Mitigation of the TWSTFT diurnal effect using software-defined receivers

Two-way satellite time and frequency transfer (TWSTFT) has been one of the most precise techniques for long-baseline time and frequency comparison. The precision achieves nanosecond level for the time comparison [1], and 10^-15 for the frequency comparison [2]. Nevertheless, it is limited by some unstable factors such as diurnal effect [3] and long-term inconsistency [4]. To improve the precision, it is required to investigate the source of instabilities.