基于单天线月球电离层研究

In tracking observation of the China’s CE-5T1 and the sub-satellite Vstar of the Japanese lunar mission SELENE, there were opportunities of a kind of lunar grazing occultation, that is we saw CE-5T1 or Vstar very close to the limb of the Moon. This kind of chance made it possible to probe the thin plasma layer above the moon surface, by using the advanced method of the radio occultation technique and coherent radio waves of the S/X band. The dual-frequency measurements were made at existing Earth-based receiving stations or tracking stations. In the line-of-sight direction between the satellite and the tracking station, the effects of the terrestrial ionosphere, the interplanetary plasma and the thin lunar ionosphere are mixed together in the combined dual-frequency Doppler or phase observables. In order to separate the variation of the ionospheric total electron content near the surface of the moon from the mixed signal, the influences of the terrestrial ionosphere and interplanetary disturbance were removed by using the short time trend extrapolation method. So we can obtain the TEC of lunar thin ionosphere.

利用我国的嫦娥5号任务中前期试验卫星再入返回飞行器服务舱CE-5T1和SELENE工程的子卫星Vstar，使用月球轨道器-地面接收站下行链路，轨道器使用恒温高精度晶体振荡器10^-9/100s，同时转发S/X波段两路耦合相干载波信号，下行接收站使用氢原子钟提供时间频率标准。在月球电离层遮掩轨道器－观测者之间的视线时，电离层延迟效应导致穿过它的无线电波被减速，产生电波的多普勒“红移”和相位的变化，与月球电离层分布特性对应。利用观测记录下行转发链路的载波信号的频率、相位，重建月球电离层物理参数剖面。

本项目利用乌鲁木齐天文站参与SELENE工程项目的两颗子卫星Vstar/Rstar观测数据，采用单星双频模式/双星双频模式研究月球电离层；并利用我国嫦娥5号任务中前期实验卫星再入返回飞行器服务舱CE5T1观测数据，采用单星双频模式进行月球电离层初步分析。.在该项目的支持下，项目组有效完成了原定的研究目标，优化和完善了基于FORTRAN语言和Matlab语言开发的控制模块、观测资料预处理模块和电离层反演模块--月球电离层星-地无线电掩星观测资料信号相位处理系统。项目执行期间，项目组成员分工明确，高效完成了既定的研究计划和内容。