BIPM TIME ACTIVITIES UPDATE

摘要

This paper describes BIPM time activities related to the calculation of international reference time scales: UTC and TAI. Monthly, TAI and UTC are computed from clock data (representing 350 clocks coming from 69 institutes) and time transfer data used to compare clocks. Results are published each month in BIPM Circular T. Due to the evolution of time transfer techniques and clock types, the process of evaluation of TAI has to be regularly updated with newer and better techniques to improve the frequency stability and the frequency accuracy of TAI. Part of the improvements concerns clock comparisons: 1. introduction of new time transfer technique as GPS PPP and GLONASS Common View, 2. creation of new statistical tools in order remove outliers in TWSTFT time links, making the best use of time transfer results, 3. another improvement is a study on clock frequency prediction in ALGOS, which deals with H-maser clock properties, in order to well understand their impact on generated time scales. This publication reports on the work of the whole staff of the BIPM dedicated to time activities.