Subjects: Astronomy >> Astrophysical processes submitted time 2021-03-30 Cooperative journals: 《天文研究与技术》
Abstract：地基雷达天文观测可以提供太阳系天体目标的地形地貌、物理特征、轨道动力等信息。文章聚焦利用地基雷达天文技术开展月球观测的原理方法和科学意义，介绍了基于我国现有深空雷达上行装置、射电望远镜条件、以及非相干散射雷达等系统，初步开展的UHF频段和X频段的地基雷达观测月球试验。通过月球反射回波的信号处理，获得了延迟、多普勒频移等参数，得到了一致的与近表层物质密度相关的月面雷达反射率，并得到了月球的左右旋圆极化率，其反映了与波长同尺度的月球近表层结构。文章积累的数据处理经验将为我国的小行星预警、行星历表等地基雷达天文观测研究提供技术基础。
Subjects: Astronomy >> Astrophysical processes submitted time 2023-06-07 Cooperative journals: 《天文学进展》
Abstract： With the rapid development of space activities, the high-orbit spacecraft would carry GNSS receivers to navigate in space, which is becoming a new research focus. This paper takes the geosynchronous orbit satellite TTS-2 as an example, analyzes the measure#2;ment data quality and noise characteristics of the onboard GPS C1/L1 single-frequency. The GPS signals received by the GEO satellite are from the side lobe signals and the uncovered part of the GPS main lobe signals. C1/L1 noise has a large distribution range, and there is an obvious relativity with the elevation angle. This paper adopts priori dynamic parameter error constraint orbit method, carries out orbit determination experiments with different strategies of priori dynamic parameter constraint. The experiment results show that the orbital overlap consistency of GEO satellite orbit determination with GPS C1/L1 onboard data is about 1 m or even sub-meter level. Under the condition of constrained satellite motion state and solar pressure parameters, the three-dimensional RMS errors of 36 h and 72 h arc orbit determination are both less than 0.65 m. When only constraining the solar pressure parameters, the three-dimensional RMS error of the 72 h arc orbit determination is 1.0 m, and the three-dimensional RMS error of the 36 h arc orbit determination is less than 1.5 m. The better orbit solution would be solved when the priori dynamic parameter error constrained orbit solution method and the reasonable dynamic parameter error restraint are adopted. The research methods and experiments in this paper have certain reference meanings for the high-precision applications of spaceborne GNSS on high-orbit spacecraft.
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