A redundant subspace weighting procedure for clock ensemble

Abstract

A redundant-subspace-weighting (RSW) based approach is proposed to enhance the frequency stability of the time scale of a clock ensemble. In this approach, multiple overlapping subspaces are constructed in the clock ensemble, and the weight attributed to each clock in this ensemble is defined using the spatial covariance matrix. Superimposition averaging of different subspace covariances somewhat reduces the correlations between clocks located in the same laboratory. After optimizing the parameters of this weighting procedure, the frequency stabilities of virtual clock ensembles are significantly improved in most cases.