Simultaneously Estimating EOPs and a TRF with KALREF

ITRF2005 was the first terrestrial reference frame (TRF) to be realized using time series of both space-geodetic station positions and Earth orientation parameters. Using time series of station positions leads to a robust frame determination by, in principle, allowing non-linear and discontinuous station motions to be corrected prior to frame determination. Using Earth orientation parameters helps tie the technique-specific frames together and yields a combined EOP series that is automatically consistent with the combined reference frame. By comparing the resulting ITRF2005 combined EOP series to other available combined EOP series and to global geophysical fluid models, it was shown that the ITRF2005 EOP series is at least as accurate, and probably more accurate, than the other available series. Following the pioneering ITRF2005 approach, KALREF (KALman filter for REFerence frame determination) has been used to determine an ITRF2008-like terrestrial reference frame from measurements of both time-dependent station positions and Earth orientation parameters. The resulting reference frame has been shown previously to compare favorably with ITRF2008. Here, the resulting combined EOP series is assessed by comparing it to other combined EOP series and to models of atmospheric, oceanic, and hydrologic excitation. The results of this comparison will be presented.