最新刊期
卷 33 ， 期 6 ， 2005
- 摘要：This paper analyzes the beam diretction squint caused by aperture fill time when linear frequency modulated(LFM) signal is used in wideband phased array radar,and classical method of using time delay units(TDU) is also given.According to the characteristic of LFM Stretch processing,digital compensation method of aperture fill time is established.Experiment and simulation results demonstrate that the method is effective.关键词：wideband radar;phased array;aperture fill time;Stretch processing;digital compensation3|1882|8更新时间：2025-07-16
- 摘要：There are both across-track and along-track baseline in Distributed Small Satellites Synthetic Aperture Radar(DSS-SAR),which complicates the correlation of DSS-SAR echoes.After modeling the single-look complex SAR image in DSS-SAR,the new correlation model for DSS-SAR echoes was proposed and derived.According to the relationship between correlation and phase difference of the DSS-SAR image pair,it is proposed that the phase difference of DSS-SAR complex image pair in DSS-SAR includes two parts:one is interferometric phase which is related to terrain elevation,another is azimuth phase which is brought from the along-track baseline and will decrease the terrain height accuracy dramatically.Then a new step,that is applied to remove the azimuth phase,must be added to the interferometric SAR data processing in DSS-SAR and the implementation of the azimuth phase removing step is presented.In the end,computer simulation is given and the results validate the correction of analysis in this paper.关键词：synthetic aperture radar(SAR);distributed small satellites;interferometric;correlation;data processing3|848|4更新时间：2025-07-16
- 摘要：SAR/GMTI is one of the stresses in SAR field.Crucial technique for SAR/GMTI is suppressing the main beam clutter,for the ground-moving target echo is often shaded by main beam clutter (echo from stationary background).First we point out the difference between clutter-suppression method studied (called RDATI) and the traditional SAR/GMTI algorithms (called DPCA),the former is space-frequency procession and the latter is space-time procession.Space-Frequency filter for RDATI is given out.Next we analyze the system parameters that will influence the clutter residue after RDATI suppression.In the third part we analyze the principle and the degree that moving targets echo can be retained after RDATI procession.关键词：synthetic aperture radar;ground moving target indicator;along track interferometer;space-frequency procession;phase compensation error2|959|0更新时间：2025-07-16
- 摘要：Due to the width spread and center shifting of the Doppler spectrum,the "spectrum splitting" phenomena may be drawn in synthetic aperture radar.Based on a proposed double threshold processing,a novel method of blind spectrum splitting is developed.Via a single range unit sampling,the proposed method may correctly realize spectrum splitting without any other auxiliary information.Lastly,simulation experiments and real data are also provided to validate the proposed method.关键词：synthetic aperture radar (SAR);spectrum splitting;double threshold processing;blind splitting solution2|1013|2更新时间：2025-07-16
- 摘要：A fast method for subspace decomposition is proposed.Given the training sequences of a desired signal,the signal subspace and noise subspace can be obtained quickly.The dimension of subspace can be correctly estimated while the signal subspace and noise subspace are acquired.The presented method does not require the formation of the covariance matrix and its eigendecomposition,thereby reducing the computational complexity significantly.Finally,numerical results show that the novel approach can achieve the asymptotic performance of the classical method.关键词：subspace decomposition;matched filter;rank reduction;multistage wiener filter2|1553|28更新时间：2025-07-16
- 摘要：A low-complexity method for signal subspace fitting is proposed based on the multi-stage Wiener filter(MSWF) can span a constringent signal subspace,which is completely equivalent to the Krylov subspace.Secondly,a new criterion function for signal subspace fitting is derived,and then a novel method for direction of arrival (DOA) estimation is developed.Analysis indicates that the proposed method can work very well even in the case where the rank of the MSWF is much lower than the number of signals.Since finding the constringent signal subspace merely involves the forward recursion of the MSWF,does not need to estimate the array covariance matrix or compute its eigenvectors,the proposed method is computationally efficient.Finally,the effectiveness of the proposed approach is verified by numerical results.关键词：reduce rank;multi-stage Wiener filter;direction of arrival;signal subspace fitting2|1013|7更新时间：2025-07-16
- 摘要：The stable adaptive fuzzy control method is proposed for a class of MIMO nonlinear systems whose states are unavailable.This method does not need the assumption that states variables are measurable,and the states variables can be estimated by designing fuzzy observer.It is proved that the proposed control method guarantees the closed-loop system stability and obtains a good tracking performance as well.关键词：nonlinear MIMO systems;observer;fuzzy adaptive control;stability2|991|5更新时间：2025-07-16
- 摘要：A multi-population genetic algorithm is presented for Job Shop scheduling problem targeting to minimize the makespan.The coding scheme of chromosomes is defined based on the process constraints,genetic operators are defined according to job operations,so all chromosomes are feasible.By the competition and sharing mechanism among populations,the computing resource is utilized more efficiently,and prematurity is overcome effectively.These improve the convergence of the multi-population genetic algorithm.Experiments on Job Shop Benchmarks show that this algorithm has good performance.关键词：job shop scheduling;multi-population;competition;sharing;genetic algorithm3|1439|8更新时间：2025-07-16
- 摘要：It is proposed that the electronic equipment test project is a tree construction due to the testing characteristics.So the optimal selection of the whole test project can be decomposed into a set of optimal selection of subprojects or grand-projects.The grey effect measure optimal selection model (GEMOSM) and grey incidence optimal selection model (GIOSM) and their corresponding algorithms are introduced.The GEMOSM method is to convert a multiple-objective optimal selection question into a data comparison question of the effect function with weighted factors through the grey data effect measure processing of project objective attribute.The decision makers can set their decision preferences by tuning the weighting factors of the model.Based on the principle of relative optimum,the GIOSM method is to determine the optimal test project by comparing the degree of grey incidence of the data sequence acquired from the projects under selection and the reference data sequence.Using two proposed models,the paper studies an optimal selection question of three projects in a electronic equipment test.The result shows that these two models and algorithm are simple,intuitive and feasible.And from the view of technology,it is reasonable to apply the grey system theory to the domain of the electronic equipment test.关键词：electronic equipment;test project;optimal decision;grey;model;algorithm2|1298|7更新时间：2025-07-16
- 摘要：This paper presents a method of combined pulse-series coding which is used to suppress range ambiguity in Synthetic Aperture Radar (SAR).This method can suppress,in both range and azimuth,range ambiguity of back-scattered signals.Specially,an azimuth phase shifting method is presented and used in this combined pulse-series coding method to suppress range ambiguity in azimuth.Azimuth phase shifting method is based on the fact that back-scattered signals with range ambiguity are generated by pulses of different eradiating time.Following this method,shift pulses by different phases firstly,and then reverse-shift the back-scattered signals by one of these phases.Consequently,the Doppler history of back-scattered signals will be disturbed except the desired signal whose shifted phase is completely reverse-shifted.关键词：SAR;combined pulse-series coding;range ambiguity;wide swath2|766|0更新时间：2025-07-16
- 摘要：A new method based on wavelet transform for multi-sensor image fusion is presented in this paper.The sensor noise is introduced into linear fusion model.At first,the fusion coefficients of multiple sensors are given based on the maximization of local variance of the desired fusion image.Then,the desired fusion image is estimated by using the multi-sensor images and the fusion coefficients.The experiment results demonstrate that this method can greatly reduce sensor noise and achieve better fusion performance.关键词：image fusion;wavelet transform;linear fusion model2|1098|2更新时间：2025-07-16
- 摘要：A parallel-track range model for spaceborne bistatic SAR is proposed,which has a much higher accuracy compared with classical two-order range model based on Doppler centroid frequency and Doppler FM rate.A wavenumber domain algorithm for spaceborne bistatic SAR imaging is then proposed based on that range model.The quality of images of simulated bistatic echoes focused by the algorithm is much better than algorithm based on two-order range model at the case of large squint angle and high resolution.关键词：spaceborne bistatic SAR;synthetic aperture radar;radar imaging;wavenumber domain algorithm2|1249|18更新时间：2025-07-16
- 摘要：In order to improve the estimation accuracy of the pole in low signal-noise-ratio,it is theoretically analyzed that the signals composed of the exponentially damped sinusoids can be still expressed as exponentially damped sinusoids after the cross-correlation.A new cross-correlation estimator is proposed,and then a novel method of the poles extraction based on the cross-correlation is given.The simulations show that in the same estimation accuracy SNR required by the novel method is 5dB lower than that of the modified Kumaresan-Tufts method or fourth-order cumulants based method.关键词：exponentially damped sinusoids;cross-correlation estimator;poles extracting2|933|4更新时间：2025-07-16
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Accurate and Efficient Calculation of Singular Integrals in Galerkin Method with RWG Basis Functions
摘要：The Galerkin's method solution of electromagnetic field integral equations for electromagnetic scattering problems of perfectly conducting object requires calculation of singular double surface integrals.The RWG(Rao-Wilton-Glisson) vector basis functions are usually applied as basis functions and testing functions.The singularity extraction technique and Duffy coordinate transformations have been traditionally used to treat these singular integrals.A more accurate and efficient method are presented.This new method removes the singularity in the integrand and allows the reduction in dimensionality of original 4-dimensional integrations by using combination of parametric coordinates,relative coordinates,domain decomposition and general Duffy coordinate transformations.The accuracy and good convergence properties of the new method are demonstrated by some numerical examples.关键词：Galerkin's method;electromagnetic field integral equations;singular integrals;singularity extraction technique2|2291|7更新时间：2025-07-16 - 摘要：The theoretical analysis and PIC simulation of a new kind of 35GHz gyroklystron is presented.This gyroklystron has all stages operate at the second harmonic to avoid the use of cryomagnets or heavy and bulky solenoids,and its three cavity's structure can greatly enhance its gain.PIC method is used to simulate this gyroklystron,the results shows that this gyroklystron can produce an output peak power of 249kW with 22.5dB gain and 23.71% maximum efficiency at 35GHz.关键词：gyroklystron;PIC;MIG;microwave circuit;Q value2|1035|7更新时间：2025-07-16
- 摘要：The detection problem of dim signal is studied based on narrowband dual-polarization radar system.Firstly,the descriptions of Instantaneous Stokes sub-Vector Sequences (ISVS) of radar target echo and noise are presented and the statistics of suited distance between ISVS of random polarization EM wave and the anticipant signal are derived.Then,utilizing the suited distance difference between radar target echo and noise to the anticipant signal,a novel detection algorithm is presented through polarization and power accumulation and the radar detection performance can be obviously improved.It can be useful to anti-radar stealthy,early warning and space detection or other applications.关键词：dim signal;detection;instantaneous polarization2|1101|4更新时间：2025-07-16
- 摘要：This paper presents a kind of improved method of correlation estimation demodulation in order to solve the problem of bit error rate of FM-DCSK in digital communication,through analyzing the relation between modulation information and symbol function of two adjacent bits.Simulation results show that the bit error rate is obviously improved in comparison with the former FM-DCSK system under the condition of the same transmission efficiency.关键词：frequency-modulated differential chaos shift keying(FM-DCSK);chaotic modulation;correlation estimation2|939|2更新时间：2025-07-16
- 摘要：This paper gives a new jamming method to GPS navigation user,which could induce GPS user away its aim toward the given wrong section by forming false GPS constellation.This is accomplished through the control of the time delay of distributed transmitter's jamming signal.By this means,it can induce GPS navigating system,like cruise missile or precisely navigating bomb to drift away from their destination to protect important target from damage.Its main advantage is that it can control the falling point of the jammed target to prevent the unpredictable case.This paper also analyzes the existence of area-mapping solution and the possibility to construct a practical system.In the end,it puts forward some theoretic and engineering problems left to be resolved in the future.关键词：GPS inducing system;deceiving jamming;transmittable jamming;time delay parameter2|1093|15更新时间：2025-07-16
- 摘要：Using wavelet-domain hidden Markov models (HMMs) can efficiently improve the performance of SAR image information extraction,where the key problem is how to estimate the hidden state under the influence of multiplicative speckle noise,which is not solved effectually yet.Making use of the principle of turbo iterative decoding in information theory and aiming at SAR image,the paper proposed a new method of turbo iterative estimation for the hidden state,in which the hidden state is estimated alternatively with two different restriction conditions in two uncorrelated sub-spaces,and the posterior probability,as an kind of extrinsic information,is exchanged between the two sub-spaces.The experimental results illustrate that the method has a rather impressive performance and very fast convergence rate.关键词：synthetic aperture radar imagery;wavelet transform;hidden Markov models;Turbo iterative decoding2|701|1更新时间：2025-07-16
- 摘要：The paper presents an improved ω-k algorithm for wide swath spaceborne SAR imagery.When classic ω-k algorithm is used to process space-borne SAR data,the farther distance from reference range,the larger image deformation and worse azimuth focusing quality will limit the width of swath greatly.Based on the ω-k algorithm the equivalent view angle and equivalent velocity compensation are presented to rectify image deformation and improve the azimuth focusing quality.The experiment demonstrates that the algorithm can process wide swath space-borne SAR data precisely and efficiently.关键词：wide swath spaceborne SAR data processing;improved ω-k algorithm;equivalent view angle and equivalent velocity compensation2|839|3更新时间：2025-07-16
- 摘要：GSM based passive radars employ the GSM signal transmitted by GSM base stations as an illuminator.A model of GSM signal,called Multi-Burst Mapping Model (MBMM),which can be convenient to depict the GSM signal data stream,is presented.The mapping structures of multi-burst GSM signal are constructed,and the mapping method is offered.With it,the multi-burst GSM signal data stream can be obtained.In a burst,the whole GMSK modeling phase is generated by compound method,thus GSM signal can be simulated.In addition,many of GSM signal ambiguity functions are observed and a feature of them is found:while the length of data is long enough (more than one frame),they belong to "thumbtack" functions.This feature is investigated in many aspects and validated via Monte Carlo method.关键词：GSM;based passive radar;signal model;"thumbtack" Ambiguity function2|1177|7更新时间：2025-07-16
- 摘要：It is well known that customers' privacy in electronic commerce should be well protected.The solutions may come not only from the ethics education and legislation,but also from cryptographic technology.A scheme for privacy protection in the E-commerce is proposed which is based on the existence of secure 1/2 oblivious transfer.It takes oblivious polynomial evaluation as its technical means to realize privacy protection for online customers and prevent the merchant from cheating efficiently; In addition,the scheme also ensure customers dealing with merchants anonymously.关键词：obliviously transfer;obliviously polynomial evaluation;digital signature;anonymous payment2|1101|4更新时间：2025-07-16
- 摘要：Separating objects touching and overlapping with each other into single ones is very important for the counting and feature extracting.Most of the existing separating algorithms are based on two hypotheses:(1)the touching objects tend to form an acute angle on the contour where objects touched,and/or (2)there would always be a lower optical density at touching points.For colony image,the bacteria cells vary in sizes and touching manners.Many touching cells are short of above hypotheses.A new separating algorithm based on 8-connected contour tracking is proposed in the paper.The boundary of touching-cell was tracked and deleted layer by layer,and judgment was made by the tracking result to determine whether the touching-cell should be separated.The experiment results show the success ratio to separate bacteria touching-cell is 10% higher than the existing algorithms.关键词：touching and overlapping;separation algorithm;8-connected;contour tracking;colony image2|1257|3更新时间：2025-07-16
- 摘要：Verification methods of workflow processes always focus on the control flow,while only a few developments have been done on the verification combining control flow with data and resource information.However achievements of business goals rely on cooperation of three basic dimensions of workflow,called control flow,data flow and resource.Semantics verification is to ensure cooperation correctness of the three dimensions.This paper endeavors semantics verification of large-scale and flexible workflow processes.It firstly presents a formal process model,not only integrating the basic three dimensions for semantics expression,but also using concept of component to facilitate scalability and flexibility of processes.By focusing collaborative logic between components,it then discusses component-based reduction technique and rules,strongly supporting semantics verification of processes.2|786|2更新时间：2025-07-16
- 摘要：A novel de-interlacing algorithm based on moving objects is presented.In this algorithm,natural moving objects,not contrived blocks,are considered as the processing basic cells.And an accurate method is introduced to detect the moving objects with the immune clonal selection algorithm accelerating the search process for matching objects.This algorithm integrates many other de-interlacing methods such as motion compensation,median filtering,Weave and Bob,so it is more adaptive to various complex video sequences.Moreover,it can perform the motion compensation for the objects with not only the translation,but also the rotation and scaling transform.The experimental results illustrate that compared with the block matching method with full search,the new de-interlacing algorithm greatly improve the efficiency and performance.关键词：de-interlace;motion object;motion detection;motion estimation;motion compensation2|1221|0更新时间：2025-07-16
- 摘要：This paper designs the on board SAR real time imaging processor using seven pieces of Xilinx FPGA,which consists of four parallel process units,one CS factor unit,one SDRAM controller unit and one control unit.The system combines pipeline process and parallel process to reduce process time,also combines fixed-point operation and floating-point operation to reduce hardware resource.This system can make image within 33 seconds when works in 100MHz,and the imaging quality can fit for the requirement by testing with the Radarsat raw data.关键词：CS arithmetic;real time imaging processor;FPGA;pipeline process;parallel process3|1195|12更新时间：2025-07-16
- 摘要：The blind multiuser detection based on subspace tracking is studied.An improved detector is proposed.The conventional blind multiuser detectors based on subspace tracking consider only the in-cell users and neglect the inter-cell interference from out-of-cell users,while the improved blind multiuser detector takes into account both intra-cell and inter-cell interference.The observation space of received signal is partitioned into three subspaces,and the tracking algorithm is improved to decompose matrix rapidly.The detector exhibits faster convergence,higher stability and less complexity.关键词：DS/CDMA;blind multiuser detection;subspace tracking2|827|1更新时间：2025-07-16
- 摘要：Based on two parallel linear arrays,a new algorithm of 2-D direction finding under multipath environment is proposed which can estimate (2M-1)(M-1)(M is the pair number of the arrays) directions at most,by sufficiently utilizing the temporal and spatial features of the signal,without the need of searching and parameter matching.In addition,this method can group the DOAs according to different users.Simulation results are provided which prove the validity.关键词：multipath;2-D direction finding;fourth-order cumulants;DOA matrix2|1259|9更新时间：2025-07-16
- 摘要：This paper describes the configuration of a typical time-hopping,pulse position modulated(TH-PPM) signal for ultrawide-band(UWB) systems and the time-domain properties of the Gaussian pulse and its autocorrelation function are derived.An antenna array model for UWB communication systems is introduced and the peak-amplitude pattern is defined and simulated.Simulative results indicate that the beam width grows narrower when the array number gets large.It also provides a rapid bi-searching beamforming algorithm.Simulations show that the convergent steps of the algorithm are between one and fifteen.The algorithm could electronically steer the beam axis to the direction of the source signal and the optimum signal reception is achieved.关键词：beamforming algorithm;antenna array;directivity pattern;auto-correlation function2|1079|1更新时间：2025-07-16
- 摘要：The article analyses the geometry and principle of spaceborne multistatic interferometric synthetic aperture radar (InSAR) system.It is shown that conventional method of InSAR digital elevation model (DEM) generation can not be used here,because of the features of multistatic,large squint angle and space baseline of spaceborne multistatic InSAR system.Two methods of multistatic InSAR geolocation and DEM generation are presented:one is based on Doppler-centroid equation,and the other is based on range model equation.Simulation results show that the two methods are correct.Doppler-centroid equation only makes use of range values between target and satellites,which is nearby the centre of synthetic aperture,while the range model equation can use all range values.So the method based on range model equation is more excellent than another one,which is proved by simulation results.关键词：distributed SAR;spaceborne multistatic formation;InSAR DEM generation;space baseline;range model equation;geolocation2|960|4更新时间：2025-07-16
- 摘要：Based on the geometrical projection of scattering center on the line of radar sight,a technique for reconstructing the 3-D distribution of target is performed in the paper,using multiple 1-D range profiles in different aspect angles.After analyzing the principle of 3-D radar imaging and the mechanism for scattering centers association,an associating and imaging method based on clustering analysis is provided.The imaging experiments based on simulation and measurement data are developed,and experimental result shows the validity and robustness of the performed algorithm.关键词：clustering analysis;association;radar imaging2|1081|10更新时间：2025-07-16
- 摘要：Ground penetrating radar(GPR) is an effective tool to detect mine.Ground penetrating radar target identification needs to distinguish mine and non-mine only,and support vector machines(SVM) can be used to two-class classification problem in practice.This paper analyzed the characteristic of shallow subsurface GPR data,proposed a method of GPR target identification based on support vector machines,and processed measurement data by using the proposed method in time sample,Fourier spectra,and discrete wavelet transform as feature data.The results of processing measurement data show this method is effective.关键词：ground penetrating radar;support vector machines;target identification;mine2|932|4更新时间：2025-07-16
- 摘要：A new method for generating the quadrature GMSK signal,called Direct Decomposing Modulation Phase(DDMP),is presented.The integrated phases of the Gaussian filtered pulse response are turned into two parts:the transient part and the stable part,and the construction of the two parts are analyzed in detail.The transient part is relative only to several near input data bits,its states being finite,which means the transient part can be made into a table to be stored into a EPROM.Although the stable part is relative to the history of all the input data,the triangle function values of it are ±1,which only cause the sign of the transient part changing.A realization scheme for generation of I-Q GMSK signal is designed.The simulating results validate the method,and the wave and the spectrum of the GMSK signal can be measured up to the GSM standard.关键词：GMSK;modulation;transient phase;stable phase2|1295|1更新时间：2025-07-16
- 摘要：The transmission properties of TE-polarized plane wave incident on frequency selective surfaces(FSS) was preliminarily explored by experiment,especially in the elementary geometry,types,the dielectric thickness,loading patterns,and the sensitivities to the varying angles of incidence.The experimental results are described as the following.The resonant frequency of FSS is mainly determined by the elementary geometry and types.The resonant frequency of FSS decreases with the dielectric loading.The transmission ratio and resonant frequency are changed with the different dielectric thickness.The dielectric symmetrically loading can stabilize the FSS transmission characteristic as the angle of incidence is varied.关键词：frequency selective surfaces(FSS);transmission properties;dielectric loading;experimental investigation;resonant frequency2|1132|7更新时间：2025-07-16
- 摘要：T/R modules are the key parts of the active phased array radar.Their design decides the cost,feasibility and the system performance of the whole radar.As the designer usually didn't attach much importance to the stability of the module system,this paper firstly brought forward the stability design of the loop in T/R module system,then its theoretic analysis is made in the case of noise power and the design function to meet the system stability is deduced,finally,several system design methods to solve the problem are suggested.关键词：T/R module;noise power;gain;isolation2|1404|7更新时间：2025-07-16
- 摘要：A new three-dimensional (3D) vehicle location and recognition method based on radar and image fusion is proposed.A vision window,which is obtained by fusing radar filtered information and image intensity information,is employed to determine the translation parameters of vehicle location and to reduce the image processing area and the environmental noises.The pose evaluation function,whose optimum solution determines the rotation parameter,is established based on improved Hausdorff distance,and by this means the computational efficiency and the matching precision are improved.The vehicle recognition is based on location technology,where the vehicle type is determined by the evaluation value of each model at its optimum pose.Experiments on 3D simulation scenario confirm that the proposed fusion method can effectively realize vehicle location and recognition.关键词：multi-sensor fusion;target location;target recognition;3D model3|997|3更新时间：2025-07-16
- 摘要：Aiming at the detection and tracking of multiple point targets distributed in cloudy background,a new method,namely the multi-stages trace association is presented.In the preprocessing,a module based on local auto-adaptive contrast threshold is given to remove the slowly varying clutter and at the same time,the noise with high intensity and the edge of clutter are filtered with a bi-directional high order correlation filter.When constructing deep-searching trees the adoption of searching strategy from both directions can be pruned earlier.In the post processing the energy along the candidate trajectories are accumulated and it can cut the false traces efficiently.Moreover,for the spatial-temporal consistency and continuity of the targets it can lock the true targets as soon as possible.The experimental results show that it can detect and track dim overlapping point targets with arbitrary trajectories accurately.It is advantageous over the traditional correlation algorithms in searching space and time complexity.关键词：and-pipeline;local contrast;bi-directional correlation filter;point target detection3|1498|2更新时间：2025-07-16
- 摘要：We propose a new efficient group signature scheme based on Strong RSA assumption.Because the scheme doesn't adopt knowledge proof signature as building block,it is simple to sign algorithm and verify algorithm in the scheme,so that the primary merit of the scheme is that the total computation of signature and verification is only 9 exponent operations and much less than the state-of-the-art ACJT scheme in computation cost.Finally,we analyze the efficiency of the proposed scheme and show that the scheme is more efficient than group signature schemes such as ACJT scheme in complexity.关键词：unlinkability;group signature;anonymity;coalition-resistant2|1508|13更新时间：2025-07-16
- 摘要：Particle filter is a computer-based method for implementing an optimal recursive Bayesian filter by Monte Carlo simulations.The method may cope with any nonlinear model without any limitations of linearization error and Gaussian noises assumption,so it can be used for the state estimation problem of non-Gaussian nonlinear systems.In order to solve the centralized multisensor sate estimation problem of non-Gaussian nonlinear system,the paper proposes a new multisensor sequential particle filter.First,the general theoretical model of centralized multisensor particle filter is got.Then,a sequential resampling method is proposed according to the characteristics of centralized multisensor system.At last,a Monte Carlo simulation is used to analyze the performance of the method.The results of the simulation show that the new method can greatly improve the state estimation precision of multisensor system.Moreover,it will get more accurate estimation with more sensors.关键词：multisensor;state estimation;nonlinear;non-Gaussian;particle filte2|1152|9更新时间：2025-07-16
- 摘要：Data association,which is one of the key and difficult problems for multi-target tracking,is the decision process of linking the measurements or the tracks deemed to be of common origin under certain criteria.All typical data association algorithms can be deducted into special assignment problems.However,present S-D assignment algorithm only associates the synchronous measurements from different sensors,which only generate the static result.The static assignment algorithm(S-D) has been generalized to the dynamic S-D one by means of combining the measurement set and the track set.On this basis,the circumstance of fresh targets existing is taken into account,and the relationship between the dynamic and the static assignment algorithms is discussed.At last,a Monte Carlo simulation is used to analyze the performance of the method.The simulation results show that the dynamic multidimensional assignment algorithm,proposed in this paper,can steadily track multi-target.关键词：multi-target tracking;Information fusion;dada association;multidimensional assignment3|1201|6更新时间：2025-07-16
- 摘要：Spaceborne parasitic SAR is a typical form of distributed small satellite system.With theoretical derivations,it's found that improving range and azimuth resolution by combination of several images from different small satellites can be explained uniformly by scattering spectrum two-dimension shifting,and improving range and azimuth resolution can be completed at the same time.A processing method is given to combine multiple images for improving spatial resolution of spaceborne parasitic SAR,which compensates spectrum shifts in two directions and fixed phase difference.Regularity of cover area in frequency domain after combination is considered to assure to get high quality images in spatial domain.Simulated data show that theoretical derivations are in good agreement with practice.关键词：spaceborne parasitic SAR;SAR;radar resolution;resolution improvement2|709|0更新时间：2025-07-16
- 摘要：Y-factor method cannot measure the noise figure of RF module with Automatic Gain Control (AGC) because it will change the power gain of the module.A new method of noise figure measurement is presented.The method has two important features:estimation of Carrier-to-Noise Ratio (CNR) in front-end with the knowledge of error rate,thus the effect due to the inconstant amplitude versus frequency characteristic over the measurement bandwidth can be avoided;almost constant total power of signal and noise at input of AGC and constant gain of AGC during the measurement,hence the noise figure of RF module with AGC circuit can be measured accurately.The effects of random error,system error,ambient temperature and measurement times on the estimation of noise figure are analyzed by theoretical derivation and numerical simulation,and the results prove the validity of the method.The research result has been applied to the satellite navigation and positioning System.关键词：noise figure;automatic gain control;carrier-to-noise ratio;error rate2|1290|2更新时间：2025-07-16
- 摘要：A new time domain algorithm which combines Super-Time-Stepping (STS) method and the multi-domain pseudospectral time domain (PSTD) algorithm is presented.This algorithm not only maintains accuracy and flexibility of PSTD for an accurate treatment of arbitrarily curved objects but also frees the explicit time integration scheme from the stability restriction,rendering it as usable as any implicit time integration scheme.Some numerical examples are given to illustrate the accuracy and stability of the proposed approach.关键词：Super-Time-Stepping(STS);multi-domain;pseudospectral time domain(PSTD);stability2|898|0更新时间：2025-07-16
- 摘要：Based on the layered-graph model,an algorithm is proposed for dynamic routing and wavelength assignment in WDM network with limited-range wavelength conversion and limited-count wavelength converters.The computer simulation shows the algorithm performance and the blocking probabilities of the networks on the two limited wavelength conversion conditions.关键词：WDM network;wavelength conversion;dynamic RWA;layered-graph2|1691|3更新时间：2025-07-16
- 摘要：Remote Sensing(RS) image rebuilding based on image feature level data fusion is a kind of image data fusion that is a sort of approach based upon spectral structure and texture feature of the objects.This paper presents feature fusion approach after enhancing remote sensing image edge with wavelet's multi-resolution analysis,and largely improve image's definition and resolving power.In the fusion process,instead of using the conventional HIS-Wavelet fusion,the author used low frequency parts of the R、G、B bands of the multi-spectral image which is decomposed by the wavelet and high frequency parts of the high-resolution image which is also decomposed by the wavelet to process the image fusion separately,and finally the new fusion image is composed by the new R、G、B bands.In this way,the author not only improves the definition and resolution of the multi-spectral image,but also retains the color feature which is important for multi-spectral fusion.At last the author validates the conclusion mentioned above with an experiment.关键词：wavelet transform;feature fusion;edge enhancement2|1106|3更新时间：2025-07-16
- 摘要：A novel and efficient algorithm is proposed to reduce the computational complexity for KNN classification.It uses two important features,the approximation coefficient of a fully decomposed feature vector with Haar wavelet and variance of the corresponding untransformed vector,to produce two efficient test conditions.Since those vectors that are impossible to be the k closest vectors in the design set are kicked out quickly by these conditions,this algorithm saves largely the classification time and has the same classification performance as that of the exhaust search classification algorithm.Experimental results based on texture image classification will verify our proposed algorithm.关键词：K nearest neighbors;wavelet transform;texture classification2|2091|13更新时间：2025-07-16
- 摘要：The sensibility of beams' nulls to the amplitude and phase errors of antenna cells leads to an average losing in suppressing interferences by nulling techniques.In order to improve the suppressing effect of nulling in a practical system,this paper proposes a pre-remedy processing on an ideal constraint model,which obviously takes the influence from antenna errors on pattern nulls.By extending this method,the problem can be solved when the elements of array have directional errors or some element is failed.The simulation results and practical data processing results have shown the effectivity of this method.关键词：null synthesis;amplitude and phase errors;directional error;element failure2|992|1更新时间：2025-07-16
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