Satellite VHF transponder time synchronization

This paper describes an experiment designed to transfer accurate time between two widely separated clocks using a VHF satellite transponder. The satellite used was the NASA Applications Technology Satellite, ATS-1. The experiment used atomic oscillators to maintain accurate time at each station, and the synchronization was accomplished by measuring the round-trip delay times between the stations. The goal of the experiment was to evaluate a VHF system, because of the low-cost ground equipment involved, in contrast to microwave systems. The paper discusses the results and the various factors that contributed to the timing errors.