Time transfer using the phase of the GPS carrier

We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code as is done in current GPS based time-transfer systems. We connected atomic clocks to geodetic GPS receivers. We then used the GPS carrier-phase observations to estimate relative clock behavior at 6 minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common-view time transfer, and agrees within error with two-way time-transfer measurements. GPS carrier-phase time-transfer has an uncertainty of 100 psec and a frequency uncertainty of 2 parts in 10/sup 15/ for averaging times of a day.