The Time Validation Facility (TVF): An all-new key element of the Galileo operational phase

Piriz, R.; Rodríguez, D.; Roldan, P.; Mudrak, A.; Bauch, A.; Riedel, Franziska; Staliuniene, Egle; Galindo, J.; Esteban, H.; Sesia, I.; Cerretto, Giancarlo; Jaldehag, Kenneth; Rieck, Carsten; Uhrich, Pierre; Rovera, Daniele

doi:10.1109/fcs.2015.7138851

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…GST follows GPS in the week numbering and in the format of reporting the predicted offset between GST and a prediction of UTC. Publications from an earlier phase of the development of Galileo describe the architecture and achieved performances (Píriz et al 2015a, Galluzzo et al 2018) in some detail. In the meantime, however, contractual responsibilities and technical implementation have significantly changed.…”

Section: Using Galileo Signals As Time and Frequency Referencementioning

confidence: 99%

On the possibility of getting traceable time and frequency measurements via GNSS receivers

et al. 2020

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The realization of Coordinated Universal Time, one of the tasks of the International Bureau of Weights and Measures, relies on a network of international time links which currently is organized in a star-like scheme that links all contributing laboratories. GPS signal reception is the technique most widely employed by the laboratories. The PTB currently plays a unique role in the process due to its function as the central pivot in the time transfer between the participating laboratories. We discuss how the PTB meets its obligations to the international timekeeping community as well as to its users in Germany. In its role as an National Metrology Institute (NMI), PTB is entrusted with the realization and dissemination of legal time in Germany. The services were offered to the public support measurements and timing applications traceable to the national and international standards to be made in calibration laboratories and in many industrial sectors. We thus discuss the meaning and definition of traceability, how different GNSS systems can be used to establish traceability and their performance in doing so.

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Section: Using Galileo Signals As Time and Frequency Referencementioning

confidence: 99%

On the possibility of getting traceable time and frequency measurements via GNSS receivers

et al. 2020

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“…For GPS, this reference is UTC(USNO), while for BeiDou it corresponds to UTC(NTSC). Galileo is a special case in this context; instead of using a single UTC(k) realization, it is monitored against a blend of five timing laboratories, including UTC(IT), UTC(PTB), UTC(OP), UTC(ROA), and UTC(SP) (Piriz et al 2015). The notation for the Galileo UTC reference is henceforward set to UTC[GAL], with the square brackets highlighting its relation to the UTC realization of more than a single laboratory.…”

Section: Utc Time Offsetsmentioning

confidence: 99%

UTC and GNSS system time access using PPP with broadcast ephemerides

et al. 2022

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The application of precise point positioning with broadcast ephemerides (PPP-BCE) is discussed as an alternative to the established all-in-view technique for multi-GNSS time transfer. It combines the use of broadcast ephemerides with low-noise carrier-phase observations for accessing GNSS system time scales and Coordinated Universal Time (UTC) with improved precision, and can be employed on stationary as well as mobile receivers in offline or real-time analyses. Using calibrated timing receivers, the method is shown to provide estimates of the GNSS-to-GNSS time offsets (XYTOs) with an accuracy at the 2 ns level. In the absence of prior calibrations, 0.5 ns consistency across different stations is achieved for GPS, Galileo, and BeiDou-3 after adjustment of systematic biases in comparison with calibrated reference stations or broadcast XYTO values. Furthermore, access to GNSS-specific UTC realizations can be obtained through predictions of the UTC offset from GNSS system time as provided in the broadcast ephemerides of individual constellations. The overall quality of the PPP-BCE-derived receiver clock offsets from UTC is assessed using calibrated receivers at various timing laboratories along with BIPM-provided UTC-UTC(k) measurements. Over the 1.5 years covered in the study, an accuracy of 1.8 ns for GPS and 2.5 ns for Galileo is demonstrated. For BeiDou, a slightly worse accuracy of 3 ns is obtained for a single timing laboratory over 9 months.

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“…The calibration of the GPS chain of the receiver was carried out by Observatoire de Paris (OP-SYRTE) during a calibration campaign carried out in 2014 in the frame of the TVF activities [4], and involving also the receiver of the first PTF at Fucino, Italy (PTF1), and the receivers at the five UTC(k) laboratories participating in the TVF [5].…”

Section: The Receiversmentioning

confidence: 99%

Relative Calibration of Galileo receivers within the Time Validation Facility (TVF)

Piriz

Rodríguez

Roldan

et al. 2015

2015 Joint Conference of the IEEE International Frequency Control Symposium &Amp; The European Frequency and Time Forum

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GMV is the prime contractor for the Time and Geodetic Validation Facility (TGVF) in the Galileo FOC phase (Full Operational Capability), a contract of the European Space Agency (ESA). Within the TGVF, the Time Validation Facility (TVF) is the subsystem in charge of steering Galileo System Time (GST) to UTC, among other duties. The TVF is operated at GMV headquarters near Madrid, Spain. Calibrated Galileo receivers are needed in the frame of TVF activities to, among other tasks, assess the UTC-GST offset broadcast in the Galileo navigation message.Absolute receiver calibration is a complex activity involving the availability of a signal simulator and of a calibrated reference antenna. An alternative data-based method to evaluate the Galileo receiver delay in E5 signals relative to GPS is also possible. The key feature of such method is the cancellation of the GPS and Galileo ionospheric delays when combining pseudoranges from two satellites with a close position in the sky.A software tool called gecal has been developed by GMV within the Galileo TVF, implementing such method and processing RINEX 3 observation files. Satellite positions are read from a SP3 orbit file. The tool allows the rapid E5 calibration of a new or existing Galileo receiver. This paper describes the tool and the calibration of three Galileo receivers used in the TVF. Galileo Signal-In-Space validation results obtained using such receivers are also presented.

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The Time Validation Facility (TVF): An all-new key element of the Galileo operational phase

Cited by 8 publications

References 3 publications

On the possibility of getting traceable time and frequency measurements via GNSS receivers

On the possibility of getting traceable time and frequency measurements via GNSS receivers

UTC and GNSS system time access using PPP with broadcast ephemerides

Relative Calibration of Galileo receivers within the Time Validation Facility (TVF)

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