Time Realization and Distribution

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href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-realization/utcnist-time-scale-0" data-drupal-link-system-path="">UTC(NIST) Time Scale</a> </li> </ul> </li> </ul> </nav> </div>  </div> </aside> <div class="nist-page__region nist-page__region--content tablet-lg:grid-col-8 desktop-lg:grid-col-9"> <div class="nist-block"> <div class="paragraph paragraph--type--hero paragraph--view-mode--default"> <div class="nist-hero grid-row grid-gap-2"> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-realization/primary-standard-nist-f1"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/09/06/nistf1.webp?itok=LLdlJ3Lv 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2016/09/06/nistf1.webp?itok=3rN2FRyH 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2016/09/06/nistf1.webp?itok=SA7scv2j 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/09/06/nistf1.webp?itok=LLdlJ3Lv 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/09/06/nistf1.jpg?itok=LLdlJ3Lv 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2016/09/06/nistf1.jpg?itok=3rN2FRyH 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2016/09/06/nistf1.jpg?itok=SA7scv2j 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/09/06/nistf1.jpg?itok=LLdlJ3Lv 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/09/06/nistf1.jpg?itok=LLdlJ3Lv" width="600" height="360" alt="NIST-F1 Cesium Fountain Atomic Clock" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-realization/primary-standard-nist-f1"> <div class="text">NIST-F1 Atomic Clock</div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-realization/utcnist-time-scale-0"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/Time_Scale_Button2.webp?itok=cGsNaomC 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2020/10/22/Time_Scale_Button2.webp?itok=GRmGX0GR 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2020/10/22/Time_Scale_Button2.webp?itok=DMeYDK9A 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/Time_Scale_Button2.webp?itok=cGsNaomC 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/Time_Scale_Button2.jpg?itok=cGsNaomC 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2020/10/22/Time_Scale_Button2.jpg?itok=GRmGX0GR 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2020/10/22/Time_Scale_Button2.jpg?itok=DMeYDK9A 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/Time_Scale_Button2.jpg?itok=cGsNaomC 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/Time_Scale_Button2.jpg?itok=cGsNaomC" width="600" height="360" alt="time scales" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-realization/utcnist-time-scale-0"> <div class="text">UTC(NIST) Time Scale</div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-distribution/internet-time-service-its"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/NIST_ITS_Button.webp?itok=UPTp8pcG 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2020/10/22/NIST_ITS_Button.webp?itok=AYn_nHJM 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2020/10/22/NIST_ITS_Button.webp?itok=YGqwxoBl 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/NIST_ITS_Button.webp?itok=UPTp8pcG 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/NIST_ITS_Button.jpg?itok=UPTp8pcG 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2020/10/22/NIST_ITS_Button.jpg?itok=AYn_nHJM 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2020/10/22/NIST_ITS_Button.jpg?itok=YGqwxoBl 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/NIST_ITS_Button.jpg?itok=UPTp8pcG 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2020/10/22/NIST_ITS_Button.jpg?itok=UPTp8pcG" width="600" height="360" alt="Internet Time Service" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-distribution/internet-time-service-its"> <div class="text">Internet Time Service (ITS)</div> </a> </div> </div> </div> </div> </div> <div class="paragraph paragraph--type--hero paragraph--view-mode--default"> <div class="nist-hero grid-row grid-gap-2"> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwv"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/04/11/wwvbuilding_1.webp?itok=O9qnXd0d 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/04/11/wwvbuilding_1.webp?itok=Vqr4yfpu 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/04/11/wwvbuilding_1.webp?itok=-NT2hmRt 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/04/11/wwvbuilding_1.webp?itok=O9qnXd0d 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/04/11/wwvbuilding_1.jpg?itok=O9qnXd0d 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/04/11/wwvbuilding_1.jpg?itok=Vqr4yfpu 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/04/11/wwvbuilding_1.jpg?itok=-NT2hmRt 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/04/11/wwvbuilding_1.jpg?itok=O9qnXd0d 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/04/11/wwvbuilding_1.jpg?itok=O9qnXd0d" width="600" height="360" alt="WWV building" title="Radio Station WWV " typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwv"> <div class="text"><p>WWV</p> </div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwvb"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/18/ant2_6.webp?itok=sHXv1VaV 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/07/18/ant2_6.webp?itok=HevID_Q7 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/07/18/ant2_6.webp?itok=o-zilDmA 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/18/ant2_6.webp?itok=sHXv1VaV 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/18/ant2_6.jpg?itok=sHXv1VaV 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2018/07/18/ant2_6.jpg?itok=HevID_Q7 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2018/07/18/ant2_6.jpg?itok=o-zilDmA 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/18/ant2_6.jpg?itok=sHXv1VaV 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2018/07/18/ant2_6.jpg?itok=sHXv1VaV" width="600" height="360" alt="Image of WWVB radio antennas" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwvb"> <div class="text"><p>WWVB</p> </div> </a> </div> </div> </div> <div class="nist-hero__item tablet:grid-col-4 "> <div class="nist-hero__item-inner"> <div class="nist-hero__image"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwvh"> <picture> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/11/30/wwvhentrance.webp?itok=ybQQyVR6 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2016/11/30/wwvhentrance.webp?itok=UY7zfAxu 2x" media="(min-width: 480px)" type="image/webp" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2016/11/30/wwvhentrance.webp?itok=BXpzTCwl 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/11/30/wwvhentrance.webp?itok=ybQQyVR6 2x" media="(min-width: 0px)" type="image/webp" width="300" height="180"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/11/30/wwvhentrance.jpg?itok=ybQQyVR6 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/1200w_x_720h/public/images/2016/11/30/wwvhentrance.jpg?itok=UY7zfAxu 2x" media="(min-width: 480px)" type="image/jpeg" width="600" height="360"/> <source srcset="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/300w_x_180h/public/images/2016/11/30/wwvhentrance.jpg?itok=BXpzTCwl 1x, /web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/11/30/wwvhentrance.jpg?itok=ybQQyVR6 2x" media="(min-width: 0px)" type="image/jpeg" width="300" height="180"/> <img loading="eager" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/600w_x_360h/public/images/2016/11/30/wwvhentrance.jpg?itok=ybQQyVR6" width="600" height="360" alt="WWVH entrance" typeof="foaf:Image"/> </picture> </a> </div> <div class="nist-hero__caption"> <a href="/web/20230130210933/https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwvh"> <div class="text"><p>WWVH</p> </div> </a> </div> </div> </div> </div> </div> <div class="nist-content-row nist-content-row--width-legible paragraph paragraph--type--text paragraph--view-mode--default"> <div class="nist-block text-long"><p>UTC(NIST) is freely distributed to many millions of users through radio, Internet, and telephone links. The services that distribute UTC(NIST) include shortwave radio stations WWV and WWVH, low frequency radio station WWVB, the Internet Time Service (ITS), the Automated Computer Time Service (ACTS), the telephone time service, and the web clock (time.gov). These services synchronize hundreds of millions of clock every day.</p> <p>UTC(NIST) is also distributed through remote calibration services to paying customers who need the highest levels of accuracy. The demanding measurement needs of these customers are met through the Frequency Measurement and Analysis Service (FMAS) and the Time Measurement and Analysis Service (TMAS).</p> </div> </div> <div class="nist-content-row nist-content-row--width-legible paragraph paragraph--type--text paragraph--view-mode--default"> <div class="nist-block text-long"><div class="nist-callout"> <h2>Notice:</h2> <p>Beginning November 15, 2021, WWV and WWVH will be broadcasting a test signal on minute 8 of each hour on WWV, and minute 48 on WWVH. This signal has been created to assist in ionospheric research, and is a joint effort of the Ham Radio Citizen Science Investigation (HamSCI) and NIST. The signal consists of various tones, chirps, and Gaussian noise bursts. The signal may be modified occasionally. For more information on HamSCI and the WWV/WWVH project, <a data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="78cf6d91-56f1-4a3f-a757-1dff313f1ac9" href="/web/20230130210933/https://www.nist.gov/pml/time-and-frequency-division/time-services/wwvwwvh-scientific-modulation-working-group" title="WWV/WWVH Scientific Modulation Working Group">click here</a>.</p> </div></div> </div> <div class="nist-content-row nist-content-row--width-legible paragraph paragraph--type--text paragraph--view-mode--default"> <div class="nist-block text-long"><h2 class="nist-block__title">NBS/NIST Radio Stations: The Story of an Old Timer</h2> <div class="grid-row grid-gap"> <div class="grid-col-3"> <figure class="align-center nist-image"><img alt="NBS/DOC" height="257" loading="lazy" src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/480_x_480_limit/public/images/2017/02/27/nbs-commerce.jpg?itok=FSjn8Gn4" typeof="foaf:Image" width="480"><figcaption class="nist-image__caption"><div class="nist-image__caption-content" data-caption-editable="true"> </div> </figcaption></figure></div> <div class="grid-col-9"> <p>This <a href="https://web.archive.org/web/20230130210933/https://www.nist.gov/pml/nbsnist-radio-stations-story-old-timer">series of webpages</a> will lead you on a journey on the history of the NBS/NIST radio stations. You can watch a <a href="https://web.archive.org/web/20230130210933/https://www.nist.gov/video/nist-colloquium-nbsnist-radio-stations-story-old-timer">video</a> as well.</p> </div> </div></div> </div> <div class="paragraph paragraph--type--dynamic-content-list-ou paragraph--view-mode--default"> <div class="nist-block "> <h2 class="nist-block__title"> <div class="string">News and Updates</div> </h2> <div class="viewsreference"><div class="views-element-container"><div class="js-view-dom-id-d05e8ea012e30bc98e6b1058a38a474f7bb8d3023767e705718c64ac7d71bce6"> <div> <article role="article" about="/news-events/news/2021/11/nist-recommends-steps-boost-resilience-us-timekeeping" typeof="schema:Article" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/news-events/news/2021/11/nist-recommends-steps-boost-resilience-us-timekeeping" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2021/11/29/resilient_time_image_%28002%29.png?itok=6wlqig_f" width="100" height="32" alt="A small rectangular device with a display screen and buttons sits next to a spool of yellow fiber. " loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/news-events/news/2021/11/nist-recommends-steps-boost-resilience-us-timekeeping"><span property="schema:name">NIST Recommends Steps to Boost Resilience of U.S. Timekeeping</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2021-11-29T12:00:00Z">November 29, 2021</time> </div> </div> </header> <div class="nist-teaser__content"> <div property="schema:text" class="text-with-summary">The nation should bolster research and development of systems that distribute accurate time via fiber-optic cable and radio as part of the effort to back up GPS</div> </div> </div> </article> </div> <div> <article role="article" about="/news-events/news/2018/06/nist-atomic-clock-comparison-confirms-key-assumptions-einsteins-elevator" typeof="schema:Article" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/news-events/news/2018/06/nist-atomic-clock-comparison-confirms-key-assumptions-einsteins-elevator" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2018/05/31/18pml021_einstein-elevator-withtext-4000px-wide-hr.jpg?itok=d3ksi8Xf" width="88" height="100" alt="Cartoon with man standing on falling blue cube representing Earth, decorated with clumps of clock faces, with yellow sun at right." loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/news-events/news/2018/06/nist-atomic-clock-comparison-confirms-key-assumptions-einsteins-elevator"><span property="schema:name">NIST Atomic Clock Comparison Confirms Key Assumptions of ‘Einstein’s Elevator’</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2018-06-04T12:00:00Z">June 4, 2018</time> </div> </div> </header> <div class="nist-teaser__content"> <div property="schema:text" class="text-with-summary">By comparing different types of remote atomic clocks, physicists at the National Institute of Standards and Technology (NIST) have performed the most accurate</div> </div> </div> </article> </div> <div> <article role="article" about="/news-events/news/2017/11/nists-next-generation-atomic-clocks-may-support-official-timekeeping" typeof="schema:Article" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/news-events/news/2017/11/nists-next-generation-atomic-clocks-may-support-official-timekeeping" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2017/11/16/17pml022_levine-with-time-scale-by-j-burrus_175x170.jpg?itok=K_0prB5m" width="66" height="100" alt="Man with gray hair standing beside computer with digital clock display" loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/news-events/news/2017/11/nists-next-generation-atomic-clocks-may-support-official-timekeeping"><span property="schema:name">NIST’s Next-Generation Atomic Clocks May Support Official Timekeeping</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2017-11-16T12:00:00Z">November 16, 2017</time> </div> </div> </header> <div class="nist-teaser__content"> <div property="schema:text" class="text-with-summary">For more than a decade, the National Institute of Standards and Technology (NIST) has been unveiling experimental next-generation atomic clocks. These clocks</div> </div> </div> </article> </div> <footer> <div class="link-list"><a href="/web/20230130210933/https://www.nist.gov/news-events/news-updates/org/6601">View All News and Updates</a></div> </footer> </div> </div> </div> </div> </div> <div class="paragraph paragraph--type--dynamic-content-list-ou paragraph--view-mode--default"> <div class="nist-block "> <h2 class="nist-block__title"> <div class="string">Projects and Programs</div> </h2> <div class="viewsreference"><div class="views-element-container"><div class="js-view-dom-id-00c30139841e031519728d74f83dea58c3a441af03c7e78cc42abe9ab87bf28d"> <div> <article role="article" about="/programs-projects/frequency-measurement-and-analysis-service-fmas" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/programs-projects/frequency-measurement-and-analysis-service-fmas" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2016/08/30/nistfmas_1.jpg?itok=UyLlE4-2" width="100" height="78" alt="NIST FMAS" loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/programs-projects/frequency-measurement-and-analysis-service-fmas"><span>Frequency Measurement and Analysis Service (FMAS)</span> </a></h3> <div class="nist-teaser__type"> <div class="nist-badge display-inline-block margin-y-1 nist-badge--blue boolean">Ongoing</div> </div> </header> <div class="nist-teaser__content"> <div class="text-long"> The NIST Frequency Measurement and Analysis Service (FMAS) makes it easy to measure and calibrate any quartz, rubidium, cesium, or hydrogen maser frequency </div> </div> </div> </article> </div> <div> <article role="article" about="/programs-projects/time-measurement-and-analysis-service-tmas" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/programs-projects/time-measurement-and-analysis-service-tmas" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2017/12/08/nistdo_chassis.png?itok=4Ns8TBSa" width="100" height="55" alt="NIST disciplined clock chassis" loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/programs-projects/time-measurement-and-analysis-service-tmas"><span>Time Measurement and Analysis Service (TMAS)</span> </a></h3> <div class="nist-teaser__type"> <div class="nist-badge display-inline-block margin-y-1 nist-badge--blue boolean">Ongoing</div> </div> </header> <div class="nist-teaser__content"> <div class="text-long"> The NIST Time Measurement and Analysis Service (TMAS) was designed to serve any organization that is required to maintain an accurate local time standard. The </div> </div> </div> </article> </div> <footer> <div class="link-list"><a href="/web/20230130210933/https://www.nist.gov/laboratories/projects-programs/org/6601">View All Projects/Programs</a></div> </footer> </div> </div> </div> </div> </div> <div class="paragraph paragraph--type--dynamic-content-list-ou paragraph--view-mode--default"> <div class="nist-block "> <h2 class="nist-block__title"> <div class="string">Publications</div> </h2> <div class="viewsreference"><div class="views-element-container"><div class="js-view-dom-id-74f7819fdbca9623906119adaff648dcfc1e9243b474b549b95d3db88f15957c"> <div> <article role="article" about="/publications/multi-source-common-view-disciplined-clock-fail-safe-clock-critical-infrastructure" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/publications/multi-source-common-view-disciplined-clock-fail-safe-clock-critical-infrastructure"><span>Multi-Source Common-View Disciplined Clock: A Fail-Safe Clock for Critical Infrastructure Systems</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2022-01-10T12:00:00Z">January 10, 2022</time> </div> </div> <div class="nist-teaser__type"> <div class="nist-field nist-field--label-inline text-long"> <div class="nist-field__label">Author(s)</div> <div class="nist-field__item"><span class="nist-author">Michael A. Lombardi</span></div> </div> </div> </header> <div class="nist-teaser__content"> <div class="text-with-summary">The multi-source common-view disciplined clock (MSCVDC) is a recent NIST invention designed to support critical infrastructure timing systems that require a</div> </div> </div> </article> </div> <div> <article role="article" about="/publications/resilient-architecture-realization-and-distribution-coordinated-universal-time-critical" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/publications/resilient-architecture-realization-and-distribution-coordinated-universal-time-critical"><span>A Resilient Architecture for the Realization and Distribution of Coordinated Universal Time to Critical Infrastructure Systems in the United States: Methodologies and Recommendations from the National Institute of Standards and Technology (NIST)</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2021-11-03T12:00:00Z">November 3, 2021</time> </div> </div> <div class="nist-teaser__type"> <div class="nist-field nist-field--label-inline text-long"> <div class="nist-field__label">Author(s)</div> <div class="nist-field__item"><span class="nist-author">Jeffrey Sherman</span>, <span class="nist-author">Ladan Arissian</span>, <span class="nist-author">Roger Brown</span>, <span class="nist-author">Matthew J. Deutch</span>, <span class="nist-author">Elizabeth Donley</span>, <span class="nist-author">Vladislav Gerginov</span>, <span class="nist-author">Judah Levine</span>, <span class="nist-author">Glenn Nelson</span>, <span class="nist-author">Andrew Novick</span>, <span class="nist-author">Bijunath Patla</span>, <span class="nist-author">Tom Parker</span>, <span class="nist-author">Benjamin Stuhl</span>, <span class="nist-author">Jian Yao</span>, <span class="nist-author">William Yates</span>, <span class="nist-author">Michael A. Lombardi</span>, Victor Zhang, Douglas Sutton</div> </div> </div> </header> <div class="nist-teaser__content"> <div class="text-with-summary">The Time and Frequency Division of the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce (DOC), was</div> </div> </div> </article> </div> <div> <article role="article" about="/publications/evaluation-dependencies-critical-infrastructure-timing-systems-global-positioning" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/publications/evaluation-dependencies-critical-infrastructure-timing-systems-global-positioning"><span>An Evaluation of Dependencies of Critical Infrastructure Timing Systems on the Global Positioning System (GPS)</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2021-11-01T12:00:00Z">November 1, 2021</time> </div> </div> <div class="nist-teaser__type"> <div class="nist-field nist-field--label-inline text-long"> <div class="nist-field__label">Author(s)</div> <div class="nist-field__item"><span class="nist-author">Michael A. Lombardi</span></div> </div> </div> </header> <div class="nist-teaser__content"> <div class="text-with-summary">Accurate and reliable time signals are an essential part of critical infrastructure systems in the United States. Because these systems often cannot function</div> </div> </div> </article> </div> <div> <article role="article" about="/publications/century-wwv-100th-anniversary-commemoration" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/publications/century-wwv-100th-anniversary-commemoration"><span>A Century of WWV: 100th Anniversary Commemoration</span> </a></h3> <div class="nist-teaser__date"> <div class="daterange"><time datetime="2019-09-24T12:00:00Z">September 24, 2019</time> </div> </div> <div class="nist-teaser__type"> <div class="nist-field nist-field--label-inline text-long"> <div class="nist-field__label">Author(s)</div> <div class="nist-field__item"><span class="nist-author">Glenn K. Nelson</span></div> </div> </div> </header> <div class="nist-teaser__content"> <div class="text-with-summary">WWV was established as a radio station on October 1, 1919 with the issuance of the call letters by the U.S. Department of Commerce. This paper will observe the</div> </div> </div> </article> </div> <footer> <div class="link-list"><a href="/web/20230130210933/https://www.nist.gov/publications/search/all">View All Publications</a></div> </footer> </div> </div> </div> </div> </div> <div class="paragraph paragraph--type--dynamic-content-list-ou paragraph--view-mode--default"> <div class="nist-block "> <h2 class="nist-block__title"> <div class="string">Awards</div> </h2> <div class="viewsreference"><div class="views-element-container"><div class="js-view-dom-id-ade98055d4cd78d36a9f8f898047cf9913415a74b1478c09cd3f0f4011ee3e15"> <div> <article role="article" about="/awards/distinguished-ptti-service-award-michael-lombardi" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/awards/distinguished-ptti-service-award-michael-lombardi"><span>Distinguished PTTI Service Award - Michael A. Lombardi</span> </a></h3> </header> <div class="nist-teaser__content"> <div class="text-long">Mr. Lombardi was recognized for system development and leadership in the successful delivery of the U.S. time and frequency standards</div> </div> </div> </article> </div> <div> <article role="article" about="/nist-awards/2020-edward-uhler-condon-award-glenn-nelson" class="nist-teaser"> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/nist-awards/2020-edward-uhler-condon-award-glenn-nelson"><span>2020 - Edward Uhler Condon Award---Glenn Nelson</span> </a></h3> </header> <div class="nist-teaser__content"> <div class="string-long">For his exemplary historical review article commemorating the 100th anniversary of NIST radio station WWV.</div> </div> </div> </article> </div> <div> <article role="article" about="/awards/2019-distinguished-associate-award-jian-yao" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/awards/2019-distinguished-associate-award-jian-yao" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/2020/06/22/JianYaoPhoto%20-%20Copy.png?itok=1ER5fZCU" width="79" height="100" alt="Jian Yao" loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/awards/2019-distinguished-associate-award-jian-yao"><span>2019 Distinguished Associate Award - Jian Yao</span> </a></h3> </header> <div class="nist-teaser__content"> <div class="text-long">For creating and networking the world's best optical atomic clocks for a 100-fold improvement in precision timekeeping over state of the art</div> </div> </div> </article> </div> <div> <article role="article" about="/nist-awards/2019-gold-medal-award-kyle-beloy-david-hume-david-leibrandt-andrew-ludlow-nathan-newbury" class="nist-teaser"> <div class="nist-teaser__image"> <div class="entity-reference"> <a href="/web/20230130210933/https://www.nist.gov/nist-awards/2019-gold-medal-award-kyle-beloy-david-hume-david-leibrandt-andrew-ludlow-nathan-newbury" hreflang="en"><img src="/web/20230130210933im_/https://www.nist.gov/sites/default/files/styles/thumbnail/public/images/annual_award/219gold-backrowshermanbeloyhumenewburyludlowfrontrowleibrandtsinclairuncropped2web0000_0.jpg?itok=0oPwBJDL" width="100" height="80" alt="Back Row: Sherman, Beloy, Swann, Hume, Newbury, Ludlow Front Row: Leibrandt, Sinclair" loading="lazy" typeof="foaf:Image"/> </a> </div> </div> <div class="nist-teaser__content-wrapper"> <header> <h3 class="nist-teaser__title"><a href="/web/20230130210933/https://www.nist.gov/nist-awards/2019-gold-medal-award-kyle-beloy-david-hume-david-leibrandt-andrew-ludlow-nathan-newbury"><span>2019 - Gold Medal Award---Kyle Beloy, David Hume, David Leibrandt, Andrew Ludlow, Nathan Newbury, Jeffrey Sherman, Laura Sinclair, William Swann, Jun Ye</span> </a></h3> </header> <div class="nist-teaser__content"> <div class="string-long">For creating and networking the world's best optical atomic clocks for a 100-fold improvement in precision timekeeping over the state of the art. </div> </div> </div> </article> </div> <footer> <div class="link-list"><a href="/web/20230130210933/https://www.nist.gov/awards/org/6601">View All Awards</a></div> </footer> </div> </div> </div> </div> </div> </div> </div> </div> </div> <div class="grid-row"> <div class="nist-resource-block nist-resource-block--first tablet:grid-col"> <div class="nist-resource-block__title-bar"> <div class="nist-resource-block__title"> <div class="nist-resource-block__icon"> <img aria-hidden="true" role="img" alt="decorative icon" src="/web/20230130210933im_/https://www.nist.gov/themes/custom/nist_www/img/resource-icons/link-icon-2x.png"/> </div> <h2> <div class="string">SIM Time Scale</div> </h2> </div> </div> <div class="nist-resource-block__content"> <div class="nist-block"> <div class="text-long"><p>To support time and frequency metrology throughout the Americas, the Sistema Interamericano de Metrologia (SIM) Time and Frequency Metrology Working Group (TFMWG) maintains the SIM time scale (SIMT), the first continuously maintained multi-national ensemble time scale that is generated and published in real time (updated every hour). 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