Abstract: A time system and reference frame are two fundamental parameters in a satellite navigation system (GNSS), which consists of coordinates and clocks of satellites and stations. A comparison of these precise parameters of IGS Analysis Center shows apparent differences. The differences include constant offsets and periodical signals, where the periodical signals of satellite orbits and satellite clocks are highly correlated. We analyzed the characteristics of the periodical signals and derived their amplitudes and frequencies. The derived periodical terms were applied for the correction of AC satellite orbits and clocks. The numbers of epochs where the agreement between AC precise products increased, amounted to 95.3% and 85.6% of all samples for orbits and clocks, respectively. Furthermore, the error in such signals was analyzed and strategies based on the parameter de-correlation are proposed for the GNSS precise data processing.