Carrier-phase two-way satellite frequency transfer over a very long baseline

Fujieda, Miho; Piester, D.; Gotoh, Tadahiro; Becker, Juergen; Aida, Masanori; Bauch, A.

doi:10.1088/0026-1394/51/3/253

Cited by 92 publications

(66 citation statements)

References 25 publications

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“…The group delay and the carrier phase of the received signals were detected by demodulation using a replica code, by which we derived the fractional frequency difference of the two H-masers. The technical details of the TWCP system are described in [14,15]. The frequency ratio of the 87 Sr lattice clocks is obtained through the ratio of the two H-masers in real time.…”

Section: Fig 1 Schematic Diagram Of the Frequency Comparison Of Twomentioning

confidence: 99%

“…As an alternative, carrier-phase based two-way satellite time and frequency transfer (TWCP), first demonstrated by U.S. Naval Observatory [13], is lately characterized in NICT for various ranges of the baselines up to 9 000 km which is realized between NICT and PTB [14,15]. Among satellite based techniques the TWCP technique has a superior short term instability (evaluated to be at the 10 −13 level at 1 s) and is thus particularly suitable for comparing frequency standards with low instabilities, e.g.…”

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confidence: 99%

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Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km

Hachisu¹,

Fujieda²,

Nagano³

et al. 2014

Opt. Lett.

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We have demonstrated a direct frequency comparison between two 87 Sr lattice clocks operated in intercontinentally separated laboratories in real time. Two-way satellite time and frequency transfer technique based on the carrier phase was employed for a direct comparison with a baseline of 9 000 km between Japan and Germany. A frequency comparison was achieved for 83 640 s resulting in a fractional difference of (1.1 ± 1.6) × 10 −15 , where the statistical part is the biggest contribution to the uncertainty. This measurement directly confirms the agreement of the two optical frequency standards on an intercontinental scale.

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Section: Fig 1 Schematic Diagram Of the Frequency Comparison Of Twomentioning

confidence: 99%

mentioning

confidence: 99%

Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km

Hachisu¹,

Fujieda²,

Nagano³

et al. 2014

Opt. Lett.

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“…These maps can also serve for precise corrections of ionospheric delays in any electromagnetic signal crossing the ionosphere, as e.g. proposed by Fujieda et al (2014) for two-way satellite frequency transfer.…”

Section: Discussionmentioning

confidence: 99%

“…The monitoring can be done in post-processing such as by the IGS which combines Global Ionospheric Maps (GIMs) from CODE, ESA, JPL and UPC (Hernández-Pajares et al 2009) or by Noveltis for the European region (SPECTRE project; Crespon et al 2007). The ionosphere is also monitored in near real-time (NRT) by DLR within the research project SWACI (GIMs and European region; Jakowski et al 2011), JPL (GIMs; Mannucci et al 1998) or NOAA/SWPC (US region; Fuller-Rowell et al 2006). The maps from these different agencies are displayed on webpages and/or distributed in ASCII data files.…”

Section: Introductionmentioning

confidence: 99%

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

Bergeot

Chevalier

Bruyninx

et al. 2014

J. Space Weather Space Clim.

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Various scientific applications and services increasingly demand real-time information on the effects of space weather on Earth's atmosphere. In this frame, the Royal Observatory of Belgium (ROB) takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere over Europe from the measured delays in the GNSS signals, and provides publicly several derived products. The main ROB products consist of ionospheric vertical Total Electron Content (TEC) maps over Europe and their variability estimated in near real-time every 15 min on 0.5°· 0.5°grids using GPS observations. The maps are available online with a latency of~3 min in IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. This paper presents the method used in the ROB-IONO software to generate the maps. The ROB-TEC maps show a good agreement with widely used post-processed products such as IGS and ESA with mean differences of 1.3 ± 0.9 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. In addition, we tested the reliability of the ROB-IONO software to detect abnormal ionospheric activity during the Halloween 2003 ionospheric storm. For this period, the mean differences with IGS and ESA maps are 0.9 ± 2.2 and 0.6 ± 6.8 TECu respectively with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution in time and space of both IGS and ESA maps compared to the ROB-TEC maps. A description of two recent events, one on March 17, 2013 and one on February 27, 2014 also highlights the capability of the method adopted in the ROB-IONO software to detect in near real-time abnormal ionospheric behaviour over Europe. In that frame, ROB maintains a data base publicly available with identified ionospheric events since 2012.

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“…5 10 16 × − between the two methods which exceeded the estimated statistical uncertainty [14]. In our current study, we aim to assess the frequency transfer capabilities of a GPS link based on a state-of-the-art precise point positioning (PPP) analysis over a baseline of 450 km.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a 450-km-baseline GPS carrier-phase link using an optical fiber link

Droste

Grebing²,

Leute³

et al. 2014

2014 IEEE International Frequency Control Symposium (FCS)

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Carrier-phase two-way satellite frequency transfer over a very long baseline M Fujieda, D Piester, T Gotoh et al.A study on the common-view and all-in-view GPS time transfer using carrier-phase measurements Seung Woo Lee, Bob E Schutz, Chang-Bok Lee et al. Abstract A global positioning system (GPS) carrier-phase frequency transfer link along a baseline of 450 km has been established and is characterized by comparing it to a phase-stabilized optical fiber link of 920 km length, established between the two endpoints, the Max-Planck-Institut für Quantenoptik in Garching and the Physikalisch-Technische Bundesanstalt in Braunschweig. The characterization is accomplished by comparing two active hydrogen masers operated at both institutes. The masers serve as local oscillators and cancel out when the double differences are calculated, such that they do not constitute a limitation for the GPS link characterization. We achieve a frequency instability of 3 10 13 × − in 30 s and 5 10 16 × − for long averaging times. Frequency comparison results obtained via both links show no deviation larger than the statistical uncertainty of 6 10 16 × − . These results can also be interpreted as a successful cross-check of the measurement uncertainty of a truly remote end fiber link.

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Carrier-phase two-way satellite frequency transfer over a very long baseline

Cited by 92 publications

References 25 publications

Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km

Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

Characterization of a 450-km-baseline GPS carrier-phase link using an optical fiber link

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