Scrapbook 3: U.S., U.K. Set Clocks Via Telstar Satellite

U.S., U.K. Set Clocks Via Telstar Satellite

Washington—Master clock of the U.S. Naval Observatory in Washington was synchronized with the master clock of the British Royal Greenwich Observatory to within 10 microseconds, roughly 100 times the accuracy previously possible, by means of the Telstar communication satellite on Aug. 25. This was the first time such synchronization has been accomplished by satellite.

The improved synchronization will facilitate experiments and studies of the propagation of radio waves at high and very low frequencies. It also will be used to check the accuracy of the timing clock to be carried by the Navy’s Transit navigational satellite.

To carry out the synchronization experiment, the American Telephone & Telegraph Co. station at Andover, Me., and the British station at Goonhilly Downs each transmitted time marker pulses simultaneously, based on time determined from the master clock of its own national observatory. Each station recorded the instant of its own transmission and the instant it received the signal from the other. From these two measurements it is possible to determine the error in synchronization between the two master clocks.

The clock at the Andover station was synchronized to the Naval Observatory in Washington by means of transmissions from a Loran-C station at Nantucket, Mass., which is synchronized to the master Loran-C station at Cape Fear, N.C., which in turn is controlled from the Naval Observatory.