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25 April 2014, Volume 34 Issue 2 Previous Issue    Next Issue

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AdvanceofDynamicsandControloftheSatellitewithLargeMeshDeployableAntenna LIU Li-Kun, ZHOU Zhi-Cheng, ZHENG Gang-Tie, TIAN Qiang 2014, 34 (2):  1-12.  doi: 10.3780/j.issn.1000-758X.2014.02.001 Abstract ( 1711 )   PDF (890KB) ( 1610 )   Save Withthedevelopmentofmobilecommunicationtechnology,thelargedeployableparabolicmeshreflectorsarewildlyusedto improve the antennagain.Consideringthelargeinertia,long-perioddeployment,andlowstiffnessproperties,theseantennaehaveagreatinfluence on thedynamicsandcontrolofthesatellites.Firstly,thestructuralcharacteristicsanditsinfluencesonthe dynamicandcontrolof thewhole-satellitewereintroducedforthelargemeshdeployableantenna.Secondly,thedynamicand controlproblemswerediscussed,such asdynamicmodelingofthedeployedantenna,verificationmethodofthedeployed dynamic model,multi-bodydynamicsofthe deploying antenna,deploying-processattitudecontrol,andpointingcontroloftheantenna,and soon.Finally,theprospectsofthedynamicsand controlofthesatellitewithlargedeployableantennawerepresented. Related Articles | Metrics

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TrajectoryTrackingControlofaReactionlessSpaceRobot ZHAO Nan, JIA Ying-Hong, XU Shi-Jie 2014, 34 (2):  13-21.  doi: 10.3780/j.issn.1000-758X.2014.02.002 Abstract ( 1397 )   PDF (498KB) ( 1394 )   Save Anewreactionlessspacerobotdesignconceptwasputforwardtoovercometheshortcomingsofthecurrentdrivetypes.Controlmomentgyros(CMGs)weremountedoneachpartmechanicalarmandsystemplatformasmovementactuators.Mechanicalarmswereconnectedwithsphericalhinges.PlatformattitudeandangulardisplacementweremeasuredbytheRodriguesparameters(RPs).BasedonsystemdynamicsmodelbuiltwithKanemethod,agraduallystabletrajectorytrackingcontrollawwasdesignedtotracktheplatformattitudeand mechanicalarmangulardisplacement,andaCMGssteeringlawwasdesignedtooutputexactexpectedcontroltorque.Moreover,thedesigned controllawscanbefurtherextendedtotrackandcontroltheworkspacetrajectorybystudyingthetrajectoryplanningalgorithms betweenthemechanicalarmsworkspaceandjointsspace.Thesimulationresultsfromthethreejointssystemshaveverifiedthefeasibility ofdesignandeffectivenessoftheproposedtrajectoryalgorithms. Related Articles | Metrics

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OrbitCorrectionStrategyofLEOVehicleBasedonLinearizedOrbitalMotionEquation WANG Tao, ZHANG Hong-Bo, TANG Guo-Jian 2014, 34 (2):  22-27.  doi: 10.3780/j.issn.1000-758X.2014.02.003 Abstract ( 1623 )   PDF (330KB) ( 1296 )   Save It is very necessary to execute orbit correction for ultra-low-orbit vehicle, whichisbadlyinfluenced by near-earth environment.The orbital motion equation which considered the non-spherical perturbation and atmospheric perturbation was linearized. Then, an impulse correction method was introduced and used to keep a near-earth vehicle flying along the standard orbit. Furthermore, a method to eliminate errors caused by linearizationwasalso studied.The feasibility of the correction method was validated by simulation. For a 120km-altitude vehicle, flying one hour, the optimal correction times is 6, the required △v is 63.7971m/s. Related Articles | Metrics

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InitialErrorPropagationofEllipticalOrbitBasedonT-HEquation CAO Yu-Hui, FAN Peng-Cheng, BAI Xian-Zong, CHEN Lei 2014, 34 (2):  28-35.  doi: 10.3780/j.issn.1000-758X.2014.02.004 Abstract ( 1401 )   PDF (435KB) ( 1411 )   Save To study the initial error propagation of elliptical orbit,a new method was developed based on the state transition matrix of T-H equation. Firstly, the true state and predict state of one space object can be considered as two objects: a real one and a virtual one.Considering predict error as relative motion between these two objects,the relative motion theory was used to study the characteristic of error propagation. Secondly, the state transition matrix of T-H equation was introduced to analyze the propagation of initial error, with which the trend of error propagation in each direction was obtained.Finally, a simulation case was designed to validate the correctness of the new method,and the Monte-Carlo method and the new method were used to calculate error propagation of typical elliptical orbit.The results were compared with the HPOP′s results. Most of the relative error is less than 2%, and is consistent with the trend of the theoretical analysis results. Related Articles | Metrics

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Numerical Study on Aerodynamic Characteristics of an X-37B-like Vehicle JIANG Chong-Wen, YANG Jia-Shou, LI Ke-Nan, GAO Zhen-Xun, LEE Chun-Hian 2014, 34 (2):  36-44.  doi: 10.3780/j.issn.1000-758X.2014.02.005 Abstract ( 1589 )   PDF (577KB) ( 1012 )   Save The aerodynamic characteristics of an X-37B-like vehicle in different flight conditions were numerically studied under 50km altitude. The CFD results were analyzed with experimental results of the Space Shuttle and the X-34 vehicle. Numerical simulations indicate that the lift-to-drag ratio of the X-37B-like vehicle is slightly different from that of the Space Shuttle under high Mach number and large angle-of-attack reentry conditions, so the lateral maneuverability of the two vehicles is equivalent. Under subsonic and small angle-of-attack conditions, the lift to drag ratio of the X-37B-like vehicle is higher than the Space Shuttle and lower than that of the X-34 vehicle which indicates that the maneuverability at low speed and the fixed point landing ability of the X-37B-like vehicle are better than that of the Space Shutter but weaker than that of the X-34 vehicle. Configuration differences of winged reentry vehicles have little influence on the lift-to-drag radio of high Mach number and large angle of attack, and have obvious influence on thelift-to-drag radio of subsonic and small angle-of-attack. Related Articles | Metrics

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Mechanism and Protection Scheme of Physical Tabling in Spacecraft Interface ZHAO Qi-Long, XIAO Yu-Zhi, LIU Lu-Jiang 2014, 34 (2):  45-53.  doi: 10.3780/j.issn.1000-758X.2014.02.006 Abstract ( 1438 )   PDF (1160KB) ( 912 )   Save It is found that coated spacecraft interfaces separate unsuccessfully despite without cold welding during the spacecraft manufacturing.To investigate the mechanism, effective factors and protection scheme of the phenomenon an experiment was carried on. In this experiment, the aluminium alloys blocks which were coated with nothing, colorless oxidation, MoS2, bright gold plating, and white anodic film respectively were pressed together in pairs, and placed in a high vacuum tank immovably for a period of time. And the separating force between the blocks was tested outside the immovably high vacuum tank. If the experimental blocks were separated unsuccessfully, new copies were placed immovably in the natural pressure and several different temperatures for a period of time.Then the separating force was tested, and the shape changing and element transfering conditions of the interfaces were analyzed. The experiment result shows that there′s much tiny concavo-convex grain in the interface of the blocks. Because of the interlocked grain, the blocks have separated unsuccessfully. Hardness and roughness of coating is the immediate cause of this phenomenon,which is called physical tabling. For immovable spacecraft interfaces, a protection method that the coating should be harder and smoother was proposed and validated. Related Articles | Metrics

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GPS Based Orbit Determination Algorithm with High Precisionand Low Computational Complexity for LEO Remote Sensing Satellites WANG Da-Bao, WANG Zhong-Guo, TANG Hai-Tao, CAO Jing 2014, 34 (2):  54-61.  doi: 10.3780/j.issn.1000-758X.2014.02.007 Abstract ( 1337 )   PDF (478KB) ( 944 )   Save High precision orbit determination of LEO remote sensing satellites is difficult both in theory and practice. The traditional method can not meet the requirements of the orbit determination accuracy and low computational complexity. So, the interactive multi-model algorithm (IMM) and multi-ratetracking (MRT) method were introduced into the orbit determination. And a novel orbit determination algorithm was proposed based on IMM and MRT. Low kinematics model error was achieved by IMM algorithm. According to the linearization degree of the models, Kalman filter or particle filter was choose respectively to improve the filtering accuracy. Meanwhile, original observation data was compressed in pattern space to reduce the computationalcomplexity. The proposed algorithm is better than the traditional Kalman filter algorithm, and can improve the accuracy of about 47%. While the computational complexity reduces about 40% compared with particle filter algorithm. The results show that the proposed method can efficiently improve the orbit determination precision with low computational complexity compared with traditional algorithm. It can meet the requirements on orbit determination for the remote sensing satellites. Related Articles | Metrics

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Push-broom Imaging Scheduling Method of the Optical Agile Satellite in the Dense Regions LIN Xiao-Hui, PAN Xiao-Tong, ZHANG Jin-Xiu 2014, 34 (2):  62-68.  doi: 10.3780/j.issn.1000-758X.2014.02.008 Abstract ( 1635 )   PDF (429KB) ( 971 )   Save The agile satellite could achieve the linescan imaging model with the ability of three-axis-maneuvering, while imaging synchronously during the maneuvering. Based on the imaging agile satellite task, the model of the problem of scheduling agile earth observing satellite（AEOS）with the linescan imaging was established. Using the Gauss projection, the preliminary method of the linescan strip was established, and solved by the existing algorithms in the Matlab. Because of the complexity of the model, the solution strategy of the hierarchical optimization was designed. During the sub-problem, generating the linescan stripe with groups, the solution method can be solved easily.In the upper scheduling problem, according to the two directions of the stripe, the hierarchical optimization based on heuristic rule was designed to solve the problem. Then, turning the stripes that could not be scheduled into the point target, the whole scheduling was completed with the second time scheduling. The simulation shows that the algorithm can solve the actualproblem of the scheduling of the linescan imaging agile satellite. Related Articles | Metrics

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Control Method Based On e/i Vector to Realize Satellites Formation with Relative Inclined Configuration WU Sheng-Gang, QIAN Shan, LI Heng-Nian, TAN Wei 2014, 34 (2):  69-75.  doi: 10.3780/j.issn.1000-758X.2014.02.009 Abstract ( 1250 )   PDF (364KB) ( 1058 )   Save The problem of relative inclined configuration design and orbit control of the distributed InSAR satellites formation flying was studied. First, the algorithm of relative inclined configuration design based on e/i vector was put forward. Then the relationship between the relative inclined configuration and the errors of eccentricity, inclination and the right ascension of ascending node were given.According to the properties of relative inclined configuration of distributed satellites, the four impulse orbit maneuver strategy was put forward based on the Gauss perturbation functions satelliteformation control model. Simulation results show that the method of relative inclined configuration design is intuitionistic, the orbit maneuver strategy is simple and the configuration is stable. Related Articles | Metrics

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Simulation and Analysis on Coverage Characteristics of Constellation Crosslink MENG Yi-Nan, FAN Shi-Wei, YANG Qiang-Wen, WU Guang-Yao 2014, 34 (2):  76-83.  doi: 10.3780/j.issn.1000-758X.2014.02.010 Abstract ( 1335 )   PDF (532KB) ( 1352 )   Save The working crosslink beams distributed in space was used to provide services for the external users, and the availability was discussed for the general users. The mathematical model based on the typical constellation structure and crosslink working strategy was established, and the simulation experiments were conducted. Furthermore, the static and dynamic coverage characteristics of the celestial sphere was analyzed. The results show that the users in the vicinity of the constellation orbit plane get the more chance to receive the crosslink signals. And the sphere coverage rate is up to 45% when the height is 40%~50% of the constellation orbit radius, and is below 15% with the radius increasing. As a result, the link planning was recommended for the general users. The conclusions and suggestions may offer new ideas for the crosslink design and provide references for the service scope extending. Related Articles | Metrics