Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used ...Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used to estimate the position and velocity of explorer. In a conventional cartesian coordinate, this navigation system can not be used to achieve accurate determination of position for linearization errors of nonlinear spacecraft motion equation. A new autonomous celestial navigation method has been proposed for lunar satellite using classical orbital parameters. The error of linearizafion is reduced because orbit parameters change much more slowly than the position and velocity used in the cartesian coordinate. Simulations were made with both the cartesiane system and a system based on classical orbital parameters using extended Kalman filter under the same conditions for comparison. The results of comparison demonstrated high precision position determination of lunar satellite using this new method.展开更多
The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the grow...The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the growth of China's industrial economy increased from the annual average of 34.07%to 89.28%while the contribution of TFP dived from the annual average of 47.34%to-4.08%.Meanwhile,TFP growth rates dropped from the annual average of 4.6%to-0.05%and marginal capital output ratio went down from0.61 in 2002 to 0.28 in 2012.This indicates that the investment-driven pattern of China's industrial growth has been confronted with severe inefficiency.Further research suggests that the tendency of worsening industrial growth efficiency already became significant prior to the global financial crisis of 2008 and the eruption of the global financial crisis is not the fundamental reason for the worsening of efficiency and only exacerbated its tendency.The current government-led and investment-driven pattern of industrial growth is the root cause of such efficiency deterioration.Therefore,in order to achieve the transition towards innovation- and efficiency-driven growth pattern,the key is to make an appropriate distinction in the relationship between market and government,i.e.,the government must create a perfect institutional system where the market plays a decisive role and take proactive initiative to promote technology innovation and transfer on the basis of respecting market mechanism and the intent of market entities.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No. 60174031)China National Space Administration
文摘Celestial navigation system is an important autonomous navigation system widely used for deep space exploration missions, in which extended Kalman filter and the measurement of angle between celestial bodies are used to estimate the position and velocity of explorer. In a conventional cartesian coordinate, this navigation system can not be used to achieve accurate determination of position for linearization errors of nonlinear spacecraft motion equation. A new autonomous celestial navigation method has been proposed for lunar satellite using classical orbital parameters. The error of linearizafion is reduced because orbit parameters change much more slowly than the position and velocity used in the cartesian coordinate. Simulations were made with both the cartesiane system and a system based on classical orbital parameters using extended Kalman filter under the same conditions for comparison. The results of comparison demonstrated high precision position determination of lunar satellite using this new method.
文摘The driving force for China's industrial growth has shifted from the synergy of efficiency and factor input to the dominance of capital input alone.With the boundary of 2003,the contribution of capital to the growth of China's industrial economy increased from the annual average of 34.07%to 89.28%while the contribution of TFP dived from the annual average of 47.34%to-4.08%.Meanwhile,TFP growth rates dropped from the annual average of 4.6%to-0.05%and marginal capital output ratio went down from0.61 in 2002 to 0.28 in 2012.This indicates that the investment-driven pattern of China's industrial growth has been confronted with severe inefficiency.Further research suggests that the tendency of worsening industrial growth efficiency already became significant prior to the global financial crisis of 2008 and the eruption of the global financial crisis is not the fundamental reason for the worsening of efficiency and only exacerbated its tendency.The current government-led and investment-driven pattern of industrial growth is the root cause of such efficiency deterioration.Therefore,in order to achieve the transition towards innovation- and efficiency-driven growth pattern,the key is to make an appropriate distinction in the relationship between market and government,i.e.,the government must create a perfect institutional system where the market plays a decisive role and take proactive initiative to promote technology innovation and transfer on the basis of respecting market mechanism and the intent of market entities.
