Time and Frequency Services:
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 intended outcome of this program is the reliable delivery of
frequency-reference and time-reference signals to the United States to support
industry, trade, science, and the general public. The telephone system, the
Internet, radio broadcasts, and satellites are all used to deliver these
signals. We serve a broad range of systems in business, telecommunications,
science, transportation, and radio/TV broadcasting.
The Division provides timing broadcasts from stations WWV and WWVB in Fort
Collins, Colorado, and from WWVH in Hawaii. WWVB has a broadcast power of
50 kW. It is substantially more useful for mobile and consumer
applications because the antenna/receiver cost and size are very small.
We also operate telephone-based and Internet-based time services. We provide a
telephone audio service and a modem-based Automated Computer Time Service (ACTS).
On the Internet, our 14 servers at 11 sites respond to all three
common transaction protocols. Usage now exceeds one billion transactions daily.
Industrial calibration laboratories are served by the Division's Frequency
Measurement Service, a system that provides these laboratories with continuous
assurance of the accuracy of their frequency measurements. The most demanding
applications are served by the Division's Global Time Service, which uses GPS
common-view time transfer to deliver to the user's site a timing reference
close in accuracy to that of the NIST time scale.
To enhance U.S. expertise in this field, the Division offers a variety of
training courses. A 3  day
metrology seminar is offered annually, and we co-sponsor an annual workshop on
synchronization in telecommunications systems. Additionally, NIST staff members
teach courses at conferences.
Accomplishments
NIST Internet Time Service
This service continues to grow rapidly and is approaching a usage level of
1 billion hits per day. Downloads of the instruction files for setting up
a users’ computer are averaging 100,000 per month. Conservative estimates of the
total number of users range as high as 50 million.
Efforts continue toward finding ways in which this service might be operated
commercially. However, the lack of a means for efficiently collecting service
fees for delivery of a few bytes of transmission serves as a stumbling block.
To deal with this continued growth, we initiated two new projects this year.
The first involves the use of switches (routers) that will be used to
load-balance among the 14 time servers, since some servers are near
saturation while others are experiencing only modest use. Four switches were
purchased and successfully tested. They will be installed soon.
Figure 4. Growth in use of the NIST Internet Time Service. |
The second project, which is only now getting started, is to implement an
encrypted time-delivery system through one or more of the servers, using a
concept we developed and patented. The objective is to provide the means for
secure delivery of time signals to systems operated by industry.
The hope is that there will be a gradual growth of commercial delivery of time
signals by companies that are targeting specific market sectors. At this point,
we are working with several companies that are interested in delivering time
services to financial traders.
WWVB Time Broadcasts
Recognizing that there has been a tremendous expansion in the number of
consumer products based on the WWVB time broadcasts, we made a variety of
improvements to the broadcast systems during the last year. These were made as
part of a long-term plan to assure continuity of operation of this service.
New insulators were installed at the ground level of all of the guy wires
supporting the eight antenna towers. These insulators are designed to be
fail-safe and retain their mechanical integrity even if the insulator should
break. This will prevent the sort of tower damage experienced several years ago
when one of the guy-wire supports failed completely due to an insulator failure.
These caused substantial damage to the tower.
A secure climbing line was added to each of the 120 m towers to comply
with OSHA tower-safety requirements. Not only will this assure climbing safety,
but it will also speed maintenance and repair activities.
Figure 5. An aerial view of the WWVB antenna systems. |
The old tower beacons were replaced with new FAA-approved beacons to improve
the visibility of the beacons to low-flying aircraft. We plan to repaint the
towers in the FAA-approved manner to assure good visibility to aircraft during
daylight hours.
Finally, we designed a field-strength meter for the 60 kHz signal and
contracted to have a number of these produced for field monitoring purposes.
These will be placed at various locations around the country to continuously
monitor signal strength. The field-strength information will be fed
periodically to the station website for use by WWVB product manufacturers and
their their customers.
First strategic focus |
Second strategic focus |
Third strategic focus |
Fourth strategic focus
"Technical Activities 2002" - Table of Contents |
