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    25 February 2009, Volume 29 Issue 01 Previous Issue    Next Issue
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    Study of Hovering Method at Any Selected Position to Space Target
    Yan Ye(National University of Defense Technology,Changsha 410073)
    2009, 29 (01):  1-5+71. 
    Abstract ( 1647 )   Save
    The research about the hovering orbit was infroduced.Dynamics analysis of a spacecraft which would hover at any selected position to a target satellite was presented.An open loop orbit control strategy was proposed to reach the goal with a Non-Kaplan orbit.The energy requirements of the hovering spacecraft at any orbit latitude and any relative hovering position was analyzed.Finally,numerical simulation about typical target were conducted to validate the theoretics.
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    New Method Derived from Time-Vector Analysis for Generation of Elevation Information Based on Interferometric SAR Satellites
    Li Yang(Institute of Communication Satellite,China Academy of Space Technology,Beijing 100094)Zhang Running(Dong Fang Hong Satellite Co.ltd,Beijing 100094)
    2009, 29 (01):  6-12. 
    Abstract ( 1891 )   Save
    In consideration of Time-varying and Three-dimensional characteristics of the formation flying InSAR satellites system parameters,a new method derived from time-vector analysis for generation of elevation information was presented.The calculation and simulation programs were also developed.The relations between the ground targets' absolute altitude and system parameters in a single flight period were analyzed in detail.As a result of vector resolution,an analytical method using matrixes to indicate system parameters' error propagation coefficients was established.The analysis of variation regularity of the ground target absolute altitude,followed with the continuous alteration of the formation flying satellite relative orbital configuration,was carried out by putting the processing module of the system parameter error propagation coefficients matrixes into the time-vector analysis model.The results provide theoretical foundation for system key techniques extraction.
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    Design of Brain Emotional Learning Model Based Turntable Servo System
    Zhen Ziyang Wang Daobo Wang Zhisheng(College of Automation Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016)
    2009, 29 (01):  13-18+25. 
    Abstract ( 1850 )   Save
    Brain emotional learning(BEL) model based intelligent controller for a turntable servo system with high precision is presented.BEL model is a bio-computational model inspired by the emotional learning mechanism in mammalians brain.BEL based intelligent controller is designed by fusing the information of system tracking error,control variables and etc.Different control structure can be designed by selecting different sensory input signals,and controller parameters are adjusted by online learning the nodes weights in BEL model based on an associative learning method,and then the adaptive tracking control of the turntable servo system is realized.Simulation and experimental results show that the BEL based intelligent controller has strong learning ability,and can restrain the nonlinear factors such as friction,and exhibits good stability and high tracking precision in application of the real-time control system.
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    Numerical Study on Oscillatory Phenomenon of Natural Convection during Melting of Phase Change Material
    Jian Lujing Zhang Jiaxun Li Jindong(China Academy of Space Technology,Beijing 100094)
    2009, 29 (01):  19-25. 
    Abstract ( 1917 )   Save
    In order to study influence of natural convection during melting of phase change material,the oscillatory phenomenon of natural convection was investigated.With enthalpy-porosity method and Boussinesq hypothesis,single-phase governed equations were set up and simulation on melting process under gravity was completed.It is shown that when the Rayleigh number Ra is small,the natural convection can be obtained with a steady solution,then the flow changes from a steady state to a periodical oscillatory state with the increase of Ra.
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    Study of the Solar Power System of Stratospheric Airships
    Shi Hong Song Baoyin Yao Qiuping(College of Aerospace Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016)
    2009, 29 (01):  26-31+40. 
    Abstract ( 2659 )   Save
    Concerning the various usage of the stratospheric platform,a study of the solar power system of the stratospheric airship was performed.The model of the solar radiation on the airship surface was developed,including direct radiation,scattered radiation and reflected radiation.With this model,the distribution of solar energy on the solar cell array of a typical stratospheric airship was calculated.The results show that the available solar energy varies obviously with the season,latitude,area of the solar energy cell array and the airship orientation,and reaches at its maximum value at the orientations where the back of the airship is toward the sun rays.
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    Application of Adaptive Particle Filtering in Ultraviolet Sensors
    Song Chen Han Chao Geng Jianzhong(School of Space Technology,Beijing University of Areonautics and Astronautics,Beijing 100191)
    2009, 29 (01):  32-40. 
    Abstract ( 1715 )   Save
    Autonomous navigation system based on ultraviolet sensors is a typical nonlinear system.For the general particle filter lacks the adaptive capacity.A new particle filtering algorithm called adaptive particle filtering was proposed which adopts a new method combining the unscented Kalman filter with the strong tracking filter to produce important density functions.The proposed algorithm adopts UKF to produce particles,in which each sigma point of each particle was updated by STF to make the algorithm have adaptive.Simulation was done based on simulated orbit and measurement data and was compared with results of other filtering algorithms to illuminate the effectiveness of the navigation method.
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    Location Evolution and Keeping of IGSO Cross Node
    Zhu Mincai1,2 Hu Songjie2(1 Beijing University of Aeronautics and Astronautics,Beijing 100191)(2 Beijing Aerospace Control Center,Beijing 100094)
    2009, 29 (01):  41-44+51. 
    Abstract ( 2430 )   Save
    The shift of the cross node of IGSO is a significant reason of changing the service region of IGSO satellite and degrading the performance of system,so the node location keeping of IGSO satellite is required.The IGSO cross node location evolution and keeping were investigated.The formula and rule of cross point evolution acted by earth gravity perturbation,third-body perturbation and bias of working orbit,were given.The maintenance strategy of IGSO node location was described.
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    Experimental Research of Working Fluid Used in Single-Phase Fluid Loop System
    Zhang Li Huang Jiarong Fan Yufeng(China Academy of Space Technology,Beijing 100094)
    2009, 29 (01):  45-51. 
    Abstract ( 1644 )   Save
    Selecting working fluid is an important content of designing single-phase fluid loop system.The chief parameters and criterions for selecting working fluid were considered.The test platform of single-phase fluid loop system was introduced.Based on comparing the chief parameters between the fluid used for Shen Zhou spacecraft and Secool-3 which is one kind of mixture,the experiments at room temperature and low temperature were carried on.The result of the experiments indicates that the single-phase fluid loop system has good performance when Secool-3 mixture is applied.
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    Empirical Dynamic Model for Deflation Process of Shen-Zhou Manned Spacecraft
    Tang Geshi1,2 Chen Ming2(1 Beijing University of Aeronautics and Astronautics,Beijing 100191)(2 Beijing Aerospace Flight Control Center,Beijing 100094)
    2009, 29 (01):  52-55+61. 
    Abstract ( 1895 )   Save
    One of the main error sources in orbit dynamic model of the ShenZhou manned spacecraft is due to the effect of deflation,which gives an extra force on the spacecraft.This effect introduces an error in orbit by the order of several kilometers at maximum in the transversal direction.An empirical dynamical model for the deflation process was developed and three model parameters were estimated based on onboard microgravity accelerometer and navigation data.It shows that the precision of orbit prediction is enhanced by over an order of magnitude,indicating that the model is a reasonable solution to the deflation process.
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    Experimental of Gas-filled Pressure Vessel under Hypervelocity Normal Impact
    Zhang Yong1 Huo Yuhua1 Han Zengyao1 Li Ming1 Huang Jie2(1 China Academy of Space Technology,Beijing 100094)(2 Hypervelocity Aerodynamics Institute,China Aerodynamics R&D Center,Mianyang 621000)
    2009, 29 (01):  56-61. 
    Abstract ( 1748 )   Save
    The hypervelocity impact(HVI) of meteoroid/orbital debris(M/OD) on spacecraft wall could cause severe damage.The failure of pressure vessels,the key parts threatened by M/OD,would lead to a catastrophic failure of spacecraft.The HVI characteristics and failure modes of the spherical pressure vessel were presented.The hole diameters under different projectile impact parameters were achieved according to the HVI tests of unpressurized vessels,then the ballistic limit diameter of projectile at a velocity 6.5km/s was analyzed.HVI tests of gas-filled pressurized vessels were also carried out to analyze the impact parameter leading to a catastrophic failure of the vessel.Finally,the prediction model of hole diameter was achieved by means of HVI test data fitting,which provided reference for M/OD shielding design of spacecraft
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    Investigation of the Angular Motion of Suspended Body in Recovery Systems
    Ding Di Qin Zizeng(College of Aerospace and Material,National University of Defense Technology,Changsha 410073)
    2009, 29 (01):  62-67. 
    Abstract ( 1881 )   Save
    12-degree dynamic model of body-parachute recovery system was established,in which pitch,yaw and roll were used to describe angular motion of the suspended body.5 basic modes and 3 representative composite modes with quantitative characteristics were summarized,and the relation ship between specific modes and corresponding angular description was presented.Simulations and analysis show that this method can be used in angular motion analysis of generic suspended body.
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    Study and Application for the Waterproof Breathable Material on Spacecraft
    Zhang Jianke Ji Yongfu(National Key Lab of Vacuum & Cryogenics Technology and Physics,Lanzhou Institute of Physics,Lanzhou 730000)
    2009, 29 (01):  68-71. 
    Abstract ( 1721 )   Save
    In order to apply the waterproof breathable material to the spacecraft,the main characteristics and specifications of a new waterproof breathable material were introduced and tested.Based on these tests,the main characteristics of the waterproof breathable material applied to the spacecraft were discussed and analyzed.The application exaplmes for the Chinese spacecraft were introduced.The characteristics of large breathable capability and well waterproof performance of the waterproof breathable material are very good and can meet requirements for spacecraft application.The waterproof breathable material can be used for the spacecraft in the future.
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