Download or read book Time and Frequency Activities at the U S Naval Observatory written by and published by . This book was released on 2002 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Naval Observatory "USNO" has provided timing for the Navy and the Department of Defense since 1830 and, in cooperation with other institutions, has also provided timing for the United States and the international community. Its Master Clock "MC" is the source of UTC "USNO", which has stayed within 5 ns of UTC in the past year, with an rms deviation of 3 ns. The data used to generate UTC "USNO" are based upon 72 HP5071 cesium and 18 hydrogen maser frequency standards in three buildings at two sites. The USNO disseminates time via voice, telephone modem LORAN, Network Time Protocol "NTP", GPS and Two-Way Satellite Time Transfer "TWSTT". The USNO would not be able to meet all the requirements of its users had it kept to the same technology it had 10 years ago; this paper will describe some of the changes being made to meet the anticipated needs of our users. While we aim to increase our accuracy and precision, we deem it equally important to bring about robustness, and we recommend this for our users as well.
Download or read book Report on the Time and Frequency Activities of the Time Service Department of the U S Naval Observatory written by and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost every aspect of USNO operations is being upgraded with a view to improving the stability and robustness of our Master Clock. One important motivation for this effort is the projected requirements of many real-time users, the best known among them being GPS.
Download or read book The Naval Observatory Time Service written by United States Naval Observatory and published by . This book was released on 1950 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directorate of Time United States Naval Observatory written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces the Directorate of Time, located at the United States Naval Observatory (USNO) in Washington, DC. Highlights USNO's role as the official source of time used in the United States. Links to: history and organization of the Directorate of Time, the National Earth Orientation Service (NEOS), the Time Scales Division, the USNO Master Clock, Automated Data Service, and an anonymous ftp server.
Download or read book Network Time Synchronization Servers at the U S Naval Observatory written by Richard E. Schmidt and published by . This book was released on 1995 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Responding to an increased demand for reliable, accurate time on the Internet and Milnet, the U.S. Naval Observatory Time Service has established the network time servers, tick.usno.navy.mil and tock.usno.navy.mil. The system clocks of these HP9000/747i industrial work stations are synchronized to within a few tens of microseconds of USNO Master Clock 2 using VMEbus IRIG-B interfaces. Redundant time code is available from a VMEbus GPS receiver. UTC(USNO) is provided over the network via a number of protocols, including the Network Time Protocol (NTP) (DARPA Network Working Group Report RFC-1305), the Daytime Protocol (RFC-867), and the Time protocol (RFC-868). Access to USNO network time services is presently open and unrestricted. An overview of USNO time services and results of LAN and WAN time synchronization tests will be presented.
Download or read book Time Service of the U S Naval Observatory Washington written by Albertson Van Zo Post and published by . This book was released on 1888 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Determination of Universal Time at the U S Naval Observatory written by Dennis D. McCarthy and published by . This book was released on 1976 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directorate of Time written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the Directorate of Time at the U.S. Naval Observatory (USNO) in Washington, D.C. Notes that the Directorate is the official source of time used in the United States. Describes U.S. Naval Observatory timekeeping, which is based on an ensemble of cesium beam and hydrogen master atomic clocks. Includes a brief history of timekeeping at the USNO and information on the National Earth Orientation Service, Time Service Department (Time Scales Division), network time services, and the Time Service Substation (Florida).
Download or read book Time Service of the U S Naval Observatory written by Julius Frederick Hellweg and published by . This book was released on 1932* with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reflections on Ten Years of Network Time Service written by and published by . This book was released on 2005 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The year 2004 marks the 10th anniversary since the start of U.S. Naval Observatory (USNO) time dissemination on the Internet using the Network Time Protocol (NTP). In 1994, our service was inauspicious: two 50MHz/32MB servers on a 56kb WAN link handling one packet every 17 seconds. Today, three servers in Washington, D.C., process over five thousand packets per second from millions of clients across the U.S. and 63 other nations. At the USNO Alternate Master Clock at Schriever AFB, Colorado, two additional servers provide NTP. Seventeen USNO servers with embedded GPS provide U.S. regional coverage from Alaska to Hawaii, from Washington state to Florida, from southern California to Maine. For the past 6 years, USNO has provided time service on the SIPRNET from Washington, D.C., and Schriever AFB. SIPRNET timing will soon expand with remote SAASM GPS servers. Throughout its history USNO, with the assistance of cooperating agencies, has provided free public time dissemination, from time balls to telegraphic time, wireless broadcasts, telephone time, LORAN, GPS, and Internet time. NTP is lightweight, reliable, accurate, and robust. Freely distributed, it has been ported to numerous devices and operating systems. The architecture of NTP is permanently in evolutionary development and in remote system maintenance.
Download or read book The U S Naval Observatory Clock Time Reference and the Performance of a Sample of Atomic Clocks written by Gernot M. R. Winkler and published by . This book was released on 1970 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Naval Observatory (USNO) uses clock averaging of about 16 selected cesium beam clocks for the derivation of an extremely uniform clock time scale. Frequency stabilities of better than 2 x 10 to the minus 14th power for very long intervals are being achieved together with utmost reliability of the time scale. Individual clocks differ widely in their performance and are carefully selected for service in the USNO clock time scale. In this set which is selected according to frequency stability, the standard deviation of a clock's average frequency difference from the mean is 1.7 x 10 to the minus 12th power, the standard deviation of the uncorrected ensemble mean frequency is 4.4 x 10 to the minus 13th power. The day to day frequency variation of individual clocks is 2.2 x 10 to the minus 13th power (rms) and the best clock observed had a frequency stability of 3 x 10 to the minus 14th power for 40 day averaging.
Download or read book The Naval Observatory Time Service and how to Use Its Radio Signals written by J. L. Jayne and published by . This book was released on 1913 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 100 Years of Precise Time written by Whitney H. Treseder and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Naval Observatory written by Gustavus Adolphus Weber and published by . This book was released on 1926 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synopsis of the Report of the Superintendent of the United States Naval Observatory written by United States Naval Observatory and published by . This book was released on 1884 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Series 1 written by United States Naval Observatory. Time Service Division and published by . This book was released on 1976* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harvard College Observatory Time Service Record Book written by Harvard College Observatory and published by . This book was released on 1885 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The record book contains a daily log of the operational status of the Harvard College Observatory Time Service, with a focus on the state and maintenance of telegraph lines and equipment. Handwritten entries are in pen and were composed in a ruled, paginated book. Only pages three through twelve contain entries, pages thirteen through 216 are empty.
