GPS link calibrations in support of CCTF-K001.UTC
Project Description
CCTF 2009 passed Recommendation 2 which states that BIPM will continue to study the characterization of GNSS equipment in use for establishing the time links between institutes contributing with their clocks to TAI. BIPM will concentrate on some selected laboratories world-wide. The RMOs are requested to support this activity by organisation of calibration campaigns linking institutes whose equipment has been or will be characterized by BIPM with other institutes.
It is planned to:
- identify current needs of EURAMET laboratories,
- identify suitable equipment,
- organise bilateral or multilateral campaigns of visits with one laboratory acting as the pilot, and
- report results to BIPM in a format which shall be developed in joint work of members of the CCTF WG on the MRA, and BIPM.
Progress Report 2024-03-25
In addition to former progress reports, ROA has conducted the next calibration campaign during 2023:
- Cal_Id=1016-2023: IFS (Zagreb, Croatia) and BIM (Sofia, Bulgary)
Similarly, PTB has undertaken next calibration campaigns:
- Cal_Id=1019-2023: VTT (Espoo, Finland)
- Cal_Id=1020-2023: LT - FTMC (Vilnius, Lithuania)
In addition, LNE-SYRTE (OP) has undertaken the next calibration campaign:
- Cal_Id=1014-2023: ILNAS (Luxembourg)
- Cal_Id=1017-2023: ORB (Belgique)
The calibration campaigns were carried out in differential mode with closure, where the travelling system served as a transfer between all systems visited during the trip and the reference receiver. They were labelled with a calibration identifier (Cal_ID) to enable the process yielding the results to be traced. The Cal_ID is used to report calibration information in Section 5 of Circular T, and the results are available on the BIPM website:
https://webtai.bipm.org/database/calib.html
Progress Report 2024-03-07
Carmen Vélez López has taken over the coordination of this project from Héctor Esteban (ROA).
Progress Report 2023-03-20
In addition to former progress reports, ROA has conducted the next calibration campaign during 2022:
- Cal_Id=1017-2022: DFM (Horsholm, Denmark)
Similarly, PTB has undertaken next calibration campaigns:
- Cal_Id=1021-2021: MBM (Montenegro, Podgorica), completed
- Cal_Id=1201-2022: NSC IM (Kharkiv, Ukraine), on site calibration at PTB, completed
- Cal_Id=1013-2022: IMBH (Sarajevo, Bosnia and Herzegovina)
- Cal_Id=1014-2022: ESTEC (Noordwijk, The Netherlands)
In addition, LNE-SYRTE (OP) has undertaken the next calibration campaign:
- Cal_Id=1018-2022: INRIM (Torino, Italy), RISE (Boras, Sweden)The calibration campaigns were carried out in differential mode with closure, where the travelling system served as a transfer between all systems visited during the trip and the reference receiver. They were labelled with a calibration identifier (Cal_ID) to enable the process yielding the results to be traced. The Cal_ID is used to report calibration information in Section 5 of Circular T, and the results are available on the BIPM website:
BIPM Time Dept database
Progress Report 2022-03-18
Since its beginning in the year 2011, ROA has supported the coordination of the EURAMET TC-TF Project 1156, to study the characterisation of GNSS equipment of the contributing institutes to TAI. Starting that year, a GPS calibration campaign was organised between three contributing laboratories: ROA (Spain), PTB (Germany) and INRIM (Italy). The time transfer results were achieved by using the P3 method and the carrier phase PPP comparison techniques.
The GPS calibration was carried out in differential mode or link calibration, where the GPS units involved in each lab and the travelling receiver were operated using common clock signals over a near zero baseline.
During 2011 and 2012, the campaign was repeated, and in 2012 two other laboratories were included in the calibration trip: NPL (United Kingdom) and OP (France).
In 2014, as a result of the CCTF recommendation of collaboration between the BIPM and the RMOs for GNSS equipment calibration, some National Metrology Institutes (NMIs) and Designated Institutes (DIs), were selected to be Group 1 (G1) laboratories, to function as regional nodes for the GPS calibrations. The mission of these Laboratories, once calibrated by BIPM, were to perform and lead new calibration campaigns between Group 2 (G2) laboratories, under the responsibility of RMOs.
PTB, OP and ROA are the only G1 laboratories in Europe. Since then, ROA has conducted several GPS G1 to G2 calibration campaigns in the frame of the EURAMET 1156 Project, involving some G2 laboratories (other NMI, DI or research institutes, non G1 laboratories, irrespective of their nature):
- Cal_Id=1011-2016: BIM (Bulgaria), DMDM (Serbia), IMBH (Bosnia & Herzegovina), UME (Turkey), BOM (FYR Macedonia), INRIM
- Cal_Id=1014-2017: NPL, SMD (Belgium)
- Cal_Id=1020-2017: SASO (Saudi Arabia)
- Cal_Id=1101-2017: JV (Norway), calibration on site at ROA
- Cal_Id=1015-2019: NPL, UFE (Czech Republic)
- Cal_Id=1201-2020: SMD, on site calibration at ROA
From this calibration onwards, whenever measurements have been available, receivers’ internal delays for GPS (C1, P1, P2) and Galileo (E1, E5a) code signals are provided.
- Cal_Id=1017-2021: IPQ
- Cal_Id=1018-2021: NPL
Similarly, PTB has undertaken several campaigns since 2016:
- Cal_Id=1012-2016: DLR, METAS, BEV, VSL
- Cal_Id=1019-2016: ESTEC
- Cal_Id=1015-2017: DTAG
- Cal_Id=1016-2017: BKG (Geodetic Obs. Wettzell, IFAG)
- Cal_Id=1102-2017: UFE
- Cal_Id=1014-2018: FTMC, GUM, AOS
- Cal_Id=1018-2018: NMISA
- Cal_Id=1011-2019: IMBH
- Cal_Id=1012-2019: DTAG
- Cal_Id=1013-2019: NMIB, SIQ
- Cal_Id=1016-2019: MIKE
- Cal_Id=1011-2020: ORB- Cal_Id=1013-2020: ESTEC
- Cal_Id=1014-2020: IFAG
- Cal_Id=1201-2021: JV, on site calibration at PTB
- Cal_Id=1011-2021: INRIM
- Cal_Id=1013-2021: UFE, VSL
- Cal_Id=1016-2021: DLR, BEV
- Cal_Id=1019-2021: EMI (United Arab Emirates)
- Cal_ID=1021-2021: MBM (Montenegro, Podgorica), ongoing
- Cal_ID=1201-2022: Ukraine, on site calibration at PTB, ongoing
In addition, LNE-SYRTE (OP) has undertaken several calibration campaigns since 2016:
- CAL_Id=1101-2016: CNES (French space agency)
- CAL_Id=1013-2016: INRIM, SP
- CAL_Id=1018-2017: ORB
- 2017: LNE-LTFB (in the context of French metrology for accredited laboratories)
- CAL_Id=1015-2018: CNES
- CAL_Id=1012-2018: LUX
- CAL_Id=1014-2019: INRIM, RISE
- CAL_Id=1012-2021: CNES, ILNAS (Luxembourg)
The calibration campaigns were carried out in differential mode with closure, where the travelling system served as a transfer between all systems visited during the trip and the reference receiver. They were labelled with a calibration identifier (Cal_ID) to enable the process yielding the results to be traced. The Cal_ID is used to report calibration information in Section 5 of Circular T, and the results are available on the BIPM website:
https://webtai.bipm.org/database/calib.html
Progress Report 2019-09-30
Since its beginning in the year 2011, ROA has supported the coordination of the EURAMET TC-TF Project 1156, to study the characterisation of GNSS equipment of the contributing institutes to TAI. Starting that year, a GPS calibration campaign was organized between three contributing laboratories: ROA (Spain), PTB (Germany) and INRIM (Italy). The time transfer results were achieved by using the P3 method and the carrier phase PPP comparison techniques.
The GPS calibration was carried out in differential mode or link calibration, where the GPS units involved in each lab and the travelling receiver were operated using common clock signals over a near zero baseline.
During 2011 and 2012, the campaign was repeated, and in 2012 two other laboratories were included in the calibration trip: NPL (United Kingdom) and OP (France).
In 2014, as a result of the CCTF recommendation of collaboration between the BIPM and the RMOs for GNSS equipment calibration, some National Metrology Institutes (NMIs) and Designated Institutes (DIs), were selected to be Group 1 (G1) laboratories, to function as regional nodes for the GPS calibrations. The mission of these Laboratories, once calibrated by BIPM, were to perform and lead new calibration campaigns between Group 2 (G2) laboratories, under the responsibility of RMOs.
PTB, OP and ROA are the only G1 laboratories in Europe. Since then, ROA has conducted several GPS G1 to G2 calibration campaigns in the frame of the EURAMET 1156 Project, involving some G2 laboratories (other NMI, DI or research institutes, non G1 laboratories, irrespective of their nature):
- Cal_Id=1011-2016: ROA, BIM (Bulgaria), DMDM (Serbia), IMBH (Bosnia & Herzegovina), UME (Turkey), BOM (FYR Macedonia), INRIM
- Cal_Id=1014-2017: ROA, NPL, SMD (Belgium)
- Cal_Id= 1020-2017: ROA, SASO (Saudi Arabia)
- Cal_Id= 1101-2017: JV (Norway)
- Cal_Id= 1015-2019: NPL, UFE (Czech Republic) – (ongoing)
Similarly, PTB has undertaken several campaigns since 2016:
- CAL_Id=1012_2016: DLR, METAS, BEV, VSL
- CAL_Id= 019_2016: ESTEC
- CAL_Id=1015_2017: DTAG
- CAL_Id=1016_2017: BKG (Geodetic Obs. Wettzell, IFAG)
- CAL_Id=1102_2017: UFE
- CAL_Id=1014_2018: FTMC, GUM, AOS
- CAL_Id=1018_2018: NMISA
- CAL_Id=1011_2019: IMBH
- CAL_Id=1012_2019: DTAG (ongoing)
- CAL_Id_1013_2019: NMIB, SIQ (scheduled start late September 2019)
In addition, LNE-SYRTE (OP) has undertaken several calibration campaigns since 2016:
- CAL_Id =1101-2016: CNES
- CAL_Id=1013-2016: INRIM, SP
- CAL_Id=1018-2017: ORB
- 2017: LNE-LTFB (in the context of French metrology for accredited laboratories)
- CAL_Id=1015-2018: CNES
- CAL_Id=1012-2018: LUX
- CAL_Id=1014-2019: INRIM, RISE (in progress)
LNE-SYRTE is grateful to PTB and ROA for having taken the largest part of the EURAMET G1/G2 calibrations over this period.
The calibration campaigns were carried out in differential mode with closure, where the travelling system served as a transfer between all systems visited during the trip and the reference receiver. They were labelled with a calibration identifier (Cal_ID) to enable the process yielding the results to be traced. The Cal_ID is used to report calibration information in Section 5 of Circular T, and the results are available on the BIPM website (via the "Current files" tab):