检索结果-南通市图书馆

维普期刊数据库

Parameters Estimation of LFM signals Based on STTFD

在线全文

学校读者我要写书评

暂无评论

Parameters Estimation of LFM Signals Based on STTFD

A Novel Algorithm for Repeated Trajectory Bistatic Spotlight SAR Imaging

2008 9th International Conference on signal processing(ICSP’2008)

作者： Long Zhang 1 2 xiao-hui He 2 Ya-chao Li 1 Meng-dao xing 1 Zheng Bao 1 1 the State Key lab for radar signal processing xidian university Shaanxi 710071 P.R.china 2 xi’an Polytechnic university Shaanxi 710048 P.R.china

The accurate estimation of the center frequency and the chirp rate of a linear frequency-modulated（LFM） signal palys an important role in radar signal *** WVD transform can show the characteristic of the center frequency and the chirp rate of a LFM signal,but the cross-terms of signals deteriorates the precision of the estimation of the center frequency and the chirp ***,in order to estimate those parameters of the LFM signals better,this paper proposes a new method based on the scaling transform in time-frequency distribution plane（STTFD） for the parameters estimation of the LFM signals,by which the frequency of each LFM signal in timefrequency plane changes from the linear distribution along the time axis to the constant distribution along the time axis,then the coupling effect between the signal time and the correlation function delay can be removed and the center frequencies and the chirp rates of the LFM signals can be accurately estimated by the peak value locations of accumulated signals realized by the Fourier transform with respect to the time *** the same time,the analysis of the characteristic of STTFD is given in ***,the simulated result shows that the method proposed in this paper can effectively weaken the effect of the cross-terms and accurately estimate the center frequencies and the chirp rates of the LFM signals.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A Novel Algorithm for Repeated Trajectory Bistatic Spotlight...

An efficient ranging method based on Chinese remainder theorem for RIPS measurement

2009 2nd Asian-Pacific Conference on Synthetic Aperture radar（APSAR2009）

作者： He Bosen 1 Zhang Ran 1 Song Meng 1 LI Bingning 2 xing Meng-dao 1 1.national key laboratory for radar signal processing xidian university 710071 xi’an P.R.china 2.PLA 61191 HangZhou 310023 china

This paper makes a detailed analysis on the echo signal of the repeated trajectory bistatic *** to the characteristic of spotlight SAR signal,an algorithm based on Spectrum Analysis（SPECAN）method is *** algorithm removes the azimuth ambiguity,and it also ensures good imaging quality over wildfield scene without defocus caused by spatial variance of target position.

关键词： Bistatic spotlight SAR SPECAN algorithm

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2010年第6期53卷 1233-1241页

作者： WANG Chen , YIN QinYe & WANG WenJie Ministry of Education Key lab for Intelligent Networks and Network Security, xi’an Jiaotong university, xi’an 710049, china 1. Ministry of Education Key lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710049 China

The radio interferometric positioning system(RIPS) measures the phase difference of the interference signal to provide high accuracy and at the same time maintain simple hardware configuration for wireless sensor ***, it suffers from phase ambiguity problem because of the periodicity of phase, which makes it hard to determine the actual distance difference only from a single phase *** solve the problem, RIPS makes multiple measurements at different frequencies so as to determine the distance difference from multiple ***, this is a computationally intensive searching process and not suitable for energyconstrained wireless sensor *** this paper, we introduce the Chinese remainder theorem(CRT) to RIPS to solve the phase ambiguity ***, we utilize some properties of the coefficients in the CRT algorithm to avoid the over-sensitivity of the traditional CRT, which increases the robustness of the *** apply this robust CRT algorithm to the ranging process which calculates the distance difference directly from a closed-form equation and therefore reduces the response time and the energy consumption of the ranging procedure.

关键词： ranging phase ambiguity Chinese remainder theorem robustness energy efficiency wireless sensor networks

A Novel Non-interactive Verifiable Secret Sharing Scheme

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A Novel Non-interactive Verifiable Secret Sharing Scheme

SOLUTION OF ASSIGNING BINARY INDEXES TO CODEVECTORS BY A KIND OF HOPFIELD NEURAL NETWORK

2006 10th International Conference on Communication Technology（ICCT 2006）

作者： Jun Ao Guisheng Liao The State Key laboratory for radar signal processing xidian university xi’an Shanxi 710071 P. R. china Chunbo Ma School of Information Security Engineering Shanghai Jiao Tong university Shanghai 200030 P. R. china

In this paper, we present a novel non-interactive verifiable secret sharing scheme constructed by Shamir’s secret sharing scheme for secure multi-party communication protocol in distributed networks. In our scheme, only the Dealer is allowed to send message and there is no communication among players. The Dealer only publishes one commitment for verification, and the number of the commitment will not increase along with the augment of the threshold of secret sharing scheme. At the same time, the efficiency of verification for each share doesn’t fall as the augment of the threshold. The security of the verifiable secret sharing scheme is based on the intractability of computing discrete logarithm.

关键词： non-interactive verifiable secret sharing

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2001年第1期18卷 79-88页

作者： Lin Jiayu(Key lab. on ISN, xidian university, xi’an 710071) (School of Electron. Sci. and Eng., national Uni. of Defence Tech., Changsha 410073) Key lab. on ISN Xidian University Xi'an 710071School of Electron. Sci. and Eng. National Uni. of Defence Tech. Changsha 410073

A method of assigning binary indexes to codevectors in vector quantization (VQ)system, which is called pseudo-Gray coding, is presented in this paper by constructing a kind of Hopfield neural network. Pseudo-Gray coding belongs to joint source/channel coding, which could provide a redundancy-free error protection scheme for VQ of analog signals when the binary indexes of signal codevectors are used as channel symbols on a discrete memoryless channel. Since pseudo-Gray coding is of combinatorial optimization problems which are NP-complete problems,globally optimal solutions are generally impossible. Thus, a kind of Hopfield neural network is used by constructing suitable energy function to get sub-optimal solutions. This kind of Hop field neural network is easily modified to solve simplified version of pseudo-Gray coding for single bit-error channel model. Simulating experimental results show that the method introduced here could offer good performances.

关键词： Joint source/channel coding Pseudo-Gray coding Hopfield neural network Neural network application

维普期刊数据库

AOD estimation in WSN localization system with synthetic aperture technique

在线全文

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2012年第10期55卷 2216-2225页

作者： WANG WenJie,YAO BoBin & YIN QinYe MOE Key lab for Intelligent Networks and Network Security,School of Electronic and Information Engineering,xi’an Jiaotong university,xi’an 710049,china 1. MOE Key lab for Intelligent Networks and Network Security School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an 710049 China

Angel of departure(AOD) based distributed localization scheme in wireless sensor networks allows the single antenna sensor node to estimate its own AOD information by an equivalent antenna array for further position ***,the condition that the number of antennas at the multi-antenna agent/anchor node should be larger than the number of multipath signal components(MPCs) constrains its actual *** this paper,we provide a more practical approach to achieve AOD information estimation under multipath *** that the sensor node can not identify the line of sight(LOS) signal component due to the insufficient degree of freedom,which is determined by the above limiting condition,we introduce a synthetic aperture technique with the aid of a fast moving multi-antenna agent/anchor *** operation greatly enlarges the degree of freedom of the equivalent antenna array constructed at sensor node end but without requiring other extra physical antennas equipped at agent/anchor node or sensor node end,which means that it relaxes the limiting ***,the AOD information of LOS signal component can be estimated and extracted successfully in complex multipath *** analysis proves the effectiveness of our proposed synthetic aperture technique and numerical simulations show great performance improvement.

关键词： angle of departure degree of freedom synthetic aperture wireless sensor networks

A wideband beamforming method based on directional uniform circular arrays

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2010年第12期53卷 2600-2609页

作者： MU PengCheng ,YIN QinYe & ZHANG JianGuo Ministry of Education Key lab for Intelligent Networks and Network Security,School of Electronics and Information Engineering,xi’an Jiaotong university,xi’an 710049,china 1. Ministry of Education Key lab for Intelligent Networks and Network Security School of Electronics and Information Engineering Xi’an Jiaotong University Xi’an 710049 China

A new method for solving the wideband beamforming problem is proposed in this paper based on directional uniform circular *** basic idea is designing a narrowband beamforming spatial filter at a specific frequency and using the obtained filter weights directly to wideband signals,which reduces the complexities of designing and *** the premise of knowing signals’ direction information,this paper uses the method of least square with linear constraints to design the narrowband spatial *** the directional uniform circular array is insensitive to the variation of frequency,coincident beams and notches are obtained at different frequencies of the wideband signal by using the obtained narrowband spatial filter *** computation complexity of array signal processing can be greatly reduced by using the method proposed in this paper,which is convenient for real-time signal processing.

关键词： array signal processing wideband beamforming uniform circular array spatial filter least square

Sparse SAR imaging based on L1/2 regularization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2012年第8期55卷 1755-1775页

作者： ZENG JinShan,FANG Jian&XU ZongBen Institute for Information and System Sciences&Ministry of Education Key lab for Intelligent Networks and Network Security,xi’an Jiaotong university,xi’an 710049,china 1. Institute for Information and System Sciences & Ministry of Education Key lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710049 China

In this paper,a novel method for synthetic aperture radar(SAR)imaging is *** approach is based on L1/2 regularization to reconstruct the scattering field,which optimizes a quadratic error term of the SAR observation process subject to the interested scene *** to the conventional SAR imaging technique,the new method implements SAR imaging effectively at much lower sampling rate than the Nyquist rate,and produces high-quality images with reduced sidelobes and increased ***,over the prevalent greedy pursuit and L1 regularization based SAR imaging methods,there are remarkable performance improvements of the new *** one hand,the new method significantly reduces the number of measurements needed for reconstruction,as supported by a phase transition diagram *** the other hand,the new method is more robust to the observation *** fundamental properties of the new method are supported and demonstrated both by simulations and real SAR data experiments.

关键词： synthetic aperture radar matched filtering compressed sensing L1/2 regularization L1 regularization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

纠错码性能仿真中的误码率估计

通信学报 2001年第9期22卷 99-103页

作者：贺玉成杨莉王新梅西安电子科技大学综合业务网国家重点实验室陕西西安710071

在纠错码性能仿真中 ,一般是在给定信噪比后 ,由实测的错误信息比特数与发送信息比特总数相比来估计误码率的 ,这种方法在大码长或者极低误码率情况下 ,可信程度不高。本文提出用仿真数据计算后验概率分布参数的方法来直接估计纠错码误... 详细信息

在纠错码性能仿真中 ,一般是在给定信噪比后 ,由实测的错误信息比特数与发送信息比特总数相比来估计误码率的 ,这种方法在大码长或者极低误码率情况下 ,可信程度不高。本文提出用仿真数据计算后验概率分布参数的方法来直接估计纠错码误码率及其置信区间 ,给出了误码率的上界 ,由少量测试数据仍然可以获得比较可靠的误码率估计。由于这种后验估计考虑了信道特性。

关键词：纠错码误比特率可靠性性能仿真误码率估计

维普期刊数据库