A simple computation technique for improving the short term stability and the robustness of GPS TAIP3 common-views

Rovera, Daniele; Chupin, Baptiste; Abgrall, M.; Uhrich, Pierre

doi:10.1109/eftf-ifc.2013.6702196

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…Time transfer between remote time scales is obtained by computing the CV differences between similar Common generic GNSS time transfer standard (CGGTTS) data recorded at the same epochs [2]. The data processing consists of removing outliers [3], in order to build a time difference mean value for each CGGTTS standard epoch. Another geodetic technique applied to time transfer between remote time scales, precise point positioning (PPP), as developed by National Resources Canada (NRCan) [4] among other groups, provides better short term stability because measurements are based on the phase of the carrier frequencies.…”

Section: Introductionmentioning

confidence: 99%

Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

et al. 2016

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This paper presents a direct comparison between two satellite time transfer techniques: common-view (CV) of satellites from the global positioning system (GPS) constellation, and time transfer by laser link (T2L2) through the low orbiting satellite Jason-2. We describe briefly both techniques, together with two independent relative calibration campaigns of the links involving four European laboratories. Between the same remote time scale reference points, the mean values of the calibrated differences between GPS CV and T2L2 are below 240 ps, with standard deviations below 500 ps, mostly due to GPS CV. Almost all sample deviations from 0 ns are within the combined uncertainty estimates. Despite the relatively small number of common points obtained, due to the fact that T2L2 is weather dependent, these results provide an unprecedented sub-ns consistency between two independently calibrated microwave and optical satellite time transfer techniques.

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Section: Introductionmentioning

confidence: 99%

Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

et al. 2016

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“…The most simple GNSS time transfer technique is CV between stations, which is commonly achieved between the SARAO and the NMISA, and was used in the previous section. Due to the MeerKAT's location, there is only a low number of GPS satellites in CV with the OP (and sometimes none), which leads to large noise and fluctuations in the CV 55,77,78 results. Therefore, time transfer based on the PPP processing developed by the National Resource Canada (NRCan) 35 was used.…”

Section: Calibration Against Op Reference Station Measurements With the Lne-syrte And Ppp Transfer With The Utc(op)mentioning

confidence: 99%

Design, implementation, and qualification of high-performance time and frequency reference for the MeerKAT telescope

Burger

Siebrits

Gamatham

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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The details of the MeerKAT radio telescope's time and frequency reference subsystem that enables sampling via low-jitter, low-drift microwave clock signals, and absolute timing (≤5 ns accurate) are discussed. The subsystem's microwave and pulse per second transmission parts are now fully qualified and commissioned for the ultra high frequency (UHF) and L-bands and also provide for a 100-MHz interface and timing interfaces for S-band receivers that were installed. The subsystem includes a cable measurement system called the Karoo array timing system (KATS). Performance and differences on different bands and seasonal drift of the cable delay measurement of KATS are reported. A time scale called the Karoo Telescope Time (KTT) (which is estimated from tracking a few atomic clocks via new software) and the issuing of timing bulletins to users have been largely implemented and verified. Absolute timing calibration and linkage of KTT to the global positioning system time scale and to different UTC(k) realizations of the Coordinated Universal Time (UTC) instances are described. The subsystem uniquely enables high-fidelity sampling and stable tied array configuration. The latter configuration enables timing and transient science over time spans of 5 to 10 years. Simultaneous subarraying is supported. The backend is unique for radio telescopes in terms of being very deterministic as far as timing is concerned.

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“…The right hand side provides the corresponding modified Allan deviations (MDEVs). The AV solutions are computed using a cleaning of outliers similar as proposed in [19] as well as an elevation dependent weighting as sin 2 (elevation). Furthermore, as there are gaps in the BeiDou solutions, the MDEVs were computed using the appropriate method for discontinuous data sampling as described in [20].…”

Section: Av From Single Constellationmentioning

confidence: 99%

Multi-GNSS time transfer based on the CGGTTS

Verhasselt¹,

Defraigne²

2019

Metrologia

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This paper studies the use of multiple GNSS constellations for time transfer. The performances of each constellation are compared to one another. We show that, with its current constellation, Galileo already provides time transfer results with the same or better performances than GPS, for which some time links are affected by a diurnal variation. The paper also investigates different ways of combining the constellations into one global time transfer solution. We show that in a global AV solution, only one constellation should be calibrated, due to the inherent intersystem biases in the multiGNSS clock products. Our results show that the best combination is to use the Galileo solution as a reference, and to combine the observations applying one bias (with respect to Galileo) per satellite of the other constellations. This allows reducing the impact of diurnal variations present in some GPS clock solutions. Combining Galileo and GPS satellites in this way improves the time transfer link with respect to the GPS only or Galileoonly solutions. Adding moreover BeiDou2 and GLONASS satellites gives, depending on the link, a solution similar or worse than the solution obtained from GPS and Galileo.

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A simple computation technique for improving the short term stability and the robustness of GPS TAIP3 common-views

Cited by 9 publications

References 3 publications

Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

Design, implementation, and qualification of high-performance time and frequency reference for the MeerKAT telescope

Multi-GNSS time transfer based on the CGGTTS

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