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Table of Content

    25 February 2001, Volume 21 Issue 01 Previous Issue    Next Issue
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    State-of-Arts and Analysis on Hyperspectral Image Classification in Imaging Spectral Technique
    Zhang Junping Zhang Ye Zhou Tingxian (Harbin Institute of Technology,Harbin 150001)
    2001, 21 (01):  . 
    Abstract ( 1897 )   Save
    Hyperspectral images are widely concerned due to their high spectral resolution.Their application is a task of top priority after solving the problems of radiance correction and calibration.The study on the hyperspectral image classification is valuable to crop growth monitoring,mineral identification and seawater analysis as well as many other useful aspects.In view of this,the development of imaging spectral technique is summarized and for the first time the classification methods are divided into two kinds:pure pixel and mixed pixel,according to the constitutions of a pixel.The object of induction and ana- lysis on the state-of-arts of hyperspectral image classification technique is expected to find breakthrough points and to strengthen our study on them.
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    Research of the Residual Propellant Dumping System
    Liao Shaoying (Machine-Electron Equipment Research Institute,Shanghai 200245)
    2001, 21 (01):  . 
    Abstract ( 1514 )   Save
    The dumping scheme demonstration and option of the residual propellant of first upper stages rocket of China are discussed.The scheme of dumping system for special use is put forward.The design,development and experiment of all process is introduced.Based on the technology,the problem of explosive disintegrate in the high altitude of upper stage rocket of Long March Model Vehicles is expected to be solved.
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    Application of Noise Analysis on Solar Array by Statistical Energy Analysis
    Han Zengyao Qu Guangji (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (01):  . 
    Abstract ( 1459 )   Save
    The necessity of noise test and vibroacoustic analysis of solar array is introduced.Statistical energy analysis is used to predict the development of the vibroacoustic mechanical environments.The feasibility of the above method is verified through the comparison of the test results.
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    Design of Pressure Leak Calibration Apparatus
    Zhang Dixin Zhang Jianjun Xu Heng Feng Yan Gong Yueli (Lanzhou Institute of Physics,Lanzhou 730000)
    2001, 21 (01):  . 
    Abstract ( 1829 )   Save
    The pressure leak calibration apparatus is a kind of a metrology standard for gas leak rate.The pressure leak can be calibrated with the constant volume method and the dynamic comparison method of quantitative gas.The calibration range is from 10 2 to 5×10 -5 Pa·L/s .The calibration principle,the design method and the parameters selection for the pressure leak calibration apparatus are introduced.
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    A Nonlinear Control Method on the Attitude Control System of Earth Observation Satellites
    Gong Jianjun Chen Yiqing (Beijing Institute of Control Engineering, Beijing 100080)
    2001, 21 (01):  . 
    Abstract ( 1639 )   Save
    A simple and efficient nonlinear controller on the Attitude Control System (ACS) onboard Earth Observation Satellites (EOS) is described. The control problems are mainly about the influence of the pointing stability from the disturbances and measurement noises, without considering the behavior of sensors and actuators. The performances of the nonlinear control system are checked by extensive simulations.
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    Exploring the Satellite Project's Management Structure and Methods Suitable for the National Conditions
    Xu Fuxiang (Chinese Academy of Space Technology,Beijing 100081)
    2001, 21 (01):  . 
    Abstract ( 1733 )   Save
    The management structure & methods will have a certain effect on the development of national satellite engineering , they must accord with not only their own development rule but also the changing situation of the country. Management status quo about Chinese Academy of Space Technology (CAST), the producer of most chinese satellites, is introduced. Inadaptabilities to the changing situation of country and its own developmental rule are analysed in some aspects ,such as management structure & method, management mode of satellite project, establishment of quality system, organi zing of assembling & measuring and management of batch manufacture. The optional countermeasures are searched by comparing the domestic situation with the overseas correlative situation. Same clear & idiographic suggestions are introduced.
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    Simulation Analysis and Optimization of Constellation's Global Continuous Coverage
    Wang Haili Chen Lei Ren Xuan (College of Aerospace and Material Engineering,National University of Defense Technology,Changsha 410073)
    2001, 21 (01):  . 
    Abstract ( 1735 )   Save
    The analysis and optimization of constellation's coverage in the opinion of simulation are introduced.The questions,which should be solved in the process of simulation analysis,are discussed firstly.Then the algorithm of global coverage decision and point coverage decision at one sample time are presented.Some parameters to analyze simulation results are given,and these parameters are integrated into Constellation Coverage Performance by the use of fuzzy analysis.Based on the research,the nonlinear optimization of constellation's global continuous coverage is discussed.
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    A Control Model for Satellite Orbit Maintenance
    Yang Weilian (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (01):  . 
    Abstract ( 1528 )   Save
    Orbit maintenance is one of very important operation tasks for geostation-ary satellites as well as earth resource satellites.In the case of geostationary orbit the satellites as well as earth resource satellites.In the case of geostationary orbit the satellite position on Earth equator will drift because the perturbation caused by Earth equator ellipticity and the control needs to be performed periodically.In the case of earth resource satellite the atmosphere drag can also cause the ground tracks drift and raising semi-major axis becomes a routine work.In addition,if the orbit is sun-synchronous one,the sun gravitation can effect the inclination and induce the drift of the right ascension of ascending node.Although physical mechanisms to cause the variations are different for different cases,the same mathematical model could be abstracted.The mathematical model for all the cases is presented first,then applications for different situations are described.
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    Formation Flying of Small Satellite and Its Orbital Configuration
    Lin Laixing (Beijing Institute of Control Engineering,Beijing 100080)
    2001, 21 (01):  . 
    Abstract ( 1618 )   Save
    The distributed satellite consisted of many small satellites flying in formation is equivalent to or even exceed the capability of a single large satellite,which is referred as “virtual satellite”.The formation flying opens up a new application for small satellites.The conception fo formation flying and its orbital configuration are presented.Then some possible applications of virtual satellite are discussed.
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    Satellite Keeping Technology of Small Satellite
    Li Xiaotong (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (01):  . 
    Abstract ( 1763 )   Save
    The basic design idea of the third-generation onboard measurement,control,management system (Satellite Keeping Operator,SKO) is deseribed.It is a satellite design technology developed based on the concepts of field control,embedded micro-controller and onboard network.Its characteristics include full digital,full network interface,full distributed structure and online-modification.Two concept-changes are put forward embedded and network.SKO is a flexible onboard service system,it coordinates and controls the interaction between onboard devices and equipment with field network,and accomplishes the dynamic operation of the steam of information and energy.Downloading tasks and modifying parameters on-line is convenient.The changes the occlusion and customization of the traditional satellite measure and control system,makes the onboard devices and equipment have the ability of“Plug and Play”.SKO is the crucial technology to construct the onboard-integrated electronics system and the kernel to create the common platform.Using SKO technology,the reliability and validity of the whole satellite are improved,and developing period and cost are reduced.Differences between SKO and OBDH,CAN and 1553B are given.
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