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The GOES Time Code Service, 1974 – 2004: A Retrospective



Michael A. Lombardi, D. W. Hanson


After nearly 30 years of continuous operation, NIST ended its Geostationary Operational Environmental Satellites (GOES) time code service at 0 hours, 0 minutes Coordinated Universal Time (UTC) on January 1, 2005. This event marked the end of an important chapter in the history of timekeeping. The GOES time code service is historically significant for at least two reasons: it was the first time code service ever broadcast via satellite; and the first time code service of any type that provided transmitter position data in addition to the time. The position data made it possible for receivers whose position was also known to compute and remove the signal path delay and improve the timing accuracy. NIST began preparing for the end of the GOES time code service in the mid-1990¿s, when it was clear that Global Positioning System (GPS) satellite timing receivers provided better accuracy and reliability that GOES at a lower cost. Nearly all GOES receivers were being replaced by GPS units, making the decision to eventually stop the service an easy one. However, during their heyday, GOES time code receivers were widely used by the electric power and aviation industries; and it is estimated that more than 10,000 receivers were sold, produced by at least three different manufacturers. This article provides a retrospective view of the GOES time code service, beginning with a look at the early days of radio time code broadcasts and the first satellite timing experiments.
Journal of Research (NIST JRES) -


broadcast services, satellites, time


Lombardi, M. and Hanson, D. (2005), The GOES Time Code Service, 1974 – 2004: A Retrospective, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 15, 2024)
Created February 27, 2005, Updated January 27, 2020