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Table of Content

    25 June 2007, Volume 27 Issue 03 Previous Issue    Next Issue
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    Study of Satellite Initial Orbit Determination Method
    Zhu Zhuanmin Xu Zongben(Mathematical College of Xi′an Jiaotong University,Xi′an 710049)
    2007, 27 (03):  1-6. 
    Abstract ( 1797 )   Save
    Actually,the satellite precision orbit determination is a iterated process to improve the initial orbit by solving the dynamic differential equation group.So that,the precision and calculating rate of the orbit is depends on the solve algorithm of the differential equation and the precision and veracity of the initial orbit.For the ranges or two-way ranges data observed by some stations synchronously,a geometry method was proposed to determine the satellite initial orbit.The method combined the radio wave refraction error correction method with itself can improved the precision greatly.
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    Numerical Method of Orbital Period Rate Determination and Prediction for Recoverable Spacecraft
    Qiu Hongxing1 Wang Xiuhong2 Wu Lianda1 Zhu Kaijian2(1 Purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210008)(2 Xi'an Satellite Control Center,Xi'an 710043)
    2007, 27 (03):  7-12. 
    Abstract ( 1917 )   Save
    Numerical method of orbit determination usually can not directly obtain mean orbit period rate used to calculate orbit maneuver strategy for recoverable spacecraft,but can solve atmospheric drag coefficient.Through the creation of sophisticated spacecraft dynamics models,numerical integrator,conversion algorithm from osculating elements to mean elements and polynomial fitting algorithm for mean period series,a calculation method of mean orbit period rate was proposed based on numerical method for precision orbit determination and prediction.Applications for the two spacecrafts have revealed to the validity of the methodology.
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    Analysis of Orbit Parameter Accuracy by use of Rate Data
    Hu Zenghui Zhu Jubo Liu Jiying Liu Ye(National University of Defense Technology,Changsha 410073)
    2007, 27 (03):  13-17. 
    Abstract ( 1734 )   Save
    With the development of radar and tracking technologies,the mode of orbit tracking and telemetry control system is evolving towards a new type of using only six or more velocity-measuring radars.As a result,it is necessary to study problems such as data processing in the new system,and the priority of various algorithms in this new system.Error propagation theory was used to compare the accuracy of point by point algorithm and that of the polynomial algorithm so as to provide theorefical supporting for the use of polynomial and spline algorithm in the new system.Computer simulations by using the two algorithms for two typical orbits were presented.It showed that the polynomial algorithm can get much higher accuracy than the point by point algorithm,besides,data structure of the polynomial algorithm was simple and suitable for real-time computation.
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    Comparison of Quaternion and Rodrigues Parameters on Attitude Algorithm of Secondary Planet
    Wang Yongjun Qin Yongyuan Yang Bo(Department of Automatic Control North Westem Polytechnical Univercity,Xi′an 710072)
    2007, 27 (03):  18-23. 
    Abstract ( 2269 )   Save
    The relations among Rodrigues parameters,modified Rodrigues parameters and quaternion were described.A method based on modified Redrigues parameters was proposed,which can avoid odd value.The differential equation and attitude matrix based on Rodrigues parameters and modified Rodrigues parameters were educed.By simulation,the computational complexity and calculation accuracy are compared among secondary planet attitude algorithms based on Rodrigues parameters,modified Rodrigues parameters and based on quaternion.The simulation results show that the calculation accuracy of the method based on the Rodrigues parameters and modified Rodrigues parameters is equal to that based on the quatemion,and the computational complexity of the former one is less than that of the later.
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    Small Scale Two Phase Thermal Bus Driven by TEC and Capillary Pump
    Cao Jianfeng Fan Hanlin(China Academy of Space Technology,Beijing 100086)
    2007, 27 (03):  24-28. 
    Abstract ( 2014 )   Save
    Small scale thermal bus for satellite thermal control,can realize three-dimensional arrangement of hot devices,and be independent with the heat radiating area.By this way,the integration intensity was improved,and the cooling requirements of large payloads integrated by function were met.A new concept about two-phase fluid loop was presented,which used capillary pump instead of mechanical pump to realize a small scale two-phase thermal bus without moving parts,high reliability and long life.The capillary pump in this loop required to be heated actively to force fluid flow,and consume some power as well.How to reduce pump′s input power is the key for capillary pumped two-phase thermal bus(CPTPTB) to get practical.Analysis and experiment indicated that thermoelectric cooler(TEC) had high coefficient of performance for heating in small temperature difference.It shows that it is more economical to heat up capillary pump with TEC than with direct electric heater.
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    Analysis of the View-angle of the Antenna on Movable Vehicles
    Guo Wenjia(Satellite Applications System Department,China Academy of Space Technology,Beijing 100053)
    2007, 27 (03):  29-32. 
    Abstract ( 1636 )   Save
    The view-angle requirements for an on-board Earth-surface vehicle's antenna, that keeps data communications between the vehicle and a known GEO satellite were analyzed,taking into account of the vehicle movements in both geographical locations(in longitude and latitude) and attitudes(in pitch,yaw and roll) within a given range.The guidance for the on board antenna was given as well.By this way,the view-angle and polarization performance of the antenna for keeping continuously communications with the satellite was defined,and any over designed performance coursing unnecessary engineering efforts can be avoided.
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    Safe on-orbit Releasing Velocity Design for Small Satellites
    Wang Gongbo Xi Xiaoning(College of Aerospace and Material Engineering,National University of Defense Technology,Changsha 410073)
    2007, 27 (03):  33-38. 
    Abstract ( 2366 )   Save
    The safe releasing velocity of small satellite which was launched from the main satellite was investigated.An analytical solution for the safe releasing velocity was presented based on the Hill equation in the constraint of the main satellite's maneuvers.The error compared with the numerical solution which has considered perturbations was at the level of 10-3m/s.This research provides a quick precise solution for the on-orbit releasing velocity design.
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    Reliability Test Methods of Spacecraft Mechanisms
    Liu Zhiquan(China Academy of Space Technology,Beijing 100094)
    2007, 27 (03):  39-45. 
    Abstract ( 1958 )   Save
    Spacecraft mechanism reliability tests were classified.The test methods based on reliability characteristic parameter mesurements were proposed.By these test methods,the reliabilities of three types of spacecraft mechanisms whose reliability characteristic parameters are life,performance parameter and the defeat number can be validated.The work mentioned offers technical approaches for reliability validation of spacecraft mechanisms.
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    Direct Updating of the Damping and Gyroscopic Matrices based on Incomplete Complex Modal Measured Data
    Yuan Yongxin Dai Hua(College of Science,Nanjing University of Aeronautics and Astronautics,Nanjing 210016)
    2007, 27 (03):  46-52. 
    Abstract ( 2370 )   Save
    An efficient numerical method for the finite-element model updating of damped gyroscopic system was developed based on incomplete complex modal measured data.It was assumed that the analytical mass and stiffness matrices were correct and only the damping and gyroscopic matrices need to be updated.By solving a constrained optimization problem,the optimal corrected damping matrix and skew-symmetric gyroscopic matrix complied with the required eigenvalue equation were found under a weighted Frobenius norm sense.
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    Method of Anti-freezing for Radiator on Docked Manned Spacecraft
    Zhang Ningli JiangJun(China Academy of Space Technology,Beijing 100094)
    2007, 27 (03):  53-57. 
    Abstract ( 1944 )   Save
    A new method using cryogenic loop system was presented to prevent radiator on docked manned spacecraft from being frozen.The numerical analysis shows that the temperature field of the radiator gets uniform apparently when the working fluid flows.Temperature difference of the radiator reduces with the increasing of flow rate.An optimum rate exists.It is a simple and feasible method for preventing space radiator from being frozen.
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    Multiple Satellites Joint Orbit Determination based on Satellite-to-satellite and Satellite-to-earth Tracking
    Wu Gongyou1 Wang Jiasong2 Zhao Changyin1 Chen Jianrong2(1 Purple Mountain Observatosy,Chinese Academy of Sciences,Nanjing 210008)(2 Xi′an Satellite Control Center,Xi′an 710043)
    2007, 27 (03):  58-63. 
    Abstract ( 2025 )   Save
    TDRSS and Double Satellite Positioning System(DSPS) usually consist of two or three GEO satellites and several LEO satellites.The satellite-to-satellite tracking data provided by these systems put forward the requiremens for multi-satellite joint orbit determination(OD).The difference between OD with known GEO ephemeredes and OD with unknown GEO ephemeredes was introduced.The measure model for the sum of range was established and the technica difficulties on multi-satellite joint OD were described.Finally,the OD accuracy was analyzed for the whole system.
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    Application of Heat-source Method on Sheet Structure
    Wang Xin Zhao Meiying Gu Yilei Wan Xiaopeng(Northwest Polytechnical University,Xi′an 710072)
    2007, 27 (03):  64-67. 
    Abstract ( 1696 )   Save
    Heat-source method is a simple and accurate method for solving temperature field on solid.The precondition of the method is to dispose the boundary condition correctly.The application of heat-source method on sheet structure was discussed and the emphasis was how many enantiomorphous heat-sources should be used.The results of heat-source method and ANSYS software for model were compared.
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    Bit Error Rate Calculation and Analysis for Space Optical Communication System
    Wang Zhaohui(Institute of Information Science and Engineering,Yanshan University,Qinhuangdao 066004)
    2007, 27 (03):  68-71. 
    Abstract ( 1868 )   Save
    The bit error rate(BER) of the space optical communication system was calculated versus two kinds of general data modulation.In the course of the calculation, avalanche photodiode(APD) is used as the optical detector,and different values of the bandwidth,background power and the load resistance of the optical detector were taken into account.The curves of BER as a function of received optical power were acquired.Result shows that all the bandwidth,background power and the load resistance of the optical detector have a great deal of effect on the BER.The BER increases with the bandwidth and the background power,and decreases with the resistance of the optical detector.
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