A Study of Space VLBI Data Recording Format -RDF and Its Data Decoding
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摘要: 空间甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)由于基线更长,在相同的观测频率下,可获得比地基甚长基线干涉测量更高的分辨率。我国正在推进空间甚长基线干涉测量科学与技术研究。俄罗斯RadioAstron空间甚长基线干涉测量项目于2018年结束,其成功经验可以借鉴。该项目采用不同于常规地面甚长基线干涉测量的专用数据格式RDF(RadioAstron Data Format)记录观测数据,利用配备的星载或地面上行氢原子频标提供频率基准,数据经采集量化后传输至地面站,打上时标并记录于硬盘。为处理RadioAstron数据,分析了RDF格式,完成了RDF数据解码及相关处理,然后对比分析了Mark5B、VDIF等地面甚长基线干涉测量通用数据格式和RDF格式的特点,为我国未来空间甚长基线干涉测量数据格式设计与处理积累经验。Abstract: Compared with ground VLBI, space VLBI provides higher angular resolution since its baseline is much longer. Our country has started the development of our own space VLBI science and technology. Russian space-VLBI project RadioAstron was finished in 2018. We can learn a lot from its successful experience. This project, which is quite different from ground-VLBI, uses a dedicated data format Radio Astron Data Format (RDF). Besides, the frequency reference is provided by the on-board or ground-based uplinking hydrogen atomic frequency standard. The data is quantized and transferred to the ground station, and is then labeled with time-tag and recorded in the hard disk. In this paper, we analyze the RDF format, carry out RDF data decoding and VLBI correlation. Moreover, we compare RDF with other commonly used VLBI data format, e.g., Mark5B and VDIF. Our work will pave the way for the format designing and data processing of space-VLBI data in China.
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Keywords:
- Space VLBI /
- RDF format /
- Data decoding /
- Mark5B
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