A TWSTFT Transmitter Prototype Compatible with SDR Receivers and SATRE Modems

Many timing laboratories employ the Two-Way Satellite Time and Frequency Transfer (TWSTFT) technique for the comparison of their high accuracy atomic clocks and time scales and contribute to the Coordinated Universal Time (UTC). Most laboratories use the SATRE (SAtellite Time and Ranging Equipment) modems developed by TimeTech, which is currently the sole European manufacturer of TWSTFT modems. Some laboratories also participate in the 2016 BIPM pilot study on the Software-Defined Radio (SDR) receiver for TWSTFT which was proven to reduce the diurnal variation seen on “traditional” SATRE links. In this work, we developed a prototype for transmitting TWSTFT signal which is compatible with both SATRE modems and SDR receivers and present a preliminary assessment of its compatibility and performance.