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High Voltage 2024年第2期9卷 275-286页

作者： Yi Luo shiyi mao Ju Tang Zijun Pan Cheng Pan State Key Laboratory of Power Grid Environmental Protection School of Electrical Engineering and AutomationWuhan UniversityWuhanChina

The surface charge accumulation on the basin insulator is a particular problem in high-voltage direct current(HVDC)gas insulated switchgears(GIS)and gas insulated trans-mission lines(GIL),which restricts the development and application of extra/ultra high-voltage(EHV/UHV)*** surface charge distribution and anti-flashover performance are closely related to the insulator *** obtain the optimal basin insulator,a shape optimisation model based on artificial bee colony algorithm was established,and the minimisation objective functions based on capacitive(initial)electric field distribution and resistive(steady-state)electric field distribution were respectively *** optimisation results of the two objective functions were calculated,and the electric field and charge distribution on the surface of the insulator before and after optimisation were evaluated and compared using the simulation *** results indicated that the optimisation based on the capacitive electric field can significantly inhibit the surface charge accumulation,and the optimised insulator can significantly reduce the surface normal electric field and make the distribution of the tangential electric field more uniform,and the maximum tangential electric field can be reduced by 10%;the optimisation based on resistive electric field can achieve similar results,but requires more computational *** on the results,the‘anti-charge’basin insulator structure suitable for the DC field was given.

关键词： insulator artificial charge

Range walk and array rotation in space-time adaptive processing:effects and compensations

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Journal of Systems Engineering and Electronics 2010年第4期21卷 537-543页

作者： Jinping Sun Guohua Wang shiyi mao School of Electronic and Information Engineering Beihang University Beijing 100191 P. R. China School of Electrical and Electronic Engineering Nanyang Technological University Nanyang Avenue 639798 Singapore

This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing（STAP） in airborne multi-channel early-warning *** on this clutter model,STAP performance is then analyzed from the perspective of covariance matrix tapering（CMT）.For STAP performance degradation due to array rotation,a determinate compensation method is proposed based on the CMT *** examples are provided to verify the analysis and the proposed compensation method.

关键词： radar space-time adaptive processing clutter covariance matrix tapering.

Knowledge-based detection method for SAR targets

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Journal of Systems Engineering and Electronics 2014年第4期25卷 573-579页

作者： Fei Gao Achang Ru Jun Wang shiyi mao School of Electronic and Information Engineering Beihang University

When the classical constant false-alarm rate （CFAR） combined with fuzzy C-means （FCM） algorithm is applied to target detection in synthetic aperture radar （SAR） images with complex background, CFAR requires block-by-block estimation of clutter models and FCM clustering converges to local optimum. To address these problems, this paper pro-poses a new detection algorithm： knowledge-based combined with improved genetic algorithm-fuzzy C-means （GA-FCM） algorithm. Firstly, the algorithm takes target region＇s maximum and average intensity, area, length of long axis and long-to-short axis ratio of the external ellipse as factors which influence the target appearing probabil- ity. The knowledge-based detection algorithm can produce preprocess results without the need of estimation of clutter models as CFAR does. Afterward the GA-FCM algorithm is improved to cluster pre-process results. It has advantages of incorporating global optimizing ability of GA and local optimizing ability of FCM, which will further eliminate false alarms and get better results. The effectiveness of the proposed technique is experimentally validated with real SAR images.

关键词： synthetic aperture radar (SAR) target detection,knowledge-based improved genetic algorithm-fuzzy C-means(GA-FCM) algorithm.

Method of moving target detection based on sub-image cancellation for single-antenna airborne synthetic aperture radar

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Journal of Systems Engineering and Electronics 2007年第3期18卷 448-453页

作者： Liu Shujun Yuan Yunneng Gao Fei mao shiyi Dept. of Electronic and Information Engineering Beihang Univ. Beijing 100083 P. R. China

The method of moving target detection based on subimage cancellation for single-antenna airborne SAR is presented. First the subimage is obtained through frequency processing is pointed out. The imaging difference of a stationary objects and moving object in the subimage based on the frequency division is analyzed from the fundamental principle. Then the developed method combines the shear averaging algorithm to focus on the moving target in the subimage, after the clutter suppression and the focusing position in each subimage is obtained. Next the observation model and the relative movement of the moving targets between the subimages estimate the moving targets. The theoretical analysis and simulation results demonstrate that the method is effective and can not only detect the moving targets, but also estimate their motion parameters precisely.

关键词： synthetic aperture radar moving target detection sub-image cancellation parameter estimation.

Knowledge-based bridge detection from SAR images

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Journal of Systems Engineering and Electronics 2009年第5期20卷 929-936页

作者： Wang Wenguang Sun Jinping Hu Rui mao shiyi School of Electronic and Information Engineering Beihang Univ. Beijing 100191 P. R. China

Automatic bridge detection is an important application of SAR images. Differed from the classical CFAR method, a new knowledge-based bridge detection approach is proposed. The method not only uses the backscattering intensity difference between targets and background but also applies the contextual information and spatial relationship between objects. According to bridges＇ special characteristics and scattering properties in SAR images, the new knowledge-based method includes three processes： river segmentation, potential bridge areas detection and bridge discrimination. The application to AIRSAR data shows that the new method is not sensitive to rivers＇ shape. Moreover, this method can detect bridges successfully when river segmentation is not very exact and is more robust than the radius projection method.

关键词： knowledge-based bridge detection SAR contextual information mathematical morphology.

MISS DISTANCE DYNAMICS IN ACTIVE RADAR HOMING MISSILES

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MISS DISTANCE DYNAMICS IN ACTIVE RADAR HOMING MISSILES

A GTD model and state space approach based method for extracting the UWB scattering center of moving target

1996 CIE International Conference of Radar(ICR’96)

作者： Ding Chibiao mao shiyi Department of Electronic Engineering Beijing University of Aeronautics and Astronautics

ISBN: (纸本)0780329147

＜正＞Combination radar homing systems with active terminal guidance are generally applied to advanced airto -air missiles[1].Formulas of miss distance of active radar homing missiles due to measurement noises, heading error and target mancuver are derived,and the normalized miss distance curves are *** effects of the seeker sampling time and the eclipsing of target on miss distance are analyzed.

关键词： radar equipment military systems missile guidance closed loop systems noise signal sampling radar signal processing miss distance dynamics active radar homing missiles radar homing systems active terminal guidance advanced air to air missiles measurement noise heading error target maneuver normalized miss distance curves seeker sampling time closed loop guidance system target eclipse

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Science China(Information Sciences) 2011年第1期54卷 182-196页

作者： WANG Jun,WEI ShaoMing,SUN JinPing & mao shiyi School of Electronic and Information Engineering,Beihang University,Beijing 100191,China School of Electronic and Information Engineering Beihang University Beijing China

Movements of the scattering center on the condition of ultra-wideband(UWB)will impact the extraction of *** paper presents an approach for extracting the moving targets’UWB scattering center parameters based on the geometrical theory of diffraction(GTD)model and the state space approach. Firstly,the UWB GTD scattering model is transformed into state-space equations in order to estimate the range and range rate through the singular value ***,the type parameter in the whole bandwidth is indicated dimension-reducedly by orthonormalized basis and estimated by traversal algorithm and minimumnorm ***,the intensity of scattering center is worked out based on the least square *** paper provides the Cramer-Rao bound(CRB)for parameter *** effectiveness of the approach is verified by computer *** approach can estimate range,range rate,reflection intensity and type parameter simultaneously in order to improve the track of scattering centers and the target identification.

关键词： scattering center extraction GTD model state space approach ultra-wideband Doppler processing

Optimal Approach to SAR Image Despeckling

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Journal of Systems Engineering and Electronics 2002年第1期13卷 48-52页

作者： Zheng Zonggui & mao shiyi Department of Electronic Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083,P.R.China Department of Electronic Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

Speckle filtering of synthetic aperture radar (SAR) images while preserving the spatial signal variability (texture and fine structures) still remains a challenge. Many algorithms have been proposed for the SAR imagery despeckling. However, simulated annealing (SA) methods is one of excellent choices currently. A critical problem in the study on SA is to provide appropriate cooling schedules that ensure fast convergence to near-optimal solutions. This paper gives a new necessary and sufficient condition for the cooling schedule so that the algorithm state converges in all probability to the set of global minimum cost states. Moreover, it constructs an appropriate objective function for SAR image despeckling. An experimental result of the actual SAR image processing is obtained.

关键词： Convergence of numerical methods Cooling Image processing Scheduling Simulated annealing

INITIALIZATION METHODS FOR GROUP TRACKING

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Chinese Journal of Aeronautics 1996年第3期9卷 182-186页

作者： Yang Cheugyang Qu Jianming mao shiyi (Beijing University of Aeronautics and Astronautics, Beijng, China, 100083) Beijing Univ. Aero. and Astronaut. Beijing 100083 China

An intuitive method is proposed to solve the diffcult problem for the initialization of group tracking. In order to initialize the group tracks. the reports obtained from the every moment must be separated as several groups at first. Then. each group in the first moment is associated with each group in the second moment. At last. group velocity vector must be estimated. In order to obtain accurate estimates meanwhile not to make the computation amount more heavier. different algorithms must be selected according to the target's number of the group in the first moment.

关键词： groups tracking group velocity Estimating

SEQUENTIAL ALGORITHM FOR MULTISENSOR PROBABILISTIC DATA ASSOCIATION

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Chinese Journal of Aeronautics 1997年第2期10卷 144-150页

作者： Hu Wenlong mao shiyi(Dept of Electronic Engineering, Bejiing University of Aeronauticsand Astronatutics, Beijing, 100083, China) Dept. of Electronic Engineering Beijing Univ. Aero. and Astronaut. Beijing 100083 China

Based upon a multisensor sequential processing filter, the target states in a3D Cartesian system are projected into the measurement space of each sensor to extend thejoint probabilistic data association (JPDA) algorit... 详细信息

关键词： multiple target tracking sensors sequential analysis data association data fusion