Kalman filter approaches for a mixed clock ensemble

Clock ensembling is a promising concept for future time scale generation as robustness and stability can be considerably improved compared to master clock approaches. While ensembles consisting of the same clock types were already demonstrated to improve robustness of the generated time scale, ensembles using different clock types can clearly benefit from the advantages of the individual single clocks contributing to the time generation process. In particular, the performance of the ensemble time can be improved over a wide range of averaging times by combining clocks exhibiting superior stabilities for distinct time scales. In future, this approach could be used to integrate newly developed clock types such as e.g. optical clocks into a clock ensemble