Uncertainty evaluation of GPS common-view time transfer and frequency stability measurements

An experiment was carried out to determine the uncertainty of GPS common-view time transfers. The receivers operated on different tracking schedules for some satellites. We found that standard deviation of about 20 ns was attainable even when there were several minutes difference in tracking schedule for some satellites. A system developed for characterizing long- and short-term frequency stability of atomic clocks is also described. Measurement uncertainties of the system were also evaluated to establish traceability to UTC.