Potential of Lunar Laser Ranging for the Determination of Earth Orientation Parameters

AbstractThe distance between the observatories on the Earth and the retro-reflectors on the Moon has been regularly measured with Lunar Laser Ranging (LLR) since 1970. In recent years, LLR observations have been carried out at infrared wavelength (OCA, WLRS), resulting in a better distribution of LLR normal points over the lunar orbit and retro-reflectors with a higher accuracy, also leading to a higher number of LLR observations in total. By analysing LLR data, Earth Orientation Parameters (EOPs) can be determined along with other parameters of the Earth-Moon system. Focusing on $$\Delta $$ Δ UT1 and terrestrial pole coordinates the accuracies have improved significantly compared to the previous results. In the past, the reported uncertainties of the estimated parameters were published as three times the formal error from the least-squares adjustment to account for small random and systematic errors in the LLR analysis. To investigate if such a scaling factor is still needed, a sensitivity analysis was performed. The current best accuracies are 12.36 $$\upmu $$ μ s for $$\Delta $$ Δ UT1, 0.47 mas for $$x_p$$ x p and 0.59 mas for $$y_p$$ y p . Also the determined corrections to the long-periodic nutation coefficients of the MHB2000 model are now significantly smaller with higher accuracies, i.e., accuracies better than 0.18 mas are obtained.