NOAA-14, 16, 17 daily clock drift error corrections >
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 Topic:
    Spacecraft Clock  and Daily ETCUP Updates

Date/Time(UTC) Message Issued:
    18 December 2003, Time 2315 UTC

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

Instrument(s) Involved:
     All

Product(s) Involved/Affected:
     AVHRR/possible effect on imagery (pointing precision)

Date/Time(UTC) of Initial Implementation:
    23 December 2003, Time 1736 UTC

Details/Specifics of Change:
SOCC has announced their plans to perform spacecraft elapsed time clock updates 
and daily ETCUP updates on December 23 to compensate for clock drift.  Updates 
will be performed as follows:

NOAA-16  - subtract 100 milliseconds (ms) from  non-control CPU clock around 
2200 UTC; subtract 100 ms from control  CPU clock around 2330 UTC;  change 
daily ETCUP bias to -5.5 ms around 2359 UTC.

NOAA-17  - subtract 100 milliseconds (ms) from  non-control CPU clock around 
2200 UTC; subtract 100 ms from control  CPU clock around 2330 UTC;  change 
daily ETCUP bias to -3 ms around 2359 UTC.

NOAA-14  - subtract 50 milliseconds (ms) from  control CPU clock around 2200 
UTC;  change daily ETCUP bias to -7 ms around 2300 UTC. 
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Posted to NOAASIS on 19 December 2003.