Joint Metoc Handboo - IHMC Ontology and Policy Management

7-Navy
- Precise time--dissemination of USNO master clock time
> Two-Way Satellite Time Transfer (TWSTT): USNO time can be transferred to
users via geostationary communications satellites to an accuracy of 1
nanosecond
> Global Positioning System: UNSO time can be acquired from GPS satellites.
Precise Positioning Service (PPS) GPS timing receivers can receive time to an
accuracy of about 30 nanoseconds and Standard Positioning Service (SPS) GPS
timing receivers can receive time to an accuracy of about 200 nanoseconds,
provided the receivers have been calibrated and certified at USNO
> Network Time Protocol (NTP): USNO time can be acquired via the NIPRNET
and SIPRNET to an accuracy of about 10 milliseconds
> Time via telephone modem: USNO time can be acquired via telephone modem
to an accuracy of about 1/100 of a second
> Telephone time voice announcer: USNO time can be acquired via telephone
time announcer to an accuracy of about 1/10 of a second
> GPS Timing Receiver Calibration Service. The USNO will calibrate GPS
timing receivers (for a fee) to remove biases and put them on time with the
USNO Master Clock.
> USNO Master Clock time data and personnel contact information is available
on the Time Service website, http://tycho.usno.navy.mil
- Earth orientation
> International Earth Rotation Service (IERS) Bulletin A: reports of the latest
determinations and predictions for polar motion, UT1-UTC, and nutation
offsets at daily intervals are distributed twice weekly by email; subscription
form is available at http://maia.usno.navy.mil/
> Earth orientation files: updated daily and available by anonymous ftp; full
descriptions available at http://maia.usno.navy.mil
> Leap seconds: announcements made in IERS Bulletin C, available at
http://maia.usno.navy.mil
> DUT1: these course values for (UT1-UTC) are transmitted with timing signals
and announced in IERS Bulletin D, available at http://maia.usno.navy.mil
• Point of contact:
Scientific Director Address: US Naval Observatory
DSN: 762-1513
3450 Massachusetts Ave., NW
Secure: DSN 762-1513 Washington DC 20392-5420
Facsimile: DSN 762-1461 PLAD: NAVOBSY WASHINGTON DC//SD//
Email: johnston.kenneth@usno.navy.mil
7.4.2.2 Navy METOC Theater Products.
• Navy METOC Regional Centers, Facilities, and Detachments shown in Figure 25 can
provide some or all of the following products:
- Prog blends - charts and messages/bulletins that merge the various models to
determine the best regional forecast
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