The calibration device for TWSTFT station at TL

Because of the nanosecond time transfer capability of the two-way satellite time and frequency transfer (TWSTFT), it is important to understand the quality of the delay difference between transmission and receiving (Tx/Rx) paths inside TWSTFT earth station. An effective technique using satellite simulator to separately calibrate the absolute Tx/Rx delays at each station was developed by VSL and TUG. In order to investigate the rigorous calibration method in absolute mode, TL had installed a calibration device, the satellite simulator developed by TimeTech, on a Ku-band 1.8 m earth station. By using this device, we performed two serial measurements to obtain the delay values of some internal loops in earth station, and then calculated the difference of the transmission and receiving delays of the TWSTFT earth station. The system structure of the calibration device and the measurement results are illustrated in this paper.