| Abstract | We report on the first characterization of the frequency transfer performance of the GPS precise point positioning with carrier-phase integer ambiguity resolution (PPP-AR) implemented by the Natural Resources Canada (NRCan) online service CSRS-PPP. We show that continuous PPP-AR links of multiple days can be formed by carefully fixing the day boundary phase discontinuity. The stability of the links can reach 7 × 10⁻¹⁶ and 1 × 10⁻¹⁶ (Allan deviation) at 1 d and 7 d averaging times, respectively, and mid to low 10⁻¹⁷ at 20 d–30 d. We compared the atomic fountain primary frequency standards (PFS) between NRC in Ottawa, Canada and PTB in Braunschweig, Germany for 135 d via GPS PPP-AR and precise point positioning links. The NRC and PTB PFS agree within a few parts in 10¹⁶, which is well below the combined systematic uncertainty. It is expected that with uncertainty at 10⁻¹⁷, the PPP-AR links will become a powerful tool for remote comparisons of atomic optical clocks, essential for the future redefinition of the SI second. |
|---|
