To all CGSIC:
Users in certain parts of the world may experience a short period of high HDOP/PDOP on the 8th of October as a result of routine maintenance with satellite #52 (PRN-31) as forecast in NANU 2009-077. For reference the text of NANU 200977 is provided below. A world view of HDOP for the 8th of October may be seen at: http://www.navcen.uscg.gov/gps/news/Oct2009/degradation_100809.htm
These predictions are based on "Best 4" satellites and effects may be slightly better for "All in view" users. As in the past, the scheduled satellite maintenance may be completed prior to or after the expected event times precluding any HDOP event altogether. This warning is for informational and mission planning purposes only.
Please report any GPS outages through the NAVCEN form at http://www.navcen.uscg.gov/gps/gpsuserinput.htm
Rick Hamilton
CGSIC Executive Secretariat
USCG Navigation Center
Text of NANU 2009077:
NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2009077
SUBJ: SVN52 (PRN31) FORECAST OUTAGE JDAY 281/0830 – JDAY 281/2300
1. NANU TYPE: FCSTDV
NANU NUMBER: 2009077
NANU DTG: 301627Z SEP 2009
REFERENCE NANU: N/A
REF NANU DTG: N/A
SVN: 52
PRN: 31
START JDAY: 281
START TIME ZULU: 0830
START CALENDAR DATE: 08 OCT 2009
STOP JDAY: 281
STOP TIME ZULU: 2300
STOP CALENDAR DATE: 08 OCT 2009
2. CONDITION: GPS SATELLITE SVN52 (PRN31) WILL BE UNUSABLE ON JDAY 281
(08 OCT 2009) BEGINNING 0830 ZULU UNTIL JDAY 281 (08 OCT 2009)
ENDING 2300 ZULU.
3. POC: CIVILIAN – NAVCEN AT 703-313-5900, HTTPS://WWW.NAVCEN.USCG.GOV
MILITARY – GPS OPERATIONS CENTER at HTTP://GPS.AFSPC.AF.MIL/GPSOC, DSN 560-2541,
COMM 719-567-2541, gps_support@schriever.af.mil, HTTPS://gps.afspc.af.mil
MILITARY ALTERNATE – JOINT SPACE OPERATIONS CENTER, DSN 276-9994,
COMM 805-606-9994, JSPOCCOMBATOPS@VANDENBERG.AF.MIL