最新刊期
卷 39 ， 期 9 ， 2011
- 摘要：A low angle estimation method based on beam-space domain in very high frequency (VHF) multiple-input multiple-output (MIMO) radar is proposed.The multipath signal model for MIMO radar is constructed with both transmitted multipath and received multipath signals being considered.Firstly,some receiving beams are formed.Secondly,a matched filterbank is used to extract the transmitted orthogonal waveform components.Thirdly,some transmitting beams are formed at the receiving side.Thus,the array data is mapped from element space into beam space.Finally,a modified generalized multiple signal classification (MUSIC) algorithm is developed for angle estimation after beam-space pre-processing.Compared with the element-space processing,the proposed algorithm has nearly the same estimation precision and owns lower computational burden.Theoretical analysis and computer simulation results demonstrate the merits of the new algorithm.关键词：multiple-input multiple-output radar;angle estimation;multipath;beam space;generalized multiple signal classification2|1780|6更新时间：2025-07-16
- 摘要：The slanting flight mode bistatic SAR system has a flexible configuration and broad application prospects.However,because of the transceiver platform's movement in the range direction,the equation of instantaneous slant range gets very complex,and motion compensation also becomes rather difficult.Through an analysis of squint flight mode geometries,the thesis expounds the keystone of motion compensation in the range domain on slant flight mode,and presents two methods of motion compensation-the taylor approximation method and model approximation method.Then through analyzing the echo which has compensated the deviation in the range domain,the bistatic SAR Algorithm with range walk correction in time domain is conducted completely.Simulation results show that the motion compensation model approximation method is superior to the first-order taylor approximation method,and is equal to the second-order taylor approximation method,as well as verify the effectiveness of the method of slanting flight mode bistatic SAR imaging.关键词：slanting flight;bistatic SAR;motion compensation;range walk correction in time domain2|1251|5更新时间：2025-07-16
- 摘要：The micro-Doppler (m-D) effect,which provides a new approach for accurate auto radar target recognition,has attracted great research attention in recent years.In this paper,the multi-input multi-output (MIMO) techniques are introduced for the m-D feature extraction.Based on the analysis of m-D effect induced by radar target with rotating parts in multi-carrier MIMO radar,an algorithm for three-dimensional micro-motion feature extraction is proposed.In the algorithm,the Doppler frequency shift induced by the target body is eliminated from the time-frequency plane of echoes,and the parameters of the curve skelectons on the time-frequency plane are extracted by utilizing the Hough transform,then the three-dimensional micro-motion features can be obtained by solving nonlinear multivariable equation systems.Simulations validate the effectiveness of the algorithm,and the robustness of the algorithm is also analyzed.关键词：micro-Doppler;multi-input multi-output (MIMO);target recognition2|1351|4更新时间：2025-07-16
- 摘要：The paper analyzes the circular loop antenna based on the theory of Maxwellian circuits,and the current distributions of the antenna are obtained.Results are verified by moment methods,the good agreements prove the efficiency and correctness of the analysis in the paper.Through closer investigation on the second order MC equation,we deduce the current's analytical formula of the circular loop antenna.The formula suits to compute the circular loop antenna of any size.The results of the paper have certain reference significance to more complicated electromagnetic structures.关键词：the theory of Maxwellian circuits (MC);circular loop antenna;method of moments (MoM)2|1219|0更新时间：2025-07-16
- 摘要：For the purpose of overcoming the influence of non-ideal factors on the performance of the radial velocity estimation,such as the channel gain and phase response error and image registration error,a new match filtering algorithm based on modifying the steering vector with the optimal weights for Wiener filtering is proposed.The validity and superiority of this method are experimentally verified by the simulated and real synthetic aperture radar (SAR) data.The results illustrate this method has a good robustness to image registration error,channel response error and the pixel correlation of the SAR image.关键词：ground moving target detection;clutter rejection;target parameter estimation2|1378|6更新时间：2025-07-16
- 摘要：Aiming at the problem of underdetermined blind identification,we propose a method of blind identification of underdetermined mixtures based on spatial time-frequency distributions (TFD).First calculate the spatial time frequency distribution of the mixtures,stack the TFD matrices corresponded to the auto-source time frequency points in a new matrix with higher dimensions,and finally estimate the mixing matrix by simultaneous matrix diagonalization and eigenvalues decomposition.The assumption that the sources are sparse or independent is not necessary for the proposed method.Furthermore,we increase the robustness of the method by detecting the auto-source points with enough energy.Simulation results indicate that the proposed algorithm estimates the mixing matrix with higher accuracy compared to the other algorithms at the same SNR.关键词：blind identification of underdetermined mixtures;spatial time frequency distributions;simultaneous matrix diagonalization;eigenvalues decomposition2|1096|3更新时间：2025-07-16
- 摘要：Based on the quaternion formulation of Maxwell equations,a pure biquaternion model (PB-MODEL) for electromagnetic vector-sensor array is proposed.Theoretical analysis shows that the pure biquaternion data covariance matrix can decorrelate the coherent noise among the electric or magnetic antennas of a vector-sensor.As a result,the corresponding pure biquaternion multiple signals classification algorithm (PB-MUSIC) can be extended to coherent noise cases. Numerical simulation verifies the correctness of our algorithm and the analytical results.关键词：biquaternion;electromagnetic vector-sensor;vector-sensor array;electromagnetic source localization2|1621|1更新时间：2025-07-16
- 摘要：The basic scattering theory of single-port antenna is illustrated in both the frequency-domain and time-domain clearly,in this paper.The polarizations of detecting antenna,detected antenna,and receiver antenna are included in the analytical course.The structural mode scattering and the antenna mode scattering are separated in the time-domain intuitively.Based on the analysis procedure above,some basic approaches of controlling antenna scattering are given.This work will serve as a good candidate for the future design of antennas with a requirement of scattering control.关键词：antennas;scattering;structural mode;antenna mode2|1352|1更新时间：2025-07-16
- 摘要：In traditional quantum-inspired evolutionary algorithm (QEA),a quantum rotate gate is the main operator in a quantum population evolution.However,the choice of rotate angle is also discrete and constant,which makes the search of the problem easy to fall into local optimum.Therefore,a modified quantum rotate gate is proposed in this paper.The new gate uses adaptive method of calculation of rotation,which makes the population have a relatively good global search capability.At the same time,the probability amplitude is modified after rotation to enable population to jump out of local optimum.For data clustering problem,a quantum-inspired evolutionary algorithm based on the modified quantum rotate gate is proposed.The simulation experiment results show,compared with the algorithm based on a normal quantum rotate gate and some of other evolutional algorithms,the proposed algorithm increases correct rate of data clustering.At the same time,the simulation experiment results on the data sets of symmetrical distribution property show,compared with the algorithms adopting a symmetrical distance measure,our algorithm also achieves better results.关键词：quantum-inspired evolutionary algorithm;data clustering;quantum rotate gat2|1907|4更新时间：2025-07-16
- 摘要：Aimed at the problem that α-stable distribution has no closed form expression for the probability density function (PDF),an approximate expression is suggested.Such model is a mixture of Gaussian and Cauchy with bi-parameter.The mixture ratio is determined by fractional low order moment (FLOM).Proposed model has a complete closed form and provides analytical convenience.Based on such model,this paper further proposes a Rao statistical test method for the detection of sine signal under the α-stable noise environment.We illustrate the detection performances of the proposed Rao test for various α, and compare them with the Rao test that based on Gaussian assumption.Simulation results show that the proposed Rao detector distinctively outperforms the Rao detector that based on Gaussian assumption.关键词：signal detection;Rao test;α-stable distribution2|1174|5更新时间：2025-07-16
- 摘要：In this paper,we proposed two new video defogging algorithms based on fog theory.One is regarding fog as the veil layer to be subtracted,and the other is taking fog as the transmission map to be separated from the original video.The former uses the luminance component image obtained by Retinex algorithm and the depth information of the original video frames to separate the veil layer.The latter applies a single transmission map obtained from the background image to a series of video frames.Experiments show that both algorithms can effectively improve the contrast and quality of the video frames.Compared with other state of the art algorithms,our algorithms restore video frames from a perspective of fog with no reference image and low computation cost.The new algorithms can remove fog effectively as well as provide a good practicability and a fast speed.关键词：fog theory;video;defog;veil layer;transmission map2|2342|13更新时间：2025-07-16
- 摘要：Application-specific instruction-set processors (ASIPs) with extended instructions (EIs) can effectively improve performance and meet time-to-market requirements.However,there are three problems to be solved when customizing EIs for embedded systems.First,design space increases exponentially as applications become more complex.Second,limited on-chip resources restrict the number and complexity of EIs.Third,current instruction-set extension (ISE) algorithms can hardly run on embedded systems due to their high complexity.We propose a fast automatic method called GISEES to address these problems.GISEES can effectively prune design space by enumerating EIs around typical operations of applications,and reduce resources overhead and the number of inserted multiplexers through sharing resources based on finding the maximal common equivalent substring (MCES).Experiment results show that,GISEES features linear complexity and can generate EIs with higher efficiency,which means it is more suitable for customizing power efficient instruction-set extension.关键词：extended instruction;instruction enumeration;instruction selection;resource sharing2|1032|2更新时间：2025-07-16
- 摘要：This paper presents an approach to scene classification,which unifies local features and filterbank features to capture rich representation information,and extracts spatial context information using the spatial pyramid matching (SPM) model.The proposed method has four characteristics.First,filterbank features are successfully embedded into the SPM model by a transformation method.Second,in the transform process,downsampling and average pooling are used to achieve good balance between spatial density and spatial extent.Third,filterbank features and local features are combined to represent images for more discriminative power.Fourth,the complementary information is extracted in pixel and modulation domains.Promising experimental results on three datasets demonstrate the effectiveness of the proposed method.关键词：context-based representation;spatial pyramid matching;pixel domain;modulation domain;scence classification2|1563|8更新时间：2025-07-16
- 摘要：In this paper,impacts on SAR/GMTI of the jamming which imitating micro-motion targets is developed focused on a Multi-Aperture SAR/GMTI system which based on Fractional Fourier Transform.Firstly the FrFT and the FrFT SAR/GMTI method were introduced.Secondly the response of the amplitude characteristic after clutter cancellation and interference phase were straightly reached,combined with analyzing the Doppler perspective of physical significance of the jamming,it easily got the jamming effects to SAR/GMTI.The expression of the amplitude and the phase were presented under the circumstance of matched rotating angle of FrFT.All the results were verified by computer simulations.It shows that the micro-motion jamming is efficiency in not only imaging but also GMTI.In the end,it gives some parameter choice advice for the jamming.关键词：SAR;moving target detection;fractional Fourier transform;micro-motion;jamming2|1213|3更新时间：2025-07-16
- 摘要：Tracking-before-detection (TBD) is well suitable for radar detection and target tracking of low-observable objects.Probability hypothesis density (PHD) filter is regarded as an efficient solution to multitarget tracking problem.However,PHD filter is hard to use in multitarget TBD problem directly.By discussing the applicable model and hypothesis,a "standard" multitarget measurement model for TBD and "Poisson" noise are presented.Consequently,a PHD filter application to multitarget TBD problem,with analytical weighting coefficient,is deduced and can exploit the power of PHD fully.Numerical simulations show our approach has better performance than multitarget particle filter.关键词：radar detection;multitarget tracking;track-before-detect;PHD filter6|2422|15更新时间：2025-07-16
- 摘要：The micro-Doppler effect based on the inverse synthetic imaging ladar is studied,and the influence of the high carrier frequency and the bandwidth of laser signal on the range profiles is also analyzed.Furthermore,the corresponding parameters equation of micro-Doppler is constructed and then the influence of the fast-time on the micro-Doppler effect is also discussed.Based on the Extended Hough Transform and the erosion and dilation operations in binary mathematical morphology,a novel extraction method of micro-Doppler effect is proposed for the inverse synthetic imaging ladar accordingly.The simulations are given to verify the theoretical derivation and the validity of the proposed method.In addition,the validity of the measurement of the inverse synthetic imaging ladar for the micro-motion at the centimeter-level or the millimeter-level is also illustrated in the simulations.关键词：inverse synthetic aperture imaging ladar;micro-Doppler (m-D);binary mathematical morphology;Hough transform;target recognition2|1202|4更新时间：2025-07-16
- 摘要：The ground clutter of the non side-looking airborne radar (non-SLAR) is range-dependent,which makes the ground clutter Doppler distribution widen in the space-time domain.When the range ambiguity is considered,the short and far slant range clutters are mixed.Although the existing range-dependence compensation methods can mitigate the range-dependence of the short slant range clutter,they change the space-time distribution of the far slant range clutter.It severely decreases the performance of the space-time adaptive processing (STAP).We propose a range ambiguity clutter compensation method which adds the constraint protection of the far slant range clutter based on the registration-based method (RBC).When the proposed method is applied to the range ambiguity clutter,it can not only mitigate the range dependence of the short slant range clutter,but also keep the distribution of the far slant range clutter unchanged.Moreover,the proposed method can achieve good performance when the antenna error exists in the clutter data.The computer simulation results show the validity of the proposed method.关键词：range ambiguity;non side-looking airborne radar;registration-based method;antenna error2|1030|2更新时间：2025-07-16
- 摘要：Underdetermined blind source separation (BSS) is discussed.Based on time-frequency analysis,an underdetermined BSS method is developed,in which sources are not necessarily sparse or independent mutually.First,we compute a sequence of matrices of time-frequency distributions (TFDs) and obtain the auto-source TF points,then we fold the TFD matrices into a third-order tensor and calculate the mixing matrix by tensor canonical decomposition,finally we obtain the sources by calculating the pseudo-inverse matrix and TF synthesis techniques.The simulations demonstrate that the proposed method outperforms the existing methods in performance significantly.关键词：underdetermined blind sources separation;time-frequency distributions;tensor canonical decomposition;time-frequency synthesis2|1105|9更新时间：2025-07-16
- 摘要：It is a challenge to detect or recognize targets with fast complex motion for high range resolution radar,by reason of migration through resolution cells (MTRC) during the observing time.Aiming at solving the problem of MTRC for rotating targets,this paper proposes a new method named Segmental Pseudo Keystone Transform (SPKT),to correct the MTRC.Observed data is divided into pieces obeying the rules firstly.Each piece of data is processed by the SPKT to realize MTRC correction.And then,data processed is put together to level the HRRP in the whole observing time.Based on which,coherent integration is carried out during the accumulation time.The fast realization is achieved by employing the Discrete Match Fourier Transform (DMFT).Computer simulations demonstrate the validity of this algorithm.关键词：fast rotating targets;segmental pseudo Keystone transform;migration through resolution cells;discrete match Fourier transform2|1374|5更新时间：2025-07-16
- 摘要：The arraying combining performance in deep space network is seriously affected by interference signals.The SNR formula of the combining signal with interference signals is derived.The phase residual estimate algorithm is analyzed by use of the cyclic cross-correlation,and another estimate algorithm of BPSK signals is presented based on the cyclic auto-correlation.The two methods are firstly used in the arraying signal combining.Theoretical analysis and simulation results show that both the two methods have highly phase difference estimation accuracy and interference suppression ability,without additional computation complexity.Compared with the cyclic cross-correlation,the cyclic auto-correlation has higher estimation accuracy and combining performance under conditions of low SNR,and has lower exchange data rate between the antennas.However,there are more cyclic frequency options for cyclic cross-correlation.关键词：antenna arraying;interference suppression;BPSK signal;cyclic correlation2|1056|3更新时间：2025-07-16
- 摘要：A new method is studied in this paper for the synthesis of nonuniform linear antenna arrays with shaped power patterns.The method at first finds a satisfactory power pattern for the required radiation characteristics by solving a constrained linear least-squares problem.Then,factorize the polynomial associated with the power pattern by using polynomial root-finding,and consequently obtain the corresponding field patterns.Finally,the forward-backward matrix pencil method is used to obtain a nonuniform linear array with optimal excitation amplitudes,phases and locations for any choice of field patterns.The weighted least-squares solution of element excitations is compared in performance with the non-weighted solution,and the coupling effect between antenna elements on the array synthesis performance is also studied.Numerical results show the effectiveness and robustness of the proposed method.关键词：nonuniformly spaced array;power pattern synthesis;polynomial rooting;matrix pencil method2|2254|2更新时间：2025-07-16
- 摘要：A new multi-channel SAR-GMTI algorithm based on DPCA-FrFT is proposed,which can work on raw data and SAR image.According to the chirp characteristic of DPCA signal,we introduce the FrFT to detect the moving target and estimate the position,velocity and radial acceleration of the moving target,which lead to an overall and accurate description on motion parameters.Then according to the parameters,we apply the FrFT to compress the raw data on azimuth direction,or repositioning and focusing the moving target in the original SAR image.The proposed approaches take the full advantage of the excellent antinoise ability of the FrFT and ideal clutter cancellation of DPCA technique,and an exact SAR-GMTI image can be acquired in a clutter-rich and low SNR environment.The results of the simulation indicate the efficiency and availability of the methods.关键词：SAR;GMTI;multi-channel;DPCA;FRFT2|1289|3更新时间：2025-07-16
- 摘要：Through deriving the matrix representations of the critical-sampled FMT system and analyzing the components of FMT signal,a new subchannel frequency-domain equalization algorithm is proposed based on maximizing the subchannel signal-to-interference-plus-noise ratio to eliminate the intersymbol interference(ISI) in critical-sampled FMT system.Simulation results show the bit error ratio (BER) performance of the proposed algorithm and its superiority in comparison with that of the previously proposed DFE equalization algorithm and the frequency domain equalization algorithm based on minimum-mean-square-error rule.关键词：Equalization;filtered multitone modulation;ISI;MSINR2|1235|0更新时间：2025-07-16
- 摘要：Non-uniformity correction(NUC)of infrared focal plane array(IRFPA)is the development direction of the future and the basic guarantee to gain high quality thermal imaging system.As both super-resolution restoration and NUC algorithm based on scene need the micro-displacement that between image sequences,we propose super-resolution image restoration and non-uniformity correction algorithm based on Poisson and Markov model maximum a posteriori (MPMAP) focus on infrared low resolution image sequences with non-uniformity noise.The results of simulator image sequences and real infrared thermal image sequences show that the algorithm is presented not only has high super-resolution performance for the image degraded with random noise,but also eliminate the fixed pattern noise effectively.关键词：infrared image;image sequences;micro-displacement motion estimation;non-uniformity correction(NUC);image restoration;Poisson and Markov model maximum a posteriori(MPMAP)2|1346|5更新时间：2025-07-16
- 摘要：For multiple input multiple output (MIMO) system using space-time block codes (STBC) with directional interferences,especially with strong directional interferences in military communication scenario,effective interference suppression is necessary to avoid system performance degradation.An iterative maximum-likelihood decoding (MLD) scheme is presented.The proposed scheme estimates equivalent channel matrix instead of real channel matrix to perform interference suppression and decoding through noise subspace projection;reduces bad effect of channel estimation error on decoding performance,and realizes MLD of STBC block by block instead of frame by frame with less searching calculations by accumulating the increment of cost function iteratively.Simulation results show that the proposed scheme is valid to suppress interference and less sensitive to the length of pilot symbols,which is more flexible in practical applications.关键词：multiple input multiple output (MIMO);space-time block codes (STBC);maximum-likelihood decoding (MLD);interference suppression;noise subspace projection2|1306|0更新时间：2025-07-16
- 摘要：Shape is a very important attribute of objects,and it plays an important role in image retrieval.Pyramid of histogram of orientation gradients (PHOG) is a powerful expressive description of object shapes.But it has a poor performance in searching images with a nature background.The distribution of image energy field among different frequency domains can be obtained by wavelet decomposition,so the wavelet character can be used in image retrieval.In this paper,a new wavelet pyramid energy distribution character is extracted from images,and is dynamically combined with PHOG character in an image retrieval framework based on SVM classifier.Experiments on a Corel image subset show that our method has a better effect than methods only using PHOG shape description character or wavelet pyramid energy distribution character.关键词：PHOG;wavelet analysis;shape character;SVM classifier;image retrieval2|2719|6更新时间：2025-07-16
- 摘要：Based on real-valued property of the non-circular sources,a new virtual array beamforming method for the uniform linear array was proposed by extending the original array utilizing the conjugate data of the real array.By analyzing the performance of the method in adaptive beamforming,some improvements were made and a computation saving method was proposed.Preserving both the time and the direction information,the virtual array is very applicable for adaptive beamforming.It provides much better performance than the original array,such as better beam pattern,higher array gain and the abilities to restrain interferes more than the freedom degrees.Several computer simulations were provided for illustrating the advantages of the proposed method.关键词：array signal processing;beamforming;virtual array;non-circular signal2|2093|4更新时间：2025-07-16
- 摘要：Traditional statistically-based SAR image change detection is usually limited by imaging conditions.We propose an unsupervised change detection algorithm based on the image inherent geometrical structures.Firstly,an approximate complete data set is constructed to describe the image local features via fuzzy derivatives,and then a feature vector space is made to represent the image inherent structures using image local neighborhood information and spatial correlation.Finally the change map is produced by simulated annealing-based k-means (SAKM) clustering arithmetic.Experimental results show great detection performance both in contour and region.Besides,it is robust to noises and registration.关键词：synthetic aperture radar (SAR);local jet;unsupervised;SAKM clustering;change detection4|1628|7更新时间：2025-07-16
- 摘要：Based on the global orientation,the local gradient and the mutual information function,a novel fingerprint orientation field fusion algorithm is proposed for incomplete fingerprint orientation field reconstruction.First,according to the properties of competition of the local fingerprint,complementation and redundancy of the global fingerprint,the gradient dispersion function is proposed,adaptively.Then,the fingerprint orientation field of the incomplete area is re-computed and measured by mutual information function.And hence the fusion orientation field is used for Gabor filtering and minutiae matching.The experimental results indicate that the proposed algorithm is effective for incomplete fingerprint.关键词：incomplete fingerprint;Information fusion;orientation field;gradient dispersion;mutual information2|1057|2更新时间：2025-07-16
- 摘要：It is confirmed by the field test that the power density of sea clutter received by the coherent radar varies in the Doppler domain,while the distribution of the amplitude of the Doppler frequency component can be mathematically modeled by the Rayleigh distribution or the Weibull distribution.A novel method for the constant false alarm rate (CFAR) detector with bi-thresholds is proposed.The proposed detector is implemented with a serial structure and has the ability for both threshold estimation and the CFAR.In addition,the proposed detector can tremendously outperform the traditional column window detector with nearly the same computational complexity.The simulation results show that the proposed method can achieve a gain of 9 dB in the term of the signal-to-noise ratio (SNR) compared to the column window detector with the false alarm probability of 10-5 and the detection probability of 90%.关键词：constant false alarm rate (CFAR);coherent radar;range-Doppler;sea clutter2|1765|6更新时间：2025-07-16
- 摘要：This paper proposes a novel method for calculating the radiation and scattering patterns of large arrays.Approximate expressions of the proposed method are derived based on the active element pattern technique and the principle of superposition.With the expressions,the large array analysis problems are converted into two simplified small array problems and the computational cost is considerably reduced.In addition,the effects of the mutual coupling and the surrounding array environment are rigorously accounted for.Example arrays of microstrip patch antennas are analyzed to assess the proposed method.A good agreement between the results calculated by the proposed method and the ones simulated by HFSS validates the accuracy of the proposed method.关键词：antenna arrays;radiation;scattering;active element pattern2|1468|5更新时间：2025-07-16
- 摘要：In future Mobile Internet,co-operation among heterogeneous networks will provide users with seamless services.Mobility of terminals and burst arrival of services cause disproportional network load distribution in time and space domain,which is a key factor influencing network performance.Adaptive radio access control scheme is an effective approach for load balancing among heterogeneous networks,improving utilization of radio resources.Firstly,a new dynamic load balance policy based on terminal mobility and service arriving cognition is proposed.Furthermore,according to statistic analysis of service arriving data,an adaptive radio access control scheme based on users' cell resident time is raised.It is realized through terminal classification and mobility modeling.Finally,performance of the above scheme is verified by simulation results.关键词：radio access control;service arrival;heterogeneous networks;load balance2|1225|3更新时间：2025-07-16
- 摘要：Although there are many implementation schemes for the ultra-wideband communication system now,there are not many researches done on the comprehensive performance evaluation and application scenario analysis.This paper describes the research status of the ultra-wideband technology,analyzes its potential application scenarios,and presents the implementation model for the ultra-wideband communication system.Based on the researches and application scenario analysis of baseband modulation,anti-multipath processing,spread spectrum and frequency carrier technologies in the ultra-wideband communication system,and taking the communication rate,communication distance,implementation complexity and power consumption as the main evaluation criteria,this paper provides the application scenarios of typical implementation schemes for the ultra-wideband communication system,including 12 kinds which meet the power spectrum density limit and 6 kinds which do not.The researches are significant in the optimized design and diversified development for the ultra-wideband communication system.关键词：ultra-wideband communication system;implementation schemes;application scenarios;communication rate;communication distance2|1927|1更新时间：2025-07-16
- 摘要：The cognitive ultra-wideband (UWB) adaptive pulses design method is presented based on Hermite matrix eigenvectors and polycycle signal to make the UWB system coexist with the existing narrow band systems.Simulation results show that the power spectral density (PSD) of the proposed adaptive UWB pulses meets with Federal Communications Commission (FCC) indoor and outdoor spectral mask and produces adaptive spectral notches.Finally,according to analysis and simulation of multi-user interference (MUI) suppression and narrow band interference (NBI) suppression for pulse amplitude modulation-time hopping (PAM-TH) UWB systems,the proposed adaptive UWB pulses have anti-interference ability.关键词：ultra-wideband;polycycle pulse;Hermite matrix;spectral notch;interference suppression2|1016|0更新时间：2025-07-16
- 摘要：The direct anonymous attestation proposed by Brickell adopts an anonymous scheme which is "all or none" for verifiers,and the direct anonymous scheme is applicable for only a few scenarios,which can not satisfy the needs in several cases.To design a flexible anonymous scheme becomes a critical issue for deploying the trusted computing platform.We analyze the problems of the anonymous scheme and propose the direct anonymous scheme with sub-group privacy enhancement properties.This proposed scheme provides the privacy solution for the small group,of which we propose two schemes and analyze the performance and security.关键词：direct anonymous attestation;trusted platform;trusted platform module;anonymous authentication2|1204|0更新时间：2025-07-16
- 摘要：The technology of interleaving plays an important role in avoiding burst errors by fading channel in communication systems and can greatly improve the reliability of data transmission.The convolutional interleave is widely used because it can reduce delay and save memory space.For the convolutional interleave in the channel coding,a method is proposed to blindly estimate the interleave parameters in the non-cooperative context.It can estimate these parameters effectively by constructing the deinterleaver,converting the initial location of the intercepted data to the delay deviation of interleaving,and then making use of Gaussian-Jordan elimination through pivoting algorithm in Galois Fields and the properties of linear block code.Computer simulation results show that the proposed algorithm can provide good performance even when the bit error rate is 0.01.关键词：linear block code;convolutional interleave;blind estimation2|1655|15更新时间：2025-07-16
- 摘要：The application performance is as important as the resource utilization when we allocate memory for guest operating systems in virtualized environments.This paper presents a memory-balancing method for virtual machines,named GOSBMB(Guest Operating System Behaviors based Memory Balancer).It aims to minimize the performance loss brought by balancing memory.The memory need of the guest operating system consists of two parts which respectively,cover the amount of the memory consumed by the process working sets,and the memory used as the page cache.GOSBMB estimates the memory need by observing VMM architecturally visible events transparently.Then it allocates the memory resource for the guest operating systems on demand.We have implemented a working prototype of GOSBMB on Xen platform.The memory can be saved up to 69.6% with only 7.6% performance loss when we use GOSBMB to balance memory dynamically.关键词：virtual machine;memory balancing;guest operating system behaviors;performance2|1243|0更新时间：2025-07-16
- 摘要：The coast-ship bistatic surface wave over-the-horizon radar(SWOTHR) uses a coast-located array to transmit signals of different carrier-frequencies and a ship-carried omni-antenna to receive echoes.The energy emitted covers a rather large sector and the equivalent transmit beampattern is formed by adopting the technique of impuslse and aperture synthesis.A method based on parameter transfer for gain and phase perturbations estimation of the transmit array is proposed using the received direct-path wave.In this method,a new unknown variable is introduced and the estimation error induced by the uncertainty of the receiver direction is transferred to the new variable.The signal model and the Cramer-Rao lower Bound for the array perturbation estimation are deduced.The computer simulation shows the effectiveness of the proposed method.关键词：surface wave over-the-horizon radar;direct-path wave;estimation of gain and phase perturbations;parameter transfer;Cramer-Rao lower bound2|839|0更新时间：2025-07-16
- 摘要：Under the spherically invariant random vector clutter,the adaptive detection of range-spread target is addressed.The parameters of cascaded binary integrator (CBI) are optimized.Moreover,based on secondary data,an adaptive CBI is derived,which is approximately of constant false alarm rate.The experimental results show that,the optimized CBI performs robustly for the mismatch between the estimated number of target scatterers and the actual one.In addition,the robustness is enhanced as the number of target scatterers increases.The optimized CBI in mismatch cases outperforms the scatterer-density-dependent detector in match cases and the non-scatterer-density-dependent detector.关键词：non-Gaussian clutter;range-spread target;adaptive detection;optimized parameters;robustness evaluation2|1213|1更新时间：2025-07-16
- 摘要：An algorithm for generating constant envelope (CE) waveforms from white Gaussian random process to realize a given covariance matrix is proposed for multiple-input multiple-output (MIMO) array systems in this paper.In our method,a memoryless nonlinear function is used to map Gaussian random variables (RV's) onto CE random variables.The relationship between the covariance matrices of Gaussian RV's at the input of the nonlinear function and non-Gaussian RV's at their output is established.Thus,CE waveforms can be obtained through the nonlinear function from the Gaussian RV's resulted from de-whitening a white Gaussian random process.In contrast to available algorithms,the proposed algorithm provides a closed-form solution to find the required waveforms,and suggests that waveforms can be chosen from finite alphabets,such as BPSK and QPSK.The numerical results illustrate the effectiveness of the algorithm proposed for MIMO array CE waveform design.关键词：MIMO array;constant envelope;mapping function;de-whitening;transmit beampattern2|1236|6更新时间：2025-07-16
- 摘要：In the SAR matching navigation system,the large size of reference image and real-time image,together with the difference in imaging angle,resolution,etc,makes the traditional matching methods can not meet the real-time performance and robustness simultaneously.Comparing various wavelet functions,we select a better one to construct the image pyramid,and realize the real-time performance via a coarse-to-fine matching strategy.The multi-scale circular templates are designed,and fused by the Dempster-Shafer (D-S) evidence theory,achieving the robustness.Evaluation results indicate that the proposed method can accommodate big distortions on the premise of ensuring the matching time.关键词：scene matching method;multi-scale circular template;wavelet transform;navigation2|1367|5更新时间：2025-07-16
- 摘要：This paper presents a novel data acquisition for ground penetrating radars (GPR) based on compressive sensing (CS) by exploiting sparseness in two dimensional FFT of B-scan data.Linear projections of the returned signal with random vectors generated by Mersenne Twister algorithm are taken as measurements.Half-quadric is used to solve l1 minimization.Using experimental GPR data,it is shown that the number of acquisition data is only the 1/15 of the number usually considered necessary.关键词：ground penetrating radars;compressive sensing;data acquisition2|1765|6更新时间：2025-07-16
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Seeker Measurement Error Suppressing Using Precision Speed Information of Inertial Navigation System
摘要：A novel missile-to-target relative motion model for terminal guidance is placed here.Aided by precision velocity information of inertial navigation system (INS),it overcomes the difficulties of actual inertial acceleration modeling in conventional methods.Missile dynamic was provided by on-board INS,while target maneuver was modeled as a first-order Markov process.On the resolution of velocity vector,the motion model using relative state vector was lastly proposed,which was directly applied into the constructing of a INS velocity information aided extended Kalman filter (IVIA-EKF).This filter could make full use of INS information to help suppressing seeker measurement error and enhancing precision striking.The proposed filter in missile terminal guidance was then validitied by simulation.关键词：extended Kalman filers;missile-to-target information;precision inertial navigation system;speed information of inertial navigation system2|1629|5更新时间：2025-07-16 - 摘要：We proposed a novel high precision spaceborne InSAR baseline estimation approach based on interferometric fringe frequency which makes the improvements from two aspects:the baseline calculation formula and the fringe frequency estimation precision.The accurate mathematic relationship between the baseline parameters and the interferometric fringe frequency was deduced considering the earth curvature.Also the Semi-Newton iterative method was introduced to estimate the fringe frequency of each pixel in the complex interferogram.Furthermore,the frequency evaluation was processed by the linear fitting to suppress the noise and the high precision fringe frequency was obtained.With the accurate frequency and the deduced baseline calculation formula,the baseline estimation precision was improved to centimeter.Finally,the computer simulation was employed to confirm the new baseline estimation approach.关键词：interferometric synthetic aperture radar (InSAR);baseline estimation;interferometric fringe frequency;semi-Newton iterative method;linear fitting2|1825|7更新时间：2025-07-16
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