通过分析预报误差与轨道确定参数误差的关系,提出一种使用二次多项式对沿迹差随时间变化的函数进行拟合,并根据拟合结果修正半长轴、面质比参数误差的定轨方法。仿真计算表明:对于稀疏观测数据,该方法的处理结果优于常规的最小二乘轨道...通过分析预报误差与轨道确定参数误差的关系,提出一种使用二次多项式对沿迹差随时间变化的函数进行拟合,并根据拟合结果修正半长轴、面质比参数误差的定轨方法。仿真计算表明:对于稀疏观测数据,该方法的处理结果优于常规的最小二乘轨道确定方法;对于高度在400km以上的低轨目标,根据该方法得到的定轨结果,预报5d的位置误差小于22km,与SGP4(Simplified General Perturbations Version 4,简化普适摄动4)/SDP4(Simplified Deep space Perturbations Version 4,简化深空摄动4)水平相当。该方法是一种适用于双屏电子篱笆稀疏观测数据的批量数据轨道确定方法。展开更多
A two-way adaptive Kalman filter is proposed by combining a two-way filter with an adaptive filter for orbit determination of a maneuvered GEO satellite.A method of using Newton's high-resolution differential form...A two-way adaptive Kalman filter is proposed by combining a two-way filter with an adaptive filter for orbit determination of a maneuvered GEO satellite.A method of using Newton's high-resolution differential formula and polynomial fitting for modeling the thrust force of a maneuvered GEO satellite is developed.The adaptive factor,which balances the contributions of the measurements and the dynamic model information,is determined by using a two-segment function and predicted residual statistics.Simulations with a maneuvered GEO satellite tracked by the Chinese ground tracking network were conducted to verify the performance of the proposed orbit determination technique and the method of thrust force modeling.The results show that refining the thrust force model is beneficial for the orbit determination of a maneuvered GEO satellite;the two-way adaptive Kalman filter can efficiently control the influence of the dynamic model errors on the orbit state estimate.展开更多
The interacting patterns and mechanism of the catechin and cytosine have been investigated using the density functional theory B3LYP method with 6-31+G* basis set.Eleven stable structures of the catechin-cytosine comp...The interacting patterns and mechanism of the catechin and cytosine have been investigated using the density functional theory B3LYP method with 6-31+G* basis set.Eleven stable structures of the catechin-cytosine complexes have been found respectively.The results indicate that the complexes are mainly stabilized by the hydrogen bonding interactions.Theories of atoms in molecules(AIM) and natural bond orbital(NBO) have been utilized to investigate the hydrogen bonds involved in all the systems.The interaction energies of all the complexes which were corrected for basis set superposition error(BSSE),are from-17.35 to-43.27 kJ/mol.The results show that the hydrogen bonding contributes to the interaction energies dominantly.The corresponding bonds stretching motions in all the complexes are red-shifted relative to that of the monomer,which is in good agreement with experimental results.展开更多
文摘通过分析预报误差与轨道确定参数误差的关系,提出一种使用二次多项式对沿迹差随时间变化的函数进行拟合,并根据拟合结果修正半长轴、面质比参数误差的定轨方法。仿真计算表明:对于稀疏观测数据,该方法的处理结果优于常规的最小二乘轨道确定方法;对于高度在400km以上的低轨目标,根据该方法得到的定轨结果,预报5d的位置误差小于22km,与SGP4(Simplified General Perturbations Version 4,简化普适摄动4)/SDP4(Simplified Deep space Perturbations Version 4,简化深空摄动4)水平相当。该方法是一种适用于双屏电子篱笆稀疏观测数据的批量数据轨道确定方法。
基金supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 2007B51)National Natural Science Foundation of China (Grant Nos. 41174008 and 41020144004)China Postdoctoral Science Foundation (Grant Nos. 20080430148 and200902444)
文摘A two-way adaptive Kalman filter is proposed by combining a two-way filter with an adaptive filter for orbit determination of a maneuvered GEO satellite.A method of using Newton's high-resolution differential formula and polynomial fitting for modeling the thrust force of a maneuvered GEO satellite is developed.The adaptive factor,which balances the contributions of the measurements and the dynamic model information,is determined by using a two-segment function and predicted residual statistics.Simulations with a maneuvered GEO satellite tracked by the Chinese ground tracking network were conducted to verify the performance of the proposed orbit determination technique and the method of thrust force modeling.The results show that refining the thrust force model is beneficial for the orbit determination of a maneuvered GEO satellite;the two-way adaptive Kalman filter can efficiently control the influence of the dynamic model errors on the orbit state estimate.
基金supported by the National Natural Science Foundation of China (30870257)
文摘The interacting patterns and mechanism of the catechin and cytosine have been investigated using the density functional theory B3LYP method with 6-31+G* basis set.Eleven stable structures of the catechin-cytosine complexes have been found respectively.The results indicate that the complexes are mainly stabilized by the hydrogen bonding interactions.Theories of atoms in molecules(AIM) and natural bond orbital(NBO) have been utilized to investigate the hydrogen bonds involved in all the systems.The interaction energies of all the complexes which were corrected for basis set superposition error(BSSE),are from-17.35 to-43.27 kJ/mol.The results show that the hydrogen bonding contributes to the interaction energies dominantly.The corresponding bonds stretching motions in all the complexes are red-shifted relative to that of the monomer,which is in good agreement with experimental results.
