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    25 August 1994, Volume 14 Issue 04 Previous Issue    Next Issue
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    A MATHEMATICAL METHOD FOR MISTRAM SYSTEM TO DETERMINE THE ORBIT
    Wang Zhengming; Zhou Haiyin (National University of Defense Technology, Changsha 410073)
    1994, 14 (04):  . 
    Abstract ( 1591 )   Save
    n this paper, by means of a detailed mathematical analysis to determine space vehicle orbit's principle of MISTRAM system, have obtained a new method to determine orbit parameters.The method does not need a nominal orbit and it is of easy calcultion and high accurary.Meanwhile, have obtained the law of error propagation.A host of simulated results and calculation of real measured data show that our method is of good efficiency.
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    CALCULATING ORBITAL HEAT FLUXES OF CONCAVE SURFACES AND MUTUALLY VISIBLE SURFACES WITH SPECULAR REFLECTION
    Weng Jianhua; Pan Zengfu(Beijing Institute of Spacecraft Systems Engineering, Beijing 100086)Min Guirong(Chinese Academy of Space Technology, Beijing 100081)
    1994, 14 (04):  . 
    Abstract ( 1571 )   Save
    After analyzing the distribution of the orbital heat fluxion space surfaces and the featuves of the specular reflection, methods of calculating heat fluxes of concave surfaces and mutually visible surfaces with specular reflection have been offered in t his paper,which are based on Monte Carlo Method. Examples such as the orbital heat fluxes of hemispherical concave surface and two mutually vertical and visible flat plates with specular reflection have been calculated.
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    OPTIMAL AEROASSISTED GUIDANCE USING LOH'S TERM APPROXIMATIONS
    Nan Ying; Chen Shilu (Northwestern Polytechnical Uniyersity,Xi'an 710072)
    1994, 14 (04):  . 
    Abstract ( 1551 )   Save
    A new Loh's model is deduced. The Loh's term may be modeled as an inverse proportion function of δ, which is t he lift coefficients ill vertical plane at a maximum lift-to-drag ratio. Based on t he Loh's model, the paper deduced the optimal control law and reentry trajectory of aeroassisted noncoplanar orbit transfer,where the exit speed is maximized and the exit altitude, flight-path angle, heading angle are fixed. By analysing the optimal control law and reentry trajectory, some important conclusions are obtained.
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    PRIMARY ANALYSIS OF DEVELOPMENT APPROACH TO CHINESE SATELLITE MOBILE COMMUNICATION
    Tong Kai(Chinese Academy of Space Technology,Beijing 100081)Guo Jianning(Beijing Institute of Satellite Information Engineering, Beijing 100081)
    1994, 14 (04):  . 
    Abstract ( 1509 )   Save
    The paper describes the development of mobile communication first, and then, after comparing the cellular mobile communication with the satellite mobile communication, points out it is necessary for China to develop satellite mobile communication.After comparing the geostationary satellite system with the low earth orbit satellite mobile communication system, as well as the single beam with the multi-beams, both used in satellite mobile communication,according to its economic status and level of satellite technology, except international satellite mobile communication the paper suggest that China, should develop a geostationary multibeam satellite for its domestic mobile communication.
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    QUALITY EVALUATION OF CCD MULTISPECTRAL SCANNING SYSTEM IMAGE OF RESOURCES SURVEY SATELLITE
    Guo Zhaozeng(Beijing Institute of Satellite Information Engineering, Beijing 100081)
    1994, 14 (04):  . 
    Abstract ( 1671 )   Save
    The quality evaluation importance,quality evaluation content and that major factors of influellce on the quality of a CCD multispectral scanning system image of resource survey satellite are summarized in this paper.The evaluation criterion and evaluation methods that were used by SPOT and TM are also summarized in this paper. The comparison between the estimated results before SPOT and Landsat launched and the evaluation results after their launching are given.
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    AN AIRBORNE ELECTRIC FIELD SENSOR
    Hui Shide(Lanzhou Institute of Plateau Atmospheric Physics,Chinese Academy of Sciences,Lanzhou 730000)
    1994, 14 (04):  . 
    Abstract ( 1770 )   Save
    In order to investigate the formation and evolution of space charge layer beneath and inside thunderclouds, developed an airborne electric field sensor which measured quasi-stable atmospheric electric field based on shielding and uns hielding a metallic stator alternatively. This paper described the operational principle, characteristics of the design, the main specifications and a brief introduction to the application of the sensor.
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    DESIGN METHOD AND RELIABILITY ANALYSIS OF 80-SERIES OF FAULT TOLERANCE MEMORY
    Yang Mengfei(Beijing Institute of Control Engineering, Beijing 100080)
    1994, 14 (04):  . 
    Abstract ( 1786 )   Save
    he paper presents a new method for memory fault tolerance through analysing the series of 80 CPUs used in space projects. The method can implement memory fault tolerance without structure switching control circuit and improves the system reliability. The paper analyses the feasibility of the method, which has been demonstrated by an example.Finally, the reliability has been analysed and the reliability comparison result with strand-by memory fault-tolerance structure in the same redundancy has been given.
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    OPTICAL DESIGN OF CCD STAR SENSOR
    Lu Xin(Beijing Institute of Control Engineering, Beijing 100080)
    1994, 14 (04):  . 
    Abstract ( 1972 )   Save
    his paper presents the selection of optical design goals for CCD star sensor. Wavelength range for the system is from 0.48μm to 0.85μm,focal length 75mm, F/1.44, field of view 8.5°.It's a complicated Petzval system. Evaluating image quality of the system with the method of spot diagram energy concentration and deviation of energy centre. Total number of elements of selected CCD is 384 × 288, pixel size 23μm × 23μm. Maximum energy centre deviation in FOV for polychrome spot diagram is 1.6μm,corresponding to 4. 39″.
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    RESEARCH OF LIGHTWEIGHT HONEY-COMB HOLE STRUCTURE OF SPHERICAL REFLECTOR OF SPACEBORNE SENSOR
    Fu Danying;Sun Jiwen(Beijing Institute of Space Machine and Electricity,Beijing 100076)
    1994, 14 (04):  . 
    Abstract ( 1714 )   Save
    The lightweight structure of honey-comb holes on the back of the sphrical reflector of spaceborne sensor is discussed in this paper. A computer program for differentiating elements, generating nodes and automatically building up files of finite element models is worked out. The structure under the selfweight load condition is computational analyzing with structural analysis program and a series of data of maximum deformation are derived on the premise of variation of relevant structure parameters.The data are fitted into curves and farthermore the experiential formula of optimal solution of the lightweight structure is deducted.
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    AN CAT METHOD FOR RECEIVING & TRANSMMITING CHARACTRISTICS OF SPACE BORNE COMMUNICATIONS SYSTEMS
    Li Litian; Li Benhua (Xi'an Institute of Space Radio Technology,Xi'an 710000)
    1994, 14 (04):  . 
    Abstract ( 1793 )   Save
    method of CAT for radiation performance test on space borne communications system level has been developed. Compared with the conventional method, by which the system performance data are got by calculation of the data gained in subsystems tests, the method described here has got higher accuracy. The test and software was set-up with a focus on getting directly the most important system charactritics,that the users are most interested in,such as EIRP coverage,coverage rale of service zone, G/T and SFD coverage.A test on the payload of DFH-3, the third generation of Chinese communications satellite, was performed and the results of the test were satisfactory.
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