181 results about "Em scattering" patented technology

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 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 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 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 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 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.

The invention relates to the technical field of electromagnetic scattering, in particular to an electromagnetic scattering characteristic prediction method and device, equipment and a storage medium. The invention discloses an electromagnetic scattering characteristic prediction method, and the method comprises the steps: carrying out the joint construction of a target structure parameter, a material electromagnetic parameter, and an incident wave parameter according to a preset mapping function, so as to obtain a joint output vector; performing simulation processing on the joint output vector according to a simulation method; training a preset incremental network model according to the simulation result and the simulation data set to obtain an updated main network model; acquiring real-time structure scene parameters, and predicting the real-time structure scene parameters according to the updated main network model to obtain electromagnetic scattering characteristics; comprehensive parameters are obtained, multi-source data are fused, a training data set is generated through simulation, an incremental network model is dynamically optimized, conventional recognition and new parameter adaptation are considered, the main network is updated, the electromagnetic scattering characteristics are predicted in real time, efficient support is provided for engineering such as radar detection, and the research and development quality and efficiency are improved.

According to the electromagnetic stealth metasurface design method universal for any frequency band, the pattern area of the metasurface unit is divided into the grids, each grid can be pasted or not pasted, and therefore ever-changing paster patterns can be formed, the combinations are optimized through the particle swarm optimization, and the expected electromagnetic scattering characteristic is achieved. The design method comprises the two steps of metasurface unit optimization design, metasurface modeling and simulation verification. The metasurface unit optimization design is an automatic optimization design process following a particle swarm algorithm, m different metasurface units can be obtained, and the m different metasurface units present specific phase gradients on a center frequency and a neighborhood frequency band; the metasurface can be formed by selecting the metasurface units from the m different metasurface units. The invention aims to provide an electromagnetic stealth metasurface design method universal for any frequency band. According to the method, the metasurface unit combination meeting the requirement can be fully automatically generated only by giving the target frequency band and setting a small number of parameters according to the rule, and the requirement for human intervention is reduced to the maximum extent.

The invention relates to the technical field of electromagnetic wave detection and imaging, and discloses a radar target echo generation method based on a physical information neural radiation field, which effectively improves the physical consistency of generated echo signals, accurately simulates the energy attenuation characteristics at different observation angles, and improves the radar target echo generation efficiency. The problem of signal completion under the sparse view angle condition is solved. The signal generated by the method is highly matched with measured data in the aspects of amplitude distribution, phase continuity and energy envelope form, a reliable data basis is provided for radar target identification and feature analysis, and the perception capability of a network on target geometric details is enhanced through high-dimensional position coding. Therefore, the generated echo signal can accurately reflect the spatial distribution characteristics of the scattering center. Meanwhile, due to the introduction of the multi-frequency coding sequence, the network can adaptively capture electromagnetic scattering characteristics under different scales, and a reliable technical means is provided for echo generation of a complex target.

The invention discloses a river water level inversion method taking altimeter footprint heterogeneity into consideration. The method comprises the following steps: acquiring an observation waveform of an SAR altimeter; space geometric parameters are calculated through footprint gridding and observation geometric modeling; constructing a water distribution scene based on the water mask and the river network, and classifying the water into a main river channel, a flood area and an adjacent isolated water body; electromagnetic scattering numerical integration is carried out based on the differentiated surface roughness parameters, and a simulated echo waveform is generated; waveform retracking and parameter inversion are realized through coarse grid search and local optimization solution; calculating an absolute water level and carrying out geophysical correction; performing multi-index quality control based on the interpretation rate of the analog waveform and the residual whitening degree; and finally outputting a water level product. According to the method, the defects of insufficient inversion precision and robustness of an existing method in a complex earth surface mixed scene are overcome, and the accuracy, reliability and physical interpretability of inland river water level monitoring are remarkably improved.

The invention relates to a target electromagnetic scattering test supporting method combining a metal support and a foam support, and relates to the field of electromagnetic scattering testing. A ground rotary table is used for bearing a target and supporting a structure to do azimuth rotation; the metal support and the foam support are combined to support a target, and the pitching angle of the target can be adjusted by adjusting the height of the foam support. The metal support rotating equipment rotates the metal support, so that the lowest electromagnetic scattering direction of the metal support is always aligned with the antenna, and the test influence is reduced; the pulse triggering device provides pulse signals for the metal support rotating device based on the rotating position of the ground rotary table to serve as reference for direction adjustment, and the method has the advantages that background clutters are reduced while the attitude and orientation of the to-be-measured target are accurately controlled, and the target erection safety is improved.

The application discloses a kind of based on three-dimensional particle special effect's airborne chaff bomb simulation method, contain the following steps: chaff individual particle modeling: based on three-dimensional particle special effect technology, simulate the motion trajectory of single chaff, the motion characteristics of chaff cloud and chaff electromagnetic scattering characteristic RCS;Complex environment modeling: including meteorological environment simulation model and electromagnetic environment simulation model;Particle special effect driven simulation calculation: under the action of the chaff individual particle model and complex environment model, first, each chaff individual is particleized;Then real-time calculation is carried out;Finally, radar wave irradiation analysis is carried out;Three-dimensional dynamic visualization output: the distribution and interference effect of chaff bomb under different height and environment are realized Real-time display.The application can highly realistic simulate the explosion, diffusion, disappearance etc. of chaff bomb in launching, including the motion trajectory of chaff bomb, diffusion distribution form and the effect of radar scattering.

The present application relates to the field of electromagnetic numerical calculation, and discloses a kind of method for solving electromagnetic scattering based on adaptive block Krylov subspace base function, method includes the following steps: step one: target region is carried out adaptive region decomposition, and target subdomain is obtained;Step two: target subdomain is expanded, and extended subdomain is formed;Step three: using optimized extended subdomain, the solving calculation of electromagnetic scattering is carried out.The main advantage of the present application is that the efficiency of constructing Krylov subspace base function is higher by using adaptive block technology, which significantly reduces the generation time of Krylov subspace base function based on block, optimizes the block expansion of subdomain, improves the solving calculation time, uses clustering algorithm to carry out region decomposition on the calculation target, and uses the average distance of clustering data points to cluster center to expand each subdomain to ensure the continuity of current, which not only ensures the calculation accuracy, but also improves the construction efficiency of base function, significantly reduces the generation time of Krylov subspace base function based on block.

The application discloses a complex lunar surface scattering coefficient image simulation method and system based on multiple data jointing, and the method comprises the following steps: firstly, terrain camera data is used to acquire terrain height data of a special geological structure of the moon as model geometric information input; secondly, a lunar soil weathering layer electromagnetic scattering model is established by using a vector radiation transfer theory and a lunar surface stone double-component method to simulate the interaction between electromagnetic waves and lunar rocks, the lunar surface, weathering layer particles and the subsurface; finally, a radar imaging mechanism is simulated based on a mapping projection algorithm, the scattering coefficient on each scattering facet is calculated by using the electromagnetic scattering model, and the scattering coefficient is mapped to an imaging area by using a ray tracing method, a shadow judgment method and the like, so that the scattering echo of each region of the complex lunar surface is rapidly estimated, and the fast scattering coefficient image simulation is realized.

The present application belongs to the technical field of stealth design of aircraft shape and structure, and discloses a surface wave electromagnetic scattering characteristic quantitative analysis method based on a two-port transmission model. The surface wave electromagnetic scattering characteristic quantitative analysis method based on the two-port surface wave transmission model has an electromagnetic discontinuous structure. By loading the electromagnetic discontinuous structure, the scattering parameters of the port network are monitored, and by changing the structural parameters of the electromagnetic discontinuous structure, the influence of the structural parameters of the electromagnetic discontinuous structure on the surface wave scattering characteristic is quantitatively studied. The surface wave electromagnetic scattering characteristic quantitative analysis method can separate the spatial electromagnetic scattering component when the spatial electromagnetic wave is directly irradiated, and can analyze the electromagnetic scattering characteristic of the surface wave in the discontinuous electromagnetic structure alone, thereby laying a foundation for studying the surface wave electromagnetic scattering characteristic of the electromagnetic discontinuous structure such as a curved surface, a gap and a step, and providing guidance for the stealth design of the aircraft shape and structure.

The invention belongs to the technical field of electromagnetic field calculation, and discloses a method and a system for calculating an electromagnetic scattering field of a moving target coated with a lossy dispersive medium. The method comprises the following steps: firstly, carrying out three-dimensional modeling on a target surface by adopting triangular surface elements to form a model file, and importing the model file into a main program to obtain geometric feature data of a target; secondly, carrying out relativistic coordinate transformation on the space-time component by utilizing Lorentz transformation, and mapping a dynamic problem to an inertial coordinate system synchronous with a target; then establishing an equivalent reflectivity model for the lossy dispersive medium coated area by adopting a transmission matrix method; then efficiently solving a transient scattering field in the motion coordinate system by adopting a time domain physical optical method; and finally, reconstructing a calculation result to a laboratory coordinate system through inverse Lorentz transformation, and outputting electromagnetic field distribution in a dynamic scene. Through the method provided by the invention, the electromagnetic scattering field of the moving target coated with the lossy dispersive medium can be quickly calculated.

The invention relates to a target and outdoor environment electromagnetic scattering coupling suppression method, which relates to the field of testing, and comprises the following steps: carrying out a dot frequency RCS test on a target, if the target is abnormal and is caused by ground reflection, determining a strong scattering point distribution angular domain according to a dot frequency curve, and obtaining a one-dimensional distance image; performing positioning analysis on strong scattering points in the one-dimensional range profile, confirming abnormal strong scattering points, dividing the abnormal strong scattering points into two types, reflecting the ground back to a target and then scattering to an oblique incidence type strong scattering source in an antenna, and fitting a circular curve; directly reflecting the ground to a strong scattering source in the antenna, fitting an elliptic curve, and calculating the position of a strong scattering point; the method has the advantages that the ground reflection points are determined through one-dimensional high-resolution testing and ground reflection point distribution fitting, and therefore the target testing precision is guaranteed through the reflection point suppression technology.

The invention relates to a target image construction method and apparatus, and an electronic device. The method comprises the steps of obtaining an echo signal obtained by detecting a target by a radar; inputting the echo signal into a preset target electromagnetic scattering parameter estimation model to obtain a structural characteristic parameter of the target; wherein the target electromagnetic scattering parameter estimation model is obtained by unfolding and solving a specified iterative algorithm and an attribute scattering center model; the iterative algorithm is an alternating direction multiplier method TSPN-ADMM algorithm based on a truncated Schattert-p norm; the attribute scattering center model is used for representing the incidence relation between the echo signal and the structural characteristic parameter of the target; and constructing a target image according to the structural feature parameters. According to the embodiment of the invention, the target electromagnetic scattering parameter estimation model is determined based on the attribute scattering center model and the expanded TSPN-ADMM algorithm, and high-quality structural characteristic parameters can be obtained through inversion from the echo signal with the missing frequency spectrum, so that the quality of the constructed target image is improved.

The embodiment of the invention provides an electromagnetic scattering calculation method based on a heterogeneous GPU cluster. The method is applied to the field of computational electromagnetism, and comprises the following steps: constructing a hierarchical bounding volume geometric acceleration structure of a target object and adding an edge index, and meanwhile, completely copying and distributing data of the acceleration structure to a video memory of each computational node in a heterogeneous GPU cluster; generating a random ray path starting from an emission source, modeling an electromagnetic scattering process as a ray path set in a probability space, and generating a ray direction through an importance sampling strategy; determining a static scheduling strategy for the ray batch based on the calculation cost of pre-sampling and geometric enhancement, and carrying out non-uniform distribution on task tiles according to the heterogeneous GPU calculation power; and monitoring the execution state of the heterogeneous GPU cluster in real time, and dynamically adjusting the distribution strategy of the residual ray tasks based on execution feedback. According to the method, the calculation overhead can be remarkably reduced while the calculation precision is ensured, and the efficiency and expandability of complex target electromagnetic scattering calculation are improved.

The invention discloses a rain clutter modeling method based on an electromagnetic scattering principle. Firstly, a radar emission signal model and a rain field model are constructed, and the rain field model comprises raindrop size, raindrop last speed and rainfall distribution; then, uniformly dividing the detection space into a plurality of scattering units; calculating the backscattering sectional areas of the raindrops, and further superposing the backscattering sectional areas of all the raindrops in the unit volume to obtain the scattering rate of the unit volume; according to the scattering rate per unit volume and the volume of the scattering unit, calculating the backscattering sectional area of the scattering unit; and finally, calculating the rain clutter echo signal of a single scattering unit, and superposing the rain clutter echo signals of all scattering units in the distance ring to obtain the rain clutter echo signal of the distance ring. And superposing the rain clutter echo signals of all distance rings to obtain a rain clutter echo signal in the detection space. According to the method, the modeling accuracy is improved, the calculation complexity is greatly reduced, and the method is suitable for large-scale real-time modeling.

This invention belongs to the field of computational electromagnetics numerical simulation and provides a simulation method for electromagnetic scattering of thin-coated targets based on Schur complement preconditions. First, for the IBC scattering target to be solved, equivalent surface current and equivalent surface magnetic current are introduced as independent unknowns. The electromagnetic scattering solution equation is established using SDIE and then discretized. Next, the impedance matrix is ​​decomposed into near-field and far-field matrices using an octree structure. For the near-field matrix, key operator sub-blocks are explicitly assembled and extracted. Then, approximate operators in block diagonal form and Schur complement operators are constructed and approximately inverted. Simultaneously, the diagonal product of intermediate blocks is pre-calculated and stored based on the approximate operators. Finally, the constructed preconditions are applied to the GMRES iterative solver. When the iteration error reaches the preset convergence criterion, the current and magnetic current distributions on the target surface are output. Further calculations of radiation characteristic parameters such as the target's radar cross section are then performed, achieving low-cost, high-efficiency, and easily parallelizable electromagnetic simulation solutions.

This invention discloses a terahertz-band foreign object detection radar system and method for airport runways. The system includes: a transmitting module for generating and transmitting a 240 GHz frequency-modulated continuous wave detection signal; a receiving module for receiving the echo signal and down-converting it to an intermediate frequency signal; a turntable system for driving the transmitting and receiving modules to rotate synchronously for azimuth scanning; and a digital control and processing module for generating baseband waveforms, acquiring angle information and intermediate frequency signals, and performing data processing to detect and locate foreign objects. This invention utilizes the physical law that the radar cross-section of a target is inversely proportional to the fourth power of its wavelength, fundamentally enhancing the electromagnetic scattering response of small targets and achieving high-sensitivity detection of millimeter-sized metal debris and non-metallic foreign objects, providing a reliable technical solution for foreign object detection on airport runways.

The application discloses a corner reflector array design method based on scattering center extraction, which studies and analyzes electromagnetic scattering characteristics of metal targets in a complex scene, and provides a feasible scheme for electromagnetic concealment of important targets, and specific contents comprise the following steps: a property scattering center model of a target is extracted according to a radar echo, and coordinate parameters of the model are used for initial arrangement of the corner reflector array; a structural similarity is used as a target function to optimize the corner reflector array, and is used as a quality evaluation index of arrangement of the corner reflector array; and finally, a false target similar to scattering characteristics of the target is obtained by constructing the corner reflector array. According to the method, the arrangement of the corner reflector array in the complex scene has a hiding performance of more than 90% to the target, and has high similarity compared with a radar image of the target.

The invention discloses a dynamic target time-frequency characteristic simulation method based on frequency domain calculation, electronic equipment and a storage medium, and the method comprises the steps: S1, building an electromagnetic scattering model of a target in a dynamic scene based on coordinate transformation and electromagnetic scattering simulation, acquiring broadband sweep frequency electromagnetic scattering response characteristics of a target at a slow time sampling moment from the electromagnetic scattering model, and taking the broadband sweep frequency electromagnetic scattering response characteristics as basic data generated by a distance-Doppler time-frequency diagram of a dynamic scene; and S2, based on the basic data, through two-dimensional transformation of a distance dimension and a slow time dimension, obtaining a distance-Doppler time-frequency diagram characteristic of a target in a dynamic scene. By establishing the electromagnetic scattering model of the dynamic scene, the target distance-Doppler time-frequency characteristic acquisition based on the frequency sweep data is realized, and reliable data support is provided for the research and identification application of the electromagnetic characteristic of the dynamic target.