APL Colloquium

January 20, 2006

Colloquium Topic: The Future of the UTC Time Scale

The International Telecommunications Union - Radio-communications Sector (ITU-R) formed a Special Rapporteur Group (SRG) on Coordinated Universal Time (UTC) in 2001 to consider possible changes to the time scale, such as discontinuing the Leap Second. Time-scale discontinuities caused by the introduction of leap seconds could create operational problems for some users. This consideration was a result of issues raised by ITU-R sector members and the Consultative Committee on Time and Frequency. Accordingly, a new Question, ITU-R 236/7 (2000) "The Future of the UTC Timescale", was released and a SRG was formed to focus studies investigating those issues and possible solutions. Major changes to the definition of the UTC timescale could have potentially significant impact on precise time distribution and network synchronization. UTC and it's adjustment by leap seconds was introduced by the ITU-R in 1972 as the means of coordinating time and frequency broadcast services throughout the world. UTC is created by adjusting International Atomic Time (TAI) by the appropriate number of leap seconds to maintain UTC within 0.9 seconds of Universal Time (UT1), the time determined by the rotation of the Earth. A principal rationale for this approach was to support wide availability of reference time for celestial navigation. UTC has since become the uniform time scale that is the basis of timekeeping for most civil, scientific and radio-communication systems in the world. The SRG has held coordination and technical exchange meetings to generate and discuss issues and alternatives to the currently defined leap second adjustment to UTC and the resultant implications for radiocommunication systems. The background, implications and related activities into a possible re-definition of the UTC time scale will be discussed.

Colloquium Speaker: Ron Beard

Mr. Ron Beard has a B.S. in physics (1967), McNeese State University in Louisiana and graduate work at GWU, Washington, D.C. A Naval Reserve Officer, he was Project Officer for Satellite Navigation, Astronautics Division, Naval Air Systems Command HQ (1968 - 1971). During this time he participated in the DDR&E Navigation Satellite Executive Steering Group established for development of advanced navigation satellite concepts. Upon separation from active duty in 1971, he began work with the U.S. Naval Research Laboratory in the TIMATION Project. During the early GPS development (1973-1979), he was in the NRL GPS Program Office that developed Navigation Technology Satellites One and Two and operated the first atomic clocks in space. From 1979-1983, he was the Deputy Project Manager for the Naval Space Surveillance System Modernization Program. In 1984, he became the Head of the Space Applications Branch and NRL GPS Clock Development Program Manager. He is a member of the Executive Steering Committee, Annual Precise Time and Time Interval (PTTI) Systems and Planning Conference, and served on a number of committees involved with advanced space technology, precise time and frequency and GPS. Notable participation includes U.S. representative to the NATO Working Group for Precise Time and Frequency Standards (AC/302-SG/4(WG/4)); chairman of the DoD Reliance Space Technology GNC sub-panel; ad hoc member USAF SAB study on Global Air Navigation Systems; and member of the NRAC summer study into Naval GPS Systems Vulnerability. He was a key participant in the NAVSEA Common Time Reference System Engineering Team and consulting with the Chief Engineer of the Navy on PNT systems architecture and the SIAP program office. He is the Navy member of Reliance Frequency Control Panel, Precise Time and Frequency committee of the DoD Militarily Critical Technology panel, vice-chairman of U.S. ITU-R Working Party Group 7A, Precise Time and Frequency Broadcast Services and Chair of the Special Rapporteur Group on the future of the UTC Time Scale. He is a member of Sigma Xi, the Institute of Navigation Satellite Navigation Section, American Geophysical Society, and American Institute of Aeronautics and Astronautics.