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    25 February 2014, Volume 34 Issue 1 Previous Issue    Next Issue
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    Maneuvering Control of an Underactuated Spacecraft Based on Dynamic Inverse Method
    GUI Haichao, XU Shijie, JIN Lei
    2014, 34 (1):  1-9.  doi: 10.3780/j.issn.1000-758X.2014.01.001
    Abstract ( 1425 )   PDF (364KB) ( 1907 )   Save
    The maneuvering control of an underactuated axisymmetric spacecraft with the symmetry axis as unactuated axis was investigated under the assumption that the angular velocity component along the unactuated axis was zero. The generalized dynamic inverse (GDI) method was utilized in conjunction with backstepping method to design a switched control logic yielding global convergence of the attitude error. Singularities inherent in the control law, which may arise at the beginning or during the steady phase of the control process, were wiped out by introducing a saturated function and properly choosing control gains. Simultaneously, the large transient amplitude, which may occur during the initial maneuver phase, was avoided. Strict proof shows that by this control law the attitude error globally converges to zero and there is at most one switching during the whole control process, thus eliminating the possibility of chattering. Numerical simulation results demonstrate the effectiveness of the proposed control law.
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    Coverage Optimization of Inclined GEO Satellite with Multi-beam Antenna
    CHEN Yu-jun, ZHOU Zhi-cheng, QU Guang-ji
    2014, 34 (1):  10-17.  doi: 10.3780/j.issn.1000-758X.2014.01.002
    Abstract ( 2010 )   PDF (342KB) ( 1097 )   Save
    Simulation and optimization for antenna coverage characteristics of inclined GEO satellite with multi-beam antenna were presented from the view of satellite orbit, antenna and pointing. Firstly, the problems of inclined orbit, sub-beam installation, inclined orbit control and beam dynamic pointing were analyzed and formulated for dynamic coverage calculation. Secondly, the evaluation indexes of antenna coverage were constructed and optimization model was built for antenna coverage. Finally, the simulation results show that the uncover problems can be solved and the coverage characteristics can be improved by optimizing the antenna pointing.
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    Initial Efficiency Evaluation Approach for Space-based Earth Observation Satellites System
    HE Dong-lei, LI Guo-ping, HOU Yu-kui
    2014, 34 (1):  18-25.  doi: 10.3780/j.issn.1000-758X.2014.01.003
    Abstract ( 1697 )   PDF (307KB) ( 702 )   Save
    Aiming at the general design and proper plan of earth observation system, the hierarchy efficiency evaluation index system was derived, and the analytic hierarchy process (AHP) approach was used to get the weight of index. The acquisition and nondimensionlization method for the qualitative and quantitative index was given. The efficiency evaluation model was derived based on fuzzy synthetical computation, and the membership function approach and the experts scoring method were used separately to compute fuzzy evaluation vector of the qualitative and quantitative index. Finally, a multi-level system efficiency evaluation flow path was put forward based on AHP-FCE(Fuzzy synthetic evaluation), and the effectiveness of the given approach was verified by a mathematical example.
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    Iterative Guidance Method of Autonomous RendezvousBased on Convex Optimization
    CHI Xian-bin, YUE Xiao-kui, LI Peng
    2014, 34 (1):  26-34.  doi: 10.3780/j.issn.1000-758X.2014.01.004
    Abstract ( 1754 )   PDF (382KB) ( 1117 )   Save
    The guidance law for autonomous rendezvous and proximity operations requires the real-time guidance capability and excellent robustness. An iterative guidance methodology based on convex optimization with a target satellite in an arbitrary orbit was presented. Firstly, by the lossless simplification and convex processing to the dynamic model of relative motion, a convex optimization problem was formed, and its solution was proven to be equivalent to that of the original autonomous rendezvous problem. Secondly, after solving the convex optimization problem by the primal-dual interior point algorithm, an iterative guidance method was used to finish the onboard planning of the chaser vehicle. Numerical experiments demonstrate the efficiency of the proposed guidance method.
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    Research on Dynamic Reentry Footprint for the SpacecraftBased on the Genetic Algorithm
    HU Hai-long, NAN Ying, WEN Xin
    2014, 34 (1):  36-41.  doi: 10.3780/j.issn.1000-758X.2014.01.005
    Abstract ( 1452 )   PDF (304KB) ( 1528 )   Save
    A new concept of dynamic reentry footprint was presented to ensure the reentry of the spacecraft safely and accurately. Concerned with all the given flight states and the constraint conditions of the spacecraft during the whole reentry flight process, the maximum reachable area on the earth surface can be calculated by the given numerical algorithm. Combined with the dynamic reentry numerical algorithm, the modified genetic algorithm was applied to optimize the reentry flight trajectories, and all the qualified trajectories which constitute the landing footprint can be calculated. Through a series of reentry flight numerical simulations, the characteristics of dynamic reentry footprint was summarized, which can be used to optimize the guidance and flight trajectory.
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    Dynamic Parameter Identification Research onthe Installation Errors and the Scale Factor Errors of the IMU
    PENG Hui, XIONG Zhi, WANG Rong, LIU Jian-ye, WANG Jie
    2014, 34 (1):  42-49.  doi: 10.3780/j.issn.1000-758X.2014.01.006
    Abstract ( 1775 )   PDF (359KB) ( 1271 )   Save
    The high dynamic flight characteristic of space vehicles may lead to a significant variation of the installation errors and the scale factor errors of the inertial measurement unit (IMU).If the errors can′t be calibrated and compensated,it may reduce the navigation precision of the inertial navigation system (INS) seriously.A method to dynamically identify the parameter of the installation errors and the scale factor errors was proposed. An augmented error model of the IMU including the installation errors and the scale factor errors of the IMU was built. Based on the Kalman filter, the dynamic parameter identification of the installation errors and the scale factor errors was designed. The observability of the installation errors and the scale factor errors with different maneuvers was analyzed. The simulation results show that the proposed dynamic identification method can effectively calibrate the installation errors and the scale factor errors online. With the calibrated results, the IMU errors are compensated and the precision of the INS is improved significantly.
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    An On-orbit Calibration Method of KBR Phase Center
    IN Ning, QIU Le-de ZHANG Li-hua, DING Yan-wei
    2014, 34 (1):  50-56.  doi: 10.3780/j.issn.1000-758X.2014.01.007
    Abstract ( 1259 )   PDF (291KB) ( 1098 )   Save
    An algorithm for on-orbit calibration of K band ranging (KBR) system phase center of the low-low satellite-to-satellite tracking (SST-LL) gravity satellite was proposed. Firstly, the attitude control algorithm was designed according to the calibration maneuver design, and the satellite control procedure was divided into thruster maneuver control procedure and stabilization control procedure. Secondly, the observation of KBR, GPS and star sensor were used to estimate the phase center of KBR based on extended Kalman filter. The pitch and yaw attitude control error are better than 1mrad, and the roll error is better than 3mard which indicates that the calibration attitude stabilization control can be realized. The calibration accuracy of three axises are all better than 1mm, which verify the fast convergence rate and the steady accuracy of the algorithm.
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    Design of Displaced Geostationary OrbitsUsing Hybrid Propulsion
    QIN Zhaohua, FU Lei, AN Xiaomin, XU Min
    2014, 34 (1):  57-62.  doi: 10.3780/j.issn.1000-758X.2014.01.008
    Abstract ( 1650 )   PDF (236KB) ( 1296 )   Save
    To satisfy the requirement of long-term on-orbit displaced spacecraft for specific tasks, a hybrid propulsion technology, consisting of solar electric propulsion (SEP) and solar sail, was studied for the displaced geostationary orbit. The relation between the sail attitude angles and the SEP acceleration for hybrid propulsion system was firstly deduced. A single variable extremum problem obtained from the first-order optimality condition was solved to minimize the SEP acceleration and acquire the control law of solar sail attitude angles. Numerical simulations show that the hybrid propulsion approach can save about 57% of fuel consumption per year compared with the SEP method. The hybrid propulsion approach achieves the goal of improving the lifetime of spacecraft and meets the requirements of the displaced geostationary orbits.
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    Influence of Reefing Ratio on Inflation Performance ofRingsail Parachute
    GAO Shu-yi, YU Li
    2014, 34 (1):  63-70.  doi: 10.3780/j.issn.1000-758X.2014.01.009
    Abstract ( 1791 )   PDF (323KB) ( 1136 )   Save
    Reefed parachute can achieve an obvious load reduction. To study the influence of reefing ratio on inflation performance and drag area, the fluid-structure interaction numerical method was proposed to study the influence of reefing ratio. Firstly, the fluid-structure interaction numerical calculation of an un-reefed ringsail parachute was conducted, and its feasibility was verified by test results. Secondly, the inflation stage of reefed parachute including five reefing ratios from 13% to 28% was simulated. The changes of canopy shape, opening load, drag area and tension of reefing line under different reefing ratios were studied. The corresponding relationship formulas were fitted. The results show that the inlet open speed is not affected by the reefing ratio, but the first open time points of inlet and vent are affected by the reefing ratio. The reefing ratio is in quadratic relationship with reefing diameter ratio and drag area. And the reefing ratio is in linear relationship with the maximum opening load. The tension of reefing line is the maximum when the reefing ratio is 19%. These results can provide reference for the selection of reefing line and optimization design of reefing ratio.
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    Efficiency Improvement Technologies for Tracking and DataRelay Satellite System
    LI Yu-heng, HUANG Hui-ming, ZHENG Jun
    2014, 34 (1):  71-77.  doi: 10.3780/j.issn.1000-758X.2014.01.010
    Abstract ( 1465 )   PDF (318KB) ( 778 )   Save
    Based on the current tracking and data relay satellites system (TDRSS), a satellite companion control strategy was presented. It takes the advantage of the coverage difference between Ka-band and S-band of a TDRS′ inter-satellite antenna to provide data relay service for two user satellites simultaneously.When these two satellites are covered by the TDRS′s antenna,one user satellite can be serviced in Ka-band and the other one can be serviced for telemetry and telecommand control in S-band. As a result, the efficiency of a TDRS′ usage can be improved by 8%. Meanwhile, in order to provide quick service for a user satellite with an emergency service demand, a hand-shaking waiting strategy which compressed the response time to 1/14 of the previous one was proposed. These innovative technologies can improve the usage efficiency of the TRDSS application.
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    Differential One-way Ranging Geometric Delay Simulation andCalculation of Deep-space Exploration
    HUANG Yi-dan, ZHENG Wei-min, MA Mao-li
    2014, 34 (1):  78-83.  doi: 10.3780/j.issn.1000-758X.2014.01.011
    Abstract ( 2144 )   PDF (272KB) ( 1104 )   Save
    The local correlation method requires more accurate DOR delay model,and the ambiguity is also more difficult to eliminate. This method has not been applied to Chinese deep space exploration yet. DOR geometric time delay algorithm was studied and validated by two ways. DOR geometric delay and DOR signals were simulated, and the local correlation method was used to get DOR delay measurement, which was different from the simulated true DOR delay in 0.2ps. CE-2 orbit data were also used to calculate VLBI geometric delay and DOR geometric delay. Transformation between the above two delays was demonstrated. The difference between VLBI delay transferred from DOR delay and the direct calculated VLBI  delay was under dozens of picosecond. The research results validate the exactitude of DOR geometric time delay algorithm and can be used in the Chinese Lunar, Mars and Venus deep-space exploration projects in the future.
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