Development of a two way satellite time and frequency transfer station at BNM-SYRTE

Achkar, Joseph; Merck, P.

doi:10.1109/freq.2003.1275230

Cited by 4 publications

(2 citation statements)

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“…Since 2003 the LNE-SYRTE participates to the European and transatlantic TWSTFT links through the INTELSAT satellites operated in the Ku band [2,3].…”

Section: Discussionmentioning

confidence: 99%

New TWSTFT link between LNE-SYRTE and NTSC in the Ku band

Rovera

Achkar

et al. 2008

2008 Conference on Precision Electromagnetic Measurements Digest

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We report first results obtained with the Two Way Satellite Time and Frequency Transfer (TWSTFT) between LNE-SYRTE and NTSC using the IS-4 commercial geostationary satellite at 72 0 E operating in Ku band.This work is part of the activities recommended by the CCTF working group on TWSTFT. The detailed study of the measurement uncertainty is presented, with particular attention to the fluctuation of Sagnac effect due to the satellite libration. SummaryThe TWSTFT [1] is a well established technique that allows sub-nanosecond time comparison between distant clocks. Since 2003 the LNE-SYRTE participates to the European and transatlantic TWSTFT links through the INTELSAT satellites operated in the Ku band [2,3].In 2007 a new station has been installed in Paris to participate to the Asia-Europe link via the IS-4 commercial geostationary satellite at 72 0 E. This link will in the near future allow regular time comparison between at least 3 European laboratories and 5 Laboratories of eastern Asia. Preliminary tests have been done comparing an Hydrogen Maser at LNE-SYRTE with a Cs beam at NTSC.

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“…Since 2003 the LNE-SYRTE participates to the European and transatlantic TWSTFT links through the INTELSAT satellites operated in the Ku band [2,3].…”

Section: Discussionmentioning

confidence: 99%

New TWSTFT link between LNE-SYRTE and NTSC in the Ku band

Rovera

Achkar

et al. 2008

2008 Conference on Precision Electromagnetic Measurements Digest

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“…The TWSTFT data are used by the Bureau International des Poids et Mesures (BIPM) in order to determine the different links between Coordinated Universal Time UTC(k) scales realized in the different national metrology institutes k, permitting to make the International Atomic Time (TAI), as it is published monthly by the BIPM Circular T [11]. OP developed in 2003 a full automated Kuband two-way earth station for INTELSAT satellite communications [12], based on a 2,4 m Gregorian dual offset antenna, active up/down-converters with 125 kHz steps, different microwave components (cables, waveguides, couplers, attenuators, splitters), and a SATRE modem allowing 2,5 MChips pseudo-noise codes for its Tx/Rx modules with an in-built Time Interval Counter (TIC). A spectrum analyzer and an external TIC are also connected to the station for additional precise measurements.…”

Section: Time and Frequency Transfer Using Thementioning

confidence: 99%

Recent time and frequency transfer activities at the Observatoire de Paris

Aclikar

Ubrich

Merck

et al. 2005

Proceedings of the 2005 IEEE International Frequency Control Symposium and Exposition, 2005.

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Important investigations in the time and frequency transfer have been done during the last four years at the Observatoire de Paris (OP). The goal was twofold: improvement of the GPS comparison technique by the use of dual frequency GPS multi-channel receivers in common-views (GPS P3) and the development of a full two-way satellite time and frequency transfer (TWSTFT) station in the Ku-Band.The advantage of the GPS P3 technique is the compensation of the ionospheric delays. The GPS P-Code is transmitted simultaneously on both carriers L1 and L2, and the dualfrequency multi-channel GPS receiver Ashtech Z12-T allows for the so-called P1 and P2 measurements. A simple linear combination gives the ionosphere free P3 measurements. The software developed by the Observatoire Royal de Belgique [1] builds from the geodetic RINEX files such P3 data in the CGGTTS format, and the Common-View method is applied. Due to the availability of several simultaneous Common-Views, a selection can be made which improves the short term frequency stability of the results. A typical result on European baselines gives an Allan Time Deviation σ x (τ) below 200 ps over an analysis period lower than 1 d between H-Masers.The TWSTFT technique, a direct comparison between ground clocks through a communication satellite, is a wellknown technique independent from GPS. In this field, OP developed a full Ku-band two-way station with a dual offset antenna, active up/down-converters and a SATRE modem. The station, calibrated in relative mode in 2004, is officially used for TAI since January 2005. A complete uncertainty budget on the two-way measurement has been evaluated giving a combined uncertainty of only 1 ns. Moreover, the realization of a satellite simulator based on an original design [2] is in progress. Such a simulator will permit mainly an absolute difference delay calibration of a two-way station. During the Primary Frequency Standard comparison done in 2004 over 27-days measurement period, it was observed that H-Masers can be reached at only 0,6 d, with a σ x (τ) = 80 ps on the OP-PTB two-way link.

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Design of a KU Band Delay Difference Calibration Device for Twstft Station

Achkar¹

2004

2004 Conference on Precision Electromagnetic Measurements

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Development of a two way satellite time and frequency transfer station at BNM-SYRTE

Cited by 4 publications

References 1 publication

New TWSTFT link between LNE-SYRTE and NTSC in the Ku band

New TWSTFT link between LNE-SYRTE and NTSC in the Ku band

Recent time and frequency transfer activities at the Observatoire de Paris

Design of a KU Band Delay Difference Calibration Device for Twstft Station

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