Monitoring of the offset between UTC and its prediction broadcast by the GNSS

Abstract

We present a new approach to report in the Section 4 of BIPM Circular T daily values of the offset between UTC and the predictions of UTC broadcast by the GNSS, this quantity we name bUTC_GNSS. In this approach, the determination of UTC - bUTC_GNSS is based on data collected by several multi-GNSS stations in selected time laboratories worldwide. Test computations over a 7-month period from July 2022 to January 2023 show that the offset between UTC and bUTCGNSS was between 30 and 50 ns for GLONASS, between 5 and 20 ns for BeiDou, and between -5 and +5 ns for GPS and Galileo. We derive the uncertainty on the reported values, which is 4.1 ns for BeiDou and GPS, 3.7 ns for Galileo and 6.6 ns for GLONASS and show that, over the test period, the reported values of UTC-bUTC_GNSS and the solutions obtained from each multi-GNSS station are all consistent within the 1-sigma uncertainties.

News from the BIPM laboratories—2023

“…Comparisons involving pure (or almost pure) beta-emitting, electron-capture-decaying or some alpha-emitting radionuclides will be performed with the ESIR, which is a recently developed instrument based on a liquid-scintillation counting technique (the triple-to-double coincidence ratio method). After validating the ESIR against the reference SIR in a pilot study using the 60 Co radionuclide and the participation of 13 NMIs/DIs [30], a list of eleven radionuclides, validated by the Consultative Committee for Ionizing Radiation (CCRI), has been defined to open the ESIR (BIPM.RI(II)-K5) comparison service in 2024.…”

“…(2) Section 4 of Circular T, which contains information on the prediction of UTC broadcast by GNSS, will be updated to include the services by Galileo and Beidou, together with the existing GPS and GLONASS. The set up and the algorithm for this evaluation has been completely modernized [60].…”