From:
4:30 PM
Subject: NOAA-12, All Instruments, Flight Software Patch, 1 October 2003 - Issued: 29 September 2003; 2030 UTC
Resent-From: nesdis.osdpd.ipd.Level-1B.notices@noaa.gov,
nesdis.osdpd.ipd.contractors@noaa.gov
Topic:
Flight Software Patch to Correct Gyro Control
Date/Time(UTC) Message Issued:
29 September 2003, 2030 UTC
Satellite(s) Involved:
NOAA-12
Instrument(s) Involved:
All
Product(s) Involved/Affected:
All products
Date/Time(UTC) of Initial Implementation:
1 October 2003, Time 2015 UTC
Details/Specifics of Change:
On October 1, orbit 64329 around 1729 UTC, SOCC will load a Flight Software
(FSW) patch to disable yaw updates and restore the use of X-gyro and
previously known yaw bias. This is necessary to correct the problem that
originally was detected on September 12, when SOCC reported the following:
"On :rev 64060 / W at 1954z on September 12: Telemetry data indicated that
on Friday (JD255) at 08:15z N-12 autonomously switched from NOMINAL to yaw
gyro compassing (YGC) mode. The switch was due to a bad yaw update reading
taken during the time when there was shading on the sun sensor assembly
(SSA). The gyro selection also changed from the orthogonal set (XYZ) to
the SYZ (the skew gyro was switched in for the X-yaw gyro). The anomaly was
detected on the first taken contact of the day on Friday during rev 64060,
19:54z. Engineers have observed a shift in the drift rate (of yaw bias)."
The software patch will switch us back to using the orthogonal gyro instead
of the skew gyro while operating in YGC mode. Users should see an
improvement in the data.
Contact Person(s) Name/Email/Phone Number for Questions:
Emily.Harrod@noaa.gov/301-457-5247 ext. 117
Cecil.Paris@noaa.gov/301-457-5247 ext. 129
Web site(s) that contain other relevant information (where applicable):
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
http://www.oso.noaa.gov/poesstatus/ - SOCC polar satellites status
http://www.oso.noaa.gov/daily-news/index.htm - SOCC morning reports