A study on reducing the diurnal in the Europe-to-Europe TWSTFT links

Most of the Two-Way Satellite Time and Frequency Transfer (TWSTFT or TW) links exhibit a daily variation (diurnal) on the order of 1 ns in the differences. The stability of TW is degraded by the diurnal. Many studies on the sources of diurnal have been carried out, but no dominating cause of the diurnal has been found. In this study, we examine the diurnal in several Europe-to-Europe TW links and report that the diurnal and the short-term transfer noise can be reduced by using the triangle difference of the transatlantic TW. We will also analyze where the improvement comes from.