Continuous time transfer using GPS carrier phase

Area of Science:

• Geodesy and Geophysics
• Time and Frequency Transfer
• Satellite Navigation Systems

Background:

• The Astronomical Institute of the University of Berne operates as an Analysis Center for the International GPS Service (IGS).
• Routine analysis of GPS station networks in Europe and North America is performed for time transfer, utilizing carrier phase observations.
• This research is conducted in collaboration with the Swiss Federal Office of Metrology and Accreditation (METAS).

Purpose of the Study:

• To develop a method for concatenating independent daily GPS time transfer solutions into a continuous time series.
• To assess the improvement in time transfer accuracy offered by a continuous series compared to daily solutions.
• To compare GPS-based time transfer results with other techniques like two-way satellite time and frequency transfer.

Main Methods:

• Analysis of GPS carrier phase observations from a network of stations.
• Independent computation of daily time transfer solutions.
• Development and application of a concatenation method to create a continuous time series.
• Comparison of concatenated GPS time series with results from other time transfer methods.

Main Results:

• Daily GPS time transfer solutions exhibited jumps up to 1 nanosecond at day boundaries.
• A continuous time series spanning over four months was successfully generated.
• The continuous time series provided a more accurate representation of continuously operating clocks.
• Comparisons indicated that the concatenated GPS results align well with other advanced time transfer techniques.

Conclusions:

• Concatenating daily GPS time transfer solutions effectively overcomes the limitations of daily analysis schemes.
• The developed method yields a continuous and more representative time series for precise timekeeping.
• This improved time transfer methodology enhances the reliability and accuracy of time synchronization using GPS data.