Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing p...Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.2732°, 1.6440° and –3.56 km (the reference lunar radius is 1738 km). The uncertainties are 0.0040°, 0.0168° and 0.18 km. The corresponding uncertainty in the tangential direction of the lunar surface is 0.52 km and the three-dimensional (3D) positioning uncertainty is 0.55 km. It is accordingly deduced that even with the present technical specifications of the radio ranges and VLBI delays, the 1 km 3D positioning precision could be guaranteed for the lander in the second stage of China’s Lunar Explora- tion Project. Concerning the trace determination of the rover on the lunar surface, because only telemetry signal will be emitted, VLBI would be the sole tracking technique from the Earth. The application of the constraint of geocentric distance is shown to be helpful to improving the positioning precision. It is worthy to pay close attention to the applications of the same beam VLBI technique, the lunar topographic model and the on-board observations of the lander and rover to the position/trace determination of the rover.展开更多
Many of the world’s powerful and wealthy nations,including China,have devoted both large amounts of funding and considerable promotion to lunar research and exploration.The launch of Chinese Chang’e-1 satellite and ...Many of the world’s powerful and wealthy nations,including China,have devoted both large amounts of funding and considerable promotion to lunar research and exploration.The launch of Chinese Chang’e-1 satellite and the construction of the scientific observation data platform created a favourable opportunity for research into the lunar geometrical,physical and chemical environment.Based on this background,a Wide Area Network(WAN)based virtual lunar environment was constructed for observation data sharing and further exploration.The systematic architecture and framework were introduced and then strategies of mass data(e.g.lunar digital elevation model,lunar digital orthophoto map and typical thematic lunar data)organisation,integration,management and scheduling were then set up to achieve the 3D visualisation of typical lunar geomorphic features.Furthermore,the integration method of 3D lunar data and the process model of impact craters were studied;thus,the whole lunar and celestial collision process could be dynamically simulated.The results indicate that the WAN-based virtual lunar platform can be used effectively for public information sharing,scientific exploration and further to promote the development of deep space exploration in China.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10778635 and 10973030)China’s Lunar Exploration Project (CE-1)+1 种基金National High-Tech Research and Development Program of China (Grant Nos. 2008AA12A209 and 2008AA12A210)STC of Shanghai Munici-pality (Grant No. 06DZ22101)
文摘Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.2732°, 1.6440° and –3.56 km (the reference lunar radius is 1738 km). The uncertainties are 0.0040°, 0.0168° and 0.18 km. The corresponding uncertainty in the tangential direction of the lunar surface is 0.52 km and the three-dimensional (3D) positioning uncertainty is 0.55 km. It is accordingly deduced that even with the present technical specifications of the radio ranges and VLBI delays, the 1 km 3D positioning precision could be guaranteed for the lander in the second stage of China’s Lunar Explora- tion Project. Concerning the trace determination of the rover on the lunar surface, because only telemetry signal will be emitted, VLBI would be the sole tracking technique from the Earth. The application of the constraint of geocentric distance is shown to be helpful to improving the positioning precision. It is worthy to pay close attention to the applications of the same beam VLBI technique, the lunar topographic model and the on-board observations of the lander and rover to the position/trace determination of the rover.
基金The work described in this article was supported by the Key Program of National Natural Science Foundation of China(grant no.40730527)the National High Technology Research and Development Program of China(key‘863’no.2010AA122202)+1 种基金the National Natural Science Foundation of China(grant no.41001223)the Direct Grant of The Chinese University of Hong Kong(grant no.2021064).
文摘Many of the world’s powerful and wealthy nations,including China,have devoted both large amounts of funding and considerable promotion to lunar research and exploration.The launch of Chinese Chang’e-1 satellite and the construction of the scientific observation data platform created a favourable opportunity for research into the lunar geometrical,physical and chemical environment.Based on this background,a Wide Area Network(WAN)based virtual lunar environment was constructed for observation data sharing and further exploration.The systematic architecture and framework were introduced and then strategies of mass data(e.g.lunar digital elevation model,lunar digital orthophoto map and typical thematic lunar data)organisation,integration,management and scheduling were then set up to achieve the 3D visualisation of typical lunar geomorphic features.Furthermore,the integration method of 3D lunar data and the process model of impact craters were studied;thus,the whole lunar and celestial collision process could be dynamically simulated.The results indicate that the WAN-based virtual lunar platform can be used effectively for public information sharing,scientific exploration and further to promote the development of deep space exploration in China.
