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25 April 2000, Volume 20 Issue 02 Previous Issue    Next Issue

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An Experimental Investigation on Porous Plate Water Sublimator Wu Zhiqiang Yuan Xiugan (Beijing University of Aeronautics & Astronautics,Beijing 100083) Han Lijun Shen Liping Li Tanqiu (Institute of Space Medico-Engineering of China,Beijing 100094) 2000, 20 (02):  .  Abstract ( 1621 )   Save The manufacturing techniques of porous plates are developed. The breadboard and tester of water sublimator are designed. An experimental investigation is carried out on water sublimator with different porous plates. The attention is focused on the effects of input temperature and flow of hot fluid, physical parameters of porous plate, pressure of feed water and placement on performance of sublimator. Test results prove the basic design concept of sublimator is feasible. Finally, some useful conclusions about further design of sublimator are presented. Related Articles | Metrics

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Research of the Real-time Transmission Technology with Large Amount Data Pan Lijun Xu Bin Zhang Heng (Institute of Mechanics,Chinese Academy of Science,Beijing 100080) 2000, 20 (02):  .  Abstract ( 1508 )   Save It is one of the key problems in the telescience technology of the space application that the real-time transmission of large amount data is achieved under the condition of the constrained message channel bandwith.A new idea is presented by combining double-bus with double-buffer.It is realized to provide the video image real-time seamless transmission and active teleoperation under the constrained condition of the fixed transmission protocol and message channel bandwith.As some key technologies have been solved,the high qualitative video image sequence can real-timely be redisplayed (when video image data is compressed to 20fold,the signal-to-noise rate is 38dB) at 2Mbit/s on ground according to CCSDS (Counsel Committee of Space Data System) bitflow protocol. Related Articles | Metrics

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Analytical Study of Active Clamp ZVS-PWM Converter Technique Wan Chengan Liu Wengui (Harbin Institute of Technology,Harbin 150001) 2000, 20 (02):  .  Abstract ( 1549 )   Save The active clamp ZVS-PWM power converter circuit has many advantages over the conventional PWM converters.The design and performances of high frequency power supplies are improved.The steady state operation of a flyback active clamp ZVS-PWM converter is analyzed.The design of active clamp ZVS-PWM used in satellite power supplies is feasible. Related Articles | Metrics

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Textile Geometry Model for Textile Structural Composites Shen Huairong (Institute of Command and Technology,Beijing 101416) Wu Delong (Design Department of Astronautical System Engineering of Beijing,Beijing 100076) 2000, 20 (02):  .  Abstract ( 1508 )   Save A general Textile geometry modelis presented for the elastic analysis of textile structural composites.The geometrical characteristics of the yarns in the unit cells are considered and based on fiber undulation and continuity in three dimensional space,actual cross sectional geometry of the yarn and the influence of mutual tangle between yarn,the model is established.A unified analytical method and software is obtained by using the model.The theoretical predicted values are compared with the experiments for 3D braid structural composites.The result are fairly good for selected test specimens. Related Articles | Metrics

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A New Kind of Spaceborne SAR Waveform and its Processing Technique Zhang Running He Yu (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2000, 20 (02):  .  Abstract ( 1583 )   Save On the basis of quantitative analysis of Doppler effects of linearly stepped frequency pulse train waveform when it is used in spaceborne synthetic aperture radar (SAR),a new method is presented to compensate Doppler Quadric phase and to avoid slant range resolution deterioration,loss of SNR and Doppler phase coupling between slant range dimension and azimuth dimension. Related Articles | Metrics

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Effect of Perigee Height on Aeroassisted Orbital Plane Change Lin Xiqiang Zhang Yulin (National University of Defense Technology,Changsha 410073) 2000, 20 (02):  .  Abstract ( 1760 )   Save The effect of perigee height on aeroassisted orbital plane change is studied.Using sequential quadratic programming,trajectories which minimize the impulse required to change the orbital plane and maximize the inclination change are calculated for different perigee heights.In each case,the stagnation heating rate is limited.Results show that with the increment of the perigee height,the ability to change orbital plane and robustness to the initial conditions are both decreased.In general,the perigee height should not be too large in aeroassisted orbital plane change. Related Articles | Metrics

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Analytic Solution of the Nonlinear Equation of Relative Motion with Small Constant Thrust Zhu Renzhang (Beijing University of Astronautics and Aeronautics,Beijing 100083) Li Yili (Chinese Academy of Space Technology,Beijing 100081) 2000, 20 (02):  .  Abstract ( 1777 )   Save Accurate equations of the relative motion are discussed,and analytic solutions of the linear equations are derived,based on analytic solutions of the linear equations,where the target vehicle moves on an elliptic orbit and the chaser vehicle is acted by small constant thrust. Related Articles | Metrics

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Research of Strength of Forced Layer of Pressure Suit Lin Ziyuan Chen Jingshan Cong Dequan (Institute of Space Medico-Engineering,Beijing 100094) 2000, 20 (02):  .  Abstract ( 1543 )   Save Based on calculation theory of thin-shell pressure vessel,scientific analysis and quantities of tests are made concerning the correlative factors of material,structure of textile,cutting,sewing technique and environment of forced layer of pressure suit.For the selection of textiles for the forced layer of perssure suit,identification of fabrication technique,and adequate environment,the definite research conclusions are given,in order to ensure the development of forced layer of pressure suit and security during forcing. Related Articles | Metrics

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Fusion TRIAD Algorithm Applied to GPS Attitude Determination Li Yong Wu Hongxin Liu Liangdong (Beijing Institute of Control Engineering,Beijing 100080) 2000, 20 (02):  .  Abstract ( 2153 )   Save The vector observation algorithms is applied to GPS attitude determination.The traditional TRIAD algorithm only uses two non-collinear vectors to determine three-axis attitudes.But it is sensitive to the master vector and can't use the third vector.An improved TRIAD algorithm is presented which efficiently resolve the problem of sensitive to the vector selection.In order to employ all measurements from three basslines,a new algorithm named fusion TRIAD is proposed on the basis of the OPTTRIAD algorithm.The fusion TRIAD algorithm can improve the accuracy of attitude solution obviously.The experiments are made by TANS vector GPS receiver.The results show that the sensitivity to the master vector actually disappears in the improved TRIAD algorithm.Compared with the traditional TRIAD algorithm,the fusion TRIAD algorithm can improve the accuracy of attitude solution 35%,19% and 34% in azimuth,pitch and roll respectively. Related Articles | Metrics

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Research on Synthesis Method of the Error of Ground Simulation Test of Docking Mechanism Guan Yingzi Liu Yuhua Shi Xueyan (Harbin Institute of Technology,Harbin 150001) 2000, 20 (02):  .  Abstract ( 1737 )   Save Synthesis of the error in simulation test is the important approach to judge accuracy and credence of simulation.Based on the Monte Carlo method,a kind of synthesis method of the error is proposed,which can be used in ground simulation test of docking mechanism implemented on the half physical synthetic simulation test bed of docking mechanism.Moreover,the statistic law of ground simulation result of docking mechanism is obtained.The confidence coefficient and the confidence interval of simulation result are given by volume simulation.The criterion for appraising accuracy and credibility of simulation results is suggested. Related Articles | Metrics

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Design and Test of a Compact Furnace for Crystal Growth in Space with Program-controlled Temperature Profile Luo Jun (Shanghai Institute of Ceramics,Shanghai 200050) Tan Xiaochen,Zhang Zhongli,Li Yijun,Cui Weixin Ma Mianjun,Hu Tingliang,Zhang Xinzu,Huang Liangpu (Lanzhou Institute of Physics,Lanzhou 730000) 2000, 20 (02):  .  Abstract ( 1568 )   Save This paper introduces a compact furnace for crystal growth in space,which temperature profile is program=controlled.The basis of this furnace is that,the furnace temperature profile changes automatically under the control of a computer system to implement the process of crystal growth,so there is no mechanical motion that would produce deleterious vibration to the microgravity environment.This furnace is constructed from 7 individual controlled heating zones.An advanced computer system,which is based on the Intel 80c31 micro-processor,is used for the temperature control of each heating zone (PID control) and the data collection.In the furnace,several different temperature profiles have been created.The performance of this furnace have been tested on earth,and the results show that it can be a precisely controlled,multi-purpose furnace for crystal growth in the Chinese returnable satellite. Related Articles | Metrics