The calibrated carier-phase GPS technique promises time transfer between remote sites with 5-minute precision approaching 20 ps. Uncalibrated time transfers between many sites are routinely made available by the Earth Orientation Department of the U.S. Naval Observatory (USNO). Although important technical issues involving long-term accuracy and calibration are still being resolved, it is possible to generate sample time and frequency scales so as to anticipate the full power of the technique. Using minor extensions of the USNO's postprocessed extended-Percival algorithm SuperP (1), a carrier-phase-based frequency scale is generated and compared to local USNO timescales.
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