to develop and
operate the frequency and
time services essential for
synchronizing important
industrial/commercial operations
and supporting trade
and commerce.
INTENDED OUTCOME AND
BACKGROUND
The Division provides continuous, reliable, time and frequency signals in a wide variety of formats and accuracies to meet diverse needs of U.S.
industry, trade, science, and the general public. NIST time and frequency information is distributed over the Internet, by radio broadcasts, over
telephone lines, and through satellites to serve customers in finance, telecommunications, science, transportation, radio/TV broadcasting, and
other businesses—and as a reliable and convenient source of official U.S. time for the general public.
NIST radio stations WWV in Ft. Collins, Colorado and WWVH in Kauai, Hawaii broadcast shortwave radio signals containing a rich variety of time and
frequency information, in the form of verbal announcements, tones, and digital time codes. NIST radio station WWVB in Ft. Collins, Colorado broadcasts
a low-frequency (60 kHz) digital time code that automatically sets consumer timepieces to official U.S. time and date, automatically correcting for
daylight saving time, leap years, and leap seconds.
NIST’s most heavily used service is the Internet Time Service (ITS), automatically setting
clocks in computers and networked devices to NIST time. The Division also provides the modem-based Automated Computer Time Service (ACTS) to set
computer and network device time. Many ACTS customers need the security of a direct connection to NIST to ensure that the time is legally traceable
to NIST and is auditable. For example, the fNational Association of Securities Dealers (NASD) requires its 600,000 members to time-stamp many billions
of dollars of electronic transactions each business day against NIST time.
IThe Frequency Measurement and Analysis Service (FMAS) and the Time Measurement land Analysis Service (TMAS) serve industrial and research customers who need tight traceability to NIST time and frequency standards. These customers receive continu-ous, real-time NIST traceability through a highly automated system remotely monitored by NIST, receiving NIST standards by
comparison
to GPS broadcasts. The Division has developed similar technology to enable coordination of time scales among nine national timing laboratories in
North America, Central America, and South America, with additional laboratories scheduled to join the network in future years. The low-cost,
user-friendly systems allow laboratories with limited technical and financial resources to synchronize their time scales to low uncertainties
previously available only to the most advanced timing centers.
To enhance U.S. expertise in this field, the Division offers a variety of training courses. A four-day metrology seminar with more than 20 expert
instructors is offered annually, a new three-day seminar has been initiated for entry-level time and frequency metrologists, and we cosponsor an
annual workshop on synchronization in telecommunications systems. NIST staff members also teach about
20 courses per year on special topics in time and frequency measurement at conferences and on-site at NIST.
Accomplishments
NIST Internet Time Service (ITS)
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Figure 3. Growth in use of the NIST InternetTime Service.
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Fourteen ITS servers at eleven locations across the Nation respond to more than two billion requests per day (as of late 2007) or setting computer and
network clocks to NIST time, automatically. (See Fig. 3.) The Division website provides free client software, complete source code, and complete
instructions (about 100,000 downloads per month). Automatic synchronization to TS is now a capability of the most popular computer operating systems,
including the atest versions of Windows, Mac OS, and many commercial versions of Linux.
The Division continually updates the
servers, software, and network infrastructure,
working with the NIST networking
group, to ensure continued
provision of ITS in light of increasing demands.
A number of companies have partnered with NIST to add traceability and audit-ability to ITS for timestamping electronic documents and financial
transactions. These applications are in rather limited use now, but are growing rapidly.
NIST Radio Stations WWV,
WWVH, and WWVB
The Division continues to upgrade the radio stations as part of a long-term modernization plan. Progress includes continuing improvements to WWV and
WWVB transmitters and broadcast systems, including systems to ensure automatic recovery from power failures or loss of primary transmitters,
replacement of WWVH (Hawaii) metal antenna towers with fiberglass towers to eliminate corrosion damage, and upgrading insulators in the guy wires
supporting the eight 122 m (400 ft) towers for the WWVB antennas (Fig. 4).
© Photo Works, Louisville, Colorado
Figure 4. An aerial view of the WWVB antenna systems. |
More than 50 manufacturers produce
WWVB-controlled timepieces, with several
million new units sold each year.
With growing sales, both manufacturers
and consumers want to know that
WWVB signal strength is sufficiently
strong across the Nation to ensure good
reception. We designed a monitor system
to measure received power from
WWVB broadcasts, and several of these
systems were constructed on contract.
We plan to place them at strategic locations
around the U.S. Through an
Internet connection, each will continuously
report back the WWVB signal
strength to the Division. The results will
be displayed on a publicly available website,
along with archives of all signal strength records.
We have been actively consulting with
WWVB-controlled timepiece manufacturers
to improve their product performance.
The monitoring data will help
manufacturers set performance specifications
for real-world signal strengths.
Consumers can also consult the website
to determine if problems with their
timepieces result from inadequate
WWVB signals or, as is almost always
the case, from problems with the timepiece itself.
The Division is publishing a "Recommended Practices for
Manufacturers and Consumers of WWVB Radio Controlled Clocks"
guide, developed in consultation with
manufacturers and enthusiast user
groups, which suggests practices to
ensure optimal timepiece performance.
First strategic focus |
Second strategic focus |
Third strategic focus |
Fourth strategic focus
"Technical Activities 2005-2007" - Table of Contents |
