SNR periodical variation of Chang'E-3 spacecraft orbiting the Moon

作     者：he qingbao liu qinghui li peijia kawaguchi noriyuki wu yajun zheng xin zhang juan xu zhijun 

作者机构：Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2016年第29卷第2期

页      面：470-478页

核心收录：

学科分类：08[工学] 082503[工学-航空宇航制造工程] 0825[工学-航空宇航科学与技术] 

基　　金：supported by the National Natural Science Foundation of China(Nos.11473059 11273049 11403082) 

主　　题：2 bits quantization Elevation angle Moon radiation SNR periodical variationVLBI 

摘      要：Chang＇E-3 spacecraft was orbiting the Moon from December 6 14, 2013, and very long baseline interferometry （VLBI） observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented. Interesting phenomenon was that signal-to-noise ratio （SNR） of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon＇s orbit, whereas SNR kept in a stable level after Chang＇E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang＇E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.