RESUMO
This article reviews the creation and technical evolution of atomic time scales. In particular, we focus our attention on the method of calculation and the characteristics of International Atomic Time (TAI), and show how it is disseminated at the ultimate level of precision.
Assuntos
Sistema Internacional de Unidades/normas , Internacionalidade , Oscilometria/normas , Fatores de Tempo , Padrões de ReferênciaRESUMO
A new algorithm for the clock frequency prediction used to calculate the Echelle Atomique Libre (EAL) is presented. The mathematical model adopted in the new prediction algorithm takes into account the effect of the frequency drift of the H-masers. We demonstrate that there is an improvement in long-term stability of EAL by using the new prediction algorithm.
Assuntos
Algoritmos , Sistemas de Informação Geográfica , Modelos Teóricos , Fatores de Tempo , Simulação por Computador , Sensibilidade e EspecificidadeRESUMO
We refine our estimate of the uncertainty in [UTC - UTC(k)] by taking into account the contribution of correlations between the links. Using a matrix formulation to facilitate computation, we re-analyze the link-based uncertainties and obtain the same solution as found previously. We then evaluate the site-based uncertainties and compare the results with the link-based uncertainties.
