A three-cornered hat analysis of instabilities in two-way and GPS carrier phase time transfer systems.

Published

May 18, 2022

Author(s)

Tom Parker, Victor Zhang, Jian Yao, Gerard Petit, Roger Brown, James Hanssen

Abstract

A three-cornered hat analysis has been performed on three independent time transfer systems between the United States Naval Observatory (USNO) and the National Institute of Standards and Technology (NIST). These include (1) a direct Two-Way Satellite Time and Frequency (TWSTFT) link provided by the USNO, (2) an indirect TWSTFT link and (3) GPS Carrier Phase (GPSCP). Time transfer instabilities, as quantified with the Time Deviation and TOTAL Time Deviation, have been calculated for averaging times between 2 hours and 170 days. Time transfer instabilities beyond one day are roughly flicker in nature and generally range between 40 and 120 ps. Frequency transfer instabilities, as quantified by the Modified Allan Deviation, are observed to be as low as 1x10-16 at twenty days and decreasing to the mid 10-17s at 100 days.

Citation

Metrologia

Pub Type

Journals

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Keywords

three-cornered hat, time and frequency transfer instabilities, two-way satellite time and frequency transfer, GPS carrier phase time transfer, time deviation and total time deviation

Citation

Parker, T. , Zhang, V. , Yao, J. , Petit, G. , Brown, R. and Hanssen, J. (2022), A three-cornered hat analysis of instabilities in two-way and GPS carrier phase time transfer systems., Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933760 (Accessed October 8, 2025)