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    25 February 2012, Volume 32 Issue 1 Previous Issue    Next Issue
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    ZHAO Guo-Qiang, BAO Yin-He-Xi, LI Jun-Feng
    2012, 32 (1):  1-7.  doi: 10.3780/j.issn.1000-758X.2012.01.001
    Abstract ( 1997 )   PDF (392KB) ( 1445 )   Save
    The trajectory design problem was transformed into two point boundary value problem (TPBVP) of ordinary differential equation and solved by differential correction. The  concept of B-plane was used nea earth and Mars. The boundary condition of the TPBVP can be analytically determined by the geometrical characteristics between B-plane and its associatedhyperbolic orbit, and the reason that four kinds of trajectories can be obtained was explained. An accurate mathematical formulation describing the closest approach time to Marswas also proposed. An illustrative example was presented and the results were coincided with satellite tool kit.
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    WANG Zhi-Yong, WANG Yong-Qiang, WANG Jun, LI Jun, WU Qiu-Yun
    2012, 32 (1):  8-14.  doi: 10.3780/j.issn.1000-758X.2012.01.002
    Abstract ( 1856 )   PDF (514KB) ( 1381 )   Save
    In the multi-satellite scheduling system of the earth observing system, considering the satellite has the capability of continuous side shift and multiple data compression rate, themulti-satellite scheduling model was constructed. Based on this model, a new scheduling and data transmission method for multi-satellite was designed and implemented,including an imaging scheduling algorithm considering continuous side shift and a data transmission method considering task priority. The experiment results show that themethod can reduce the cost and meet the application requirements.
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    Algorithm for Coning Error Compensation Based on Angular Velocity
    DUAN Guang-Ren, ZHANG Ze, SUN Yong
    2012, 32 (1):  15-20.  doi: 10.3780/j.issn.1000-758X.2012.01.003
    Abstract ( 2028 )   PDF (351KB) ( 2485 )   Save
    For a strap down inertial navigationsystem, the coning error compensation accuracy will be decreased and its real time capability will be worse, whenusing the angular velocity according to the traditional method. In order to solve this problem, a new algorithm was proposed by using the angular velocitydirectly without obtaining the angular increment from the angular velocity through Simpson formula or trapezoid formula. Moreover, the four sample rotationvector algorithm was derived, and the mechanism of the coning error was given. At last, the simulation results of the proposed algorithm and thetheoretical one were compared.
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    Multi-level Multi-sensor Integrated Navigation System Without Feedback
    LIN Xue-Yuan
    2012, 32 (1):  21-26.  doi: 10.3780/j.issn.1000-758X.2012.01.004
    Abstract ( 1904 )   PDF (330KB) ( 1487 )   Save
    The centralized, distributed and combined information fusion methods are usually used by the traditional multi-sensor integrated navigation system, butthe multi-level information algorithm is the upgrade of the above methods, and can fulfill the fusion at the high grade space. Thus, the multi-levelinformation fusion method of the multi-sensor integrated navigation system without feedback information was studied, and then the theoretical analysisshows that this method is equivalent to the federated Kalman filter algorithm without feedback information. Finally, the SINS/GPS/SST/altimeter was usedto simulate and verify the above methods.
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    High Precision Nonlinear FDD Design Using RBF with the Ability to Learn
    WANG Zheng, LI Yan-Jun, SUN Xiao-Wei
    2012, 32 (1):  27-35.  doi: 10.3780/j.issn.1000-758X.2012.01.005
    Abstract ( 1647 )   PDF (437KB) ( 1691 )   Save
    On-orbit spacecraft fault detection and diagnosis (FDD) problem nonlinear model always needs to deal with. It′s also important to improve the accuracy ofthe methodology as far as possible. Radial basis function (RBF) neural network was firstly applied for compensation of modeling error in order to increase the accuracy of the scheme, a Lyapunov function was used to prove its property. The residual and threshold and fault detection time were got through nonlinear observer. Fault signal was reconstructed by using RBF network, and accordingly a learning FDD strategy was presented. Validations were respectively designed for characteristics of residual threshold, detection time and the ability of RBF for reconstruction. The simulation results show the effectiveness of the proposed algorithm.
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    Design and Implement of CAN bus Based Virtual Ethernet Interface
    DONG Shao-Jin, LIU Bo, YU Wan-Rong, ZHAO Bao-Kang
    2012, 32 (1):  36-42.  doi: 10.3780/j.issn.1000-758X.2012.01.006
    Abstract ( 1782 )   PDF (350KB) ( 1542 )   Save
    In order to transfer IP packets between various satellite payloads through CAN bus, the IPoverCAN mechanism was proposed to virtualize the CAN bus.Through the mapping of IP address and CAN address, IP fragmentation and reassembly, management of multi-buffer queue, the mechanism abstractsthe CAN device as virtual standard Ethernet interface. The experiments results on real embedded platform show that the mechanism can transfer the CANpackets and IP packets efficiently and timely, which can be used for the satellites payloads whose size and weight are limited strictly.
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    Novel 4M mode for SOFDM Transmitting in CMMB System
    YANG Tong
    2012, 32 (1):  43-50.  doi: 10.3780/j.issn.1000-758X.2012.01.007
    Abstract ( 1705 )   PDF (513KB) ( 1513 )   Save
    Inspired by the creative work of designing a new 4k transmitting mode in EURO DVB-H system and based upon the existing 8M/2M modes in China mobile multimedia broadcasting (CMMB) system, a novel 4M transmitting mode for satellite orthogonal frequency division multiplexing (SOFDM)was proposed.The 4M mode was demonstrated that it can provide a higher data rate than the 2M mode, as well as a more sufficient spectrum utility than the 8M mode. As a result, according to a more reasonable pilots and data patterning, 4M mode presents a better BER performance in comparison with 4k mode.
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    Performance Analysis of Multimedia LEO Satellite Networks Based on Discrete-time Topology and Traffic Model
    JIANG Wen-Juan, ZONG Peng
    2012, 32 (1):  51-59.  doi: 10.3780/j.issn.1000-758X.2012.01.008
    Abstract ( 2105 )   PDF (563KB) ( 1408 )   Save
    Regarding to rapid development of the multimedia satellite networks, a novel analytical model was proposed to study the performances of low earth orbit (LEO) satellite networks  in a quantitative mode. In this model, the mapping relationship of discrete time traffic and topology (DT-TT) was established according to the dynamic characteristics of a constellation topology and complicated global traffic. Based on Markov process theory and the constraints of link capacity, some quantitative formulas of the performance indexes, in terms of blocking probability and end-to-end delay, were derived by using probability analysis method on real-time and non real-time traffic. Numerous simulation and numerical results show the validity and correctness of the methodology. The proposed method can be also applied to the design of QoS routing control and resource allocation for multimedia LEO satellite networks. 
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    Risk Analysis Model of Aerospace Engineering Project Incorporating Human and Organization Factors
    MENG Hua, MAI Qiang, AN Shi
    2012, 32 (1):  60-65.  doi: 10.3780/j.issn.1000-758X.2012.01.009
    Abstract ( 1903 )   PDF (384KB) ( 1169 )   Save
    The mechanism of project risk caused by human and organization factors was revealed, and a model of risk analysis for aerospace engineering project incorporating the human and organization factors based on the mechanism was proposed. Based on the model, the quality of spacecraft component manufacturing considering the human and organization factors was evaluated, and then the consistency probability between the operational task quality  and the different types of defect was assessed, and the defect severity was calculated according to Poisson distribution. Finally, the prior default rate of component was updated based on Bayesian theorem. The model framework was validated by an aerospace engineering project with modified data.
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    Quaternion Method with Modified Constraint Equation for Nonsingular Orbital Elements
    WEI Peng-Xin, JING Wu-Xing, GAO Chang-Sheng
    2012, 32 (1):  66-71.  doi: 10.3780/j.issn.1000-758X.2012.01.010
    Abstract ( 1803 )   PDF (329KB) ( 1512 )   Save
    The singularity problem of orbital elements for describing the orbital motion of the spacecraft can be solved by quaternion method. Due to the inherent double value of the quaternion, it is difficult to select positive or negative value of the quaternion for the integration of the motion equation. The quaternionmethodology with a modified constraint equation was introduced to describe Lagrange′s planetary equations. The influence of the earth oblateness perturbation on the orbit of the geostationary satellite was researched. The results show that when the eccentricity is less than 1, the quaternion can be  used to solve singularity problem caused by orbital elements. Compared with the modified equinoctial orbit elements, the quaternion has a clearer  physical and geometrical interpretation. The variable motion equation with the quaternion can be calculated more simply and integrated more efficiently. In addition,the calculation error can also meet the requirements.
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    Phase Interferometer Method for the Actual Angle measure
    JI Qiang, LUO Yi-Jun, LI Jin, TIAN Mao
    2012, 32 (1):  72-76.  doi: 10.3780/j.issn.1000-758X.2012.01.011
    Abstract ( 1998 )   PDF (261KB) ( 1273 )   Save
    To improve the positioning precision for short distance and to eliminate the calculation error caused by adopting the assumption of parallel incidence, the effects of approximate error on angle estimation and phase unwrapping ambiguity were analyzed. And the prerequisite for satisfying the approximation of parallel incidence was obtained. Furthermore, the method for the phase difference estimation of the actual incident angle and the relevant angle calculation was proposed, and the angle estimation precision could be improved. This angle detecting method with high precision by using phase interferometer is suitable for engineering applications with high requirement for precision, such as reciprocal positioning of multiple motion platforms, the rendezvous and docking for the spacecraft, short range object positioning on ground.
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    Numerical Optimization for Spacecraft Module Identification
    LIU Yong-Jian, LIU Yu-Qiang, SHI Jun, TAN Chun-Lin
    2012, 32 (1):  77-83.  doi: 10.3780/j.issn.1000-758X.2012.01.012
    Abstract ( 1712 )   PDF (455KB) ( 1498 )   Save
    To overcome the problem that spacecraft module identification mainly relies on experience and qualitative methods,a general numerical optimization for module identification method was constructed. Function units based numerical design structure matrix (DSM) was obtained by using functional decomposition method, relativity evaluation criteria and coevolution mechanism between design matrix and DSM. A general DSM based optimization model was constructed which conformed to axiomatic design axioms. A genetic-simulated annealing algorithm was used to construct a module identification method which could co-optimize the mode and the number of module identification. Finally, an evaluation method for different optimization targets was put forward. Simulation results show that the proposed method can divide a spacecraft into several modules with high cohesion degree and low coupling degree.
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