Instant Determination of Earth’s Polar Motion by Lunar Laser Ranging Common View

摘要: The Lunar Laser Ranging (LLR) technology has been used to determine the Earth Rotation Parameters (ERP) since the 1970s.
Conventional determination methods incorporate state-of-the-art models and LLR data spread over decades.
The up-to-date studies achieve an accuracy of tens of microseconds for UT1 and several milliarcseconds (mas) for polar motion coordinates (PMC). This paper determines the instant PMC using the lunar laser ranging common view method (LLRCV). Through quantitative analysis of derivatives of lunar range residual to ERP variation, we formulated a linear equation to solve for the instant PMC with simultaneous range measurements. The precision of the solution were evaluated from the precision of the measurement through the analysis of the linear equation. We found 184 LLRCV events in the LLR data during 2012-2022 to solve for PMC. To form the solution errors, the results of our method are compared to the IERS C04 data.
The results showed that 29.3% of the solution errors were less than 150 mas, and 21.7% of the solutions were more accurate than the prediction data. This method has the potential to address short-term and transient geophysical changes.  Nonetheless, its dependence on long-term geodetic data means it is not a substitute for conventional techniques.