Abstract:Hydrogen maser and cesium atomic clock are the mainly precise frequency sources which can produce the international atomic time and national standard time. They have excellent features of shortterm and longterm stability. How to make full use of the shortterm stability of hydrogen maser and the longterm stability of cesium clock has become a key technology during the process of time generation. To improve the longterm and shortterm stability of the time scale, a method for generating the fusion time of hydrogen maser and cesium clock using VondarkCepek combined filtering is proposed. Firstly, AT1 method is used to generate a clock ensemble time scale for hydrogen masers and cesium clocks, respectively. Then, the key parameters of VondarkCepek combined filter are selected according to the least square principle. In further, the performance of the time scale of cesium clock ensemble is enhanced by the differential information of the time scale of hydrogen maser ensemble. In this way, the fused time scale of hydrogencesium is obtained. The calculation results show that the 1hour stability of the time scale is 336×10-15 and the 15day stability is 3×10-15. These results are better than the performance of single time scale of single cesium clock or single hydrogen maser in the same average time.