最新刊期
卷 33 ， 期 3 ， 2005
- 摘要：A fast approach for analysis of microwave scattering from wind-driven ocean surfaces is developed using the single integral equation with the method of moments.Triangular patches are employed to tightly model the random rough surfaces.The underlying algorithm is the FFT-based multilevel sparse-matrix canonical-grid method.A localized approximation method is introduced for the highly conductive seawater medium.Numerical examples are provided to demonstrate the merits of the proposed scheme.Simulation results are presented for ocean-like surfaces illuminated by microwave beams at L-band.关键词：ocean surfaces;microwave scattering;single integral equation;moment methods;parallel computing2|1209|3更新时间：2025-07-16
- 摘要：Accurate modeling and efficient evaluation are discussed in this paper for electromagnetic scattering from perfectly conducting object penetrating half-space interface by methods based on mixed potential integral equation.Proper Green's functions for half-space are adopted to satisfy the special boundary condition du to the object penetrating the interface and to simplify numerical discretization.Optimization upon the procedure of impedance matrix filling is made in conjunction with tabulation and interpolation for evaluating the Green's functions to speed the generation of impedance matrix.The proposed methods can be used to accurately solve the half-space problems and on the whole overcome the difficulties resulted from object penetrating the interface.关键词：mixed potential integral equation for multilayered media;Green's functions for half-space;Sommerfeld integrals;space-domain interpolation2|832|0更新时间：2025-07-16
- 摘要：Using a full-vector model,we investigate the properties of a kind of high birefringence index guiding photonic crystal fibers.We concentrate on the polarization properties including linear polarization of fundamental modal field,modal birefringence and polarization mode dispersion.Two-fold rotational symmetry was introduced into the fiber structure by creating a regular array of air hole of two different sizes disposed about a pure silica core.The degeneracy of two orthonormal polarized-modes of the fundamental mode was removed.This creates a possibility to attain a modal birefringence of at least one order of magnitude higher than that of conventional high birefringence fibers.A beat length of 0.4067mm is obtained at the wavelength 1540nm.We can obtain much higher birefringence and larger difference of group time delay by choosing different structure parameter of fibers.The numerical results are in very good agreement with the results of experiment.关键词：photonic crystal fibers;birefringence;beat length;polarization mode dispersion2|1449|3更新时间：2025-07-16
- 摘要：The selective operation of pattern sample and abstracting method of typical sample data are discussed in this paper.In order to improve obvious shortcoming existing in neural networks in which error precision and convergent rate will be sensitive to initial weight values, even more depending on them, the Gabor function model of visual perception field is applied to optimize initial weight value of neural networks.In this way a good start in learning process can be provided.It is more important to obtain plastic superiority adaptive to complicated alterable environment for the neural network model,and to implement optimal computing principle in which operation load of structuring element weights in morphological filter can be distributed according to their contributive rate.关键词：computer vision;image processing;mathematical morphology;data abstraction;state optimization2|803|1更新时间：2025-07-16
- 摘要：Theoretical channels model of synthetic aperture radiometer are presented.Based on this model,how amplitude imbalance,phase imbalance and mutual coupling between the different receiving channels effect brightness temperature retrieving is analyzed.The computer simulation results are also presented,in which the cause of the along-track streaks usually appeared in the retrieved image is identified.In addition,a new system calibration approach is introduced to solve this problem: using digital I-Q vector modulators to simulate the point source in the antenna range,we can get more accurate G Matrix to retrieve the brightness temperature image.This new approach,as compared with the existing calibration methods,is especially suitable for in situ use.2|1278|10更新时间：2025-07-16
- 摘要：Signal processing algorithm of LFMPCW signal is analyzed.Based on the traditional algorithm of DFT detection within sliding time window,a new signal processing method,time-domain correlated detection is put forward.In the new algorithm,the range information of target is obtained from correlated processing of radar echoes in time domain,then the range processing of signal can be accomplished along with compensating the radar receiving system,so the new algorithm is more practicable in application.关键词：LFMPCW;time-domain correlated detection;compensation of receiving system2|812|1更新时间：2025-07-16
- 摘要：Due to the aspect sensitivity of high-resolution range profile (HRRP),traditional radar HRRP target recognition methods usually use average profile within some aspect region as aspect template.Actually,the amplitude fluctuation property of HRRPs also represents some feature information of target.According to the scattering center model,a new feature extraction method using the amplitude fluctuation property of HRRPs is proposed in this paper.The weighted HRRP extracted by the new method can represent the scatterer distribution in every range cell,thereby it can describe the scattering property of target better.The experimental results based on the measured data show that the new feature extraction method can improve recognition performances greatly.关键词：radar automatic target recognition (RATR);high-resolution range profile (HRRP);feature extraction;scattering center model;average profile;variance profile2|1388|11更新时间：2025-07-16
- 摘要：Clutter cancellation algorithm for passive coherent detection of weak moving targets in a non-cooperative bistatic radar system using commercial FM illuminating is provided.The algorithm presented a method for canceling clutter with arrival time located exactly at integral sampled intervals,and a method exploiting fractional delay interpolation for better rejection of the interference from strong direct signal and multipath reflected clutters.After direct signal and multipath clutter cancellation,the moving targets can be easily detected and tracked using cascade long-term coherent match filtering of received signal.The efficacy of the method is demonstrated by offline processing real collected data sets as well as real-time processing via a mobile experimental system.关键词：non-cooperative illuminating;passive coherent detection;fractional interpolation;clutter cancellation2|1751|20更新时间：2025-07-16
- 摘要：We establish the relation expression between scattering fields and illuminating fields in local coordinate system.Simulating horizontally polarized and vertically polarized incident waves,we can get all elements of scattering matrix.The result can be used to numerically simulate the distribution of the fully polarized backscattering RCS(Radar Cross Section) of sea fractal surface.The changing of fully polarized backscattering RCS with different directions of flying direction are simulated.The result shows that the distributions of the fully polarized backscattering RCS of different of flying direction are identical among the four sorts of polarization.Our model is the base of fully polarizing radar imaging.关键词：fractal;sea surface;polarization;scattering matrix2|1202|6更新时间：2025-07-16
- 摘要：A correlation attack method on combiners is presented,which is based on multi-linear correlations between the inputs and outputs of combiners.This method can effectively reduce the amount of data needed in correlation attacks.Specially,we apply this method to bluetooth combiners,and reduce the complexity of attack effectively.关键词：stream cipher;combiners;correlation attack;bluetooth combiner2|933|3更新时间：2025-07-16
- 摘要：Based on optical polarization theory and the relation and character among Stokes images,a wavelet based image fusion rule is proposed to reduce the clutter in image based on the character of the Stokes images' energy and noise.The remnants clutter to clutter (RCC) and signal to clutter ratio,which is proposed,are used to evaluate the effect of clutter reduction.Through experiment and simulation,it is shown that this method can work well in clutter's reduction.关键词：polarized character;Stokes images;wavelet transformation;image fusion2|1286|13更新时间：2025-07-16
- 摘要：A Stepped-Frequency Continuous-Wave Ground Penetrating Radar(SFCW-GPR) system with array Vivaldi antenna for landmine detection has been developed.In developing such GPR system,a new antipodal Vivaldi antenna has been designed and constructed.Different from the normal antipodal Vivaldi antenna usually used in microwave and mm engineering,the newly developed antenna with a parallel strip line as its feeding configuration possesses much better properties.An antenna array with ten antipodal Vivaldi antenna elements has been developed.In order to improve the detected landmine images,some advanced signal processing methods,such as synthetic aperture radar(SAR) technique and f-k migration method have been applied to highlight the landmine images.The effectiveness and validities of the above methods for processing GPR Anti-personnel(AP) landmine detection data are studied and compared with each other.关键词：ground penetrating radar(GPR);landmine detection;Vivaldi antenna;SAR technique;f-k migration technique2|2473|20更新时间：2025-07-16
- 摘要：A wavelet zerotree image coding method based on memory optimization and heuristic Depth Finding Strategy (DFS) is presented in this paper.The form of flag and heuristic DFS are introduced in the sorting and refining process.The flag map instead of lists in the refining process is used to keep significant wavelet coefficients.The DFS is used to search insignificant wavelet sets in the sorting process.Therefore,both the memory of coding and the oriented information of sorting are decreased.Experimental results show that compared to the existing wavelet zerotree coding method,the memory is significantly reduced.Although the PSNR is little lower than SPIHT's,it is higher than EZW's and LZC's.This proposed method provides an efficient hardware implementation.关键词：wavelet aerotree;memory optimigation;hearistic depth finding strategy2|922|2更新时间：2025-07-16
- 摘要：In the background of phase ambiguity via using phase interferometer to estimate the direction of arrival,a new method is proposed for estimation direction of arrival by using the second-order of the phase of interferometer array.The possibility of correction is analysed.The conclusion is supported by simulation results.关键词：phase interferometer;estimation direction of arrival;second-order difference of phase2|1040|11更新时间：2025-07-16
- 摘要：The problems on solving resonant frequency of an entrant cavity by classical electromagnetic theory and operator theory are discussed.The classical method for boundary field matching by Green's function of Hφ is discussed firstly.The equation set for Green's function,the boundary conditions and method for solving Green's function are all given.This method can be only used for zero order mode.For higher order modes operator theory is used.The Green's functions of higher order modes,the method for boundary field matching and the calculation for eigenvalues of higher order modes are given.It is an essential condition for solving the problems of axially unsymmetrical coupled cavities system.关键词：operator theory of electromagnetic field;Green's function;coupled resonant cavity;eigenvalues2|1213|0更新时间：2025-07-16
- 摘要：In the Linear FMCW radar,the echo signal of moving target with acceleration has Doppler aberration which will degrade the detection performance and parameter estimation of target.Based on the Polynomial Phase Transform method,the paper first estimates the target's acceleration from the Doppler signal with the polynomial phase transformed,then compensates the Doppler signal with the estimated acceleration,finally,estimates the target's velocity from the compensated Doppler signal.The simulation indicates that the method can improve the detection performance and velocity estimation precision of the accelerated targets.关键词：Linear FMCW radar;Polynomial Phase Transform;Acceleration aberration;Velocity estimation;acceleration estimation2|1172|14更新时间：2025-07-16
- 摘要：The E-cash schemes that are revocable anonymous with the help of trusted third party cause additional costs and the level of anonymity is uncertain.Kulger et al adopted auditable tracing to control deanonymization without trusted third party (TTP),but the users have to audit the tracing frequently.Combining Camenisch et al's method of inserting mark with proof and Abe et al's partial blind signature,a new revocable anonymous off-line E-cash scheme without TTP is proposed.In this scheme the bank demands users to decrypt the mark of the coin when tracing is needed so that the user and coin can be linked together and then user is certain about tracing.So the scheme resolves the problem of the E-cash anonymity control without TTP simply and practically.关键词：e-cash;anonymity control;restrictive blind signature;partial blind signature2|1312|3更新时间：2025-07-16
- 摘要：A method for along-track motion compensation of the airborne strip-map SAR(Synthetic Aperture Radar) is presented.No complex interpolation is involved in this algorithm,hence the high computational efficiency and the improved image quality are achieved.Theoretical analysis,simulation results and the real data images show that it is of great value in real-time imaging.关键词：SAR;strip-map;motion compensation2|1144|14更新时间：2025-07-16
- 摘要：In current pre-FFT OFDM (pre-Fast Fourier Transform Orthogonal Frequency-Division) adaptive antenna systems,the CSI (Channel Statement Information) estimation is made in the element-space and the performance may deteriorate due to its poor anti-jamming ability.An adaptive antenna scheme based on beam-space CSI estimation is proposed to improve the accuracy and robustness of the estimation.The simulation results show that a prominent performance improvement can be achieved.In environments with strong interferences,the proposed scheme still performs well,while the element-space scheme may fail to work.关键词：OFDM;adaptive antenna array;beam-space;CSI estimation3|954|0更新时间：2025-07-16
- 摘要：With the change and development of modern multi-target tracking system,it is very difficult to deal with data association problems simply using the feasible rule based on the hypothesis in which the association of measurements with targets is one-to-one correlated to each other,as is commonly used in JPDA.We have noticed that T.Kirubarajan and Bar-Shalom et al.gave some new results trying to solve the problem.But the performance,especially the computing burden of the algorithm can not be satisfied by most real time systems.In this paper,we put forward a new feasible rule which is more suitable for practical environment of multi-target tracking system.Based on the new feasible rule,we define a new concept of generalized joint event.We present a method to segment the generalized joint event set into two generalized event sets and then a combination method with the two sub-sets is put forward.A Generalized Probability Data Association (GPDA) algorithm is deduced by using Bayesian rule.Additionally,we analyze the performance of GPDA algorithm in various given tracking environments by using Monte Carlo simulation.We compare the computation burden and computing memory with JPDA algorithm.All simulation results show that the performance of GPDA is superior to that of JPDA,and the algorithm has much smaller computation burden than JPDA.关键词：multi-target tracking;data association;generalized joint event;generalized probability data association3|1992|18更新时间：2025-07-16
- 摘要：A natural gradient algorithm with an adaptive learning rate for blind source separation is proposed.The adaptive learning rate only depends on the negative exponential of the square sum of the kurtosis of neural networks outputs.The initial convergence speed is very fast because of large learning rate (according to small kurtosis).After an initial period,the learning rate decreases slowly due to large kurtosis,giving rise to small steady-state errors.Simulation with under-Gaussian as sources and in the instantaneous mixing case shows that the proposed algorithm has faster convergence and smaller steady-state error than those without adaptive learning rate.关键词：adaptive;learning rate;blind source separation;kurtosis2|1597|7更新时间：2025-07-16
- 摘要：Based on the analysis about cyclostationary inflection from the autocorrelation of samples in radio fading channel,a modified real-time K-step channel fading predicting algorithm is proposed.Mathematic derivation,and also error analysis,are finished based on MMSE criteria.Simulating results show that the proposed algorithm with power-control-loop can reduce the prediction error and obtain BER improvement in wireless Jakes channel.关键词：second-order statistic;cyclostationary;long-term channel predicting;cyclostationary area2|960|0更新时间：2025-07-16
- 摘要：Nose-to-nose calibration procedure used to calibrate the bandwidth sampling oscilloscope was established under a premise that the kick-out pulse is proportional to the impulse response of the oscilloscope.Dr.Jan Verspecht and NIST verified it by S parameters.We researched it from the circuit of the sampling head,and found the generation mechanism of the kick-out pulse,which is a different point with before. And drew the conclusion that the kick-out pulse is related to not only the parameters of the circuit but also the strobe pulse,which could not be explained before.And the mathematic expression which is given in the paper shows the correctness of the analysis.Simulations validate it also.关键词：calibration;nose-to-nose;kick-out pulse;broadband sampling oscilloscope2|849|3更新时间：2025-07-16
- 摘要：A sort of effective method to test clutter distribution category is put forward in this paper.First,a clutter observation sequence is transformed by probability density transform method,and then the distribution category of the original sequence is tested by testing whether the transformed sequence is normal distribution or not.For Rayleigh,Weibull and Log-normal distribution clutter,simulation results showed that the proposed method has higher test precision,less calculation burden and stronger universality compared with χ2 and KS test method,and overcomes the above-mentioned test method's shortcomings that they are easily influenced by interval partition,parameter estimation and calculation complexity.Based on clutter test result,the CFAR detector for Multi-class clutter distribution is designed by using OS-CFAR and log-t CFAR detection methods.For the CFAR detectors of given clutter categories,when they don't match up to input clutter categories,CFAR detection performance is simulated and analyzed.关键词：CFAR detection;clutter test;clutter distribution2|1170|6更新时间：2025-07-16
- 摘要：A modified Time-domain Integral Equation (TDIE) method is proposed and used to calculate the transient electromagnetic scattering by arbitrary conducting objects.Some typical targets,including a pie-shaped plate,a cube,a sphere and a specific conical model,are analyzed and discussed using the Implicit Marching-On-in-Time scheme.The present approach gives correct transient responses from conducting objects,and late-time instability is not observed.关键词：time-domain integral equation;method of moments;transient electromagnetic scattering;conducting objects2|951|0更新时间：2025-07-16
- 摘要：A universal forgery attack on the 3F-L digital signature scheme is given.To avoid the flaw of long signature result,a modified version of the 3F-L signature scheme of Nyberg-Ruppel type is proposed.The security and computation efficiency of the modified scheme are analyzed,and the result shows that the security is based on the computational infeasibility of discrete logarithms on GF(p3).关键词：fibonacci-lucas sequence;3F-L cryptosystem;digital signature of Nyberg-Ruppel type2|862|0更新时间：2025-07-16
- 摘要：In the encoding algorithm of H.264,each possible coding mode should be checked to choose the best one for each part of the picture,thus make the process of mode-decision rather complex.In this paper,a fast mode decision algorithm is proposed to reduce the complexity of mode decision procedure in H.264 encoder.,in which possible modes are judged beforehand based on the temporal and spacial correlation and the whole procedure of mode decision is simplified then.The results show that the algorithm can increase the encoding speed by more than 20% at most with little degradation in rate-distortion performance.关键词：H.264;video coding;mode decision2|866|1更新时间：2025-07-16
- 摘要：In urban aerial images,the poor visibility of features in shadowed regions created by buildings prevents recognition of objects.It is necessary to compensate and remove the shadowed region.In this paper,a fuzzy retinex is proposed to overcome the limitation of the well known image enhancement technique—retinex.The fuzzy retinex restricts the center/surround spatially contrast operation in region with homogeneous illumination so that the robustness of retinex is reinforced in scene with strongly variational illumination.Based on the fuzzy segmentation of an image into shadowed and unshadowed regions,shadows are compensated and removed using the fuzzy retinex while the natural tint of original image is retained.The proposed method enriches the research and application domain of the retinex.Experimental results are given to show its effectiveness.关键词：aerial images;fuzzy retinex;shadow removal2|1082|12更新时间：2025-07-16
- 摘要：In order to extend the ability of radar-based air traffic control system to monitor ADS targets,this paper gives an information conversion method to transform ADS targets to pseudo-radar targets.Four steps are demonstrated,including:target tracking,profile estimating,target capturing and data reconstructing,to realize asynchronous conversion of target information.After data conversion,the radar-based air traffic control system can process ADS targets directly without any modification.关键词：automatic dependent surveillance;radar;target;information transform2|1039|3更新时间：2025-07-16
- 摘要：This paper proposes a low complexity partial parallel interference cancellation (LC-PPIC) scheme for an uplink multi-carrier direct sequence code division multiple access (MC-DS-CDMA) system.Specifically the proposed algorithm utilizes the results of channel estimation to classify users as reliable,invalid or ordinary in every subscriber.Reliable users are first subtracted after performing partial parallel interference cancellation (PPIC),while,thereafter,the same process is executed among ordinary users,and invalid users are ignored.Finally,maximal ratio combining (MRC) is carried out for reliable and ordinary users to come up with the final detection results.It is worth noting that the algorithm takes advantage of channel estimation and frequency diversity,achieving improved performance with only a little increase in implementation complexity.Simulation results show that the proposed LC-PPIC detector outperforms both the after-MRC PPIC detector and the before-MRC detector,especially in a high system load and high signal to noise ratio (SNR) case.关键词：multi-carrier direct sequence code division multiple access (MC-DS-CDMA);low complexity partial parallel interference cancellation (LC-PPIC)2|825|0更新时间：2025-07-16
- 摘要：In this paper,a novel improved High-impedance Surface structure is introduced.Using the improved structure,the gain of microstrip patch antenna is increased by about 0.9dB,and the back radiation is decreased by about 15dB.The performance is improved much more than the antenna using normal High-impedance Surface structure.Several antennas are manufactured,and the measured results are basically accordant to simulated results.关键词：photonic crystals;Electromagnetic Band-gap;High-impedance Surface;surface wave;gain;back lobe2|1036|2更新时间：2025-07-16
- 摘要：A novel nonstationary radio interference cancellation scheme was given to improve the performance of target detection in high frequency surface wave Over-the-Horizon radar.First,the optimum algorithm was proposed that suppresses the nonstationary interference to the utmost by modifying the array steering vector under the permitted error limit;then,a method based on the idea of maintaining the sea clutter response was introduced to settle the problem of floor increasing for the reason of the clutter scatter.The interference cancellation frame was synthesized by the two methods at last.And the experimental results show it is efficient to reject the nonstationary interference.关键词：HF radar;interference rejection;beam form;sea clutter maintain2|1215|2更新时间：2025-07-16
- 摘要：A theoretical approach analyzing electrical performance for dielectric loaded dual-layer Frequency Selective Surface (FSS) configuration with dissimilar lattice and element geometries is proposed.The forward and reverse waves are periodic with corresponding FSS respectively,and an explicit description of vectorial propagation as well as of evanescent modes is provided.A group of coupled integral equations is derived by applying tangential electromagnetic field boundary conditions,and electromagnetic properties can be obtained by moment method.Calculation results show that,dual-layer configuration can shape frequency response curves because of the coupling of evanescent modes between FSSs,and electrical performance has great improvements as compared with single-layer configuration.关键词：frequency selective surface;Floquet modes;coupled integral equations;radar stealth2|1580|15更新时间：2025-07-16
- 摘要：Kaisa Nyberg and Takashi Satoh gave some methods for constructing multiple output bent functions in paper respectively,while these bent functions belong to Maiorana-McFarland bent functions.In this paper,an optimizing method for multiple output bent functions in paper is presented by using Cryptographic functions` input-variety compounding reversible transform.As a result,many new multiple output bent functions were obtained,and these functions have following properties:(1)they do not belong to Maiorana-McFarland bent functions;(2)they have highest algebraic degree and maximal number of output bits;(3)they also have good construction number.Moreover,it also means that compounding reversible transform is very useful for constructing good Cryptographic functions and the method is concise and easily implemented.关键词：multiple-output bent functions;compounding reversible transform;reversible matrix;algebraic degree2|808|1更新时间：2025-07-16
- 摘要：With the guidance of the theory of instantaneous polarization time-frequency analysis,the notion of polarization filtering in time-frequency domain is presented for high-resolution polarimetric radar system.Using instantaneous polarization STFT,a novel high-resolution polarimetric radar signal detection algorithm is designed through integration over time-frequency domain.Simulation results verify its feasibility and validity.关键词：polarization;high-resolution;signal detection;instantaneous polarization STFT;T-F polarization filtering2|1038|10更新时间：2025-07-16
- 摘要：We presented a modified approach of weak sinusoid signal detection by using the sensitive dependence on parameters of chaotic system.Through Linear Least Square (LS) method,we find the relationship between the amplitude of weak signal and the characteristic exponent of chaotic dynamical system;we also give the estimator a weak signal amplitude.Theory and simulation study have shown that this approach has high-accuracy estimation and lower computational complexity and is easy to realize in engineering.关键词：weak sinusoidal signal;chaos detection;linear least square method2|1086|12更新时间：2025-07-16
- 摘要：Quick acquisition of satellites signals and positioning is a key technology in the high dynamic GPS receiver's research and development.In this paper,the method for estimating valid almanac for the GPS satellites is introduced,and for the received GPS signals how the Doppler shift components impact the satellites signals acquisition time are analyzed.On the basis of above,a new algorithm for satellites signals quick acquisition is proposed,which can efficiently shorten the warm start time for the GPS receivers.关键词：high dynamic GPS receivers;warm start;quick acquisition of satellites signals2|1133|6更新时间：2025-07-16
- 摘要：Electromagnetic scattering from the one-dimensional fractal rough sea surface under the Gaussian-beam incidence is studied by using the beam simulation method.Compared with the traditional Method of Moment,the difficulty in numerical calculating is avoided for the limitation of the memory of the computer,the validity of the beam simulation method applied to deal with the scattering from the rough surface is analyzed,the dependence of the accuracy of the numerical results on the number of the sub-beam,the polarization characteristics and the fractal dimension is discussed in detail.关键词：fractal rough sea surface;electromagnetic scattering;beam simulation method;method of moment2|880|2更新时间：2025-07-16
- 摘要：A new restoration algorithm was proposed for a solution to the problem of data loss in image signal.To describe the incomplete signal as a function multiplied by a window can turn the restoration task into deconvolution in frequency domain.It has enabled the task to be simple and normative.As the position coordinate of lost segments in arbitrary shape could be indicated by a unitary window function,the algorithm was applicable to restore these lost segments.The paper illustrated the simulation examples and discussed the effect of segment shape and loss amount on restoration.Some ability of the algorithm to connect automatically the boundary was also pointed out in the paper.关键词：data restoration;spectrum decomposition;deconvolution2|751|1更新时间：2025-07-16
- 摘要：The constrained FIR filter design with equality constraints in time-and frequency-domain is considered in this paper.A projected least-squares algorithm is presented.The algorithm consists of a least-squares part providing an analytical initial solution,and a projection part that projects the initial least-squares solution successively onto each equality constraint.An iterative procedure with the algorithm as the iteration core has been applied to minimax design of Nyquist filter.Design examples demonstrate the effectiveness and robustness of the proposed algorithms.关键词：constrained FIR filter;constrained least-squares problem;projected least-squares;Nyquist filter2|1237|1更新时间：2025-07-16
- 摘要：The segment correlation-video integration method using square-law detector for binary phase-coded signals detection under carrier Doppler,in which the signal is successively IF integrated,square-law detected and video integrated,are analyzed.The processing loss formula has been derived.Using the maximum processing loss minimum criterion,the optimum IF integration time is analyzed in two different cases,one is specifying the whole integration time and the other is specifying the detection performance.The results can be used for receiver design of spread spectrum system and navigation system.关键词：binary phase-coded;Doppler;square-low detector;IF integration;video integration;spread spectrum2|1193|10更新时间：2025-07-16
- 摘要：The wavelet based wideband cross ambiguity function can be used for joint time delay and Doppler stretch estimation.But it cannot suppress the effect due to correlated Gaussian noises.A definition of fourth-order wavelant is given by combining the wavelet and the higher-order cumulant.And a higher-order wavelant based wideband cross ambiguity function algorithm is presented based on the definition.This method can overcome the fault of the traditional algorithm and can be used in unknown correlated Gaussian noise environment.The simulation results are presented to demonstrate the effectiveness of this novel approach.关键词：higher-order wavelant;wideband cross ambiguity function;time delay;Doppler stretch2|881|2更新时间：2025-07-16
- 摘要：The design of a novel 1×16 dual-polarized linear microstrip antenna array is introduced.The element is the dual-polarized corner-fed square patch,while the vertical polarization port of the array is fed with a coplanar feed,and its horizontal polarization port is fed with the aperture-coupled feed.In addition,the pair-wise anti-phase feeding technique is used in both feed networks.The experimental results show that the bandwidths of VSWR＜1.5 reach 15% and 13.5% for the two ports,respectively,and the isolation between the dual polarized ports is better than 33dB within the operating bandwidth,whose maximum reaches 43dB.This linear array can be used as a sub-array of spaceborne synthetic aperture radar (SAR) system by connecting it with the active transmitter/receiver (T/R) components.关键词：microstrip antenna;antenna array;dual polarization;isolation;bandwidth;synthetic aperture radar2|3448|6更新时间：2025-07-16
- 摘要：Subband adaptive array processing for mitigation of both intersymbol interference(ISI) and cochannel interference(CCI) in digital mobile communications is proposed in [6].The application of subband filter banks to wideband adaptive antenna sidelobe cancellation is studied and an efficient method is proposed.It has been shown that the signal correlation of main channel and auxiliary channel can be enhanced via exploitation of subband filter banks.So the interference cancellation performance can be improved.Appropriate oversampling can improve the interference cancellation performance further.Computer simulation and real data processing results show that the method is effective and the theoretical analysis is correct.关键词：adaptive sidelobe cancellation;subband filter banks;wideband;correlation2|709|2更新时间：2025-07-16
- 摘要：Wire conical monopole antennas at an arbitrarily conducting ground plane are analyzed by the Method of Moment (MM).The basis function presented by RWG is used to present the current on the surfaces.The triangular basis function is used to present the current on the wires,and a special basis function is used to present the current on the wire/surface junctions.Finally,as an example,conical antennas on a circular and a square ground plane in 400MHz~2100MHz frequency band are analyzed respectively.Numerical results and comparisons show the efficiency of the method and the finite ground plane plays an important role in adjusting the impedance matching.关键词：conical monopole antennas;arbitrarily conducting ground plane;method of moment;triangular basis function2|1194|2更新时间：2025-07-16
- 摘要：Through extracting the local mean value curve of nonlinear and non-stationary data,any complicated data set can be adaptively decomposed into a finite number of Intrinsic Mode Functions (IMFs) which have physical meaning and can be expressed in a kind of joint energy-frequency-time distribution form by the HHT (Hilbert-Huang Transform),a typical realization of the Local Wave Analysis (LWA),so a meaningful instantaneous frequency can be obtained.The method has some good features compared to the other methods,such as having better joint time-frequency resolution than Wavelet analysis,and without cross terms that exist in Wigner-Ville distribution analysis.Therefore,it is especially powerful for analysis of non-stationary and nonlinear signals.In this paper,the mathematic expressions of IMFs and the limit of frequency resolution of the HHT are discussed further,and a new principle and method of adaptive frequency multiresolution analysis is put forward for developing the theory of the LWA.关键词：adaptive multiresolution analysis;Hilbert-Huang transform;local wave analysis2|1134|20更新时间：2025-07-16
- 摘要：To cover the shortage of the existing attitude determination algorithms based on the gravitational field and geomagnetic field vectors observation,a new quaternion-based recursive optimal estimation algorithm is proposed.The unit length of the estimated quaternion is guarantied inherently in the new algorithm.The algorithm eliminates the limitation of knowing the exact geomagnetic field vector which is required in the former recursive estimation algorithms.And the attitude-rate information can be synchronously provided.The simulation results show that the presented method can markedly improve the measuring accuracy.关键词：attitude determination;nonlinear estimation;gravity acceleration;geomagnetic field;quaternion2|1693|5更新时间：2025-07-16
- 摘要：This paper introduces the concept of instantaneous polarization time-frequency distribution(InPol TFD),and presents the definition of instantaneous polarization Wigner-Ville distribution(WVD) and pseudo Wigner-Ville distribution(PWD),which are used to describe the polarization property of radar target's return in time-frequency domain.Next,a feature vector,formed by the singular values of each component of the InPol PWD of target's return,is used as input vector for the classifier based on BP neuron network.The target recognition results show that the proposed method has better performance than conventional one.关键词：instantaneous polarization;time-frequency distribution;target recognition2|695|5更新时间：2025-07-16
- 摘要：The IETF has addressed the congestion control by advocating the deployment of active queue management mechanisms,such as RED,in the network.But RED has some problems,such as the average queue length changes slowly when congestion starts and ends.To alleviate this problem,we propose a dynamic-weight tune RED which can quickly be conscious of the congestion and dynamically tune the weight.Dynamic-Weight RED can alleviate the congestion and drop when the congestion is over.The time of congestion is shorter than the RED.关键词：RED;dynamic weight;congestion control2|967|1更新时间：2025-07-16
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