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25 December 2002, Volume 22 Issue 06 Previous Issue    Next Issue

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Thermal Distortion Analysis and Test of Space Micro-Strip Array Antenna Wei Juanfang Guan Fuling(Zhejiang University,Hang Zhou 310027) Zhao Renjie Wang Fengbin Tao Xiaoxia(Xi'an Institute of Space Radio Technololgy, Xi'an 710000)$$$$ 2002, 22 (06):  .  Abstract ( 1905 )   Save The structural characters of space microstrip array antenna are studied The mechanical equation is formed based on un symmetric panel of composite material and analyzing results of thermal distortion are given To verify the results, a thermal distortion test in normal pressure and high temperature is designed The methodology, data measuring system and procedure of the test are described in detail The results of the test meet well to the analysis results and it shows the structure design and FEA model are reasonable for the antenna Related Articles | Metrics

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Optical Design and Optical Efficiency of Cylindrical Fresnel Lens for Solar Concentrator Jia Fuyun Ma Mianjun Sun Yanjie Wang Duoshu Guo Juntao Luo Chongtai Huang Liangfu (Lanzhou Institute of Physics,Lanzhou 730000)$$$$ 2002, 22 (06):  .  Abstract ( 1977 )   Save The optical design and optical efficiency of line focus cylindrical Fresnel lens for solar concentrator are discussed. The design parameters of the lens are optimized according to theoretical analysis, and some lens samples are accomplished based on the optimized design. The influences of factor F and modeling plate on the lens' optical efficiency are also analyzed. Related Articles | Metrics

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The Study on Integrated System of Three-Star/SINS of Pseudo-range Lin Xueyuan Liu Jianye Fan Shenglin (Center of Navigation, Nanjing University of Aeronautics and Astronautics,Nanjing 210016)$$$$ 2002, 22 (06):  .  Abstract ( 1900 )   Save Double star navigation system is one regional global navigation system (RDSS) built up by our country. The disadvantage of Double star navigation system is given and one navigation system made up of three earth synchronous satellites based on Double star navigation system is put forward. The receiver can calculate the position of user according to the three measured pseudo ranges and the altimeter's message. And the integration navigation system of Three star navigation system and SINS based on pseudo range are further studied. The simulation results show that this integration method can improve the navigation precision effectively, and is one kind of inertial/satellite integration navigation system fit for our country. Related Articles | Metrics

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A Study on Confidence Level in Reliability Prediction Guo Weichang (Beijing Institute of Spacecraft System Engineering, Beijing 100086)$$$$ 2002, 22 (06):  .  Abstract ( 2203 )   Save The concept of confidence level is introduced into process of reliability prediction on electronical equipments. A novel method of reliability prediction with confidence level is established sequentially. The reliability of an unit equipment, the reliability of a voting system and the reliability of a parallel system are predicted respectively and the results are compared by using these methods. The results show that a potential conservative systemic error is eliminated. Hence, the system reliability can be predicted more accura tely by using this novel method. Related Articles | Metrics

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Study and Implementation of a Scaling and Locating Methodology Based on Eye-in-Hand Vision Meng Cai Wang Tianmiao Chou Wusheng (Robotics Institute from Beijing University of Aeronautics and Astronautics,Beijing 100083)$$$$ 2002, 22 (06):  .  Abstract ( 1988 )   Save Computer Vision plays a great role in enhancing robot′s intelligence and ability to overcome uncertainties in unknown environment.Since spacial telerobot works in a hazardous and uncertain environment, a method is proposed to scale and position unknown objects based on eye in hand vision which can help the telerobot estimate whether it can grasp the unknown object, and determine where and how to grasp.In repositioning tasks, it can locate the object fast by using their prior information and avoid moving the manipulator frequently. The theory on which the method is based is addressed and then the method is validated by an experiment and the error is analyzed. The result confirms that this method can achieve high accuracy. Related Articles | Metrics

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The Risk Management and its Application in Space Program Jin Xunshu (Beijing Institute of Space Science and Technology Information, Beijing 100086)$$$$ 2002, 22 (06):  .  Abstract ( 2276 )   Save The risk management is one of the important constituents of the management work in space program/project. Great emphasize is given to it and a risk management plan is made for each space program, which has become a systematic approcah to deal with the risk. An introduction of risk management in space program, its content, requirements and process are introduced, and some exemples of the application of risk management are also given. Related Articles | Metrics

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Drag Perturbation Model and Orbit Prediction Accuracy of Manned Spacecraft Tang Xisheng Tang Geshi Diwu Yazhou (Beijing Aerospace Control Center, Beijing 100094)$$$$ 2002, 22 (06):  .  Abstract ( 2025 )   Save Normally, the manned spacecraft is maintained in three axis stabilized and earth acquisition (in pitch) mode. Meanwhile the solar array drag model are more complicated because the solar array does not, in general, point into the air stream. It is necessary for body and solar array panel of manned spacecraft separately to be modeled with the atmospheric drag perturbation is described. Using USB tracking data from the local area TTC network, orbit fitting and prediction is developed in higher precision for returning maneuver of manned spacecraft. Related Articles | Metrics

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The Research and Development of Space Solar Dynamic Power System Cui Haiting Yuan Xiugan Xing Yuming Hou Xinbin (Beijing University of Aeronautics and Astronautics,Beijing 100083)$$$$ 2002, 22 (06):  .  Abstract ( 1881 )   Save Solar Dynamic power system has been identified as a promising technology for the future space power system.It is a new energy system and should be applied to space as the result of its excellent performance and low cost.It′s already been over forty years since the beginning of the research.In the present paper,the working principle and the technology development of SDPS is introduced from thermodynamic cycle and main constituents.The advantage of SDPS is indicated by comparing with other power systems.The suggestion of developing the SDPS is also put forword. Related Articles | Metrics

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Study of Performance and Stability of Flexible Satellite Thermal Control Materials Lu Yusun * Fan Benyao ** Feng Yudong * Zhai Houming * Wang Yi * ( *Lanzhou Institute of Physics, Lanzhou 730000) ( ** Chinese Academy of Space Technology, Beijing 100081)$$$$ 2002, 22 (06):  .  Abstract ( 1613 )   Save In China,the flexible thermal control materials have been researched and developed for over 15 years. Performance of the thermal control material and its stability under the simulated space environments is discussed. The results of measuring and testing indicated that optical, thermal and electrical performance of the products is good. Especially, its stability for example, UV radiation, electron beam irradiation, atomic oxygen action and in wet thermal store ambient is also excellent. The AFM analysis show that the methods and technology of preparing TO and high reflectance Al films are very important. At the same time, the thermal control materials punched with holes are developed successfully. Related Articles | Metrics

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Design of Real-Time Image-Decoding and Reconstructing System Based on Variable-Length Code Jiang Hongxu Cheng Zijing Zhou Xiaokuan (Beijing University of Aeronautics and Astronautics, School of Space Technology,Beijing 100083)$$$$ 2002, 22 (06):  .  Abstract ( 1737 )   Save An image compression and decompression algorithm of RBC(resampling based compression)is introduced,and a VLSI design and hardware implementation of the image decompression is given in details.The image coding algorithm of RBC is characterized with multimode and variable bit rate which are hard to use in hardware design.In order to resolve these problems,some simple and effective methods are given.They can not only deal with the questions of variable bit rate decoding successfully,but also greatly improve the processing speed of the decompression system.The high speed real time image data decompression hardware system is finished successfully,and its processing speed is not less than 265Mbit/s,meeting the required processing speed of 224Mbit/s. Related Articles | Metrics