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A type of M2 -transmitter N2 -receiver MIMO radar array and 3D imaging theory

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science china(Information sciences) 2011年第10期54卷 2147-2157页

作者： ZHU YuTao & SU Yi school of electronic science and engineering,national university of defense technology,changsha 4.0073,china 1. school of electronic science and engineering National University of Defense Technology Changsha 410073 China

With two-dimensional synthetic apertures,a wideband radar array can realize 3D imaging of air targets,but this needs large numbers of antenna ***,when the transmitting frequency is very high,the interval of array elements makes it hard to fit the available space,which makes the imaging resolution *** paper proposes a type of M 2 -transmitter N 2 -receiver multiple-input multiple-output (MIMO) radar,which is equivalent to a rectangular radar array with (M N) 2 T/R antenna elements based on phase center approximation theory,and which can realize the 3D imaging of air *** 3D imaging theory and MIMO inverse synthetic aperture radar (MIMO-ISAR) 3D imaging theory are also proposed in this paper,and two simulations are given to show their validity.

关键词： MIMO radar array phase center approximation 3D imaging ISAR

Focusing transform-based direction-of-arrival method exploiting multi-cycle frequencies

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Progress in Natural science:Materials International 2005年第6期15卷 491-495页

作者： HUANG Zhitao*, JIANG Wenli and ZHOU Yiyu(school of electronic science and engineering, national university of defense technology, changsha 4.0073, china) school of electronic science and engineering National University of Defense Technology Changsha 410073 China

When single cycle frequency is employed, the existing spectral correlation-signal subspace fitting (SC-SSF) algorithms usually contain two disadvantages: those single-cycle estimators cannot reach the best performance; it is inconvenient to be applied in practice since the right cycle frequency has to be selected. Based on the Jacobi-Anger expansion and the idea of focusing transform, a new approach exploiting multi-cycle frequencies of cyclostationary signal is discussed in this paper. Simulation results demonstrate the effectiveness of the new method.

关键词： cyclostationary signal direction-of-arrival multi-cycle frequencies focusing transform.

Sidelobe reduction based on spectrum reshaping in microwave imaging

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science china(Information sciences) 2011年第1期54卷 204-212页

作者： WANG HuaiJun,SU Yi,XU HongBo & ZHU YuTao school of electronic science and engineering,national university of defense technology, changsha 4.0073,china 1. school of electronic science and engineering National University of Defense Technology Changsha 410073 China

Sidelobe artifacts are a common problem in image reconstruction from finite-extent Fourier data obtained by microwave imaging *** order to enhance the image quality,sidelobe reduction must be *** the sidelobe reduction in microwave imaging as the research subject,this paper presents Fourier imaging technique *** the point spread function is obtained through Fourier inversion of rectangular spectral support data and the changing effect of sidelobe direction due to reshaping spectral support is *** reshaping makes that the sidelobes of two Fourier images do not *** on the idea of separating sidelobes from mainlobe,a nolve method that reduces sidelobe levels while maintaining the imaging resolution is *** performance of this method is ***,the simulated and measured data of typical microwave imaging systems such as synthetic aperture radar(SAR),inverse synthetic aperture radar(ISAR)and real aperture radar are used to demonstrate the validity of the proposed method.

关键词： microwave imaging Fourier imaging sidelobe reduction spatial spectrum point spread function

Jamming de-chirping radar using interrupted-sampling repeater

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science china(Information sciences) 2011年第10期54卷 2138-2146页

作者： FENG DeJun ,TAO HuaMin,YANG Yong & LIU Zhong school of electronic science and engineering,national university of defense technology,changsha 4.0073,china 1. school of electronic science and engineering National University of Defense Technology Changsha 410073 China

Interrupted-sampling repeater jamming (ISRJ) is a novel jamming mode for pulse compression radar in *** this paper,a jamming approach of applying ISRJ to de-chirping radar is *** principles of ISRJ are expounded,and the ways to achieve a train false target for de-chirping radar are *** characteristics of false target,including time-domain characteristic,frequency-domain characteristic and amplitude characteristic,are *** on this,the power requirement for jammer is put forward and the key elements that determine the space distribution location between true and false targets are discussed in *** last,simulation results are presented and *** work is beneficial to the jamming design and use of ISRJ.

关键词： interrupted-sampling repeater de-chirping wideband radar linear frequency modulated signal

Design and performance analysis of orthogonal coding signal in MIMO-SAR

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science china(Information sciences) 2011年第8期54卷 1723-1737页

作者： ZOU Bo,DONG Zhen & LIANG DianNong school of electronic science and technology,national university of defense technology,changsha 4.0073,china 1. school of electronic science and technology National University of Defense Technology Changsha 410073 China

Multi-input multi-output (MIMO) radar which has evident advantages in many applications is a new radar *** the MIMO technique to the earth observing synthetic aperture radar (SAR) system offers effective ways for the improvement of high resolution and wide swath imaging and ground moving target indication (GMTI) *** the optimal orthogonal waveform is a crucial problem in the research on MIMO ***,the index definition of synthetic integrated side-lobe level ratio (ISLR) is proposed by focusing on the SAR application and considering the cross-correlation energy influences between orthogonal coding signals with the same frequency ***,it is theoretically demonstrated that the performance of synthetic ISLR of orthogonal coding signals with the same frequency band cannot meet the demands of SAR imaging,which has been proved by one-dimensional numerical simulation. Third,it has been shown through numerical simulation that the performance of synthetic ISLR of orthogonal coding signals still cannot be improved by dealing with the mismatched ***,a set of orthogonal phase coding signals are designed for multiple MIMO-SAR *** conclusions are verified through MIMO-SAR imaging and InSAR simulation experiments.

关键词： MIMO-SAR waveform design orthogonal coding signal synthetic ISLR

Micro-Doppler characteristics of sliding-type scattering center on rotationally symmetric target

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science china(Information sciences) 2011年第9期54卷 1957-1967页

作者： MA Liang,LIU Jin,WANG Tao,LI YongZhen & WANG XueSong school of electronic science and engineering,national university of defense technology,changsha 4.0073,china 1. school of electronic science and engineering National University of Defense Technology Changsha 410073 China

The feature of micro-motion is one of the most effective features used for radar recognition in midcourse *** present,the study of feature extraction and recognition is usually based on the assumption that the micro-motion of the scattering center and warhead itself is the same,and the radar echo is sinusoid-FM ***,this assumption ignores the fact that the scattering center would slide on the warhead with the change of the aspect *** this paper,a complete micro-motion model is set for the scattering centers of different positions on the warhead,and the mathematical expression of the micro-Doppler of the sliding-type scattering center is obtained for the first *** approximation of Taylor expansion under the background of missile confrontation is studied *** curve of this micro-Doppler is not the generally assumed *** measurement of a precessional target in microwave anechoic chamber is done to vividly observe the sliding feature of the scattering *** measurement results agree with the theoretic analysis in this *** research on micro-Doppler characteristics of sliding-type scattering center provides a more accurate model for the micro-motion simulation and feature extraction of precessional warheads.

关键词： rotationally symmetric target sliding-type scattering center precession micro-Doppler

Statistical assessment of H/A target decomposition theorems in radar polarimetry

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science china(Information sciences) 2010年第2期53卷 355-366页

作者： LIU Tao 1,2 , HUANG GaoMing 1 , WANG XueSong 2 & XIAO ShunPing 2 1 school of electronic engineering, Naval university of engineering, Wuhan 430033, china 2 school of electronic science and engineering, national university of defense technology, changsha 4.0073, china 1. school of electronic engineering Naval University of Engineering Wuhan 430033 China2. School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

Target decomposition (TD) theorems have been widely applied in radar polarimetry, serving as the bridge between radar measurements and the physical parameters of a scatterer. The H/A target decomposition is one of the most suitable tools for performing data interpretation in the study and characterization of natural scatters. In this paper, the statistics of the parameters of eigenvalue, eigenvector and H/A have been analyzed via a novel method, and the probability density functions (PDF) have been obtained. It is pointed out that all these parameters can be seen as asymptotically nonbiased with respect to the number of looks. In order to reduce the biases for a small number of looks, a novel estimator for the parameters has been proposed. We give the basic theorems for accurate estimation of parameters.

关键词： target decomposition theorems H/A characteristic parameters statistical analysis MLE

Narrowband imaging method for spatial precession cone-shaped targets

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science china(Technological sciences) 2010年第4期53卷 942-949页

作者： DING XiaoFeng1,FAN MeiMei1,WEI XiZhang1,LI Xiang1 & Xiao HuaiTie2 1 Institute of Space electronics Information technology,national university of defense technology,changsha 4.0073,china 2 school of electronic science and engineering,national university of defense technology,changsha 4.0073,china 1. Institute of Space electronics Information technology National University of Defense Technology Changsha 410073 China2. School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

The imaging method of the mid-course missile is the key technique of the missile defense *** of the special precession character of the ballistic missile warhead,the inverse synthetic aperture radar method cannot realize phase compensation with the constant phase offset function,which leads to blurring of the *** this paper,we propose a new narrowband radar imaging method for the precession cone-shaped *** method acquires the Doppler modulation of the precession target's scattering centers with high resolution time-frequency analysis method and extracts the Doppler parameter from the result of the time-frequency analysis with the general Radon transform,then reconstructs the scattering centers positions in the parameter *** experiment results with the anechoic chamber data of the representative cone-shaped object showed the effectiveness of the method.

关键词： narrowband radar imaging time-frequency analysis general Radon transform

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Review on abort trajectory for manned lunar landing mission

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science china(Technological sciences) 2010年第10期53卷 2691-2698页

作者： XI XiaoNing1, HUANG WenDe2 & WANG Wei2,3 1 College of Mechatronics engineering and Automation, national university of defense technology, changsha 4.0073, china 2 College of Aerospace and Material engineering, national university of defense technology, changsha 4.0073, china 3 school of Surveying and Spatial Information System, university of New South Wales, Sydney, NSW 2052, Australia 1. College of Mechatronics engineering and Automation National University of Defense Technology Changsha 410073 China2. College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China3. School of Surveying and Spatial Information System University of New South Wales Sydney NSW 2052 Australia

Abort trajectory is a passage that ensures the astronauts to return safely to the earth when an emergency occurs. Firstly,the essential elements of mission abort are analyzed entirely based on summarizing the existing studies. Then,abort trajectory requirement and rational selection for different flight phases of typical manned lunar mission are discussed specifically. Considering a trade-off between the two primary constrains of an abort,the return time of flight and energy requirement,a general optimizing method for mission abort is proposed. Finally,some suggestions are given for china’s future manned lunar landing mission.

关键词： manned lunar landing mission abort trajectory design free return trajectory

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