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25 February 1999, Volume 19 Issue 01 Previous Issue    Next Issue

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A Search Method of Recognizing Abnormal Data Tang Binbing Wang Zhengming (National University of Defense Technology,Changsha 410073) 1999, 19 (01):  .  Abstract ( 1692 )   Save In this paper,a search method based on the area of triangle and quadrilate ral is presented to solve the problem of recognition of abnormal data in trajectory tracking system.The validity and ability of the method to data process in real time and afterward were proved through theoretical analysis and simulation calculation. Related Articles | Metrics

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Nonlinear Dynamic Modeling of Deployable Truss Structures With Clearances Huang Tieqiu Wu Delong Yan Shaoze (Beijing Institute of Astronautical Systems Engineering,Beijing 100076) 1999, 19 (01):  .  Abstract ( 1547 )   Save Joint behaviors of a large deployable truss structure are analyzed and the force relationship between internal body and external body of the clearance is acquired,then the finite elements of two typical joints with clearances are established,finally the general nonlinear dynamic equations of such structures are formulated. Related Articles | Metrics

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Using Two TDRS to Determine Trajectory of a Carrier Rocket Hu Shaolin Sun Guoji (Systems Engineering Institute,Xi'an Jiaotong University,Xi'an 710049) 1999, 19 (01):  .  Abstract ( 1575 )   Save Generally,it is impossible to determine the 3 dimensions location of a moving body only by two TDRS's tracking distance data.In order to do this work,some accessory information must be given.In this paper,six kinds of condition are summarized and a series of locating algorithms are constructed,based on the theoretical trajectory of rocket .The influence of tracking error and the bias of the theoretical trajectory departure is discussed,also.At the end of this paper,some simulation is done.The simulation results show that these location algorithms given in this paper is efficient. Related Articles | Metrics

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Resolution Performance of Satellite Borne SAR Yuan Xiaokang (Shanghai Institute of Satellite Engineering,Shanghai 200240) 1999, 19 (01):  .  Abstract ( 1868 )   Save In this paper,the resolution performance for satellite borne synthetic aperture radar (SAR) are analyzed in detail.The expressions of range resolution,the azimuth resolution,and the radiometric resolution have been derived.The various definitions for the radiometric resolution and the error probability also compared with each other.The resolution volume and the interpretability for SAR images are introduced.The resolution of the equivalene square cell for SAR images is also given.This paper is significant for estimating the SAR image quality and selecting reasonably the SAR system parameters. Related Articles | Metrics

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Study on Impact of Origin Positioning Deviation of DGPS Precise Surveying Cai Hongxiang (Wuhan Technical University of Surveying and Mapping,Wuhan 430070) 1999, 19 (01):  .  Abstract ( 1579 )   Save In this paper,the impact of the origin positioning deviation on precision of GPS baseline is discussed theoretically,simulated calculation of the GPS raw data is made and the result fits well with that calculated theoretically.The following conclusions could be drawn:the origin positioning deviation does not affect the internal accuracy but makes a systematic error that varies with the origin positioning deviation and tyB m(B m is a mean latitude of the baseline)to the result of baseline.Finally,suggestions are made as to how to get a more accurate WGS84 coordinates when carrying on DGPS(Differential GPS)precise surveying. Related Articles | Metrics

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Application of Finite Element Method in the Thermal Analysis of Spacecraft Antenna Reflector Zhang Lihua (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 1999, 19 (01):  .  Abstract ( 1534 )   Save The finite element method is an attractive means for the thermal analysis of spacecraft components with high thermal stability requirements.The application of finite element method in the thermal analysis of spacecraft antenna reflector is discussed.The on orbit steady and transient temperature profiles of a spacecraft parabolic antenna reflector are calculated by using finite element method.The necessary temperature data were provided for the thermal distortion analysis and the selection of the thermal control measures. Related Articles | Metrics

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Numerical Simulation on Action of Atomic Oxygen to Spacecraft Surface Material Gao Shaolun Zhou Ding (Harbin Institute of Technology,Harbin 150001) Cai Guobiao (Beijing University of Astronautics and Aeronautics,Beijing 100083) 1999, 19 (01):  .  Abstract ( 1684 )   Save This paper introduces the influence of the LEO environments on spacecraft surface materials and the evaluating technology of lifetime of spacecraft surface materials in LEO.In this work,numerically simulate influence of atomic oxygen on polyimide with or without coated layer both in LEO and ground experiment environments.As a result,the present work provides a good guideline to the design of spacecraft. Related Articles | Metrics

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A Combined Method for Gauging Liquid Propellant Remaining on Satellite Zhang Tianping Da Daoan Chen Zhen Zhu Xiaolan (Lanzhou Institute of Physics,Lanzhou 730000) 1999, 19 (01):  .  Abstract ( 1465 )   Save A principle method of combining flowmeter with PVT was proposed and discussed.And it can be applied to measure liquid propellants on a satellite in orbit with high accuracy. Related Articles | Metrics

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Stochastic Simulation of the Effects of the Internal Interfering Factors on the Liquid Rocket Engine Performance Shen Chibing Wu Jianjun Wang Kechang Chen Qizhi (National University of Defense Technology,Changsha 410073) 1999, 19 (01):  .  Abstract ( 1739 )   Save A pump fed Liquid Rocket Engine (LRE) is researched.Based on the actual variation range of the internal interfering factors,the method of drawing random sample,the estimate method of the probability density parameters and the method of Pearson's chi square test are employed.On the various conditions that each internal interfering factor obeys the normal distribution,Weibull distribution and uniform distribution respectively,a nonlinear mathematical model of static characteristics of LRE is employed to simulate stochastically the effects of the internal interfering factors on the engine performance,and to obtain the statistical distribution laws of the engine performance parameters. Related Articles | Metrics

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Some 256Kbit SRAM Single Event Upset Rates and Distributions Sui Houtang (Center for Space Science and Applied Research,Academia Sinica,Beijing 100080) 1999, 19 (01):  .  Abstract ( 1641 )   Save In this paper,using Single Event Upset (SEU) data collected by high speed static RAM IDT71256D and asynchronous static RAM HM8832 of SEU Monitor on board SJ 4 spacecraft,the total upset rate,the device type and the logic upset rates are obtained and compared with other space experiment results.In addition,the SEU distribution histograms and fit exponential decay curves for the differences of SEU address on chip and arrive time are given by statistic analysis based on portion of SEU data,and finally the conclusions are given. Related Articles | Metrics

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Error Analysis of Measurement of Constant Pressure Flowmeter Meng Yang (Lanzhou Institute of Physics,Lanzhou 730000) 1999, 19 (01):  .  Abstract ( 3365 )   Save The constant pressure flowmeters (CPFMs) were used to calibrate vacuum leaks and vacuum gauges in some national laboratories.The errors of measurement of CPFM and CPFM with a reference chamber were theoretically analyzed in the paper.The variation of temperature and pressure in the measurement process is one of the main parts of measurement errors.With the aid of a reference chamber,the error of measurement contributed by the variation of temperature in the variable chamber can be reduced. Related Articles | Metrics

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A Simulation Equipment Used for Determing Outgassing and Contamination Property of Non metal Spacecraft Materials Wang Xianrong Chai Qiang Zen Keren Wang Yi (Lanzhou Institute of Physics,Lanzhou 730000) 1999, 19 (01):  .  Abstract ( 1778 )   Save A simulation equipment used for determing the outgassing and contamination property of non metal spacecraft materials has been built recently.It's used to measure Collected Volatile Condensable Materials (CVCM) in a simulated space vacuum environment and will give out all the CVCM data of the entire outgassing measuring process.The stability of temperature control system is ±0 1℃.Measure system consists of 4 QCM.The equipment resolution reaches the 4 4×10 -8 g/cm 2.The main desing is the same as the equipment type of NASA and ESA.So that the test and its data could be compared and exchanged internationally. Related Articles | Metrics