Calibrated PPP time transfer among time scales generated at Time and Frequency Laboratories

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Hollie Summers
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1 Calibrated PPP time transfer among time scales generated at Time and Frequency Laboratories Alejandro Ceballos + #, Ricardo Piriz*, David Calle*, Giancarlo Cerretto + ([email protected]) + Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy # Politecnico di Torino, Italy * GMV, Madrid, Spain 1

Outline Introduction Objective and context of the proposed analysis magicppp evaluation for Time and Frequency Transfer (TFT) applications Proposing a way to calibrate uncalibrated geodetic estimates

2 Outline Introduction Objective and context of the proposed analysis magicppp evaluation for Time and Frequency Transfer (TFT) applications Proposing a way to calibrate uncalibrated geodetic estimates applying for calibration campaign HW estimated delays; PPP with IGS products and comparison with other TFT techniques; PPP with IGS and GMV regional/global ODTS products comparison; Time Transfer experiment with Galileo. Conclusions 2

for calibration campaign HW estimated delays; PPP with IGS products and comparison with other TFT

Introduction -In time metrology, different techniques can be involved for the time transfer, basically TWSTFT (Two Way Satellite Time and Frequency Transfer), GPS CV (Common View) and GPS AV (All in

3 Introduction -In time metrology, different techniques can be involved for the time transfer, basically TWSTFT (Two Way Satellite Time and Frequency Transfer), GPS CV (Common View) and GPS AV (All in View). -In recent years, many national timing laboratories have collocated geodetic GPS receivers together with their traditional GPS/GLONASS CV/AV receivers and TWSTFT equipments. -CCTF, at its 17th meeting in September 2006, passed a recommendation Concerning the use of Global Navigation Satellite System (GNSS) carrier phase techniques for time and frequency transfer in International Atomic Time (TAI). -Several works have been performed in order to evaluate the time and frequency transfer capabilities of PPP, leading the BIPM to start to regarly compute TAI links, providing a much improved statistical uncertainty. The PPP algorithm used for the BIPM TAI link computation has been developed by the Natural Resources Canada (NRCan). 3

-CCTF, at its 17th meeting in September 2006, passed a recommendation Concerning the use of Global Navigation Satellite System (GNSS) carrier phase techniques for time and frequency transfer in

Objective and context of the proposed analysis (1/2) - To synchronize and monitor atomic clocks and UTC(k) time scales collocated at different Time and Frequency Laboratories, connected to geodetic

4 Objective and context of the proposed analysis (1/2) - To synchronize and monitor atomic clocks and UTC(k) time scales collocated at different Time and Frequency Laboratories, connected to geodetic GNSS stations and contributing to BIPM TAI computations with the GMV magicgnss PPP algorithm/tool; - To propose a formal procedure to calibrate un-calibrated geodetic estimates (through a.atx like file, i.e..clx ) -To evaluate the magicppp tool for time and frequency transfer applications, in terms of comparison with other techniques/estimates: - Time Transfer experiment with Galileo IOV satellites (GPS only, GPS+GALILEO and GALILEO only modes comparison). 4

5 Objective and context of the proposed analysis (2/2) IGS GMV PPP GMV ODTS Sat orbit/clocks (final products/high latency) Sat orbit/clocks (global/regional network-reduced latency) Stations clocks Stations clocks Stations clocks Time and Frequency Transfer Evaluation Facility IT-PTB (IENG-PTBB) / IT-USNO (IENG-USN3) (May 2013) TWSTFT BIPM Circ. T BIPM UTCr Calibration Delays (.clx) Time links ( baseline ) 5

Stations clocks Stations clocks Time and Frequency Transfer Evaluation Facility IT-PTB (IENG-PTBB) /

6 ODTS network(s) Global Network (56 globally distributed IGS stations) Regional Network (8 stations colocated at NMI Active Hydrogen Maser based): 30 minutes latency. 6

7 Calibration delays A.atx like file proposed to report station delays (.clx file) 7

8 PPP with IGS products and comparison with other TFT techniques (1/7) 8

9 PPP with IGS products and comparison with other TFT techniques (2/7) 9

10 PPP with IGS products and comparison with other TFT techniques (3/7) 10

11 PPP with IGS products and comparison with other TFT techniques (4/7) 11

12 PPP with IGS products and comparison with other TFT techniques (5/7) 12

13 PPP with IGS products and comparison with other TFT techniques (6/7) 13

14 PPP with IGS products and comparison with other TFT techniques (7/7) 14

15 PPP with IGS and GMV regional/global ODTS products comparison (1/4) 15

16 PPP with IGS and GMV regional/global ODTS products comparison (2/4) 16

17 PPP with IGS and GMV regional/global ODTS products comparison (3/4) 17

18 PPP with IGS and GMV regional/global ODTS products comparison (4/4) 18

19 Time Transfer experiment with Galileo 19

Conclusions Evaluation of GMV PPP calibrated estimates for Time (and frequency) Transfer applications; Comparison with other techniques used in timing community; Dependency on network size and

20 Conclusions Evaluation of GMV PPP calibrated estimates for Time (and frequency) Transfer applications; Comparison with other techniques used in timing community; Dependency on network size and distribution products (satellites orbits and clocks) is evaluated; First experiment with Galileo measurements; GMV PPP is providing results comparable with other geodetic tools in an easy way, coping with Time and Frequency Laboratories needs, in terms of monitoring of their atomic clocks and time scales with a reduced latency (through the use of magicgnss ODTS satellite orbits/clocks products). 20

measurements; GMV PPP is providing results comparable with other geodetic tools in an easy way, coping with Time and Frequency Laboratories needs,

International time scales Atomic standards

International time scales Atomic standards E.F. Arias International Committee for GNSS, 2 nd Meeting Meeting of GNSS experts Bangalore, 5 September 2007 OUTLINE International coordination for metrology;