TIME AND FREQUENCY ACTIVITIES AT THE

The Time and Frequency group at the National Physical Laboratory (NPL) maintains an active program of work in time and frequency metrology. This paper provides an overview of the group’s principal activities. These include the maintenance and development of the national time scale UTC (NPL), development of a cesium fountain primary frequency standard and research into cold-atom standards and techniques, time transfer activities, development of data analysis methods and clock algorithms, knowledge transfer activities, and the operation of services for time and frequency dissemination in the UK