Research on Enhancing the dUT1 Independent Monitoring Capability of China Next-Generation VLBI NetworkOA

The Earth orientation parameters play a crucial role in positioning and navigation.Very-long-baseline interferometry(VLBI)stands as the sole technology that offers a comprehensive set of Earth orientation parameters.The technology offers a highly precise measurement of dUT1.In order to facilitate diverse space activities,it is imperative for China to establish an independent capability for high-precision dUT1 support.To this end,China Next-Generation VLBI Network(CNVN)has been constructed.In this paper,VieSched++is employed to identify the optimal single baseline for dUT1 estimation among 11 potential VLBI Global Observing System antenna locations in China,followed by the determination of an optimized 3-station network.We integrated CNVN with a space-tracking vessel to enhance the precision of dUT1 estimation.The results demonstrate that the optimal single baseline between Jiamusi and Kashi in China yields dUT1 estimates with a mean formal error of less than 13μs and a repeatability better than 33μs during observations lasting for both 1 and 1.5 h.The optimal 3-station network comprising Jiamusi,Kashi,and Shanghai demonstrates the capability to provide dUT1 estimates with an mean formal error of less than 8μs and a repeatability of less than 31μs.The North Atlantic Ocean is identified as the optimal location for the space-tracking vessel when combined with the 4-antenna CNVN,enabling an estimation of dUT1 with an mean formal error of less than 5μs and a repeatability of less than 15μs after 1 h of observation.