VGOS超宽带观测的首次UT1测量数据处理及分析

在国际甚长基线干涉测量（very long baseline interferometry, VLBI）大地测量与天体测量服务组织协调下，首次利用隶属于VLBI全球观测系统（VLBI global observing system, VGOS）的美国Kokee和德国Wettzell观测站及并置的传统VLBI观测站开展了世界时（universal time, UT1）联合测量试验，观测数据在上海VLBI中心进行了干涉处理。结果表明，VGOS超宽带观测系统的UT1测量精度约为7 μs，并置基线的传统S/X双频系统测量精度约为14 μs，VGOS系统的UT1解算结果优于S/X系统。通过试验建立了从相关处理、相关后处理到UT1参数解算的完整数据处理流程，验证了上海VLBI相关处理机的VGOS数据处理能力，为承担国内和国际VGOS观测数据的相关处理任务奠定了基础。

Data Processing and Analysis for the First UT1 Session Using VGOS Broadband System

  Objectives  The very long baseline interferometry(VLBI) global observing system (VGOS) is a new generation of geodetic VLBI system which is equipped with broadband receiver and fast slewing antenna in order to achieve very high accuracy for measuring station coordinates, source positions as well as Earth rotation. Within the framework of the international VLBI service (IVS) for geodesy and astrometry, the first UT1 observing session was conducted using the VGOS stations at Kokee in USA and Wettzell in Germany, with a goal to validate VGOS data processing pipeline and estimate UT1 parameters.  Methods  The raw data were correlated at Shanghai VLBI correlator, followed by post-correlation processing and data analysis. The UT1 measurement results were derived and compared using VGOS database files produced from Shanghai correlator and the other correlator. Moreover, VGOS results were compared with those from the parallel UT1 session, which was conducted in the same time span using co-located legacy S/X-band stations.  Results  The UT1 estimation results obtained from Shanghai correlator output agree very well with those from the other correlator. The UT1 formal error obtained from VGOS observations is about 7 μs, approximately 2 times lower than the UT1 formal error obtained from the parallel legacy S/X-band observations.  Conclusions  VGOS system has the capability to obtain better UT1 measurement results than the legacy S/X-band system. The data processing pipeline established at Shanghai VLBI correlator has been validated and laid a foundation for regular VGOS data correlation in the near future.