equation, and performing physical consistency correction to output an enhanced fusion image, thereby solving the technical problem of poor physical consistency of the fusion result caused by lack of physical model constraint when the synthetic aperture radar image and the multispectral image are fused.

The invention relates to a multi-target structured scene electromagnetic calculation method based on a bounce ray algorithm, and the method comprises the steps: generating a corresponding ray tube based on a surface element for a structured complex scene; ray tube tracking is accelerated by adopting a BVH method; and completing ray tube electromagnetic calculation by adopting a GPU parallel calculation mode to obtain an electromagnetic scattering characteristic result corresponding to the structured complex scene. Compared with the prior art, aiming at single-target and multi-target structured scenes, a bounce ray (SBR) method is developed, a ray tube is constructed through a triangular patch, ray tracing is carried out based on forward and backward rays, a hierarchical bounding volume acceleration tree structure is adopted in the ray tracing process to improve the calculation efficiency of the SBR method, GPU acceleration calculation is adopted in the scattered field calculation process, and the calculation efficiency of the SBR method is improved. The bottleneck that a traditional moment method is low in calculation efficiency when processing a large scene and a physical optical method is limited in calculation precision can be broken through, and the calculation efficiency and the calculation precision are effectively improved.

The invention discloses a radar detection imaging method, which comprises the following steps: firstly, calculating the electromagnetic field intensity of a radar signal of a radar to a target point after being transmitted and propagated through an evaporation waveguide medium by using an electromagnetic propagation model; utilizing an electromagnetic scattering model to calculate a radar signal backward far region scattering field of the target and the random sea surface composite scene, namely electromagnetic scattering characteristics; and finally, electromagnetic imaging is carried out on the radar signal backward far region scattered field by using an electromagnetic imaging algorithm. The evaporation waveguide serves as a transmission medium of radar electromagnetic waves, the detection capacity of the radar can be remarkably improved, beyond-visual-range detection can be achieved, meanwhile, compared with free space transmission, the enhancement effect of the evaporation waveguide layer on target electromagnetic signal echoes can improve the detection signal-to-noise ratio of signals, and the detection precision is improved. The method can be applied to a high frequency band to provide a high radar resolution, radar electromagnetic waves are propagated in the evaporation waveguide at a low glancing angle, sea clutter interference in the target echo detection process is reduced, and the precision and reliability of target detection are improved.

The invention relates to the technical field of electromagnetic scattering characteristic analysis and modeling, in particular to a scattering center establishing and correcting method based on a geometric model and reference data. The method comprises the following steps: inputting a target geometric or grid file, and extracting geometric features of a plane, an edge and a curved surface to construct an initial scattering center model; inputting electromagnetic scattering reference data of the same target, solving a scattering center correction coefficient by adopting a pseudo-inverse or Tikhonov regularization method, and optimizing an initial model; and outputting an optimized scattering center model with angle and frequency expansibility. According to the method, the electromagnetic scattering characteristics of metal and coating type complex structure targets in single-station, double-station and full-polarization scenes can be uniformly represented, and the problems of insufficient model precision, incomplete types and high data dependence degree in the prior art are solved; the method achieves the excellent effects that the RCS root-mean-square error is smaller than 2dB and the high-resolution imaging structure similarity exceeds 90% in typical target modeling, and is suitable for the fields of target characteristic simulation and characteristic extraction and recognition.