A New Algorithm Combining Angular Momentum and Other EOP Inputs to Improve IERS Rapid Service/Prediction Center Predictions

A new weighted cubic spline algorithm has been developed to combine state and derivate-state inputs. The algorithm speeds and improves the evaluation of new inputs to the Earth Orientation Parameters (EOPs) combination/prediction procedures. Use of this new algorithm with International GNSS Ultra Rapid (IGS) Observation Length-of-Day (LOD) and atmospheric angular momentum (AAM) inputs has already shown significant improvements in 0- and 1-day UT1-UTC predictions. Further investigations of the potential improvements obtained using various input data sets will be presented. These data sets may include AAM from the Navy Global Environmental Model (NAVGEM) and the National Oceanic and Atmospheric Administration (NOAA) / National Centers for Environmental Prediction (NCEP) global analyses, ocean angular momentum (OAM) from the Hybrid Coordinate Ocean Model (HYCOM), and EOPs from the IGS and USNO Ultra Rapid observations, the VLBI Global Observing System Intensives (VGOS), and the Very Long Baseline Array (VLBA) series.