最新刊期
卷 34 ， 期 12 ， 2006
- 摘要：A novel medium access control (MAC) protocol for the single-channel multi-hop Ad Hoc network is proposed.Using omni-directional antenna,the control frame tagged with the routing information can be sensed by the neighboring nodes.Furthermore,the ACK message send by the upstream node triggers the CTS-only handshake of the downstream node and,the three-way exchange (CTS/DATA/ACK) is performed.This mechanism lowers the probability of the control message collision in heavy load network.Simulation results demonstrate that with various topologies our proposed scheme can outperform IEEE 802.11 with throughput and delay betterment.关键词：multi-hop Ad Hoc;MAC;IEEE 802.11 DCF;MARCH;ROADMAP2|886|5更新时间：2025-07-16
- 摘要：A new chaotic fragile watermarking algorithm is presented.With the high sensitivity on initial value of the chaotic mapping and the block-wise independent technology,the image DCT sub-high coefficients and a watermarking key are combined as the initial value of logistic maps for the generation of the watermarks,then the watermarks are embedded into the DCT high coefficients to get watermarked image.The watermarks can be blindly extracted according to the DCT coefficients.Experimental results show that the algorithm can detect any modification to the watermarked image and localize the tampers on the watermarked image.关键词：fragile watermarks;chaos;logistic maps;image authentication2|1228|12更新时间：2025-07-16
- 摘要：For detecting and tracking multitarget under the background of low signal-clutter-ratio (SCR),a radar track-before-detect (TBD) algorithm of multitarget based on the dynamic programming (DP) is presented.This algorithm can correctively estimate the number of targets in the observed area,and optimally separate the tracks of these targets.Therefore it can solve the problems of missed alarm and much false alarm,which usually arise,when the pervious track-before-detect algorithm are used to detect multitarget on the condition of unknown number of targets.关键词：track-before-detect (TBD);dynamic programming (DP);multitarget;weak target4|1750|20更新时间：2025-07-16
- 摘要：In the application of radar dim target detection,dynamic programming (DP) is an effective method in integrating target energy.This paper analyzed the characters of images of dim radar multi-target with DP,and achieved multi-target detection by using extreme value theory.The probability of false alarm and the probability of detection have been analyzed theoretically.The results of the simulation show that the method brings 4~5dB gain of noncoherent integration compared with traditional detection method.关键词：dynamic programming;track-before-detect;extremum;dim multitarget detection2|1450|11更新时间：2025-07-16
- 摘要：Based on the fractional Fourier transform,the fractional spectrum of non-uniformly sampled signal,which occurs in practical applications,has been analyzed and studied.Then the spectrum representation of a non-uniformly sampled chirp signal in the fractional Fourier domain has been derived.And the properties of fractional spectrum for non-uniformly sampled chirp signal have been investigated.The simulations are also proposed in the last to verify the correctness of the results.关键词：non-uniform sampled signals;sampling theory;fractional Fourier transform;chirp signal;spectral analyze3|1282|7更新时间：2025-07-16
- 摘要：An adaptive particle filtering algorithm based on color feature is proposed.Under non-occlusion condition,adaptively choose the number of particles and the variance of Gaussian stochastic noise in the dynamic model based on the accuracy degree of the deterministic prediction to guarantee the real-time tracking and valid particles.Under occlusion,the dynamic modal is changed and the particles only do Brownian motion,then the particles are optimized by one-step iteration of the mean shift algorithm to decrease the number of particles and resume the right tracking more quickly.Experimental results indicate it is robust and has good performances under complex background.关键词：target tracking;particle filter;occlusion2|2647|15更新时间：2025-07-16
- 摘要：Nonlinear mapping plus linear classification,i.e.,mapping inseparable input space into a hidden space via some nonlinear mapping,and designing a linear classifier to classify the data in the hidden space,is one of the most popular approaches for designing a classifier for an inseparable classification problem.In fact,multi-layer perceptron (MLP),support vector machine (SVM),relevance vector machine (RVM) and radial basis function (RBF) are the examples of such approach.In this paper,we propose a novel classifier which is not based on this approach,but on stimulating pulse-coupled neurons such that the neurons belonging to a same class activate each other while those belonging to different classes inhibit each other according to the stimulus and the geometry of neurons in the input space.The result of the competition between neurons is that all the neurons belonging to one class will fire earlier than all the other neurons in the net,which is used for classification.A large number of experiments were conducted for classification of Iris data and simulated data where the overlap between patterns is very serious,as well as automatic target recognition for the model targets whose high-resolution range profiles were obtained from real microwave house.The experiments show that the proposed method is very effective in designing a classifier with good generalization ability and simple structure.关键词：pulse-coupled neural network(PCNN);capture and inhibition between the fires of neurons;robust classification3|1019|3更新时间：2025-07-16
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Performance Analysis of the Robust Adaptive Beamforming Based on Worst-Case Performance Optimization
摘要：The performance of adaptive beamforming degrades dramatically in practice due to steering vector mismatches.As a solution,diagonal loading is usually used to improve its robustness.However,how to select the loading level remains an open problem.In this paper,the robust adaptive beamforming (RABF) which determines the loading level based on worst-case performance optimization is investigated and a simple closed-form solution to the optimal loading is derived after some approximations,revealing how different factors affect the optimal loading.On the basis of this solution,a performance analysis is carried out,focusing mainly on the source power estimation and signal-to-interference-plus-noise ratio (SINR).The corresponding analytical results are presented for performance prediction.Finally,numerical examples demonstrate the correctness of the analysis in this paper.关键词：robust adaptive beamforming (RABF);steering vector mismatches;worst-case performance optimization;optimal loading;performance analysis;source power estimation;signal-to-interference-plus-noise ratio(SINR)2|977|7更新时间：2025-07-16 - 摘要：In recent years,the continuing development of remote sensing technology makes the conventional remoting sensing image registration techniques inefficient.An accurate and efficient image registration method for remote sensing images is introduced.The method integrates image hierarchical structure,multi-resolution wavelet decomposition technique and Harris corner detector to create a feature point pyramid.And the improved Hausdorff distance is used as the similarity measure for realizing remote sensing image registration.关键词：remote sensing image;image registration;Harris corner detector;wavelet decomposition;Hausdorff distance2|1097|10更新时间：2025-07-16
- 摘要：For the problem of signal leakage into noise subspace using Multi-stage wiener filter (MSWF) technique to estimate the signal subspace,this paper presents a subspace estimation algorithm.This method does not require the training signal and pre-knowledge of source number.Then,a post detection method is proposed for the source number estimation.And the source number detection and DOA estimation can be simultaneously completed.The whole algorithm does not need computing covariance matrix and eigen-decomposition,so the complexity is greatly decreased.Compared with the classical eigen-value decomposition (EVD) based methods,the procedure has less computation complexity with the approximation performance in the simulation of uniform linear array and uncorrelated signals.The simulation results demonstrate its effectiveness.关键词：multi-stage Wiener filter;direction of arrival;source number detection;array signal processing4|1101|5更新时间：2025-07-16
- 摘要：To the questions of battlefield situation assessment (BSA),a technique for BSA based on intuitionistic fuzzy decision is proposed.First,BSA is concluded to an issue of synthetic judgement,and an intuitionistic fuzzy model for synthetic judgement is derived with a proof of the model normalized.Then,a system of evaluating goals for BSA is constructed,and approaches to effectiveness measures for evaluating goals and normalization of their values are described.Subsequently,methods of Delphi integrated with analytic hierarchy process (AHP) are exposed to be used for finding weight vectors of goals.Finally,the evaluating instances detailed in the course of joint operations of air defense get into investigation.The simulated results show that the technique can make sense of efficient synthetic assessment and comprehension to current battlefield situation with a higher dependability.关键词：Information fusion;situation assessment;intuitionistic fuzzy decision;synthetic judgement4|1916|24更新时间：2025-07-16
- 摘要：In order to suppress angle glint in monopulse radars system,a maximum entropy method for angle estimation in wideband monopulse tracking radar is presented.Spectrum widen of difference beam echoes due to the pattern modulation is investigated.Basing on the relations between the spectrum widen,center of target angular motion and waveform entropy,a novel angle estimation method by maximum waveform entropy searching is presented,and an improved method to reduce computational complexity is given later.Compared with high resolution angle estimation methods available,the novel method performs more conspicuous in angle glint suppression.Simulations show the effectiveness of the new method.关键词：monopulse;angle estimation;angle glint;maximum entropy;high resolution2|1081|5更新时间：2025-07-16
- 摘要：A new method for full-polarization SAR images classification integrated with speckle reduction is proposed.SAR image is firstly decomposed by Pauli-decomposition approach and three combined polarization channels which are denoted by three different colors are obtained.Then the speckle of each color channel is reduced by using ICA sparse-coding shrinkage algorithm (ICA-SCS).After speckle reduction,the three channels are constituted to rebuild a classified image with less speckle noise.This method well keeps the relative phase information among the polarization channels.Furthermore,the channels after speckle reduction are directly used for classification without any other combination.The classification results of real SAR images indicate that the classification accuracy is improved obviously.关键词：independent component analysis (ICA);full-polarization SAR;relative phase information;speckle reduction;Pauli decomposition;color channels2|995|4更新时间：2025-07-16
- 摘要：In order to decrease the computation and storage load,different sampling-rates,together with the Sampling-rate Conversion,are often used in a system.When a signal is analyzed in the fractional Fourier domain,the lower sampling-rate could be adopted than the Nyquist sampling-rate,which means that the traditional sampling-rate conversion theory,founded in the frequency domain,could be disabled under the circumstances.The traditional sampling-rate conversion theory is generalized to obtain the version for the fractional Fourier transform (FRFT).First,the formulas and signification of decimation and interpolation are studied in the fractional Fourier domain.Based on these results,the sampling-rate conversion theory for the FRFT with a rational fraction as conversion factor is deduced.It's obvious that the sampling-rate conversion theory for the FRFT changes to the traditional version when the FRFT order equals π /2.Finally,the theory obtained in this paper is verified by some simulations.关键词：fractional Fourier transform;sampling-rate conversion;decimation;interpolation2|636|0更新时间：2025-07-16
- 摘要：A robust localized space-time adaptive processor which is called FDSP (Flexible DOF STAP Processor) is presented.The processor adjusts its system DOF (degree of freedom) adaptively with variable interference environment.Compared with fixed DOF STAP processor,FDSP reduces large computational complexity and improve the performance of clutter and jammer suppression.The implementation of FDSP is illustrated.The validity of FDSP is proved by measurement data processing result.关键词：clutter rejection;jammer suppression;STAP;DOF2|856|0更新时间：2025-07-16
- 摘要：Spatial-temporal modeling of radio channels is the key for space-time wireless channel study.The widely used geometrically based single bounce elliptical model(GBSBEM)has the limitations in the description of Time-Of-Arrival(TOA).By introducing two physical concepts of effective scatterer and reflecting probability to GBSBEM,an enhanced elliptical scattering model is presented,while the probability density functions of TOA and Angle-Of-Arrival(AOA)are also derived.The detailed analysis proves that the enhanced model not only overcomes the limitations of GBSBEM,but also has an advantage of broad application extent.关键词：radio propagation;space-time channel model;geometrically based single bounce elliptical model;time-of-arrival;azimuth-of-arrival2|766|1更新时间：2025-07-16
- 摘要：Based on the application of Geometry Dilution of Precision (GDOP),5 main aspects of GDOP are studied.It is concluded that different constellation parameters influence GDOP of different latitude.GDOP,PDOP and TDOP are not changed but HDOP and VDOP are changed by coordinate conversion.GDOP decreases along with the number of satellites,but the decreasing extent reduces too.The more a satellite contributes to GDOP,the more the positioning error it produces when it has fault.Using weighted GDOP reduces the positioning error effectively.关键词：satellite navigation;dilution of precision;constellation deploy parameter;precision of positioning;weighted GDOP2|2617|32更新时间：2025-07-16
- 摘要：Based on a proposed two-dimensional space-time clutter model and detailed analyses of the ground clutter spectrum structure,gives some important principles for design of bistatic airborne early warning(AEW)radar in condition of arbitrary geometric configuration.Furthermore,the inherent causes are interpreted and the detailed simulations are also provided to verify the proposed principles.These studies are significant to realize the clutter suppression and STAP processing for real bistatic AEW.关键词：bistatic airborne early warning radar;ground clutter spectrum;space-time adaptive processing(STAP);geometric configuration2|1185|13更新时间：2025-07-16
- 摘要：The watermark is constructed by dyadic value chaotic sequence,which has very good pseudorandom properties.In order to perform the tradeoff between robustness and imperceptibility,the embedding factor consists of three sub-factors:signal-to-noise ratio(SNR)factor α ,activity measure factor β and interest factor γ . α is obtained through determining the optimal watermarking intensity,based on SNR. β represents different perceptual significances of human visual system(HVS)to smooth,edge and textured regions of image. β is calculated in the l3 space.Due to the HVS selectivity,the inserted watermark intensity is adjusted suitably by γ in the region of interest(ROI),so that the visual effect of the watermarked image can be enhanced.The experimental results show that the algorithm is effective.关键词：digital watermark;image characteristics;perceptual property;wavelet transform2|712|2更新时间：2025-07-16
- 摘要：The signal integrity(SI)of high-speed interconnects on meshed ground/power reference plane in high-speed multilayer PCB is investigated both by measurement and simulation.The analysis is mainly based on experimental measurement which incorporated 3D full-wave EM and circuit and system simulation in frequency and time domain.The frequency characteristics of band-pass(band-stop)is theoretically analyzed which caused by the periodic structure of the meshed ground plane.The results are shown that the transmission characteristics of signal lines across the meshes are largely affected by the meshes on the reference plane.Even the band-stop can appear in the frequency ranges of the transmission signal in part,which can degrade the quality of high-speed signal.Finally,the design rules for high-speed interconnects on the meshed ground plane are derived from the results obtained.关键词：high-speed interconnects;meshed ground reference plane;signal integrity;periodic structure;band-pass (band-stop) characteristics3|1167|2更新时间：2025-07-16
- 摘要：A fuzzy decentralized model reference tracking H∞ output feedback control method for a class of nonlinear interconnected systems is studied based on state observer.First,an equivalent T-S fuzzy model represents the nonlinear interconnected system and fuzzy decentralized observer is designed.Then a decentralized fuzzy observer and model reference H∞ fuzzy controller based on the observer are developed.The sufficient conditions for the stability of the fuzzy decentralized system are proposed by using Lyapunov function combined with linear matrix inequality (LMI).Finally,the simulation example is given to illustrate the effectiveness of the proposed methods.关键词：decentralized fuzzy H∞ control;parametric uncertainties;observer;linear matrix inequalities;stability analysis2|836|0更新时间：2025-07-16
- 摘要：Aiming at fast fading channel,this paper presents a improved first order quantized FSMC model and a new method to validate performance of the model by analyzing the distribution of the error sequence.The simulation is carried out to emulate selection,equal-gain,maxim-ratio combining and no combining in the Nakagammi distribution fading channel and simulations results verify the accuracy of the improved first order quantized FSMC model.关键词：FSMC;Nakagami-m distribution;channel model2|839|0更新时间：2025-07-16
- 摘要：The bird strike hazard is a worldwide problem to aviation,which has received prevalent attention from international academe.The studying of avian detection based on radar has made much progress and some practical radar avian surveillance systems have been set up.A survey of research on radar avian detection,including progress actuality of foreign radar avian detection system,the characteristics of bird echo and the method of identification and detection,are presented.The new research are proposed in three aspects,Geographic Information Systems(GIS),Artificial Neural Network (ANN) and computer network,which are combined with radar avian detection system to set up a high-efficient,real-time,3D radar avian detection network.Finally,several research topics in future are suggested.关键词：avian surveillance;radar;geographic information systems(GIS);artificial neural network(ANN)2|1885|10更新时间：2025-07-16
- 摘要：A novel interdigital-hairpin bandpass filter using multilayered stripline structure is proposed.The new structure can not only reduce the size of the filter,but also provide transmission zeros to improve its stopband characteristics.As an example,a four-pole bandpass filter centered at 2.25GHz with a fractional bandwidth of 31% using the proposed structure is designed,fabricated and measured.The simulated and experimental results show an excellent agreement.关键词：interdigital filter;hairpin filter;stripline;multilayered structure;cross coupling;transmission zero2|1897|3更新时间：2025-07-16
- 摘要：Mumford and Shah’s variational model in the 2-phase piecewise constant case is very efficient in image segmentation.However,if the original image is contaminated by some noise,the level set method for solving the model is very sensitive to the initial level set function and the parameter of the length of the evolving contour.Here we propose a two-step segmentation method,where in the first step,a coarse segmentation is obtained by using some traditional method,and in the second step,the coarse segmentation is used as an initial solution in the variational model.Moreover,we gave a model for adaptively estimating the parameter of the length of the evolving contour,where the parameter is defined as an increasing function of the variance of the noise.Combination of the two-step segmentation and the adaptive estimation model not only enables automatic evolution but also ensures fast and accurate partition.Experiment on some computer- produced images and real images shows that the algorithm proposed here is very efficient.关键词：image segmentation;variational model;partial differential equations2|1165|5更新时间：2025-07-16
- 摘要：Air-or vehicle-borne ground penetrating synthetic aperture radar(GPSAR) has the capability to detect landmines and landmine fields over large area from a standoff distance quickly,which is the trend of landmine detection.In order to reduce the false alarms in landmine detection,it is needed the design efficient detector on the electromagnetic characteristics between landmine and clutter.A 2-dimensional electromagnetic signature modeling method of subsurface metallic landmine in GPSAR is proposed,whose results fit real data collected by the Rail-GPSAR system.Electromagnetic modeling result shows that the image of subsurface metallic landmine has the two-peak characteristic,which will improve the landmine detection performance greatly.关键词：ground penetrating;synthetic aperture radar;metallic landmine;electromagnetic signature2|1072|7更新时间：2025-07-16
- 摘要：In order to effectively preserve SAR image edges while filtering,the authors propose an anisotropic diffusion filtering algorithm for speckle noise based on speckle reduction anisotropic diffusion (SRAD) model.On one hand,it can be proved that the diffusion coefficient in the proposed algorithm theoretically satisfies the conditions for the design of diffusion coefficients presented by Charbonnier,et al;on the other hand,the proposed algorithm can achieve a series of different filtered results,through the simple adjustment of two parameters.One parameter is a threshold of the accumulative histogram in the edge image,and the other one is a threshold of the relative signal to noise ratio.And the algorithm is applicable in different applications,including mapping and applications in which fine details and high resolution are required.The experimental results show that the proposed algorithm has capabilities of efficiently filtering speckle noise and preserving edge and texture features.Moreover,it outperforms the four traditional filtering methods in speckle smoothing,edge and texture preservation and visual assessment.关键词：anisotropic diffusion;speckle noise reduction;SAR(Synthetic Aperture Radar) image;diffusion coefficient;filtering algorithm2|1331|9更新时间：2025-07-16
- 摘要：This paper presents a kind of soft-sensing method of oxygen content in flue gas based on new generalized predictive control (GPC) algorithm.Contrastive measurement of oxygen content in flue gas between soft sensor based on traditional GPC algorithm,zirconia sensor and the method in this paper is done,whose results show that the soft sensor structured by new GPC algorithm can reflect the actual conditions of any period time in boiler combustion process,improves the measurement precision and optimizes the capability of boiler combustion control coefficients.Soft-sensing technique of oxygen content in flue gas based on new GPC algorithm provides a new method for industrial boiler oxygen measurement,paves a new way for key parameters measurement,such as accurate,real-time,on-line soft sensing of gas temperature,and has significant meaning for the realization of combustion system’s closed-loop control and optimization running.关键词：soft sensing;oxygen content in flue gas;industrial boiler;GPC3|679|1更新时间：2025-07-16
- 摘要：A non-unitary non-coherent space-time code is proposed based on full diversity quasi-orthogonal space-time block code.This code can make use of the coherent time of the wireless channel as possible as it can.The conclusion that the proposed code can achieve full algebraic diversity is proved in terms of the definition of algebraic diversity.To exploit the quasi-orthogonal structure for simple decoding an iterative decoding algorithm based on EM algorithm is employed to the proposed non-coherent code.Simulation results demonstrate the iterative decoding algorithm can converge fast and it enjoys a favorable performance-complexity tradeoff.关键词：expectation maximization(EM) algorithm;quasi-orthogonal space-time block code;full algebraic diversity;non-unitary non-coherent space-time code2|655|0更新时间：2025-07-16
- 摘要：A modified genetic algorithm (MGA) for the element spacing synthesis of linear sparse array is described.Under the optimization constraints of the number of element,the aperture and the minimum element spacing,the MGA has been utilized to reduce the peak sidelobe level (PSLL) of the array.It improves the optimization efficiency of GA by the application of real valued coding of chromosome,the manner of individual description allows the GA to search a smaller solution space.For the sake of avoiding infeasible solution during the process of recombination and mutation,constraint matrix and its transforms are designed,and the broad sense crossover operator and mutation operator of GA are applied.When the aperture and the number of elements are a priori fixed,the synthesis of linear sparse arrays using this new method can run with the adjustable minimum element spacing.The flowchart of the MGA and the simulated results confirming the validity and the robustness of the algorithm are provided.关键词：sparse arrays;genetic algorithm (GA);sidelobe level;optimum arrays2|1619|14更新时间：2025-07-16
- 摘要：Magnetic field vector is a function of the satellites position.Autonomous navigation of LEO satellite can be achieved based on the measurement data of the onboard three axis magnetometer(TAM).For the orbit estimation algorithm based on the measurement of the geomagnetic field vector,when measurement data influenced by outliers,filtering occurs deviation,convergence becomes slow and even diffuses.Based on residual orthogonal EKF(Extended Kalman Filter)Fault tolerant filtering method,the instant modifying and fault diagnosis are implemented and the filter obtains stronger robustness.Simulation results show the effectivity of the method.关键词：autonomous navigation;fault-tolerant filter;EKF2|1172|5更新时间：2025-07-16
- 摘要：A rapid and effective shot boundary detection algorithm is proposed.First,the video sequence is mapped into a temporal evolution curve (TEC) by using the L2-norm of HS histogram.Then singularity detection with wavelet is employed to identify the potential shot boundaries in TEC curve.Next then,we utilize intensity of motion intensity and block-based edge direction histogram to distinguish shot boundaries from the false positives caused by rapid motion and complex flashlight scenes.At last,gradual transition is further classified into dissolve,wipe and fade in/fade out.The experimental results compared with other methods achieve satisfying precision and recall of detecting shot boundaries in this algorithm.关键词：shot boundary detection;wavelet transformation;singularity detection;gradual transition;video2|906|7更新时间：2025-07-16
- 摘要：As a precondition for generalized K-distributed clutter model,the speckle component and the amplitude modulated component should obey the generalized Gamma distribution.The paper put forward a model parameters estimation algorithm based on the parameter decoupling technology.This estimation algorithm convert a 4-D nonlinear optimization problem to an 1-D optimization problem,which can not only improve the estimation performance,but also reduce the calculation burden and the number of necessary clutter sample.Finally,the simulation experiment is carried out to prove the validity and veracity of the parameters estimation algorithm.关键词：generalized Gamma distributed;generalized K-distributed;parameters estimation2|1074|3更新时间：2025-07-16
- 摘要：The representation of OVSF codes by copying is developed firstly.Based on this scheme,non-rearrangeable and rearrangeable compact assignment algorithms are proposed.The two algorithms can dramatically reduce the call-blocking rate,as well as the hardware complexity,and leave the system as flexible as possible after each code assignment.关键词：orthogonal variable spreading factor codes;copy;code division multiple access2|1188|0更新时间：2025-07-16
- 摘要：A kind of recurrent fuzzy neural network (RFNN) is constructed,in which,recurrent neural network is used to realize fuzzy inference and temporal relations are embedded in the network by adding feedback connections on the first layer of the network.On the basis of the proposed RFNN,an adaptive control scheme is proposed,in which,two proposed RFNNs are used to identify and control plant respectively.Simulation experiments are made by applying proposed adaptive control scheme on AC servo control problem to confirm its effectiveness.关键词：recurrent fuzzy neural network;adaptive control;AC servo2|1263|6更新时间：2025-07-16
- 摘要：In order to counter the non-stationary short wave radio interference and improve the performance of target detection,a robust least squares interference cancellation algorithm based on the dual-polar receiver was proposed for high frequency surface wave radar.Based on the idea of convex optimization,we modify the sample of horizontal auxiliary channel,and get the best performance of interference rejection in the worst case error circumstance under the limit of maximum error bound.Converting the convex optimization question to simple one dimension search,we get the effective method to settle the optimal weight coefficient.The experimental result shows that the proposed method is very effective.关键词：HF radar;interference rejection;robust least squares;convex optimization2|891|2更新时间：2025-07-16
- 摘要：Due to the desire for real-time information processing of optical imaging system,such as infrared search/track (IRST) systems,we proposed a space-temporal dim target detection method in ego-motion imaging systems.A spatial two-dimensional generalized likelihood ratio test algorithm was employed to extract underlying objects.Then the measurable discriminable feature was combined to a feature vector which was associated with the object.The correct target in image sequence was detected by multistage hypothesis testing(MHT) method using its associated feature vector.The algorithm made a good trade-off between its statistic performance and computing complexity,and had acquired great performance in practical applications.关键词：optical imaging systems;detection of dim targets;track-before-detect;ego-motion2|979|2更新时间：2025-07-16
- 摘要：When the multidomain pseudospectral time-domain(MPSTD) algorithm is used to analyze a complex problem,many types of interfaces will exist in adjacent subdomains of the whole computational domain,exchanging information between subdomains is realized by matching conditions for these interfaces.Because the characteristic variables(CV) matching condition is limited to only apply to some special types of interfaces,an improved characteristic variable(ICV) matching condition is presented for any type of interface,and interface field update relations are obtained for the ICV matching condition.Based on it,a broad wall centered- inclined slot coupler comprised two crossed rectangular waveguides is analyzed by using the MPSTD with the ICV matching condition,agreement of the MPSTD and FDTD numerical results illustrate the accuracy and validity of ICV matching condition.The analysis of a broad wall centered-inclined slot coupler of rectangular waveguide extends also application fields of the MPSTD.关键词：multidomain pseudospectral time-domain(MPSTD) algorithm;improved characteristic variables (ICV) matching condition;slot coupler;centered-inclined slot2|856|2更新时间：2025-07-16
- 摘要：The received signal model of polarization sensitive array is presented under array mutual-coupling condition,then mutual coupling error is decomposed of orthogonal-array-element-factor-error and array-factor-error,which represent signal polarizational information error and spatial information error respectively.Under array mutual-coupling condition,we give the mathematical expressions of some important filtering parameters,such as spatial matching coefficient,polarizational matching coefficient,and the maximum SINR.Then under condition of one interference source,effect of array mutual coupling on filtering performance of polarization sensitive array is analyzed.关键词：array-mutual-coupling;polarization;polarization sensitive array;signal-interference-noise-ratio(SINR)2|953|4更新时间：2025-07-16
- 摘要：It was previously shown that the number of array elements must exceed the number of sources for subspace-based steering vector estimation.This is clearly not practical for a wireless system since the number of mobile users is very large.To overcome the restriction,a blind adaptive technique based on subspace method to estimate steering vector of an antenna array is proposed.By summing the received signals of each element,the superposition of the signature waveforms of expected source is obtained.This superposition is also expressed by a group of bases of the signal subspace by subspace method.Since the superposition involves the steering vectors,the expected steering vector can be estimated without requiring the number of antenna elements being greater than that of data sources.Simulations demonstrate the effectiveness of the proposed algorithm.关键词：antenna array;steering vector;subspace;blind adaptive estimation2|911|2更新时间：2025-07-16
- 摘要：Imaging of Airborne bistatic SAR (synthetic aperture radar) which requires a two-dimensional space-variant correlation is like that of monostatic SAR.Different image algorithms use different approximation to handle the two-dimensional space-variant correlation.Approximation and relation of different algorithms are analyzed:algorithm with ignoring range-azimuth coupling,bistatic range-doppler algorithm,algorithm of straight applying stationary phase principle.The phase approximation of different algorithms is given in analytic.Finally,the simulation is given to validate analytic result.关键词：bistatic SAR;imaging algorithm;two-dimensional space-variant correlation2|920|2更新时间：2025-07-16
- 摘要：Multi-rate models are used to realize a high-grade tracking through the decomposition of the target's original measured results and state model to multi-resolution.A Markov chain is introduced into the interacting multiple model (IMM) algorithm to control the interaction of the several models to realize the tracking of high maneuvering targets.A full-rate tracking method of a maneuvering target by means of interacting among multi-rate models is proposed here.High precision and full-rate of the tracking are guaranteed by interlacing several times' filtering results.Simulation results and analysis demonstrate that compared with conventional full-rate IMM algorithm the new method offers a much better tracking.关键词：multi-rate model;interacting multiple model;maneuvering target;target tracking;data fusion2|732|1更新时间：2025-07-16
- 摘要：A long pulse power supply has been designed and simulation calculated for linac.For the high-energy accelerator,a high efficiency power supply is desired.The conceptual power supply uses only 30 μF storage capacitor that charged directly to the working voltage of klystron via DC supply and then droops approximately 5.59%,3.02% and 1.52% during the 1.5ms,800 μ s and 400 μ s pulse widths.The droops are compensated for by the use of a compensation circuit,and the output pulses are therefore flat to within ±0.50% during those pulse widths.This article is the description of the long pulse modulator calculation.关键词：long pulse power supply;linac;compensation circuit2|1015|0更新时间：2025-07-16
- 摘要：The half space green’s function is utilized to compute the scattering from ships on sea surface lighted by radar wave.The integral function is solved by Method of Moment (MoM) together with GFB algorithm.The surface current and bistatic RCS are computed as a function of the incidence angle,frequency and surface roughness and compared with the results in free space.关键词：half space Green function;GFB;rough surface and ships;scattering2|978|2更新时间：2025-07-16
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