Frequency transfer using Precise Point Positioning

Using precise point positioning (PPP) we show the potential for comparing frequency standards with time stabilities of under 300 ps in flicker phase noise for time periods of 1 to 10 d. This leads to comparisons at 1 part in 1015 or better at 10 d. We compare short baseline PPP results with 2 hour data from the NIST Measurements System. We compare results from the NIST - USNO baseline with hourly two-way satellite time and frequency transfer results.