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25 April 2001, Volume 21 Issue 02 Previous Issue    Next Issue

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Precise Computation for Nonlinear Transient Temperature Distribution of Solar Array An Xiang Zhang Duo (Northwestern Polytechnical University,Xi'an 710072) 2001, 21 (02):  .  Abstract ( 1615 )   Save An effective numerical method called nonlinear item compensation method (NICM) based on precise computation method and state transfer method is proposed.NICM is a development of the precise computation method which is a high precision algorithm for transient analysis,and can be used for numerical computation of nonlinear transient temperature distribution of spacecraft's solar array.Approximating to analytic solution even though the time step is considerable large is the most significant advantage of NICM.The numerical examples obtained by NICM also show the high convergence and stability of the present method. Related Articles | Metrics

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Design Regional Coverage Walker Constellation by Point Coverage Simulation Method Lin Xiqiang Zhang Yulin (National University of Defense Technology,Changsha 410073) 2001, 21 (02):  .  Abstract ( 1633 )   Save The optimal Walker constellations for continuous regional coverage are designed by Point Coverage Simulation Method.The appropriate orders of objects and variables are given.Some helpful conclusions are derived from the analysis of the results of the eight different regions with single and quadruple coverage requirements. Related Articles | Metrics

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Research of Sun Synchronization Orbit Satellite Power System Design Computation Method Yan Wanjuan (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2001, 21 (02):  .  Abstract ( 1830 )   Save First two basic architectures of SSO satellite power system are introduced.Then the design and computation method based on this two power system is analyzed,and computation formula based on single orbit or several orbits energy balance are achieved.This method is validated by computing an example.Solar array area and battery capacity needed are computed.Finally single orbit or several orbits energy balance results by energy balance analysis are obtained. Related Articles | Metrics

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A Method of Autonomous Orbit Determination for Spacecraft Using Star Sensor Yang Bo Fang Jiancheng Wu Xiaojie (Beijing University of Aeronautics and Astronautics,Beijing 100083) 2001, 21 (02):  .  Abstract ( 1724 )   Save A autonomous real-time determination of position for spacecraft by using the extended kalman filtering is put foward.The elevation angular of star is observed by star sensor and horizontal instrument.The effect on the number of sighting star,the precision of star sensor and the change of sampling period to the error determination is analyzed and compared. Related Articles | Metrics

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Discussion of the Relationship Between Packet Length and Frame Length in Packet Telemetry Gu Yingqi (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2001, 21 (02):  .  Abstract ( 2138 )   Save Two models of packet length are developed at the entrance of transfer layer in packet telemetry.The distribution of framing time is analyzed for different ratio of frame length to packet length.And the relationship between frame efficiency and frame waiting time is also analyzed.These results might help to analyze data stream and data delay in transfer layer,and determine the proper packet length to achieve high system performance. Related Articles | Metrics

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The Research of Simulation Method of Dynamic Flux of Spacecraft by Infrared Heating Cage Jia Yang (Beijing Institute of Spacecraft Environment Engineering,Beijing 100029) Xu Li Liu Qiang Jia Hong (Institute of Spacecraft System Engineering,Bijing 100086) 2001, 21 (02):  .  Abstract ( 1667 )   Save The dynamic mathematical model of infrared heating cage and flux sensor is founded by theory analysis,simulation research and experiment research in the engineering apply background of thermal balance test of some spacecraft.On the base of the model,the technique of simulation of dynamic flux of spacecraft in orbit is discussed,using infrared heating cage as flux simulation unit and adiabatic flux sensor as measure unit. Related Articles | Metrics

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The Integrative Design of Attitude Control and Satellite Keeping System in Small Satellite Liao Minghong Geng Yunhai Wu Xianghu Cheng Guangming (Harbin Institute of Technology,Harbin 150001) 2001, 21 (02):  .  Abstract ( 1551 )   Save An integrative design of attitude control and satellite keeping system are introduced.In this case,the number of on board computers can be reduced,the real time characteristic of the information process can be enhanced,and the advantage of the light,small and low cost of the small satellite can also be realized.The hardware architecture of the attitude control system,the fly modes of satellite and their control strategy,the architecture and layout design of the satellite keeping system,the interface of the attitude control system and the satellite keeping system are discussed here. Related Articles | Metrics

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Study on the Relative Problem of GPS-Based Geometric Orbit Determination in Real Time Wen Yuanlan Wang Wei Liu Xinyue (National University of Defense Technology,Changsha 410073) Yang Yuanxi (Xi’an Research Institute of Surveying and Mapping, Xi’an 710054) 2001, 21 (02):  .  Abstract ( 1638 )   Save First,the point positioning and all sorts of differential GPS techniques are discussed on GPS based geometric orbit determination in real time.Differencing pseudo range is proposed to use to determine the satellite geometric orbit in real time because it can weaken the effect of GPS satellite orbit error and clock error,and particularly effect of SA,and because it is not difficult to carry out.The result computed from practical observation proves that it can improve the precision of geometric orbit determination obviously.Then,robust estimation is tested to weaken or eliminate the effect of contaminated GPS based signal,and the result verfies that robust estimation can improve the precision of geometric orbit determination further. Related Articles | Metrics

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Fault Detection and Recovery Method Based on Hierarchic Alliance of Filters Dong Xijun (School of Astronautics,Harbin Institute of Technology,Harbin 150001) Wang Yufei (Beijing JHD New tech Company,Beijing 100086) Hong Xingchang (Shanghai Space Industry Bureau,Shanghai 200233) 2001, 21 (02):  .  Abstract ( 1568 )   Save As the high precision aircraft such as the modern spacecraft becomes more complicated,the safe operating problem also becomes more and more significant.FDIR (Fault Detection,Isolation and Recovery) techniques are important guarantee of the reliability of spacecraft.Based on Kalman filtering estimation algorithm,a kind of FDIR method based on hierarchic alliance of filter family is proposed.According to the concept of the backup filter,this method constructs a kind of dendriform hierarchic alliance structure of fusion filter.On the basis of that,the multilevel FDIR can be designed and performed.A simulation example of INS/GPS/Doppler integrated navigation system illustrates the feasibility and effectiveness of this method.The multi sensor information processing technique based on the hierarchic alliance filter structure can resolve the limitation of the centralized Kalman filter and the normal federated filter,and has significance to enhance the fault to lerant ability of the system.Fault Detection,Isolation and Recovery) tech Related Articles | Metrics

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Solving the Service Angle of EMR System Robot With a Decomposing Method Huang Xianlong Liang Bin Chen Jianxin Wu Hongxin (Beijing Institute of Control Engineering,Beijing 100080) 2001, 21 (02):  .  Abstract ( 1806 )   Save It is necessary to know the adaptive ability of robot operating or dexterity within its reachable workspace in the applying field.Service angle,dexterity,and line with an equivalent extent pitch are put forward as performance index.At first,the structure feature and freedom of EMR system robot are analyzed,and the service angle is determined as performance index of system dexterity.Then,several methods of solving robotics service angle are presented,and the decomposing method is discussed in detail.This method can be adapted to control online with little computer time. Related Articles | Metrics

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Research of Dual-Sheet Shield Structure with the Normal Impact Ma Wenlai Pang Baojun Zhang Wei Zhang Zehua (Harbin Institute of Technology,Harbin 150001) 2001, 21 (02):  .  Abstract ( 1595 )   Save Characteristic of the normal impact of cylindrical projectile onto LY12 aluminum Whipple shielding Concept within the first doorsill value are studied with an example of dual-sheet Whipple structure through experimental investigation.So,shielding Concept damage behaviors with projectile velocity are presented.Within the first doorsill value of normal impact,the change of velocity,thickness of shielding and target,prevention distance can deeply affect the results of shielding ang target. Related Articles | Metrics

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A MEO Satellite Constellation for Regional Mobile Communication Yang Weilian (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2001, 21 (02):  .  Abstract ( 1655 )   Save A MEO satellite constellation for Asian and pacific regional mobile communication is suggested.The minimum elevation of 30 degree is guaranteed for the ground users.The constellation consists of six satellites placed in six orbital planes which are even distributed along the equator.The circular orbits have same inclinations of 28 5 degrees and same periods of 12 hours with the altitude of 20183km.All six satellites will move on the same ground track,but even separated. Related Articles | Metrics