基于高灵敏度VLBI观测改进南天球射电参考架

以国际天球参考架（ICRF）为代表的射电参考架是基于一组河外致密射电源的精确位置定义的，在深空导航、空间测地、相对天体测量等领域具有重要的应用，但ICRF在南天球的射电源数量较少、位置精度较差。依托国内VLBI网设备，利用亚洲大洋洲VLBI（AOV）观测时间，开展南天球高灵敏度VLBI天体测量，增加参考射电源数量，提高位置测量精度，观测结果将提交IVS（国际测地与天体测量VLBI服务）数据库，以纳入未来的国际天球参考架。开展K波段天体测量实验和VGOS（VLBI Global Observing System）系统的超宽带（3-12GHz）观测实验，获取参考射电源在不同频段的精确位置、结构图像和流量密度，分析参考射电源的位置稳定性。上述工作将有助于改进南天球射电参考架。

The International Celestial Reference Frame (ICRF), a type of radio reference frames, is defined by a set of positions of extra-galactic compact radio sources. The ICRF plays an important role in deep space navigation, space geodesy and relative astrometry. Based on Chinese stations and Shanghai Correlator, we will take advantage of the AOV (Asian Oceanian VLBI) observing time to conduct high sensitivity VLBI astrometry, with a goal to increase the sources in the south hemisphere and improve their positions. The observational data will be submitted to the IVS (International VLBI Service for geodesy and astrometry) so that those target sources will be included in the future ICRF. We also plan to conduct K-band astrometry, and broadband (3-12 GHz) astrometric experiments using VGOS (VLBI Global Observing System) stations. We will try to obtain the accurate positions, source structure and flux densities of the target sources in the south, followed by analysis of their positions stability. Such work will improve the ICRF in the south.