One of the most efficient ways to probe the lunar inner structure at present is through the study of its rotation.Range and range rate(Doppler) data between the Chang’E-3 lander and station on the Earth were collected from the beginning of the Chang’E-3 lunar mission in 2013.These observation data,taken together with the existing lunar laser ranging data,provide a new approach to extend research on the Earth-Moon system.The high precision of current observation data imposes exacting demands,making it necessary to include previously neglected factors.In this paper,motivated by progress of the Chinese lunar exploration project and to use its data in the near future,two lunar models:a one-layer model and a two-layer model with a fluid core,were applied to the rotational equations based on our implemented algorithm of the Moon’s motion.There was a difference of about 0.5′′in φ and ψ,but 0.2′′in θ between the two models.This result confirms that stratification of the inner structure of the Moon can be inferred from rotation data.We also added precise Earth rotation parameters in our model;the results show that this factor is negligible at present,due to the limited precision of the existing data.These results will help us understand the rotational process clearly and build a more realistic Earth-Moon model when we combine Lunar Laser Ranging data with high precision radio data to fit lunar motion in the near future.
Yong-Zhang YangJin-Song PingJian-Guo YanJin-Ling Li
A local survey was implemented at the newly constructed Shanghai Tianma 65-m radio telescope.In this article,the survey implementation and data analysis are described.Particularly,by application of coordinate transformation,dimensionality reduction and step fitting of parameters,as well as adoption of reliability test measures of parameters,the mathematical model of data analysis is simplified,the detrimental effects of observation noises and unevenly spatial coverage of sample points are effectively compressed,the stability and precision of parameter solutions are improved,and so the geocentric three-dimensional coordinates of the reference point of this telescope in the precision of millimeters were determined,and the axisoffset was shown not significant on the precision level of3 mm.The outcome provides important reference to the subsequent activities of antenna maintenance and scientific application,including the establishment of precise antenna orientation model,orientation guidance,fringe searching in data cross-correlation,analysis and application studies of VLBI observations.It is also important archive data for monitoring possible subsidence and lateral displacement of antenna foundation as well as deformation of antenna tracking-rail and structure.
Jinling LiFuwen XiongChenglei YuJinwei ZhangLi GuoQingyuan Fan
