Table of Content

    25 June 2010, Volume 30 Issue 03 Previous Issue    Next Issue
    For Selected: Toggle Thumbnails
    Impact of UPF Filter Parameters on Spacecraft Celestial Navigation Performance
    Ning Xiaolin Fang Jiancheng Ma Xin(School of Instrument Science & Opto-electronics engineering,Beihang University,Beijing 100191)
    2010, 30 (03):  1-11. 
    Abstract ( 2112 )   Save
    In spacecraft celestial navigation system,the state and measurement models are strongly nonlinear,and noises are non-Gaussian.UPF shows a better navigation performance compared with EKF and UKF.In the celestial navigation system based on UPF,parameters τ,Q,R,particle number and resampling scheme in the UPF have great impact on the navigation performance.The impacts of these parameters on navigation performance of spacecraft autonomous celestial navigation system were studied by some simulations.The conclusions are useful for the design of autonomous celestial navigation system based on UPF.
    Related Articles | Metrics
    Spectral Characteristic Analysis and Prediction Model Research of Navigation Satellite Broadcast Ephemeris Errors
    Huang Wende Wang Wei Xi Xiaoning(College of Mechatronics Engineering and Automation,National University of Defense Technology,Changsha 410073)
    2010, 30 (03):  12-18. 
    Abstract ( 2009 )   Save
    Ephemeris error is one of the most important factors which affect positioning precision when satellite navigation was used.First,taking the GPS as an example,the spectral characteristic of broadcast ephemeris error was analyzed,in which the spectral analysis method was applied.And then ephemeris errors were predicted by using the spectral analysis model and the combined model which of the AR model and the spectral analysis model.The results of research demonstrate that the GPS broadcast ephemeris has periodical wave error,the main period variations of broadcast ephemeris can be determined by the spectral analysis model though its prediction precision is not high.After compensation,the precision of ephemeris was at 0.5 meter level (1σ) when the spectral analysis and AR combined model was used.
    Related Articles | Metrics
    Augmented Beidou Satellite System by Airborne Pseudolites
    Wang Wei1 Liu Zongyu2(1 School of Instrument Science & Opt-electronics Engineering,Beihang University,Beijing 100083) (2 Beijing Institute of Control Engineering,Beijing 100083)
    2010, 30 (03):  19-24. 
    Abstract ( 2216 )   Save
    Aiming at the problem that Beidou satellite system is unable to realize the passive positioning and the accuracy can not meet the higher requirements of the users,the scheme of airborne pseudolites augmented Beidou satellite system was proposed and the key technologies,including geometry,self-fix of airborne pseudolites and system synchronization,were investigated.Airborne pseudolites can not only augment Beidou system to perform passively,but also have the advantages of larger coverage area,better geometry characteristics and so on.
    Related Articles | Metrics
    Error Analysis of the Relative Motion in Formation Flying Satellites Based on Two J_2 Perturbation Models
    Zhang Hao1,2 Li Mingtao1,2 Zhang Xiucheng1,2(1 Center for Space Science and Applied Research,Beijing 100190) (2 Graduate School of Chinese Academy of Science,Beijing 100190)
    2010, 30 (03):  25-30. 
    Abstract ( 1910 )   Save
    To study the motion of formation flying satellite in one orbital period,the J2 instant perturbation model was derived based on the perturbation acceleration theory.To explore the effect of J2 instant perturbation,a SSO Satellite and a two-satellite formation were taken as examples.Compared with the J2 average perturbation model,for the satellite in one orbital period,the semi major axis had an error of 18km,the eccentricity had an error of 10-3,and the orbit inclination angle had an error of 10-2 degree.And for the formation in one orbital period,the relative radial position offset was 5km,the relative ink-track position offset was 19km,the relative normal offset was 10-2,and the relative distance offset was 19km,and they grew with time went on.
    Related Articles | Metrics
    Attitude Independent GPS Ambiguity Resolution Using UKF
    Han Lu Jing Zhanrong Li Dong Duan Zhemin (School of Electronic&Information,Northwestern Polytechnical University,Xi′an 710072)
    2010, 30 (03):  31-36. 
    Abstract ( 2077 )   Save
    The vehicle′s attitude should be known in advance in order to resolve GPS double differenced integer ambiguity when using motion-typed algorithm.To eliminate the dependence on the attitude,a novel algorithm for integer ambiguity resolution was investigated.Converting original vector measurement equation into scalar measurement equation,the attitude matrix of carrier vehicle was canceled out.After a short data collection period,a batch algorithm was employed to attain a coarse float estimate of the ambiguity.The batch algorithm included the centerted estimate algorithm and the whitening filter.Then the float ambiguity resolution was passed into an unscented Kalman filter as initial state value.UKF estimated the precise ambiguity resolution in real time with the initial value.Finally,simulation was implementeda and the results indicate that with the off-line batch algorithm UKF provides a correct ambiguity resolution without prior knowledge of vehicle′s attitude,which validates the proposed algorithm.
    Related Articles | Metrics
    Long-term Evolution and Control of Inclination for High Eccentric Orbit
    Tan Lifen Yan Ye Zhou Ying Tang Guojin(College of Aerospace and Material Engineering,National University of Defense Technology,Changsha 410073)
    2010, 30 (03):  37-42+50. 
    Abstract ( 1967 )   Save
    The inclination will drift because of the inference of solar gravity perturbation and lunar gravity perturbation.The analytic equations for computation of long-term evolution of inclination of HEO with small inclination were deduced.The maintenance strategy of inclination was put forward.The deviation of the inclination,comparing with numeric results calculated by STK,was within 5% which indicate the preciseness of the deduced analytical equations.The simulation of inclination maintenance was also executed.The results show that the maintenance strategy of inclination is effective and the deduced analytical equations have good engineering prospect application.
    Related Articles | Metrics
    Prediction Method Analysis of PIM Power Level in Nonlinear Medium
    Tang Zhihui Li Hongchao Wang Suming(City College of Dongguan University of Technology,Dongguan 523000)
    2010, 30 (03):  43-50. 
    Abstract ( 2030 )   Save
    Passive intermodulation (PIM),as an important interference affection in base station and satellite antenna systems was widely recognized.Prediction of the PIM power level is one of difficult points in the PIM studies.Two prediction methods of PIM power level were compared and analyzed.The mathmatical model was set up,and the measurment errors of 3,5,7 order PIM were obtained by the two methods under different output measurement errors and same input voltage through computer simulation.The validities were discussed by comparing our data with the actual measurment data in other relative paper.
    Related Articles | Metrics
    Calculation of Far-field of an Elliptical Aperture Reflector Antenna by Fourier-Bessel Method
    Xie Sulong(Xi′an Division,China Academy of Space Technology,Xi′an 710000)
    2010, 30 (03):  51-54+62. 
    Abstract ( 1973 )   Save
    In the applications of satellite and ground antenna,the reflectors of an elliptical aperture are often used.Compared with other methods,the Fourier-Bessel method is of the advantages of fast calculation,simple math format,easy understanding and application.Based on the PO and circular aperture,a Fourier-Bessel method was developed to calculate and analyze the radiation fields of parabolic and shaped reflectors.Compared with the direct integral method,the reliability and validity of this method was proved.
    Related Articles | Metrics
    Fade Countermeasure Techniques for Ka-band Satellite Communication Links
    Zhai Zheng′an Tang Chaojing(National University of Defense Technology,Changsha 410073)
    2010, 30 (03):  55-62. 
    Abstract ( 2383 )   Save
    The radio wave rainfall attenuation model was used to analyze the influence of rain attenuation on Ka band satellite communication links.It shows that the uplink should be in horizontal polarization and the downlink in vertical polarization.By this way,it can reduce the influence of rain attenuation at most and interferences between uplink and downlink will be the least.It was presented that the real-time dynamic rain attenuation compensation should be employed on the uplink and the fixed rain attenuation compensation on the uplink.This can simplify the satellite control.By using rain attenuation information of the downlink,setting compensation limit and injecting signal compensation flow,the wrong compensation induced by factors other than rainfall can be sovled and a high compensation precision can be got.
    Related Articles | Metrics
    Acceleration Life Test and Reliability Assessment for Hybrid Thick Film DC-DC Converter
    Liu Gang Wang Qigang (Lanzhou Institute of Physics,Lanzhou 730000)
    2010, 30 (03):  63-69. 
    Abstract ( 1906 )   Save
    A single step-stress acceleration life test method for hybrid thick film DC-DC converters was proposed.Sampling three kinds of hybrid thick film DC-DC converter,the acceleration life tests were conducted by raising the environmental temperature and under fixed-time curtailment,which can finish the sample′s reliability assessment in a relatively short time.By analyzing the failed sample,it was able to determine the fault of design & process,provide basis of improvement,and lay the foundation of passing reliability qualification and realizing space use for the hybrid thick film DC-DC converter.
    Related Articles | Metrics
    New Satellite Structure Design Technology
    Yao Jun Cui Wei Man Xiaoying Du Sheng(Shanghai Institute of Satellite Engineering,Shanghai 200240)
    2010, 30 (03):  70-75+83. 
    Abstract ( 2277 )   Save
    The composition of satellite structure was introduced and viewed from the function.Key technologies were described to meet the requirements,such as the strategy of comparison,satellite structure optimization,the satellite cylinder of honeycomb sandwich which combined column and taper,the structure material optimization for thermal deformation control of space environment,and high precision guarantee for star sensor.Finally the structure characteristics were summarized.The proposed technologies can be used for reference.
    Related Articles | Metrics
    Satellite Application Mission Decomposition Method Based on Hierarchical Task Network
    Ran Chengxin1 Xiong Gangyao2 Wang Huilin1 Ma Manhao1(1 College of Information System and Management,National University of Defense Technology,Changsha 410073) (2 Beijing Institute of Tracking and Telecommunication Technology,Beijing 100094)
    2010, 30 (03):  76-82. 
    Abstract ( 2129 )   Save
    With the rapid development of satellite technology,satellite applications are more and more complicated.The applicability of using Hierarchical Task Network (HTN) to do complex satellite application task decomposition was studied and the relevant working frame was given.The main contents and steps of the pretreatment of the satellite application task requirements were put forward,and the domain model of satellite application tasks was constructed.Finally the definitions of complicated tasks and it′s decomposing method were presented and HTN was used to calculate the complex satellite application mission decomposition and an estate space forward searching arithmetic based on HTN was presented.
    Related Articles | Metrics