Examining Short-Term Noise in GPS Carrier Phase Time Transfer

Abstract

GPS carrier phase time transfer (GPSCPTT) common-clock zero-to-short baseline experiments have demonstrated short-term stability on the same order of magnitude as that demonstrated by pairs of co-located rubidium-fountain frequency standards, where “short-term” refers to averaging times of 300 s – 24 h. GPSCPTT has not yet demonstrated that level of short-term stability over longer distances, however, limiting its potential use for disseminating the frequency of rubidium fountains and for optical frequency standards under development. Optical-fiber transfer offers an alternative, but is costly and requires substantial interagency cooperation. The goal of this study is to identify the major contributors to GPSCPTT noise over non-zero baselines at averaging times of less than one day, with emphasis to be placed on (a) averaging times of less than six hours, as this is where gains are needed for optical-frequency-standard dissemination and (b) GPSCPTT solutions generated using precise point positioning, as the usage of and results available from this technique are widely available.