Department of Defense master clock

The Department of Defense master clock is the atomic master clock to which time and frequency measurements for the United States Department of Defense are referenced.

Naval Observatory master clock is designated as the "DOD Master Clock".

The other standard time and frequency reference for the U.S. Government is the National Institute of Standards and Technology (NIST) master clock.

Naval Observatory also maintains an alternate clock designated "USNO Alternate Master Clock" at Schriever Space Force Base, Colorado.

[2] This article incorporates public domain material from Federal Standard 1037C.

The master atomic clock ensemble at the U.S. Naval Observatory in Washington D.C. , which provides the time standard for the U.S. Department of Defense. [ 1 ] The rack mounted units in the background are caesium beam clocks. The black units in the foreground are hydrogen maser standards.