摘要
武汉大学近年来逐步完善了13 m天线中用于深空探测的硬件设施,且收集了大量观测数据,包括月球探测器嫦娥三号(Chang’E-3, CE3)、火星探测器火星快车(Mars Express, MEX)和火星轨道勘察器(Mars Reconnaissance Orbiter, MRO)、土星探测器Juno等。对近两年的观测数据做了整体分析,包括信号接收功率、接收频率精度、氢钟稳定性、总相位抖动等方面。分析结果显示,接收信号的信噪比在制冷接收机安装之后提高了1倍,接收频率的精度在氢钟安装之后也提高了1倍,达到20 m Hz。13 m天线的氢钟在ms量级稳定性较差,但1 s稳定度达到10-12量级,能够满足当前深空探测的需求。另外,还提出一种事后计算总相位的方法,能够适应于极低信噪比情况。总相位受等离子体影响的分析结果与国际上研究结果接近。整体分析结果表明,13 m天线的观测数据除了可提取高精度多普勒频率应用于测定轨之外,还可提取相位抖动做空间介质等科学研究。
The 13 m antenna of Wuhan University has now equipped with hydrogen atomic clock, X-band cryogenic receiver and digital back ends. It performed observations on Chang’E-3(CE3), MRO(Mars Reconnaissance Orbiter), MEX(Mars Express) and Juno.We processed and analyzed the observational data of the past two years. The results showed SNR(Signal to Noise Ratio) increased by 3 dB after installing the cryogenic equipment on receiver, and the accuracy of received frequency with 1 s integration reached 20 mHz after replacing rubidium atomic clock by the hydrogen atomic clock. Analysis found that the stability of local frequency generated by hydrogen atomic clock was low when the integration time was in the order of millisecond. However, the stability reached the level of 10-12 when the integration time was 1 s, which indicated it could meet the requirements of current space missions. What’s more, we presented a new method of calculating total phase of received signals. It can be feasible in the case of signals with very low SNR. We calculated the total phases of MRO and MEX. Power spectrum results were in good agreements with studies carried out by other researchers. The overall results showed that Doppler frequency with high accuracy and total phase fluctuations can be obtained by the 13 m antenna observing deep space probes. They can be used not only in orbit determination, but also in the study of solar plasma.
作者
贺庆宝
陈祎豪
杨轩
鄢建国
李斐
HE Qing-bao;CHEN Yi-hao;YANG Xuan;YAN Jian-guo;LI Fei(Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen 518055,China;LIESMARS Laboratory,Wuhan University,Wuhan 430079,China)
出处
《天文学进展》
CSCD
北大核心
2020年第4期457-469,共13页
Progress In Astronomy
基金
测绘遥感信息工程国家重点实验室专项科研经费。
关键词
等离子体
氢钟
总相位
信噪比
Solar plasma
hydrogen atomic clock
total phase
SNR
