Abstract
The time transfer technique based on Precise Point Positioning (PPP) has proved to be a very effective technique allowing the comparison of atomic clocks with a precision of a hundred picoseconds, and with latency of 2 days. Using satellite orbit and clock information from the IGS real-time products, it is now possible to compute very precise time transfer solutions based on PPP in near real-time, i.e., with a latency down to some minutes. We present PPP-based time transfer results obtained in near real time with the new version of the GNSS data processing software Atomium, and the satellite products mentioned above. We additionally analyze the results that can be obtained with low latency using the NRCan Ultra-Rapid products (EMU) available with a delay of 90–150 min. From the statistics of the results, it is concluded that the real-time IGS products allow detection of a clock jump larger than 1.5 ns after some minutes; the detection threshold falls down to 0.8 ns when using the EMU products about 2 h later. It is also shown that in near real time, a frequency change larger than 2e-14 can be detected when looking at the last 24 h data or larger than 2e-13 when looking at the last 2 h. As demonstrated, the quality of the monitoring depends on the distance between the two stations, so that distances shorter than about 3,000 km should be preferably used for a near real-time comparison of atomic clocks based on PPP.
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References
Arias F, Harmegnies A, Jiang Z, Konaté H, Lewandowski W, Panfilo G, Petit G, Tisserand L (2012) UTCr: a rapid realization of UTC. In: Proceedings of European Frequency and Time Forum, Gothenburg, Sweden, 2012, pp 24–27
Caissy M, Agrotis L (2011) Real-time working group and real-time pilot project. Int GNSS Serv Tech Rep 2011:183–190
Cerretto G, Tavella P, Lahaye F, Mireault Y, Rovera D (2012) Near real-time comparison and monitoring of time scales with Precise Point Positioning using NRCan Ultra-Rapid Products. IEEE Trans Ultrason Ferroelectr Freq Control 59(3):545–551. doi:10.1109/TUFFC.2012.2226
Defraigne P, Baire Q (2011) Combining GPS and GLONASS for time and frequency transfer. J Adv Space Res 47(2):265–275. doi:10.1016/j.asr.2010.07.003
Defraigne P, Bruyninx C (2007) On the link between GPS pseudorange noise and day-boundary discontinuities in geodetic time transfer solutions. GPS Solut 11(4):239–249. doi:10.1007/s10291-007-0054-z
Defraigne P, Guyennon N, Bruyninx C (2008) GPS Time and frequency transfer: PPP and phase-only analysis. Int J Navig Obs 2008, Article ID 175468. doi:10.1155/2008/175468
Defraigne P, Baire Q, Lahaye F, Cerretto G, Rovera D (2012) Near real-time comparison of UTC(k)’s through a Precise Point Positioning approach. In: Proceedings of European Frequency and Time Forum, Gothenburg, Sweden, 2012, pp 349–353
Esteban H, Palacio J, Galindo FJ, Feldmann T, Bauch A, Piester D (2010) Improved GPS-based time link calibration involving ROA and PTB. IEEE Trans Ultrason Ferroelectr Freq Control 57(3):714–720. doi:10.1109/TUFFC.2010.1469
Hadas T, Bosy J (2014) IGS RTS precise orbits and clocks verification and quality degradation over time. GPS Solut. doi:10.1007/s10291-014-0369-5
Hatch R (1982) The Synergism of GPS Code and Carrier Measurements. In: Proceedings of the Third International Symposium on Satellite Doppler Positioning at Physical Sciences Laboratory of New Mexico State University, Feb. 8–12, vol. 2, pp 1213–1231 Also available as Magnavox Technical Paper MX-TM-3353-82, No. 11024/D
Kouba J, Heroux P (2001) Precise Point Positioning using IGS orbits and clock products. GPS Solut 5(2):12–28. doi:10.1007/PL00012883
Larson K, Levine J, Nelson L (2000) Parker T (2000) Assessment of GPS carrier-phase stability for time-transfer applications. IEEE Trans Ultrason Ferroelect Freq Contr 47:484–494
Mireault Y, Tétreault P, Lahaye F, Héroux P, Kouba J (2008) Online precise point positioning: a new, timely service from Natural Resources Canada. GPS World 19(7):59–64
Orgiazzi D, Tavella P, Lahaye F (2005) Experimental assessment of the time transfer capability of Precise Point Positioning. In: Proceedings IEEE International Frequency Control Symposium, Vancouver, Canada, 2005, pp 337–345
Petit G, Harmegnies A, Mercier F, Perosanz F, Loyer S (2011) The time stability of PPP links for TAI. In: Proceedings of Joint Meeting European Frequency and Time Forum and IEEE International Frequency Control Symposium, 2011, pp 1041–1045. doi: 10.1109/FCS.2011.5977299
Proia A, Cibiel G, White J, Wilson D, Senior K (2011) Absolute calibration of GNSS time transfer systems: NRL and CNES techniques comparison. In: Proceedings of Joint Meeting European Frequency and Time Forum and IEEE International Frequency Control Symposium, 2011, pp 1–6. doi: 10.1109/FCS.2011.5977799
Zumberge JF, Heflin HB, Jefferson DC, Watkinsand MM, Webb FH (1997) Precise Point Positioning for the efficient and robust analysis of GPS data from large networks. J Geophys Res 102(B3):5005–5017. doi:10.1029/96JB03860
Acknowledgments
The authors thank the IGS community, and especially the IGS Real-Time Working Group members for the real-time clocks and orbits and the NRCan analysis centers for the hourly EMU products which allow us to process these near real-time clock comparisons.
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Defraigne, P., Aerts, W. & Pottiaux, E. Monitoring of UTC(k)’s using PPP and IGS real-time products. GPS Solut 19, 165–172 (2015). https://doi.org/10.1007/s10291-014-0377-5
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DOI: https://doi.org/10.1007/s10291-014-0377-5