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25 June 1992, Volume 12 Issue 03 Previous Issue    Next Issue

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RESEARCH ON PHENOMENA OF RF INTERFERENCE IN TRANSMITTER GROUP AND DISTURBANCE TO CO-SITE RECEIVER He Zhenghua (Shanghai Institute of Spacecraft Engineering) 1992, 12 (03):  1-8.  Abstract ( 1674 )   Save On the complex spacecraft with many transmitting and recei-ving frequencies,sometimes the complicated phenomena of RF intermodu-lation interference in the transmitter group and disturbance to the onboardreceivers would occur.Those problems,which cause troubles and can not besolved easily,will hinder the development of the spacecraft.From thepoint of view of spacecraft system designing,this paper studies the mecha-nism of those phenomena,gives a simple,effective and very fast designmethod for prevention from those problems. Related Articles | Metrics

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A PHYSICAL APPROACH TO COLOR IMAGE UNDERSTANDING Huang Yuming (Beijing Institute of Control Engineering)Xu Guangyou (Qing Hua University)Ye Peijian (CAST) 1992, 12 (03):  9-18.  Abstract ( 1854 )   Save We present an algorithm of color image understanding whichsegments the image after analyzing surfaces with color variations due tolighting condition and object colors. The work is based on a theory——theDichromatic Reflection Model——which describes the color of the reflectedlight as a linear combination of light from surface reflection (highlight)and body reflection (object color).A peculiar cluster shape (skewed T) isformed by color pixels of an object area in 3D histogram in color space.The analysis of cluster's property helps to determine the color of lightand objects,but at same time the meaningful cluster is generated by theprojection of certain object area of image. According to the strategy ofhypothesis and test,following the continuity of the image and the featureof color clusters,the algorithm completes the image segmentation and givesforth the physical description of imaging process,including intrinsicimages,segmented image,the color of light and objects. The intrinsicimages are composed of both matte image and highlight image reflectingrespectively the properties of light condition and every objects. Related Articles | Metrics

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AN INVESTIGATION ON OUTER BOUNDARY OF THE EARTH'S SURFACE BAND REGION COVERED WITH A SATELLITE IN ORBITAL MOTION Li Dayao (Beijing Institute of Space Machine and Electricity) 1992, 12 (03):  19-26.  Abstract ( 1576 )   Save According to the solving principle of envelope for a family ofsingle parameter—surface curves,the solution to outer boundary of theearth's surface band region covered with a satellite in orbital motion isgiven. The influence of the earth rotation upon the longitudinal width ofregion above is discussed. Related Articles | Metrics

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ANALYSIS OF V-DIPOLE ABOVE GROUND USING MOMENT METHOD Zhang Weikang (Shanghai Scientific Instrument Factory) 1992, 12 (03):  27-32.  Abstract ( 1704 )   Save This paper analyzes and calculates the radiation patternand other characteristics of a V-dipole above the ground using MomentMethod.The theoretic values and the measured values are given. Theresult illustrates:the values are very close to each other.the V-dipoleabove the ground can be used not only as a kind of linear antenna but alsoas a kind of primary feed of plane antenna. Related Articles | Metrics

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SPACE DEBRIS AND ITS THREAT Chen Yiyuan (Chinese Academy of Space Technology) 1992, 12 (03):  33-38+70.  Abstract ( 2221 )   Save The number of man—made objects orbiting around the earthhas become so high that collision risks have to be taken into account inthe mission planing and operation of spacecraft,especially of manned spa-cecrafts. In this paper,the scenarios for the future development of spacedebris and collision probabilities are derived. A further steady increase ofthe basic population would always lead to and speed up a chain reactioncollisions. Related Articles | Metrics

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GMS STRETCHED VISSR DATA RECEIVING AND PROCESSING Xu Jianping (Satellite Meteorology Center,SMA) 1992, 12 (03):  39-45.  Abstract ( 1584 )   Save The features of GMS satellite stretched VISSR data receivingand processing are analysed.The configurations and functions of a developeddata receiving system and the three data processing systems of differentscale (real-time image processing system,microcomputer data processingsystem and large scale computer system) are described. Related Articles | Metrics

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ANALYSIS AND COMPARISON FOR IMAGE ENHANCEMENT TECHNIQUES Wang Fenghua Yang Hao (Beijing Institute of Satellite Information Engineering) 1992, 12 (03):  47-51.  Abstract ( 1538 )   Save In this paper,the global and the local techniques for imageenhancement are discussed and analysed. The characteristics and the virtuesand defects of each techniques suitable to different images are also summarizedand several algorithms for two techniques are described in this paper.Meanwhile it presents the development trend of image enhancementtechniques. Related Articles | Metrics

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AN APPLICATION OF TWO-CHANNELS RECEIVER TO MONOPULSE RADAR Mi Jinlong (14th Research Institute of the Ministry of Machinery and Electronics) 1992, 12 (03):  53-59.  Abstract ( 2053 )   Save Two-channels receiver is widely used in modern precision ins-trumentation radar.In the perspective of design and use,two-channels re-ceivers of both tone modulation and 0/π modulation are discussed in thispaper,and performances as well as features of two-channels receiver of thetwo modulations are analysed and compared with the emphasis on angle-measuring system.In the same time,the problems claiming attention in theapplication of two-channels receiver of 0/π modulation are shown.At last,the experimental data on angular performances of two-channels receiverare listed in this paper. Related Articles | Metrics

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FAILURE ANALYSIS OF SiO_2/Ag MIRROR SYSTEM IN THE SCANNING RADIOMETER Yang Dequan Fan Chuizhen (Lanzhou Institute of Physics,CAST) 1992, 12 (03):  60-63.  Abstract ( 1598 )   Save SiO_2/Ag thin films system is an important part of mirror inscanning radiometer.Failure analysis of the mirror have been performed byhigh resolution Scanning Auger Microprobe (SAM) and Scanning ElectronMicroscope (SEM).Results of SEM Showed that there is a lot of segrega-tion on surface of the failed mirror.We have found that these segregationare mainly Ag and Cu as well as a few of oxides and sulfides by SAM.Auger depth profiles results indicated that atomic diffusion have been occ-urred among SiO_2/Ag/Cu thin films.The diffusion characteristic of atomicAg,Cu and O are discussed.It is suggested that a bad density of SiO_2 thinfilm may be a possible cause of mirror failure. Related Articles | Metrics

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A SIMPLE AND DIRECT COMPUTING METHOD FOR CHEBYSHEV OPTIMIZATION DISTRIBUTION COFFICIENTS Yi Nianxue Bu Binlong (Xi'an Institute of Space Radio Technology) 1992, 12 (03):  64-70.  Abstract ( 2043 )   Save A simple and direct computing method is described for designof optimization distribution for manifold electrical units by means ofChebyshev Polynomial. By using the method the Optimization Distributionparameters can be calculated directly,and need not to start off with primalChebyshev Polynomial. The method is directly perceived,convenient,rapidand exact. Related Articles | Metrics