Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar park...Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.展开更多
According to the history of lunar detection, the relationship between selenodesy and lunar detection is reviewed , and the focus of the lunar detection and the lunar detection plan of China are summarized. The key tec...According to the history of lunar detection, the relationship between selenodesy and lunar detection is reviewed , and the focus of the lunar detection and the lunar detection plan of China are summarized. The key techniques of selenodesy are presented, and the applications of selenodesy to the lunar detection are discussed.展开更多
目前广泛应用的月球统一控制网2005(Unified Lunar Control Network 2005,ULCN2005)是由1994年的克莱门汀(Clementine)影像和之前的遥感数据联合平差构建的。提出利用21世纪获取的分辨率更高、精度更好的多探测任务数据,建立新一代月球...目前广泛应用的月球统一控制网2005(Unified Lunar Control Network 2005,ULCN2005)是由1994年的克莱门汀(Clementine)影像和之前的遥感数据联合平差构建的。提出利用21世纪获取的分辨率更高、精度更好的多探测任务数据,建立新一代月球控制网的方案与关键技术。该方案基于全球覆盖的月球遥感影像与激光高度计数据的联合平差,同时利用在月球轨道侦察器窄角相机影像上能高精度定位的绝对定位精度在厘米级的5个激光棱角反射标志点作为绝对控制。此外,还通过新的无线电测量方法对嫦娥三号着陆器进行高精度定位,将其定位结果也作为一个新的绝对控制数据。新一代控制网构建的重点有高精度的轨道器严密及通用成像几何模型的构建、多任务多模态数据间的多尺度特征提取与匹配、最优化多重覆盖影像的选择、全月球整体平差等。基于新的数据和技术,新一代月球控制网的精度和点的密度有望远超ULCN2005。展开更多
文摘Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.
基金Funded by the National 973 Programof China (No.2006CB701301) the Basic Research of Geomatics and Geodesy of the Key Laboratory of Geo-space Environment and Geodesy, Ministry of Education, China (No.03-04-10) .
文摘According to the history of lunar detection, the relationship between selenodesy and lunar detection is reviewed , and the focus of the lunar detection and the lunar detection plan of China are summarized. The key techniques of selenodesy are presented, and the applications of selenodesy to the lunar detection are discussed.
文摘目前广泛应用的月球统一控制网2005(Unified Lunar Control Network 2005,ULCN2005)是由1994年的克莱门汀(Clementine)影像和之前的遥感数据联合平差构建的。提出利用21世纪获取的分辨率更高、精度更好的多探测任务数据,建立新一代月球控制网的方案与关键技术。该方案基于全球覆盖的月球遥感影像与激光高度计数据的联合平差,同时利用在月球轨道侦察器窄角相机影像上能高精度定位的绝对定位精度在厘米级的5个激光棱角反射标志点作为绝对控制。此外,还通过新的无线电测量方法对嫦娥三号着陆器进行高精度定位,将其定位结果也作为一个新的绝对控制数据。新一代控制网构建的重点有高精度的轨道器严密及通用成像几何模型的构建、多任务多模态数据间的多尺度特征提取与匹配、最优化多重覆盖影像的选择、全月球整体平差等。基于新的数据和技术,新一代月球控制网的精度和点的密度有望远超ULCN2005。
