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25 October 2001, Volume 21 Issue 05 Previous Issue    Next Issue

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High-Frequency Response Research of Beam Structure Han Zengyao Qu Guangji (Beijing Institute of Spacecraft System Engineering，Beijing 100086) 2001, 21 (05):  .  Abstract ( 1863 )   Save The high-frequency response characters of a simple-sup po rted beam is obtained by NASTRAN. The result is strongly influenced by the mesh size. The comparison based on FEM, SEA and the closed form solution reveals th e effectiveness of SEA in the prediction of high-frequency response. Next, the energy transmission between two coupled beams is obtained through FEM, and then the CLF used by SEA is built. The method is verified through the comparison bet ween FEM and SEA in order to establish a new method which get the SEA parameter by FEM. Last, the effects of concentrated mass and boundary condition are consi dered. Subject Term Finite element method Beam structure Response High frequency Statistical energy analysis Related Articles | Metrics

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Effect of Time Asynchronous of Integrated Navigation System on Initial Alignment of Inertial Navigation System Chen Bingfang Zhang Yulin (National University of Defense Technology,Changsha 410073) Zhao Huali (Xichang Satellite Launching Centre,Xichang 615000) 2001, 21 (05):  .  Abstract ( 1598 )   Save The effect of GPS measurement delay on initial alignment of GINS is analyzed.The simplified error models are presented.Under the conditi on of circular trajectory,the estimation error of heading angle will be erroneou s if the time asynchronous between INS and GPS is ignored. Subject Term Combined navigation Global positioning system Initia l aiming Related Articles | Metrics

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Nonlinear Control Law of Satellites Attitude at Zero-Speed of Reaction Wheels Fei Congyu Li Yingtang (Shanghai Institute of Satellite Engineering,Shanghai 200240) 2001, 21 (05):  .  Abstract ( 1948 )   Save When reaction wheels rotate at nearly zero speed,the mom ent of friction will vary discontinuously.This leads to the uncertainty of contr ol moment,which influences the performances of satellite attitude control. Based on a nonlinear control approach,a nonlinear control law is developed to im prove attitude control performances.The analyses show the control law is convinc ing for zero-speed wheel.Finally,a simulation example is provided.Compared with traditional linear control law,the nonlinear control law is fully effective in d ealing with the uncertainties of wheels' control output. Moreover,the nonlinear control law is also quite simple.It occupies few memory c apacity compared with the linear control law and consumes a little CPU time.As a result,it is possible that the nonlinear control law is used directly on board. Subject Term Attitude control Reaction wheel Nonlinear control S atellite Related Articles | Metrics

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The Theory of Changing Satellite Orbit Inclination Using Moon Gravitation Jia Shijin She Mingsheng (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2001, 21 (05):  .  Abstract ( 2394 )   Save The activity of Hughes using moon gravitation for orbit change of “Asiasat-3” satellite made great sensation in the world.In this pap er,through the concept of effect sphere,explained the theory of orbit inclinatio n changing using gravitation of celestial body is explained.To use this theory,t he orbit and the space position of the celestial body must fulfil certain condit ions.A supposed orbit to show the effect of the moon gravitation on the orbit in clination is also introduced. Subject Term Gravitation transfer-orbital technique Orbit inclina tion Transfer orbital control Communication satellite Related Articles | Metrics

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A General Method of FEM Perturbation Zhu Anwen Qu Guangji Gao Yaonan (Beijing Institute of Spacecraft System Engineering，Beijing 100086) 2001, 21 (05):  .  Abstract ( 1621 )   Save Formerly the FEM perturbation method is to make the same small varieties of mas s mat rix and stiffness matrix,then calculate changes of system's eigenvalue and eigen ve ctor.The different varieties of mass matrix and stiffness matrix are given,and t he changes of system's eigenvalue and eigenvector are figured out. New method is better in the following example. Subject Term Structural model Structural analysis Perturbation M ethod Related Articles | Metrics

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Experimental Investigation of Heavy Ions Induced SEMU in High-Density SRAMs Zhang Qingxiang Yang Zhaoming (National Laboratory of Vacuum & Cryogenics Technology and Physics, Lanzhou Institute of Physics,Lanzhou 730000) 2001, 21 (05):  .  Abstract ( 1671 )   Save Single event multiple upset (SEMU) experimental results of high-density static random access memory (SRAM) are presented.The devices un der tests (DUTs) were bombarded by heavy ions from HI-13 tandem accelerator an d h eavy ion research facility in Lanzhou (HIRFL).A high-resolution tester for sing le event upset (SEU) in SRAMs,which is based on network communication protocol, was utilized to detect SEMUs occurred.Experimental results show that different me chanics can cause SEMU,SMU in HM628128ALP and HM628512LP were due to diffusing o f changes created by single ion to neghbouring junction.It was confirmed that sin gle event transients (SET) occured in peri-pheral circuit could cause SMU a nd pro ducts of spallation reactions of incident heavy ions with encapsulation material s also could contribute to SEMUs in case of glancing incidence.SMU rates of Hita chi SRAMs in geosychronous orbit and two sunsychronous obits were predicted. Subject Term Static storage Radiation effect Multiple bit u pset Experimentation Related Articles | Metrics

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Experimental Study on Single-Groove Heat Pipe Miao Jianyin Shao Xingguo Li Tinghan (Institute of Spacecraft System Engineering, Beijing 100086) 2001, 21 (05):  .  Abstract ( 1542 )   Save The structure and characteristics of single-groove heat pipe are introduced. Studies on single-groove heat pipe during the past ten y e ars in China are reviewed. The single-groove heat pipe and normal axial-groov e heat pipe are compared with each other on their heat transfer capacity. Based o n the experimental results, the V-shape groove in the vapor channel is optimize d, and methods to decrease temperature difference and fluctuation are achieved. Subject Term Heat pipe Heat transfer Temperature gradient Experi mentation Research Related Articles | Metrics

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Determination of Angular Velocity Based on GPS Zhao Wei Yuan Xin (Nanjing University of Aeronautics & Astronautics,Nanjing 210016) 2001, 21 (05):  .  Abstract ( 1672 )   Save In order to determine three-dimensional angular velocit y of moving object,the differential carrier phase rate of GPS is used and the ma thematical model of measurement and error analyses is also presented.Simulation is carried out and the result is satisfied. Subject Term Global positioning system Angular velocity measuremen t Mathematical model Computerized simulation Related Articles | Metrics

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Analysis for Some Factors Affecting the Temperature Distribution of a CCD Camera Li Guoqiang Jia Hong Liu Qiang (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2001, 21 (05):  .  Abstract ( 1709 )   Save In order to maintain the long life and high reliability of satellites,suitable temperature range and relative small temperature gradient between each component of a CCD camera must be controlled accurately.By therma l analysis for the CCD camera,some factors affecting the temperature distribution of the camera have been analyzed.The abovementioned factors include:thermal co n trolling mode,heat leak from the multilayer insulations (MLI),transient and stea dy numeric method,the flying season of the satellite and the performace degradat ion of thermal material. Subject Term Charge coupled device camera Temperature distribution Thermal analysis Related Articles | Metrics