COMPARISON OF GPS COMMON-VIEW AND 2-WAY SATELLITE TIME TRANSFER OVER A BASE-LINE OF 800-KM

For about one year the time scales UTC (OCA) and UTC (TUG) were compar ed by means of GPS common-view and two-way satellite time transfer. At the end of the experiment, both links were independently ''calibrated '' by measuring the differential delays of the GPS receivers and the s atellite Earth stations by transportation of one GPS receiver and one satellite terminal to the other site. The results obtained by the two methods differ by about 3 ns, but reveal a seasonal variation of about 8 ns which, most likely, is mainly the result of temperature-dependen t delays in the GPS receiving equipment used.