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NOAA Polar Satellites - Level 1B Clock Drift Corrections , 30 October 2002 - Issued: 29 October 2002; 1730 UTC

Topic:
Level 1B Clock Drift Corrections

Date/Time(UTC) Message Issued:
29 October 2002; 1730 UTC

Satellite(s) Involved:
NOAA-11, 14, 15, 16, and 17

Instrument(s) Involved:
All

Product(s) Involved/Affected:
All data users

Date/Time(UTC) of Initial Implementation:
30 October 2002 1600 UTC

Details/Specifics of Change:
The Satellite Operations Control Center (SOCC) is performing daily clock
drift corrections at 23:59:00 UTC for each satellite as indicated below.
Under this notice, the Information Processing Division is adjusting level
1B clock corrections to reflect the daily SOCC updates. SOCC plans to
remove residual errors some time in the near future. Users will be notified
when this occurs. The user should see an improvement in the accuracy of the
current earth locations beginning with the orbits given below. Although the
clock drift file was updated for NOAA-17, Level 1B clock corrections are not
turned on for this spacecraft. The user should not see a change for
NOAA-17.

The first orbits to be processed after the change are:
NOAA-11:
NSS.TIPS.NH.D02303.S1449.E1839.B7271214.GC

NOAA-14:
NSS.HRPT.NJ.D02303.S1640.E1654.B4038181.GC
NSS.TIPS.NJ.D02303.S1135.E1525.B4037880.GC

NOAA-15:
NSS.GHRR.NK.D02303.S1303.E1459.B2320001.GC
NSS.HRPT.NK.D02303.S1806.E1820.B2320303.GC

NOAA-16:
NSS.HRPT.NL.D02303.S1756.E1811.B1085252.WI
NSS.GHRR.NL.D02303.S1445.E1640.B1085051.WI
NSS.LHRR.NL.D02303.S1716.E1722.B1085151.WI

NOAA-17 (No changes should be seen):
NSS.HRPT.NM.D02303.S1857.E1907.B0182121.GC
NSS.GHRR.NM.D02303.S1533.E1728.B0181920.GC

On October 24, SOCC reported the following errors for each satellite. TIP
clock error data for NOAA-12, NOAA-14, NOAA-15, NOAA-16 and NOAA-17 are
from the new system for tracking time offset (not NOAA-11). The IPD clock
drift files have been updated to properly reflect these errors and the new
SOCC daily updates.
NOAA-11 -1457 msec
NOAA-12 +246 msec (No level 1B or clock drift file update for this
notice)
NOAA-14 +147 msec
NOAA-15 +272 msec
NOAA-16 -041 msec
NOAA-17 +046 msec (No level 1B update for this notice; clock drift file
update performed)

NOAA-14: As of 07/23/02 the TIP clock is corrected daily by 8 msec to
compensate for drift.
NOAA-15: As of 08/27/02 the TIP clock is corrected daily by -7.7 msec to
compensate for drift.
NOAA-16: As of 08/27/02 the TIP clock is corrected daily by -4.6 msec to
compensate for drift.
NOAA-17: As of 08/27/02 the TIP clock is corrected daily by +0.6 msec to
compensate for drift.
NOAA-11: As of 09/03/02 the TIP clock is corrected daily by +70 msec to
compensate for drift.

Contact Person(s) Name/Email/Phone Number for Questions:
Emily D. Harrod/Emily.Harrod@noaa.gov/301-457-5247 ext 117

Web site(s) that contain other relevant information (where applicable):
http://www.oso.noaa.gov/daily-news/index.htm - SOCC morning reports
http://www.osdpd.noaa.gov/PSB/PPP/PPP.html - History of level 1B
notices
http://www.ssd.noaa.gov/PS/SATS/messages.html - All user notices


ppp@nesdis.noaa.gov

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