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    25 February 2013, Volume 33 Issue 1 Previous Issue    Next Issue
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    Trajectory Design of Crewed Exploration to Asteroid
    WU Jiang-Kai, WANG Kai-Qiang, ZHANG Bai-Nan, BAI Ming-Sheng, LI Zhi-Hai
    2013, 33 (1):  1-6.  doi: 10.3780/j.issn.1000-758X.2013.01.001
    Abstract ( 1826 )   PDF (404KB) ( 1200 )   Save
    Trajectory design is an important part of research on crewed asteroid exploration.Firstly, combined with the basic condition and postulate of trajectory design,the trajectory model was built based on the Lambert theory.The validity of the model was verified through computer simulation. The trajectory model was used for the crewed exploration to asteroid 89136, and the trajectory design results were given.Secondly,different failure modes were considered,the abort trajectory and the characteristics were analyzed, and the ability of the explorer to return to the earth in an emergency was discussed.Finally, the related conclusions were drawn.
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    Research on Momentum Wheel Reconfiguration Design of Zero-momentum Satellite
    GU Peng, WANG Da-Yi, LIU Cheng-Rui
    2013, 33 (1):  7-14.  doi: 10.3780/j.issn.1000-758X.2013.01.002
    Abstract ( 1687 )   PDF (365KB) ( 1357 )   Save
    The selection of momentum wheel configuration in satellite attitude control system design was investigated. Five different orientations of momentum wheel system were summarized. The design criteria of momentum wheel reconfiguration, the saturation of the momentum wheel under disturbance torque, energy consumption and reliability in different orientations were proposed by comparing the angular momentum envelope. The proposed method could be applied to the design of momentum wheel control system.
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    Analysis and Control of Disturbance Torque in SGCMG Gimbal Servo System
    LU Ming, ZHANG Xin, LI Yao-Hua
    2013, 33 (1):  15-20.  doi: 10.3780/j.issn.1000-758X.2013.01.003
    Abstract ( 1568 )   PDF (397KB) ( 1069 )   Save
    Deficient capability of disturbance torque attenuation restricts further improvements on the speed control performance of control moment gyro gimbal servo system. Based on the analysis of the disturbance torque and its influences, a terminal variable structure controller combined with disturbance observer was proposed. Utilizing the characteristics of invariance and fast response of the variable structure controller, high precision control was realized under the condition of disturbance torque fluctuations especially high frequency disturbance torque fluctuations. Simulation results show that the proposed method is feasible and efficient. Comparing with the proportional integral derivative controller, the speed fluctuating quantity decreases more than 2/3.
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    Configuration Analysis and Singularity Visualization of Single Gimbal Control Moment Gyroscopes
    WEI Kong-Ming, WU Zhong, LIU Tao
    2013, 33 (1):  21-29.  doi: 10.3780/j.issn.1000-758X.2013.01.004
    Abstract ( 1740 )   PDF (657KB) ( 1361 )   Save
    The configuration efficiency and controllable efficiency are important indices in  evaluating the configuration of a single gimbal control moment gyroscope (SGCMG) system. But the configuration efficiency is non-normalized, and the controllable efficiency depends on the magnitude of the angular momentum envelop. By normalizing the configuration efficiency and excluding the impact of the angular momentum envelop to the controllable efficiency, two improved indices, which are capacity ratio and nonsingular capacity ratio, were introduced. As the singularity of SGCMGs is complex and these scalar indices do not indicate the whole properties of the configuration, visualization techniques were used to compare the singular surfaces of different configurations. The analysis results show that the quality of the SGCMG and the symmetries of the configurations mainly affect the configuration indices and the complexity of the singular surface.
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    Kinetic Characteristics and Continuation Algorithm of Periodic Families
    LIU Lei, LIU Yong, CAO Jian-Feng, TANG Ge-Shi, HU Song-Jie
    2013, 33 (1):  30-36.  doi: 10.3780/j.issn.1000-758X.2013.01.005
    Abstract ( 1784 )   PDF (467KB) ( 881 )   Save
    Study on halo orbit period and scope of kinetic characteristics is the premise of halo orbit applications. For the applications and some numerical issues on a big halo orbit and a whole halo family, considering the wide applications of the libration points in the Sun-Earth/Moon and Earth-Moon system, the kinetic characteristics and the continuation algorithm of periodic families were studied under the circular restricted three-body problem. The method of numerical halo family determination by the continuation algorithm was presented.  Influences of family parameter selection on family determination were analyzed. Finally, the halo families with a large scope were given in the Sun-Earth/Moon and Earth-Moon system, together with their kinetic characteristics of orbit periods and locations. The results show that the family parameter of x is preferable for an L1 halo family and the y velocity or T is preferable for L2. The method is fit for the numerical halo family determination in any three-body system, especially for those under perturbations by a simple modification of state transition matrix.
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    Partial Ambiguity Fixing Method and Analysis for Precise Point Positioning
    ZHAO Xing-Wang, ZHANG Cui-Ying
    2013, 33 (1):  37-44.  doi: 10.3780/j.issn.1000-758X.2013.01.006
    Abstract ( 2658 )   PDF (572KB) ( 1099 )   Save
    According to the slow convergence of precise point positioning(PPP) in noisy environment, a partial ambiguity fixing(PAF)method was proposed based on LAMBDA algorithm, and then the ambiguity subset with constraint of maximum success rate and Ratio value was defined according to the basic idea of the more accuracy for the float solution, the easier for right fixing. Finally, the validity of PAF method for PPP fixed solution was analyzed in terms of the reliability of ambiguity fixed, convergence speed and positioning accuracy. The results show that the performance of precise point positioning is improved by the PAF method. Compared with traditional method, the convergence time of ambiguity resolution is shortened by about 1/4, and the reliability is increased by almost 2 times. Especially for less measurement information in the initialization stage or lager residual error in which it is difficult to fix all the ambiguity, a higher accuracy for PPP fixed can be quickly obtained solution by PAF method.
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    Application and Improvement of Temperature Prediction Method for Thermal Balance Test of Space Camera
    SHI Jin-Feng, WU Qing-Wen, HUANG Yong, YANG Xian-Wei
    2013, 33 (1):  45-52.  doi: 10.3780/j.issn.1000-758X.2013.01.007
    Abstract ( 1904 )   PDF (460KB) ( 858 )   Save
    In order to predict the balance temperature of thermal balance test for spacecraft, equation for predicting the thermal balance temperature was established. The parameters which influenced the prediction accuracy were analyzed. Firstly, the formula of balance temperature was derived by the node network method. The solution process of the formula based on the non-linear least square method was introduced. The iterative equation of balance temperature was deduced. Secondly, based on a large number of experimental data, a statistical analysis for three factors that influenced the results of the iteration equation was done, and a reasonable range of each factor was determined. Finally, the balance temperature of a space-camera′s temperature balance testing in low temperature condition was predicted by the temperature prediction process. At the end of the experiment, the analysis results were compared with the experiment results. It is shown that the error between the predicted temperature and the test data is less than ±1℃(the error is within 3%). It meets the accuracy requirements of the test. The accurate prediction of the balance temperature could short the test time and save the cost of test effectively.
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    Determination Method of Overall Technology Index for Space Manipulator
    XU Wen-Fu, DU Xiao-Dong, WANG Cheng-Jiang, LIANG Bin
    2013, 33 (1):  53-60.  doi: 10.3780/j.issn.1000-758X.2013.01.008
    Abstract ( 2573 )   PDF (497KB) ( 1786 )   Save
    The determination of the overall technology index is a key to the overall design of space manipulator. An overall performance indexes determination method of a space manipulator were presented. The dynamic simulation study was also performed. Firstly, considering the mission objectives and combining with the overall constraints, the main technology indexes, including manipulator length, end-effector positing and orientating accuracies, the maximum end-effector velocities, and joint drive torques, and so on, were demonstrated. Secondly, the multi-body dynamic model of a space robotic system was created. Based on this model, the manipulation process of the space robot carrying a payload under normal and extreme conditions was simulated. Simulation results show that the proposed ideas and methods are very useful for the development of the space robot system.
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    SSA and BSS Based Separation Algorithm for Single-channel Signals
    YU Ning-Yu, MA Hong-Guang, JIANG Qin-Bo, SHI Lei
    2013, 33 (1):  61-68.  doi: 10.3780/j.issn.1000-758X.2013.01.010
    Abstract ( 1856 )   PDF (478KB) ( 1270 )   Save
    In blind source separation(BSS),the single-channel broadband receiver often intercepts the multiple independent emitter signals. A new algorithm was proposed, in which SSA(singular spectrum analysis)and BSS methods were jointly used. The single-channel signal was firstly changed into pseudo-array signals via SSA method. Then, each source signal was separated via a conventional BSS algorithm. Simulation results indicate that the proposed algorithm can effectively separate the single-channel signals which consist of the signals normally used in electronic reconnaissance, for example, when the single channel signal was mixed by a single-frequency signal and a linear frequency modulation signal, the semblance coefficient between original and separated signals are greater than 0.9 when SNR is 6dB. For the single-channel signal mixed by the different phase shift keying signals, their bit error rate is less than 0.01 after the source separation when SNR is 4dB.
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    Plucker Linear Based Relative Position and Attitude Determination Algorithm for RVD
    LI Jing, WANG Hui-南, LIU Hai-Ying
    2013, 33 (1):  69-74.  doi: 10.3780/j.issn.1000-758X.2013.01.010
    Abstract ( 1736 )   PDF (344KB) ( 1380 )   Save
    In order to describe the relative position and attitude measurement information of RVD spacecraft, a combination method of binocular vision measurement and Plucker linear equation was proposed to determine the relative position and attitude parameters of RVD spacecraft. The relative position and attitude of spacecraft was separately measured and calculated in traditional algorithm, while, the Plucker linear equation jointly describes relative position and attitude information of the two spacecraft. At first, the binocular vision algorithm was used to calculate two non-coplanar lines′coordinate value in tracking spacecraft. Then, the two lines′relative position and attitude relation in two coordinates calculated by Plucker linear equation was obtained. Finally, the relative position and attitude information of the two spacecraft was calculated by the singular value decomposition method. Simulation results show that the algorithm can not only jointly measure position and attitude, but also meet the measurement requirements of RVD spacecraft and verify the scientific rationality and calculation efficiency of the algorithm.
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    Novel Resource Allocation Scheme Based on Multi-satellite Terminals in MF-TDMA Satellite Systems
    YU Jia, ZONG Peng
    2013, 33 (1):  75-83.  doi: 10.3780/j.issn.1000-758X.2013.01.011
    Abstract ( 1767 )   PDF (528KB) ( 1273 )   Save
    Regarding to the limited and costly resources, multi-frequency time-division multiple access (MF-TDMA) technique is widely applied to the uplink of broadband communication satellites. The time slot allocation strategy is the key to guarantee the efficient utilization of the system resources. A novel satellite slot allocation based on priority function was proposed, and efficiently improved the performance of resource utilization. The time delay and channel utilization of the algorithm can be validated through the simulation for different types of traffic. The performance of classical schemes was compared. The theoretical analysis and simulation results show that new algorithm can efficiently improve channel utilization in satellite resource allocation, especially when the number of satellite terminals is large. The algorithm is simple and easy to implement in satellite communication system.
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