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Narrow-band tomographic radar imaging of precession cone targets

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Journal of Systems Engineering and Electronics 2012年第6期23卷 866-874页

作者： xizhang wei Shixian Gong Xiaofeng Ding School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 E R. China

The principle and method of the narrow-band tomo-graphic radar imaging （NBTRI） of the precession cone target are studied. Firstly, the motion model and electromagnetic scattering characteristics of the precession cone target are introduced. Secondly, based on the traditional NBTRI algorithm, a novel narrow-band tomography clean radar imaging （NBTCRI） algorithm is proposed to enhance the image quality of NBTRI results. In addition, the resolution performance of the NBTRI algorithm is analyzed. Finally, based on the ideal scattering point model, this paper discusses the relationship between the precession angle and the estimated target size from NBTRI results. By using the target＇s chamber data, NBTRI and NBTCRI results of the precession cone target are further analyzed, which indicates the effectiveness of the proposed method.

关键词： narrow-band tomographic precession tomographyclean.

Motion compensation algorithm in narrowband imaging for mid-course targets

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Journal of Systems Engineering and Electronics 2017年第1期28卷 40-50页

作者： xizhang wei Zhen Liu Xiaofeng Ding Bo Peng School of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China Unit 31006 of the PLA Beijing 100086China

Imaging precession targets based on the narrowband radar to distinguish the real warhead from mid-course targets is a new technique in missile defense systems. Aiming at the typical mid-course flying scene, this paper describes the principle of the narrowband imaging method, and analyzes the influence on the narrowband imaging by the target translational motion. Then the precision qualification is deduced for both the distance compensation and the velocity compensation, and the conclusion that the velocity compensation is more appropriate for the motion compensation in the narrowband imaging is given. Furthermore, this paper proposes a motion compensation algorithm for the narrowband radar which reduces the interference of the signal phase chaos caused by the rebuilt real signal phase, thus realizing the precise translational motion compensation of the narrowband signal. Finally, the effectiveness of this method is proved by both theoretic analysis and experiment results. © 1990-2011 Beijing Institute of Aerospace Information.

关键词： Radar Radar imaging

Dimensions estimation for cone-cylinder target based on sliding-type scatterers analysis

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Journal of Systems Engineering and Electronics 2017年第1期28卷 10-18页

作者： Yuling Liu xizhang wei Bo Peng Yongshun Ling School of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China Electronic Engineering Institute of PLA Hefei 230000China

Scatterers often exhibit aspect or frequency dependence which affects the micro-Doppler shift in scattering response. For cone-cylinder targets, sliding-type scatterers which slide on the edge discontinuity with the change of the incident angle are the most dominant nonideal scattering models. A method is proposed to discriminate among the scatterers on the cone-cylinder target based on the deviation degree of micro-Doppler from sinusoid. By extracting the amplitude and initial phase, the micro-Doppler is estimated as sinusoid. Then the deviation degree is evaluated by the error between the extracted sinusoidal micro-Doppler and the actual micro-Doppler curve. Threshold for the classification is determined with the simulation data. After classification, the micro-Doppler features of sliding-type scatterers are exploited to estimate the target dimensions. The influence of parameters errors and noise on estimation of target dimensions is also illustrated with the simulation data. © 1990-2011 Beijing Institute of Aerospace Information.

关键词： Cylinders (shapes)

False-target image synthesizer for countering ISAR via inverse dechirping

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Journal of Systems Engineering and Electronics 2016年第1期27卷 99-110页

作者： xizhang wei Shaokun Xu Bo Peng Zhen Liu School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China Unit 63891 of the PLA Luoyang 471003 China

For real-time jamming signal generation in deceiving inverse synthetic aperture radar（ISAR）,the target characteristics modulation is always processed in the expensive field programmable gate array（FPGA）.Due to the large computational complexity of the traditional modulating operation,the size and structure of simulated false-target are *** regard to the principle of dechirping in range compression of linear frequency modulated（LFM） radar,a novel algorithm named ＂inverse dechirping＂ is proposed for target characteristics *** algorithm only needs one complex multiplier in the FPGA to generate the jamming signal when the radar signal is intercepted,which can be obtained by multiplication of radar signal samplings and the equivalent dechirped target echo in the time *** the complex synthesis of dechirped target echo can be realized by cheap digital signal processor（DSP） within the interpulse time,the overall cost of the jamming equipment will be reduced and the false-target size will not be limited by the scale of *** simulations are performed to verify the correctness and effectiveness of the proposed algorithm.

关键词： radar jamming inverse dechirping inverse synthetic apeture radar(ISAR).

Analysis about the speckle of radar high resolution range profile

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Science China(Technological Sciences) 2011年第1期54卷 226-236页

作者： ZHANG Rui wei xizhang LI Xiang LIU Zhen Research Institute of Space Electronics Information Technology National University of Defense Technology Changsha 410073 China

The aspect sensitivity is the main problem in radar automatic target recognition using high resolution range profile (HRRP). In the traditional viewpoint,HRRPs are assumed to be highly similar if the aspect variation is not enough to cause range migration. However,some experiments in anechoic chambers don’t agree with the assumption. Particularly,some abnormal HRRPs often occur in the measured data. Based on the scattering center model,this paper focuses on the reason of abnormal HRRP,which is named as the speckle. The theoretical model of speckle is established and the "spurious dual peaks" feature of the speckled HRRP is analyzed. Then the occurrence condition of speckle is concluded,and so is the relationship between the speckle probability in HRRP and radar carrier frequency. At last,the experiment in an anechoic chamber is used to verify all the analyses about the speckle.

关键词： radar automatic target recognition high resolution range prof'de aspect sensitivity speckle

Tolerance analysis of multiple-element linear retrodirective cross-eye jamming

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Journal of Systems Engineering and Electronics 2020年第3期31卷 460-469页

作者： LIU Tianpeng wei xizhang PENG Bo LIU Zhen SUN Bin GUAN Zhiqiang College of Electronic Science and Technology National University of Defense TechnologyChangsha 410073China School of Electronic and Communication Engineering Sun Yat-sen UniversityShenzhen 518107China Beijing Institute of Tracking and Telecommunication Technology Beijing 100094China Beijing Huahang Radio Measurement Institute Beijing 100013China

Tolerance sensitivity limits the practical application of the cross-eye *** literature has demonstrated that retrodirective cross-eye jamming with multiple antenna elements possesses the advantage of loose tolerance requirements compared to traditional cross-eye ***,the previous analysis was limited,because there are still some factors affecting the parameter tolerance of the multiple-element retrodirective cross-eye jamming(MRCJ)system and they have not been investigated completely,such as the loop difference,the baseline ratio and the jammer-to-signal *** paper performs a comprehensive tolerance analysis of the MRCJ system with a nonuniformspacing linear *** results demonstrate the tolerance effects of the above influence factors and give reasonable advice for easing tolerance sensitivity.

关键词： electronic warfare(EW) electronic countermeasure(ECM) cross-eye jamming radar active jamming tolerance

Mathematic principle of active jamming against wideband LFM radar

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Journal of Systems Engineering and Electronics 2015年第1期26卷 50-60页

作者： Shixian Gong xizhang wei Xiang Li Yongshun Ling School of Electronic and Information National University of Defense Technology Electronic Engineering Institute

The inherent mathematic principle of active jamming against the wideband linear frequency modulated（LFM） radar is investigated. According to different generation strategies, the active jamming methods are reclassified into three groups, i.e.,non-coherent jamming（NCJ）, convolution jamming（CJ） and multiplying jamming（MJ）. Based on the classification, the mathematic principles of different active jamming groups are put forward, which describe the relationships between the modulated signals and the jamming results. The advantages and disadvantages of different groups are further analyzed, which provides a new perspective for the study of jamming/anti-jamming methods and a potential for engineers to integrate similar jamming methods into one jammer platform. The analyses and simulation results of some typical active jamming methods prove the validity of the proposed mathematics principle.

关键词： linear frequency modulated(LFM) mathematic principle active jamming

Wideband electromagnetic characteristics modeling and analysis of missile targets in ballistic midcourse

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Science China(Technological Sciences) 2012年第6期55卷 1655-1666页

作者： XU ShaoKun LIU JiHong wei xizhang LI Xiang GUO GuiRong School of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China

The wideband electromagnetic characteristics of missile targets in midcourse are the foundation of midcourse attack-defense confrontation. This paper proposes a novel electromagnetic scattering modeling method for midcourse targets based on a pre- cise scattering center model, in which the nonideal scattering phenomenon, shielding effect and micro-motion are taken into consideration for the first time. Firstly, a precise scattering center model incorporating both the sliding scattering and artist- tropic scattering is established. Then the change rule of the target attitude is generalized, and a checking method of the scatter- ing center shielding effect is proposed for rotationally symmetric targets. Afterwards, a novel dynamic electromagnetic scat- tering model is presented, where the scattering center model updates along with the variation of the target attitude and can characterize the change of the electromagnetic characteristics of midcourse targets exactly. Finally, in light of the established model, the dynamic electromagnetic characteristics within different attitude angle bounds are analyzed by stages, and some useful conclusions are obtained. Experiment results from the measured data in anechoic chamber verify the validity of the proposed modeling method and relevant analysis.

关键词： ballistic midcourse wideband electromagnetic characteristics micro-motion shielding effect nonideal scattering

THE INFLUENCE OF SPECKLE ON HIGH RESOLUTION RANGE PROFILE RECOGNITION BASED ON THE MATCHING SCORE

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Journal of Electronics(China) 2012年第3期29卷 222-228页

作者： Zhang Rui wei xizhang Li Xiang Research Institute of Space Electronics Information Technology National University of Defense TechnologyChangsha 410073China

Template database is the key to radar automation target recognition based on High Resolution Range Profile (HRRP). From the traditional perspective, average HRRP is a valid template for it can represent each HRRP without scatterer Moving Through Range Cell (MTRC). However, template database based on this assumption is always challenged by measured data. One reason is that speckle happens in the frame without scatterer MTRC. Speckle makes HRRP fluctuate sharply and not match well with the average HRRP. We precisely introduce the formation mechanism of speckle. Then, we make an insight into the principle of matching score. Based on the conclusion, we study the properties of matching score between speckled HRRP and the average HRRP. The theoretical analysis and Monte Carlo experimental results demonstrate that speckle makes HRRP not to match well with the average HRRP according to the energy ratio of speckled scatterers. On the assumption of ideal scattering centre model, speckled HRRP has a matching score less than 85% with the average HRRP if speckled scatterers occupy more than 50% energy of the target.

关键词： Radar automatic target recognition High Resolution Range Profile (HRRP) Aspect sensitivity Matching score Speckle