Abstract: This paper proposes a method of establishing a time reference without a free paper time scale. The core idea is predicting and steering each atomic clock versus external reference time scale, respectively.Each clock can obtain a time scale steered by the external reference time scale. Then, the time reference is a weighted average of the steered time scales. The new method avoids the problems resulting from the correlation of the paper time scale and the time difference of each contributing clocks of traditional methods. Moreover, prediction algorithms and steering algorithms can be optimized according to different clocks with different characteristics, respectively. At the beginning, this paper briefly describes the basic principles of traditional methods and their weaknesses. Then, the basic principle, the theoretical advantages and the design principles of the prediction algorithm, steering algorithm and weighting algorithm of the new method are described in detail. An experiment shows the weakness of traditional methods. A simulation shows the traditional method and new method performances, and also preliminarily validates the excellent performances of this method.

Key words: time reference, atomic clock, free paper time scale, prediction, steering, weight