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Table of Content

    25 October 1989, Volume 9 Issue 05 Previous Issue    Next Issue
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    HIGH ACCURACY ORBIT DETERMINATION OF GEOSTATIONARY SATELLITE
    Zhang Renwei (Beijing University of Aeronautics and Astronautics) Sun Huaisu (Satellite Meteorological Center)
    1989, 9 (05):  1-9. 
    Abstract ( 1546 )   Save
    The paper has described the determination of geostationary orbitusing single station tracking and trileteration data.A new efficient algorithmfor orbit determination has been developed.Satellite subpoint position accuracyis better than 30 meters.
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    DESIGN OF A CIRCULAR WAVEGUIDE DIELECTRIC-SLAB POLARIZER
    Ye Yunshang (Beijing Institute of Spacecraft System Engineering)
    1989, 9 (05):  10-24. 
    Abstract ( 2827 )   Save
    Starting with analysis,this paper has introduced a circuler wa-veguide dielectric-slab polarizer.Compact dimension and no need to adjustare its advantages.When it is used in the satellite ground receiving antenna,low axial ratio of circular polarization and low standing wave ratio can beachieved.This paper has given formulas curves used for calculation,anddata tables which can be directly used in the design of the polarizer.
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    3-D MODEL FOR SPACE RADIATION SHIELDING ANALYSIS
    Zhang Yongwei (Beijing Institute of Spacecraft System Engineering)
    1989, 9 (05):  25-28. 
    Abstract ( 1627 )   Save
    Space radiation effect on the operating satellite and 3-D shieldinganalysis by computer are described in this paper.The results obtained by3-Dmodel is more accurate and can be used to assess the result obtained by 2-Dmodel.
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    CAD TECHNOLOGY AND ITS APPLICATION IN SATELLITE ENGINEERING
    Zhang Guofu Ye Peijian Lin Baozhen
    1989, 9 (05):  29-35. 
    Abstract ( 1601 )   Save
    Computer Aided Design(CAD)is being widely applied inmany different fields including astronautics technology,due to its highefficiency,high quality and high accuracy.CAD is playing an important rolein these fields.Specially,MCAD and ECAD draw a great attention.Thispaper presents the activities,functions,structures and other main technolo-gies about CAD in combination with satellite research and application.Weare very glad if this paper will do somethings to promote CAD and to pre-pare an integration base of CAD/CAM in CAST.
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    ON SOME ASPECTS OF RELIABILITY DESIGN FOR SATELLITE ELECTRONIC EQUIPMENT
    Liao Jiongshen (Beijing lnstitute of Control Engineering)
    1989, 9 (05):  36-44. 
    Abstract ( 1786 )   Save
    In satellite reliability practice,developing reliability design forsatellite equipments is a keystone.In this paper some aspects of reliabilitydesign for satellite electronic equipments are reviewed.
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    HYPOTHESIS ON BUBBLE VOLUME OF ALTITUDE DECOMPRESSION SICKNEES AND RELATION BETWEEN O_2 PREBREATHING TIME AND PRESSURE IN SPACE SUITS
    Xu Guolin Zhang Ruguo (Institute of Aerospace Medico-Engineering)
    1989, 9 (05):  46-51. 
    Abstract ( 1661 )   Save
    Suppose that the increase of the gas bubble volume is bound tobe followed by the increase of the incidence of decompression sickness(DS).It can be deduced that relative volume of gas bubbel in the tissue(the ratiobetween the bubbel volume and the tissue volume,V_b/V)has linear relationto the radio of N_2 tension in the tissue before decompression and that afterdecompression(P_(N2)/P_(dN2)).N_2 tension after decompression(P_(dN2))equals thesum of environmental pressure and synthetic pressure(P_s).P_s depends onactivity level.When the activity level increases,P_s decreases,V_b/V increasesand incidence of SD increases.In accordance with this hypothesis and experi-mental data on SD,the curves of the relation between O_2 prebreathing timeand the pressure in space suits are obtained.
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    ON LIFETIME OF CHARGED ARTIFICIAL SATELLITE
    Li Linsen (Department of physics,Northeast Normal University)
    1989, 9 (05):  52-56. 
    Abstract ( 1833 )   Save
    The theory of the lifetime of a charged artificial Satellite mov-ing in the earth's gravitational and magnetic field under the atmospheric dragis studied from an energy point of view in this paper.The formula of thelifetime is derived Which is concerned with charged Satellite in circularOrbit.We conclude that the lifetime of a charged Satellite is longer thanthat of the same noncharged Satellite,the more charge it has,the longer life-time it will have.As an example,the effect of charge carried on the Sate-llite on its lifetime is estimated numerically.
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    THE APPARENT POLARIZED ANGLE ON THE EARTH FROM THE LINEAR POLARIZED RADIATION OF A GEOSTATIONARY COMMUNICATION SATELLITE
    Chen Shiping Chen Shufeng (Xi'an Institute of Radio Technology)
    1989, 9 (05):  57-62. 
    Abstract ( 1614 )   Save
    This paper gives a formula strictly derived to calculate theapparent polarized angle for both anywhere on the earth and any linearpolarized radiation from a geostationary communication satellite.As an example,this paper also provides the results of the apparent polarized angle atseveral main earth stations in China from two Chinese practical communicationsatellites launched in 1988.
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    PIXEL DECOMPOSITION BASED ON PRINCIPAL COMPONENT ANALYSIS
    Shao Meizhen Deng Guanglin Information Engneering Institute of the PLA,Zhengzhon) Xu Xiru (Institute of Remote Seneing,Peking University)
    1989, 9 (05):  63-68. 
    Abstract ( 2088 )   Save
    In this paper,the method of mixed pixel decomposition based onPrincipal Component Analysis(PCA)is mainly introduced.Usually PCA isapplied to enhance image and reduce the dimensions of data space,withoutchanging the space construction of data.With the method of target test in thispaper,it can be realized to decompose mixed pixels.Because of the fixedresolution of Land-sat data,a large amount of mixed pixels exists in remotesensing image.Is one of the major reasons of the same spectrum for differentsurface features and different spectrums for the same surface feature.If it ispossible to decompose mixed pixels,this will be very helpful for extensivelyutilizing the remote sensing data.
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