by Staff Sgt. Robert Cloys
50th Space Wing Public Affairs
12/5/2012 - SCHRIEVER AIR FORCE BASE, Colo. -- After
nearly a decade of planning and development, the first of three
Rubidium Fountain Clocks arrived here Dec. 4 from the United States
Naval Observatory in Washington D.C.
The USNO houses the nation's most precise and stable time pieces for not
only the Department of Defense, but for the entire world. Atomic
measurements from clocks in the U.S. account for roughly 30% of the
composite clock used to calculate Coordinated Universal Time.
"The relationship between the USNO and the 2nd Space Operations squadron
is symbiotic," said Lt. Col. Thomas Ste Marie, 2 SOPS commander. "USNO
maintains Universal Time using a myriad composite of atomic clocks both
in Washington DC and here at Schriever AFB. In fact, each GPS satellite
and monitor station is a contributor to this composite clock. The GPS
constellation broadcasts that time to billions of users worldwide. It's
both this technical relationship and solid organizational partnership
that allows for continually record breaking time-transfer performance
and navigation accuracies."
Getting the new alternate master clock from a loading dock to its final
resting place in the master clock room here was no easy feat. In order
to minimize damage to the equipment the clock was floated, much like a
hovercraft, across a series of mats until it reached its final
destination. This form of movement was used in order to minimize any
potential damage to the components.
According to their website, the USNO is responsible for determining
precise time and managing the dissemination of that time. Modern
communications systems, such as the satellite-based Global Positioning
System, increasingly depend on precise time interval.
"This clock will be a component clock in our local mean, but it will do a
lot more than just that for the alternate master clock," said Jim
Skinner, USNO mathematician at Schriever. "It will give us a very stable
long term reference that we can use to compare to its brothers in
Washington via different forms of time transfer. That should help us
study seasonal and other effects in our various forms of time transfer
between USNO and AMC. In the long term allowing us to learn more about
how we are currently disseminating time to users."
GPS, used by millions across the globe, uses an internal timing system
derived from USNO clocks that steer its timing accuracy. Specifications
state that users must be able to obtain a time transfer accuracy to UTC
within 40 nanoseconds. According to Ste. Marie, the accuracy at
Schriever has routinely been below 4ns.
UTC is more accurate than man-made time based on the earth's rotation,
according to Chris Ekstrom, division chief for clock development at the
USNO in Washington D.C.
"The arrival of this clock marks a quantum leap in the accuracy of the
U.S. Naval Observatory's Alternate Master Clock, which continually
provides the world with precise timing via the Global Positioning
System," said Col. James Ross, 50th Space Wing commander. "We are
pleased to help our mission partners from USNO realize this significant
To call and hear the official time, dial 567-6742.