最新刊期
卷 28 ， 期 3 ， 2000
- 摘要：An angle acquisition method is proposed in this paper based on Total Least Squares (TLS) estimation with phased array radar.Not only the perturbations in observation vector but also the perturbations in the data matrix in the linear model are considered.By applying TLS estimation,the Frobenius norm of the error matrix is minimized,which includes errors in both the observation vector and the data matrix.关键词：acquisition;TLS;sequential lobing;phased array radar2|802|0更新时间：2025-07-16
- 摘要：For HF ground-wave OTH radar to detect ship targets in the shipboard environment is faced with a range of technical challenges.One of them is that the spreading of the first order Bragg lines will obscure targets with Doppler frequencies within the range of this spreading.In this paper,the properties of the spreading are firstly analyzed with the aid of the synthetic aperture theory.On this basis,the feasibility of canceling sea-clutter and retaining target returns by the space filtering is proved.The experimental results presented in the end further demonstrate the effectiveness of the technique put forward in this paper.关键词：OTH radar;sea-clutter-canceling;synthetic aperture;target detecting2|1821|3更新时间：2025-07-16
- 摘要：A method is presented for estimation of the frequency,azimuth and elevation angles of the signal over a very wide frequency band (2~18GHz) with sub-Nyquist spatio-temporal sampling.Using a uniform circular array and antennas time-delaying,it can provide unambiguous frequency estimation under temporal undersampling,and provides unambiguous azimuth and elevation estimation using integer search algorithm under spatial undersampling.The estimations of azimuth and elevation and corresponding frequency are automatically paired.It not noly can use second-order statistics in element space or DFT beamspace,but also can use fourth-order cumulants to estimate the parameters of non-Gaussian sources in Gaussian white or colored noises.The variance of the azimuth and elevation estimates of this method is 1~2 orders less than that of L-shaped array algorithm under the same antenna numbers and the maximum aperture in DFT beamspace.Simulations are presented to show the capabilities of the algorithm.关键词：sub-Nyquist spatio-temporal sampling;fourth-order cumulants;three dimensional parameters estimation;automatic pair;Gaussian noise2|1671|7更新时间：2025-07-16
- 摘要：In this paper,a method is developed for speckle reduction of high resolution one-look spaceborne synthetic aperture radar images.This method,named TDRGMAP,makes high spatial resolution and high radiometric resolution one-look SAR image possible by means of smoothing speckle with MAP filter,removing bias for one-look image,using edge and line detector,and preserving detected point targets.TDRGMAP is discussed in detail,and its efficiency is demonstrated with simulated spaceborne SAR image.关键词：speckle reduction;local coefficient of variation;point target detection2|1486|12更新时间：2025-07-16
- 摘要：The feasibility of combinational estimation for redundant data using Markov estimator in bistatic/multistatic radars has received little attention so far.It is with respect to this particular issue that the present research is undertaken and a theorem is presented.It is theoretically discovered that if there are same components in two measurement subsets the combinational estimation for redundant data can not be made.Simulation is made in the situations where combinational estimation is feasible.The simulation results show that much better positioning performance can be achieved in bistatic/multistatic radars,especially in the region of the base line,the side line,and the neighbor region of the transmitter station and the receiver station.关键词：bistatic/multistatic radar;combinational estimation;location accuracy;measurement Subset2|1598|9更新时间：2025-07-16
- 摘要：The characteristics of the ground and sea clutter have some important effects on the airborne PD radars with look-down mode.Based on the analysis of the PD radar system,this paper studies in detail the modeling method of distance-doppler clutter graph of the radar by using an elevation graph of 3D digital terrain and the corresponding classification of terrain with arbitrary postures of the aeroplane.Finally,the validity of the method has been proved by the simulation results.关键词：3D terrain;clutter;airborne PD radar;algorithm2|1633|6更新时间：2025-07-16
- 摘要：HF radar backscatter from the ocean surface shows nonlinearities and time variation of its spectrum.However,the spectrum analysis method cannot reflect the evolution of the HF backscatter in time domain.In this paper,the chaotic dynamic approach is used to analyze the chaotic characteristics of the HF backscatter,and based on the observed data,it is concluded for the first time that the HF radar backscatter from the ocean surface possesses some nature of chaotic process.This conclusion will be of much significance in the target detection and ocean sensing of HF radar.关键词：HF radar;sea backscatter;chaos;fractals4|1427|12更新时间：2025-07-16
- 摘要：This paper deals with feature of extraction target signal with ISAR radar.Since the size of the rarget is larger than range resolution of ISAR radar,the back-scattered power of the target is represented as a function of time.The method of improved detection performance with ISAR are FFT and signal amplitude integration of each range cell,which presents the signal of the target.But in LRR the signal integration is vectoried integration,the output forms of the methods are given by this paper and theoretical calculation agrees with experimental measurement satisfactorily.关键词：high-resolution radar;radar signal processing;radar signal detection;ISAR2|1410|2更新时间：2025-07-16
- 摘要：This paper describes simply the principle of real-time DBS,discusses a few problems on real-time approach,provides the designed software and hardware combined with a PD radar,and show the result of the flying test.关键词：radar imaging;doppler beam sharpening;real-time signal processing;digital signal processing2|1856|16更新时间：2025-07-16
- 摘要：In this paper a refined chirp scaling algorithm for spaceborne synthetic aperture radar (SAR) imaging is presented.At first,three range models of spaceborne SAR are analyzed.Based on the squint range model which has the least error among the three models,a refined chirp scaling algorithm is derived.And it is suitable for precise imaging of high resolution spaceborne SAR with large range cell migration.Based on the refined chirp scaling algorithm,the effects of Doppler parameters on the quality of SAR image are analyzed as well.Finally,this algorithm is tested by computer simulation.关键词：synthetic aperture radar;radar imaging;chirp scaling algorithm;estimation of doppler parameters2|2469|43更新时间：2025-07-16
- 摘要：Frobenius norm correction algorithm on target's polarization scattering matrix is studied in connection with radar target's reciprocity correction.The physics and application background of Frobenius norm correction algorithm are stated.Frobenius corrected matrix is achieved by using the Lagrange Multiplier Method.It's shown that there is a little difference of a positive scalar factor between Frobenius corrected scattering matrix and the optimal Cameron corrected ones.The Frobenius algorithm is proved to be a local optimal algorithm with the Frobenius corrected matrix being unique.Finally,characteristics of two kinds of correction algorithm are compared by experiment and conclusions in this paper are verified.关键词：target;polarization scattering matrix;correction on reciprocity;Frobenius norm correction algorithm2|1128|0更新时间：2025-07-16
- 摘要：A kind of parallel structure of the IIR filter is obtained by decomposing the polynomial signal.Through the analyzing of this parallel structure,a high efficient systolic structure of the IIR filter is presented.This structure has the advantage of small array size and high processing rate.关键词：IIR filter;parallel;systolic structure3|1791|0更新时间：2025-07-16
- 摘要：A new method of VHF channel access protocol analysis based on semi-Markov model is presented in this paper.A model of channel access state transition for air-ground datalink is established.By introducing the state mean holding times(HT) and state transition probabilities (TP) into this model,the presentation of the safe state probability and the number of busy users is obtained,which is a new way for property analysis and evaluation of channel access protocol.By using this approach,system parameters are not restricted to an exponential distribution,which is close to the practical situation.The method has been applied into VHF datalink system and the simulation results show that it is effective.关键词：VHF datalink;air-ground communication;CSMA;semi-markov model4|1037|0更新时间：2025-07-16
- 摘要：In this paper,we apply conformal mapping into compact 2D/FDTD algorithm,gave the difference formula of conformal mapping FDTD algorithm,propose the treatment method of focus.The cutoff wavelengths and dispersion curves of elliptic and of cocoon-section waveguides are calculated,and the cutoff wavelengths of high order modes of shield two parallel lines are also given by this method.关键词：conformal mapping;FDTD method;focus;Cassinian transformation2|1065|1更新时间：2025-07-16
- 摘要：On the basis of the novel concept "measuring ring",two new kinds of methods are presented to determine MEI coefficients in this paper.The numerical results demonstrate that the MEI coefficients obtained using the technique,which takes dipole layer excitation as the "Metron" and the Green function in free space as the integral Kernel,are of higher precision over other techniques.The analysis and summarization of numerical experimenal results cause us to achieve a better comprehension of the MEI method.On the other hand,the instability and the validity of the MEI method are explained by using mathematical analysis approach.The parameters of complicated microstrip lines are calculated by the method here,and the results are in good agreement with those in references.关键词：measured equation of invariance (MEI);unbounded electromagnetic field;numerical analysis2|996|1更新时间：2025-07-16
- 摘要：The setting up of ion channel and its transient properties were studied and modelled by MAGIC code in this paper,and the factors affecting its performance were also discussed.The results are valuable for the development of plasma microwave devices and ion channel lasers.关键词：ion-channel;electron beam;plasma;transient;model2|1120|3更新时间：2025-07-16
- 摘要：The ridge-loaded ring-plane traveling wave tube (TWT) is an important type of high power broad band microwave amplifier.Making use of field matching method,combining with the variational method,the dispersion equation of the ridge-loaded ring-plane slow wave structure and small signal gain of this type of TWT are presented in this paper.The influences of all geometrical dimensions on the propagation characteristics,and the effects of the electron parameters on the gain are discussed,respectively.A large signal numerical calculation has also been done to investigate the nonlinear phenomena in this kind of TWT.In order to get higher power in broader operating bandwidth for this kind of TWT,the optimum opening angle,a smaller radius of the loaded ridge,and appropriate electron parameters must be chosen.This paper provides the theoretical basis for design of the ridge loaded TWT.关键词：Ridge loaded ring-plane circuit;Slow wave structure;Small signal gain;Large signal2|852|0更新时间：2025-07-16
- 摘要：A nonlinear polarization-vector translation method has been proposed by Poelman,which can effectively increases the interference suppression ability of the polarization filter.But the algorithm becomes more complicated as the nonlinear degree increases.Thus in this paper,a real weighting polarization vector translation method is put forward,which is simple and suitable for realizing in reality.It is shown that the intrinsic interference suppression capability of a polarization filter based on the rule of minimum interference output is only 50%.In other words,only half of the interference in polarization domain can be filtered out.By using the new method,the interference suppression capability of the filter is improved from 57.7% to 100% corresponding to different polarization states of the desired signal.关键词：polarization filtering;interference suppression;polarization mismatch loss2|1023|8更新时间：2025-07-16
- 摘要：In this paper,kinetic theory of ECRM is used to analyze third harmonic complex cavity gyroton.A self-consistent nonlinear theoryetical model for a complex cavity gyrotron with abrupt transitions is presented.The model accounts for mode coupling in the transition region of the complex cavity.The interaction between the electron beam and H61-H62 RF field in the complex cavity with abrupt transition for a third harmonic gyrotron is simulated.A 35GHz third harmonic complex cavity gyrotron is predicted to yield a efficiency of 24% and an output power of 210kW with a 45kV 30A α=v⊥/v//=2.0beam.关键词：gyrotron;complex cavity;high cyclotron harmonic;mode coupling;nonlinear interaction2|794|0更新时间：2025-07-16
- 摘要：Qualitative properties of a class of high-order Hopfield neural networks are studied in this paper.Several fundamental issues such as global exponential stability,existence,and uniqueness of the equilibrium of such networks are established by means of Liapunov function and Banach fixed point principle.As a special case,some new stability criteria are obtained for the corresponding one-order Hopfield neural networks.关键词：Hopfield;high-order neural networks;equilibria;qualitative analysis2|1350|8更新时间：2025-07-16
- 摘要：In this paper,error-tolerant techniques are studied for large-vocabulary speaker-independent Chinese continuous speech recognition and understanding systems.When N-best syllable candidates with their corresponding acoustic scores are generated and a syllable lattice is constructed by the acoustic recognizer,an error-tolerant linguistic parser is used to search through the syllable lattice and find the optimal Chinese character sequence in which syllables of some characters may not be included in the lattice because additional possible candidates are considered.In such a way,some acoustic errors are corrected and the robustness of the parser is improved.Our experiments show that the error-tolerant parser can increase the understanding rate from 91.83%,a 28.4% error reduction over the conventional trigram model based parser without error-tolerant techniques.关键词：error-tolerant techniques;language mode;perplexity;levenshtein distance2|1324|2更新时间：2025-07-16
- 摘要：Straight-flight constrained 2D route planning for unmanned air vehicle is conducted in this paper.To meet the request of straight-flight constraint,2D flight route can be simplified as canonical route that consists of line and arc segment,and the definition of turning points (TPs) is given.Based on this definition,a new method for straight-flight constrained route planning is presented.Experiments shows that the obtained optimal route not only meets the request of minimal radius constraint,but also keeps air vehicle fly straight passing through turning points,facilitating matching navigation and flight photographing for air vehicle.关键词：turning radius;turning points (TPs);route planning2|2048|3更新时间：2025-07-16
- 摘要：In this paper,the high-order fractal feature is employed to analyze radar signal.The new fractal feature-lacunarity is used to identify target and clutter.We derive formula of lacunarity in additive noise.The experiments show that higher detection accuracy of sea-surface targets can be obtained by using lacunarity feature than by fractal dimension.关键词：high-order fractal feature;Target Detection2|1308|8更新时间：2025-07-16
- 摘要：On the basis of multiple-channel antenna SAR geometry relation,a completed multi-channel antenna synthetic aperture radar (SAR) echo signal model is built and the multi-channel antenna SAR adaptive clutter suppression method and practical structure based on phased array antenna forming multiple receiving channel antenna using the spatial element repetition structure are presented in this paper.Conclusion can be drawn from theoretical analysis and computational simulation that it can achieve good low speed moving target detection performance in airborne SAR imaging by combining multiple channel antenna technology with spatial-temporal adaptive clutter suppression technology.关键词：synthetic aperture radar;spatial-temporal adaptive signal processing;clutter suppression4|1001|1更新时间：2025-07-16
- 摘要：In this paper,we present a new method for frontal-view face detection.Instead of viewing face patterns as a single cluster in the high-dimensional space as several previous approaches,we propose that face patterns can be better described by multiple clusters.We obtain four clsters by employing an optimal clustering method.Using each cluster center as a template,we adopt Mahalanobis-distance-based template matching to find the face location in an image.The experimental results show that our method outperforms the methods that are based on a single cluster.关键词：face detection;template matching2|1235|4更新时间：2025-07-16
- 摘要：In this paper,the miss distance measurement problem for targets in rectilinear motion and with constant accelerations is studied.A miss distance measurement equation is derived.Based on it,the meaurement problem is represented as the nonlinear least square fitting of Doppler frequency time series in the course of interceptions,and then nonlinear optimizing algorithms are discussed for solving it.Simulations show that the new method for Doppler miss distance measurement can eliminate the systematic errors of methods based on a uniform rectilinear motion model.关键词：miss distance;measurement;parameter estimation;data processing2|1446|8更新时间：2025-07-16
- 摘要：Mainly studies target tracking problem on 2-dimensional plane in non-linear systems.Analyses the influence of sensors' measurement accuracy on two sensors' fusion tracking accuracy.From theory and simulations,it is found that,under some conditions,adjusting the included angle between the sensors and target can improve the target tracking accuracy.The conclusions are of momentous significance on multisensor target tracking.关键词：multisensor;target tracking;data fusion4|1268|5更新时间：2025-07-16
- 摘要：The coplanar waveguide on the substrate with finite dimensions is a physical model which is very closed to the engineering situation.The coplanar waveguides are analyzed using conformal mapping techniques,and the exact solutions including the effective dielectric constant,the capacitance per unit length and the characteristic impedance are obtained.The results obtained in this paper have been compared with that of the coplanar waveguide with infinitely wide substrate.关键词：coplanar waveguide;conformal mapping;substrate with finite dimensions;effective dielectric constant;characteristic impedance2|1427|1更新时间：2025-07-16
- 摘要：In this paper,a new fast partial spectrum computation method called subband spectrum analysis (SSA) is presented,which is based on the theory of subband decomposition.The new method not only holds the high-resolution feature of ZFFF using complex modulation,but also has the advantages of simplicity,easy implementation,less arithmetic operations and memory requirements.SSAalgorithm has been successfully used in the maneuvering target velocity tracking system.Accuracy and efficiency of the method are proved by the simulation results.关键词：subband decomposition DFT;frequency spectrum analysis;zoom2|1034|3更新时间：2025-07-16
- 摘要：Based on raindrop size distribution (DSD) data measured in Qingdao,Guangzhou and Xinxiang,the radar reflectivity factor Z for spherical raindrops,the radar reflectivity factor ZH and diferential reflectivity ZDR for oblate ellipsoid raindrops are calculated.The reflectivity-rainfall relation (Z-R relation) for conventional meteorological radar and reflectivity,differential reflectivity-rainfall relation for multiparameter radar (ZH,ZDR-R relation) are given by regression,and the performance difference of two kinds of radar for measuring rainfall and difference for measuring rainfall in different regions are also discussed in the paper.关键词：conventional meteorological radar;multiparameter radar;raindrop size distribution;radar rainfall estimation2|1346|2更新时间：2025-07-16
- 摘要：A new approach,the multipole theory(MT) method,is briefly described for analysis of waveguide eigenvalue problems.The essential concept is to represent the solution of the waveguide partial differential equation by the generalized MT formula of 2-D Helmholtz equation.The applied rules and the procedure of the MT method are also introduced.By calculating and analyzing some engineering problems,it is shown that the MT method is an effective approach for analysis of waveguide eigenvalue problems.关键词：multipole theory;waveguide;eigenvalue4|1165|3更新时间：2025-07-16
- 摘要：Adjoint network of linear circuits is used to solve microwave nonlinear circuits problems.In the paper,a unified adjoint network method of linear and nonlinear circuits is presented.This method can calculate sensitivity quickly.关键词：nonlinear microwave circuit;sensitivity;adjoint network method2|1193|0更新时间：2025-07-16
- 摘要：This paper presents derivation of anisotropic quasi-perfectly matched layers absorbing boundary condition in generalized orthogonal coordinates (GOC).The anisotropic quasi-perfectly matched layers absorbing media in rectangular coordinates,cylindrical coordinates and conformal mapping cylinder coordinates are given in this paper.Numerical results illustrate the effectiveness of absorbing in anisotropic perfectly matched layers.关键词：generalized orthogonal coordinates;FDTD;quasi-perfectly matched layer absorbing boundary4|853|2更新时间：2025-07-16
- 摘要：In this paper,an improved Genetic Algorithm (GA) was applied to the design of high performance E-plane waveguide filters at the first time.For dealing with the shortcoming of GA as low efficiency in local optimum searching,the idea based on Parallel Genetic Algorithm (PGA) known as separate local optimization was presented.By separating the whole population into sub-populations,and adding a new operator known as crossover between two sub-population,the new method can provide as 2~3 times quickly as traditional GA.All numerical examinations illustrated the high convergence speed and good global searching of the new algorithm,and proved the validity of it.关键词：genetic algorithm;waveguide filter2|880|1更新时间：2025-07-16
- 摘要：This paper studies the optimization problem in Neyman-Pearson(NP) sense in distributed CFAR detection.The difference of optimization between the distributed CFAR detection based on binary local decision and local test statistic (LTS) is elaborated.R and S type LTSs are proposed.It is proved that the optimal distributed CFAR detection based on the above two LTSs in NP sense is in form of likelihood ratio test (LRT).Their suboptimal fusion schemes are developed (OS-R-GLRT and OS-S-CA).The results show that suboptimal fusion schemes could attain similar performance to that of optimal fusion.关键词：distributed detection;CFAR;homogeneous background;multiple target situations;clutter edge2|1048|5更新时间：2025-07-16
- 摘要：Shamir and Schorr proposed an attack to Rabin's digital signature.The attack is called Shamir attack.In this paper,we will present a new and efficient bit perturbing method to avoid the Shamir attack.Harn and Kiesler proposed a public-key cryptosystem,digital signature and authentic encryption scheme based on Rabin's cryptosystem.In this paper,we will point out these cryptosystem are insecure and we also propose a secure digital signature scheme.关键词：signature;cryptosystem;quadratic residues2|952|0更新时间：2025-07-16
- 摘要：The influence of atmospheric media in rain and fog weather on imaging for outdoor scene is analyzed in this paper.We get the theoretical relationship of visibility distance and image contrast and resolution,and present the formulas for image synthesizing.The simulated images are compared with the captured gray level ones for rain weather and color ones for fog weather in our experiment.关键词：image synthesis;point spread function;modulation transfer function;image contrast;image resolution4|1395|10更新时间：2025-07-16
- 摘要：Floating genetic algorithms (FGAs) are optimization methods simulating the natural evolution mechanism.FGAs have been widely used in science and technology by virtue of their simplicity,robustness,freedom of calculating the gradient of the objective function,high precision and the ability of solving multi-dimensional numerical problems.With the convergence analysis of FGAs,it is proved in this paper that FGAs with the fittest individual holding in each generation can converge to the global optimum while simple FGAs can not.In the light of the theoretical convergence analysis,improved FGAs with the fittest individual holding and the continuous mutation are proposed,which overcome the incompatibility between the high precision and low computational cost.The improved FGAs have been applied to extracting the semiconductor device model parameters,and have gained about 27% reduction to the computational cost.关键词：genetic algorithm;convergence;Markov chain;model parameter extraction;continuous mutation2|1104|6更新时间：2025-07-16
- 摘要：In order to provide a software workbench of debugging embedded software for developer,we develop a simulation development system for embedded software.In the beginning,this paper simply discusses the development tool ESDL and simulation debugger for embedded software,then mainly discusses the simulation technique of running environment for embedded software.关键词：high-level simulation model;event driven algorithm based on process;embryonic circuit;genetic program6|1489|5更新时间：2025-07-16
- 摘要：In this paper,a novel algorithm,which is based on the DQM,is proposed to approximate part of the partial differentials in Maxwell's equations.This algorithm can reduce the number of meshes of TD-FD,and thus can save computer memory and improve the efficiency of electromagnetic analysis.关键词：TD-FD;DQM;electromagnetic analysis2|1425|1更新时间：2025-07-16
- 摘要：Based on a model to support the software reuse founded on Agent,network and domain,this paper outlines the frame representation of the model and the specifications of the software built by components on different levels.The distributed class-library is constructed for description of domain frame and domain components.Agents are used in component searching and management.The logic of Agents and relations between them are given.A prototype system of the model is implemented by ASP,Java,JDBC,SQL etc.and tested in some software development.关键词：Web;software component;agent;CASE2|1543|1更新时间：2025-07-16
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