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Statistics for quantifying aging in time transfer system delays



Tom Parker, Roger Brown, Jeffrey Sherman


The time delays in time transfer systems such as Two-Way Satellite Time and Frequency Transfer (TWSTFT), or GPS carrier phase (GPSCP) change over time. A double difference such as TWSTFT – GPSCP provides information on the changes in the relative time delays of the two systems. These changes are referred to as aging or time dispersion. The Time Deviation statistic (TDEV) provides information on the magnitude and nature of the random fluctuations in aging. This paper describes analytical and Monte Carlo techniques used to estimate the aging (time dispersion) from a TDEV statistic.


time transfer system delays, time dispersion, aging, TDEV, ADEV


Parker, T. , Brown, R. and Sherman, J. (2023), Statistics for quantifying aging in time transfer system delays, Metrologia, [online],, (Accessed June 17, 2024)


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Created November 10, 2023, Updated June 7, 2024