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Science China(Information Sciences) 2012年第6期55卷 1280-1289页

作者： QI HaiMing 1,2,HUA Bin 1,2,LI Xin 1,2,YU WeiDong 1 & HONG Wen 1,2 1 Institute of Electronics,Chinese Academy of Sciences,beijing 100190,China 2 national key laboratory of microwave imaging technology,beijing 100190,China Institute of Electronics Chinese Academy of Sciences national key laboratory of microwave imaging technology

Codebook of conventional VQ cannot be generally used and needs real time onboard updating,which is hard to implement in spaceborne SAR *** order to solve this problem,this paper analyses the characteristic of space-borne SAR raw data firstly,and then utilizes the distortion function of multidimensional space as criterion,and finally the adaptive code book design algorithm is proposed according to the joint probability density function of the input ***,the feasibility of the new algorithm in cascade with entropy coding and the robustness of the algorithm when error occurs during transmission are analysed based on the encoding and decoding *** results of real data show that codebook deriving from the new algorithm can be generally used and designed off-line,which makes VQ a practical algorithm for space-borne SAR raw data compression.

关键词： synthetic aperture radar (SAR) compression raw data block adaptive quantization (BAQ) vector quantization (VQ)

Maximal effective baseline for polarimetric interferometric SAR forest height estimation

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Science China(Information Sciences) 2012年第4期55卷 867-876页

作者： ZHOU YongSheng 1,2,3,HONG Wen 1,2,WANG YanPing 1,2 & WU YiRong 1,2 1 national key laboratory of Science &technology on microwave imaging,beijing 100190,China 2 Institute of Electronics,Chinese Academy of Sciences,beijing 100190,China 3 Academy of Opto-Electronics,Chinese Academy of Sciences,beijing 100094,China national key laboratory of Science & technology on microwave imaging Beijing China Institute of Electronics Chinese Academy of Sciences Beijing China Academy of Opto-Electronics Chinese Academy of Sciences Beijing China

The concepts of critical baseline and maximal effective baseline have been defined for interferometric SAR (InSAR) DEM application based on the spatial decorrelation (which is a function of baseline).This paper puts forward these two concepts to polarimetric interferometric SAR (Pol-InSAR) forest height estimation *** application makes use of volume decorrelation,which is also a function of *** both the spatial decorrelation and volume decorrelation are considered to determine Pol-InSAR critical and maximal effective *** various decorrelation effects are *** the calculation formula of Pol-InSAR maximal effective baseline are presented and compared to that of *** validation,RVoG-based and PolSARpro-based simulation data and DLR ESAR data are *** concept of Pol-InSAR maximal effective baseline is of practical significance in selection of Pol-InSAR image pairs as well as in the design of further Pol-InSAR systems.

关键词： Pol-InSAR maximal baseline forest height estimation

GPS short-delay multipath estimation and mitigation based on least square method

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Journal of Systems Engineering and Electronics 2009年第5期20卷 954-961页

作者： Zhang Shengkang~(1,2),Wang Hongbo~(1,2),Yang Jun~(1,2) & He Leiming~(1,2) 1.beijing Inst.of Radio Metrology and Measurement,beijing 100854,P.R.China 2.national key laboratory of Metrology and Calibration technology,beijing 100854,P.R.China beijing Inst. of Radio Metrology and Measurement Beijing 100854 P. R. China National Key Laboratory of Metrology and Calibration Technology Beijing 100854 P. R. China

The GPS multipath signal model is presented, which indicates that the coherent DLL outputs in multipath environment are the convolution between the ideal DLL outputs and the channel responses. So the channel responses can be estimated by a least square method using the observed curve of the DLL discriminator. In terms of the estimated multipath channels, two multipath mitigation methods are discussed, which are equalization filtering and multipath subtracting, respectively. It is shown, by computer simulation, that the least square method has a good performance in channels estimation and the multipath errors can be mitigated almost completely by either of the methods. However, the multipath subtracting method has relative small remnant errors than equalization filtering.

关键词： global positioning system short-delay least square method multipath mitigation.

维普期刊数据库

Studies on MB-SAR 3D imaging algorithm using Yule-Walker method

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Science China(Information Sciences) 2010年第9期53卷 1848-1859页

作者： WANG Bin1,2*,WANG YanPing1,HONG Wen1,TAN WeiXian1,2 & WU YiRong1 1national key laboratory of microwave imaging technology,Institute of Electronics,Chinese Academy of Sciences,beijing 100190,China 2Graduate University of Chinese Academy of Sciences,beijing 100049,China national key laboratory of microwave imaging technology Institute of Electronics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Multibaseline synthetic aperture radar(MB-SAR) can form a synthetic aperture in the height direction with multiple parallel observations,so it has the resolving capability in the height direction and can realize three-dimensional(3D) imaging for the *** analytic model of MB-SAR based on spectrum estimation is analyzed in this *** on the more general geometric model,we derive the signal model for MB-SAR 3D *** then Yule-Walker algorithm is proposed to realize MB-SAR 3D imaging meanwhile the principle is analyzed and the steps of Yule-Walker algorithm are *** algorithm can get the 3D image of the target with high resolution using fewer ***,the experimental results of MB-SAR 3D imaging using Yule-Walker algorithm are presented,which are generated with the simulated data and the data collected in anechoic chamber.

关键词： MB-SAR 3D SAR imaging algorithm SAR spectrum estimation Yule-Walker method

Density functional theory study of the reaction paths of reactions of CH3C（O）O2 radicals with HO2 in the gas phase

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Progress in Natural Science:Materials International 2006年第12期16卷 1269-1274页

作者： ZHOU Yuzhi~ 1,2 , ZHANG Shaowen~1 and LI Qianshu~1**(1. State key laboratory of Explosion Science and technology, beijing Institute of technology, beijing 100081, China 2. beijing Institute of Education, beijing 100044, China) State key laboratory of Explosion Science and technology Beijing Institute of Technology Beijing 100081 China beijing Institute of Education Beijing 100044 China

A DFT study on the reactions between CH_3C（O）O_2and HO_2radicals has been carried out. It is suggested that both the triplet and singlet potential surfaces involve a complex mechanism with the formation of loosely bound intermediate complexes of reactants and products. The reaction prefers to occur on the triplet surface to produce peracetic acid (CH_3C（O）O_2H) and triplet O_2molecule. The CH_3C（O）O_2H can further convert into CH_3C（O）O and HO radicals.

关键词： acetyl peroxy radicals HO2 radicals reaction mechanism DFT.

Performance improvement in multi-ship imaging for ScanSAR based on sparse representation

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Science China(Information Sciences) 2012年第8期55卷 1860-1875页

作者： XU Gang1,SHENG JiaLian1,ZHANG Lei1&XING MengDao1,2 1N ational key laboratory of Radar Signal Processing,Xidian University,Xi'an 710071,China 2national key laboratory of microwave imaging,Institute of Electronics,Chinese Academy of Sciences,beijing 100080,China national key laboratory of Radar Signal Processing Xidian University Xi’an China national key laboratory of microwave imaging Institute of Electronics Chinese Academy of Sciences Beijing China

There is always a compromise between unambiguous wide-swath imaging and high cross-range resolution owing to the constraint of minimum antenna area for conventional single-channel spaceborne synthetic aperture radar(SAR)*** overcome the inherent systemic limitation,multi-channel SAR imaging has been ***,this still suffers from various problems such as high system *** simplify the system structure,a novel algorithm for high resolution multi-ship ScanSAR imaging based on sparse representation is proposed in this paper,where the SAR imaging model is established via maximum a posterior estimation by utilizing the sparsity prior of multi-ship *** the scheme,a wide swath is generated in the ScanSAR mode by continuously switching the radar footprint between ***,high crossrange resolution is realized from sparse subapertures by exploiting the sparsity feature of multi-ship *** particular,the SAR observation operator is constructed approximately as the inverse of conventional SAR imaging and then high resolution SAR imaging including range cell migration compensation is achieved by solving the *** with multi-channel SAR imaging,the system complexity is effectively reduced in the ScanSAR *** addition,enhancement of the cross-range resolution is realized by incorporating the sparsity prior with sparse *** a result,the amount of data is effectively *** based on measured data have been carried out to confirm the effectiveness and validity of the proposed algorithm.

关键词： synthetic aperture radar(SAR) ScanSAR wide-swath sparse representation high resolution

Fuzzy dynamic characteristic model based attitude control of hypersonic vehicle in gliding phase

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Science China(Information Sciences) 2011年第3期54卷 448-459页

作者： LUO Xiong 1,2 & LI Jiang 1 1 Department of Computer Science and technology, key laboratory of Advanced Control of Iron and Steel Process (Ministry of Education), University of Science and technology beijing, beijing 100083, China 2 national laboratory of Space Intelligent Control, beijing 100190, China Department of Computer Science and technology Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing national laboratory of Space Intelligent Control

The intelligent autonomous control of hypersonic vehicles has aroused great interest from the field of spacecraft. To solve the problem of longitudinal attitude control of hypersonic vehicle in gliding phase, a new intelligent controller is proposed in this paper. This new controller is based on the fuzzy dynamic characteristic modeling method. The fuzzy logic is introduced into the characteristic modeling by dividing the whole restriction range into several subspaces. Simulations show that this modification greatly improves the performance of the original method. With the same whole restriction range the fuzzy dynamic characteristic modeling decreases the time of convergence, and at the same time makes the attitude angle tracing more precise and robust. Since the sub-model is a characteristic model that has stronger adaptiveness than a fixed local model, the number of fuzzy rules is greatly reduced. Our model sharply reduces the complexity in constructing a fuzzy dynamic model. Finally, simulation results are given to show the effectiveness of the proposed approach in dealing with the attitude control problem of hypersonic vehicle in gliding phase.

关键词： hypersonic vehicle gliding attitude control fuzzy dynamic characteristic modeling

Influence of Ru addition on microstructure and stress-rupture property of Ni-based single crystal superalloys

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Progress in Natural Science:Materials International 2010年第1期20卷 61-69页

作者： Jing-yang CHEN~1,Qiang FENG~(1,2),La-mei CAO~3,Zu-qing SUN~1 1.State key laboratory for Advanced Metals and Materials,University of Science and technology beijing, beijing 100083,China 2.national Center for Materials Service Safety,University of Science and technology beijing,beijing 100083,China 3.national key laboratory of Science and technology on Advanced High Temperature Structural Materials, beijing Institute of Aeronautical Materials,beijing 100095,China State key laboratory for Advanced Metals and Materials University of Science and Technology Beijing national Center for Materials Service Safety University of Science and Technology Beijing national key laboratory of Science and technology on Advanced

The effects of Ru on the microstructure and stress-rupture property were investigated in two experimental Ni-based single crystal superalloys with and without Ru addition(5.1%,mass fraction).The results indicate that the morphology ofγ' precipitates in the dendrite core and interdendritic region are intermediate and nearly spherical,respectively,in the Ru-free alloy after being aged at 1100℃for 8 *** Re partitioning ratio increases due to Ru addition and Ru partitioned preferentially to theγphase in both dendrite core and interdendritic region of the Ru-containing alloy,which results in more negative lattice misfit and more cuboidalγ' ***,theγ' volume fraction increases while the precipitate size and y channel width decreases due to Ru addition in both dendrite core and interdendritic *** addition improves the stress-rupture life at 1100℃/140 MPa significantly due to higherγ' volume fraction,more negative lattice misfit and a well rafting structure as well as lessγchannel width.

关键词： Ni-based superalloys ruthenium elemental partitioning ratio lattice misfit γ’ morphology stress-rupture property

Sparse microwave imaging:Principles and applications

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Science China(Information Sciences) 2012年第8期55卷 1722-1754页

作者： ZHANG BingChen1,2,HONG Wen1,2 & WU YiRong1,2 1Science and technology on microwave imaging laboratory,beijing 100190,China 2Institute of Electronics,Chinese Academy of Sciences,beijing 100190,China Science and technology on microwave imaging laboratory Beijing China Institute of Electronics Chinese Academy of Sciences Beijing China

This paper provides principles and applications of the sparse microwave imaging theory and *** aperture radar(SAR) is an important method of modern remote *** decades microwave imaging technology has achieved remarkable progress in the system performance of microwave imaging technology,and at the same time encountered increasing complexity in system *** sparse microwave imaging introduces the sparse signal processing theory to radar imaging to obtain new theory,new system and new methodology of microwave *** on classical SAR imaging model and fundamental theories of sparse signal processing,we can derive the model of sparse microwave imaging,which is a sparse measurement and recovery problem and can be solved with various *** exist several fundamental points that must be considered in the efforts of applying sparse signal processing to radar imaging,including sparse representation,measurement matrix construction,unambiguity reconstruction and performance *** on these considerations,the sparse signal processing could be successfully applied to radar imaging,and achieve benefits in several aspects,including improvement of image quality,reduction of data amount for sparse scene and enhancement of system *** sparse signal processing has also been applied in several specific radar imaging applications.

关键词： sparse microwave imaging sparse signal processing compressive sensing synthetic aperture radar radar imaging