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    25 December 2000, Volume 20 Issue 06 Previous Issue    Next Issue
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    Data Association in Multisensor Multitarget Tracking
    Xie Meihua Wang Zhengming (National University of Defense Technology, Changsha 410073)
    2000, 20 (06):  . 
    Abstract ( 1790 )   Save
    A method of data association(DA) and data fusion (DF) in multisensor multitarget tracking (MSMT) is discussed. First, data association in single sensor is rea lized by increasing measuring elements. Second, integer programming is applied to realize scanning association, which is also extended to route association. Finally, a fusion method to represent trajectory parameter with spline function is used, which solve the problem of huge computational cost. This simple method has higher correct association percent and smaller computational cost, and also utilize the measuring information fully.
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    Detection and Correction of SEU in the Data-Handling System of Micro-Satellite
    Xiong Jianping Jia Huibo You Zheng (Tsinghua University,Beijing 100084)
    2000, 20 (06):  . 
    Abstract ( 1868 )   Save
    Because of radiation in space environment,micro-satellite will normally experience Single Event Upset (SEU) errors in its Random Access Memory at a scale of small probability.These errors affect key data storage and the functions of on-board computer or data handling system.The error correction methods used in Tsinghua l micro-satellite are described and the details of design which implements (12,8) and (39,32) Hamming coding and Triple-Module-Redundancy coding based on FPGA are given.
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    Research on Simulation and Stationkeeping Strategy of the Circular Constellation
    Zhang Honghua Li Hongming Zou Guangrui (Beijing Institute of Control Engineering,Beijing 100080) Li Xin (Tsinghua University,Beijing 100084)
    2000, 20 (06):  . 
    Abstract ( 1985 )   Save
    The architecture of a constellation can be described jointly by the position of the satellite relative to the earth and the position of the satellite relative to other satellites in the constellation.Due to effect of the disturbance force,the architecture of the constellation will decay gradually.So it needs to be controlled in order to keep the architecture.The mathematical model for the motion of two satellites in the same circular orbit is deduced.And the precision of the model has been tested through the simulation.The control law based on the linear quadratic(LQ)control theory is presented in order to control the relative position of the two satellites.A kind of relative position control strategy cha- racterized with the adjustable nominal position is developed.The validity of the strategy has been explained through the dissertation and supported by the simulation result.
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    Adaptive Control for Space Manipulators in Task Space
    Wang Jing Liu Liangdong Liang Bin Wu Hongxin (Beijing Insitute of Control Engineering,Beijing 100080)
    2000, 20 (06):  . 
    Abstract ( 1577 )   Save
    For the space manipulator with an attitude-controlled base, an adaptive control algorithm in task space is presented in this paper,which proves that the displacement tracking errors in task space amd the joint errors and joint velocity errors in joint space are both asymptotically convergent. Simulation results confirms the effectiveness of the algorithm.
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    H_∞ Hypo-Optimal Control for Spacecraft Orbital Rendezvous
    Wu Tao Yang Yikang Yu Junqi Huang Yongxuan Hu Baosheng (Xi'an Jiaotong University,Xi'an 710049)
    2000, 20 (06):  . 
    Abstract ( 1542 )   Save
    The problem of control for two spacecrafts rendezvous is investigated.The method is presented that orbital design uses optimal control method and controller is gotten by H ∞ control means.The method is validated by a simulation example.The method has robust control effect and hypo-optimal orbital character.The results provide the practicable method for the engineering design of spacecraft rendezvous.
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    Analysis of the Operational Mechanism of the Inverted Meniscus Type Capillary Wick
    Zhang Jiaxun Hou Zengqi (Institute of Spacecraft System Engineering,Beijing 100086)
    2000, 20 (06):  . 
    Abstract ( 1615 )   Save
    With the study of the CPL(Capillary Pumped Loop),the operational mechanism of the inverted meniscus type capillary wick under the disturbance is investi- gated.By the analysis,it is concluded that,the decrease of the permeability of the wick is helpful to reduce the oscillation in the wick during the operation,however,very low permeability can lead to dry-out of the wick.Also,it is obtained that low porosity has a negative effect on the operation Additionally,it can be known that,the minimum capillary radius of the wick is of great importance to the working ability of the wick and the ability of the wick to dampen the oscillation during the operation.
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    Primary Investigation of Experiment and Performance on Low Power Arcjet
    Tang Haibin Liu Yu Dai Wuye (School of Astronautics, Beijing Univ. of Aeronautics and Astronautics, Beijing 100083)
    2000, 20 (06):  . 
    Abstract ( 2179 )   Save
    Electric propulsion technology has been widely applied in space flight. Arcjet is the highlight of investigation and application because of its high specific impulse, high ratio of thrust and power and multiplicate propellant use.A brief description about the research of experiment and performance on low power Arcjet is presend,and the main composition of experiment system is introduced. Some primary operation performance parameters and experiment results analysis are given.
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    Constellations Design and the Establishment of the InterSatellite Links
    Geng Liang Wu Shiqi (Inst.of Information Systems UESTC,Chengdu 610054)
    2000, 20 (06):  . 
    Abstract ( 1536 )   Save
    The position of LEO/MEO satellites used in the Mobile Satellite Systems vs the earth and the relative position of satellites are both time-variant.To establish InterSatellite Links (ISLs),it is necessary to make sure of the exact relative position of the satellites to calculate the azimuth and the distance of two satellites using ISLs.After presenting several constellation types and designing methods,the geometrical parameters of the ISLs are given, and the relationship between the azimuth and distance of two sate- llites in ISLs and constellation design in detail are analyzed.Some useful conclusions are also drawn.
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