Clock Synchronization via Relay II Satellite

Joint experiments were carried out February 15 to 20, 1965, by the U. S. Naval Observatory at the NASA tracking station, Mojave, and the Radio Research Laboratories at Kashima, Japan, to synchronize clocks via the communications satellite Relay II. During one part of a pass the pulses from Mojave were retransmitted by Kashima, which also injected its own pulses. A fourtrace oscilloscope at Mojave showed the Mojave transmitted, the Mojave retransmitted, and the Kashima pulses, and also time markers. In the other part of the pass Mojave retransmitted the Kashima pulses and injected its own. This gave an independent value of the clock difference, V. The probable error of the difference in the mean values of V for the same pass, after correcting for relative drift of the clocks, is ±0.01 , μs. However, systematic effects may be present. It is estimated that the clocks were related to ±0.1 μus on each pass. Measurements were made as a check by use of portable cesium-beam atomic clocks and by use of the VLF transmission of NLK/NPG.