An Introduction to Modern Timekeeping and Time Transfer

Dr. Parameswar Banerjee received his undergraduate degree from the University of Calcutta and his Ph.D from the University of Burdwan.  He joined National Physical Laboratory, India (NPLI) in 1976, where for thirty five years he worked on circuit design, satellite communication, time measurement, GNSS time transfer, and timescales. The patents he secured for designing NPLI’s digital telephone service have been licensed to four different manufacturers. He served as Acting Director of NPLI for a few months, and in 2008 he became head of the Electrical and Electronics Standards Division.After retirement he became a professor at Amity University and a visiting researcher at Burdwan University, supervising many undergraduate and PhD students while also developing curricula and chairing academic committees. He has organized many international conferences and served as a member or chair of numerous scientific committees.  Frequently asked to review articles for technical journals, he is currently associate editor for the Radio Science Bulletin and on the board of the International Journal of Metrology and Quality Engineering. He is a Senior Member of Institute of Electrical and Electronics Engineers (IEEE) and a Fellow of the Institution of Electronics and Telecommunication Engineers (IETE), the Metrology Society of India (MSI), the International Union of Radio Science (URSI), and the Institution of Engineering and Technology (IET). He has published more than 100 papers, given more than 60 invited talks, presented 90 conference papers, and holds 7 patents.  He has received the Union of Radio Scientists (URSI) Young Scientist Award, the 2006 IETE Hari Ramji Toshniwal Gold Medal, and the Lifetime Achievement Award from the SKF Group of Institutes. Dr. Demetrios Matsakis grew up in St. Louis, received a BS in physics from MIT, and a PhD in physics from UC Berkeley, where he studied under Nobel Laureate Charles Townes.  He then worked for 40 years at the U.S. Naval Observatory (USNO), where he at first used radio interferometry and built water-vapor radiometers to measure the variable rotation of the Earth.  In 1989 he was asked to work part-time on a mercury stored-ion clock.  In 1997 he became director of the USNO’s Time Service department, and 16 years later he became Chief Scientist. Now a consultant, he has worked on the faculty of Virginia Tech on finding better methods to predict the Earth’s rotation, and on Kalman filter theory.    As Chief Scientist for Masterclock he advises on and tests new products, writes a blog, and otherwise remains active in the timekeeping community.  Frequently asked to review articles for technical journals, he is also a special editor for the GPS Solutions topical collection on timekeeping. He has participated in or chaired numerous national and international committees and working groups, served for three years as president of the International Astronomical Union’s Time Commission (#31), and represented the USA in Paris and Geneva.   He has published over 160 scientific papers covering most aspects of timekeeping including Earth rotation, timescales, pulsars, and time-transfer.  He holds one patent and published five science fiction short stories.  In 1996 he received the USNO’s Newcomb award, the highest internal award for science research, and in 2023 he was given the Institute of Navigation’s PTTI Distinguished Service Award.

Time and Its Definition.- Pre-Atomic Timekeeping.- Introduction of Atomic Clock.- Frequency Stability.- Time and Frequency Measurements.- Early Time Transfer Modes.