Reconstruction of UTC (NIM)

NIM has reconstructed UTC (NIM) since 2010 at new campus, and the official UTC (NIM) was switched to the new campus in October 2012. The new clock ensemble includes 6 Hydrogen masers and 7 Cesium clocks, with 1 Hydrogen maser and 2 Cesium clocks placed at the old campus. The master clock is a Hydrogen maser at new campus, and UTC (NIM) is generated from a micro phase stepper steered by a new algorithm and UTC, the frequency of the Hydrogen maser is predicted and rapid UTC data is used to steer UTC (NIM). A dual mixer time difference measurement system is used to measure the time difference between the clocks and UTC (NIM) at new campus, the clocks at old campus are linked to UTC (NIM) by GPS. GPS and TWSTFT data are reported to BIPM everyday automatically. The GPS receivers at new campus are calibrated with reference to one GPS receiver calibrated by BIPM. The UTC (NIM) has been operated normally at new campus; the accuracy and stability are improved. In this paper the generation of new UTC (NIM) is described and the performance of UTC (NIM) is presented.