A physically realized timescale combining five Cesium atomic clocks

Timescales are developed and maintained across various precise timing facilities for either metrological or navigation time-keeping. These timescales are generated using an ensemble of atomic clocks such as Cesium clocks and Active Hydrogen Masers (AHM). Theoretically, the ensemble output displays better frequency stability than any of the individual participating clocks. However, due to frequency corrections carried out during the physical realization of the same signal, the frequency stability is often not maintained. A timescale with an ensemble of five Cesium clocks was physically realized and compared to each of the participating clocks. It was observed that the ensemble output performs better than all the Cesium clocks and is close to its theoretical performance. The ensemble was implemented using the Kalman plus weights algorithm. In order to remove occasional spikes from the measurement data, an ARIMA (0, 1, 1) filter was used as a pre-filtering mechanism.