Redundancy and correlations in TAI time links

Abstract

The network of time links for the computation of TAI has always be chosen such as to allow a unique solution, i.e. not using any redundancy. In the present situation, many links can be computed with two or more techniques (mostly TW and GPS) and the TW network itself is highly redundant. In addition, the covariance matrix for the measurements from these two may now be determined with adequate uncertainty, so that it makes sense to use all the available information and to compute TAI links using the available redundant network. In the paper, we examine the formalism to be used in this aim and the consequences of using such a procedure