
César GATTANO Studying impacts of strategy choices concerning the Celestial Reference Frame on the estimates of nutation time series during geodesic VLBI Analysis César Gattano, Observatoire de Paris, SYRTE Sébastien Lambert, Observatoire de Paris, SYRTE Christian Bizouard, Observatoire de Paris, SYRTE Very Large Baseline Interferometry (VLBI) is the only technique which permits to determine Earth's precessionnutation at submilliarcsecond accuracy. With its 35 years of observations, at the rate of 2 observing sessions a week during the last decade, it allows to estimate nutation over periods from 14 days to 20 years. But VLBI data analysis is of such a complexity that there are as much different nutation time series that there are analysis center working on it. So, it is worthful to investigate the nature of these differences in relation with the choices in the analysis strategy. Differences between the operationnal nutation time series are considered as composed of a signal and a noise, determined by mean of wavelets and Allan variance analysis. We try to explain them by the choices made on the Celestial Reference Frame. In particulary, the ICRF2 catalog is perturbed by introducting random shifts on all the 3414 sources, and we investigate the consequences on nutation. 