[IGSSTATION-4679] spurious navigation messages for PRN24/SVN24
Jake Griffiths
Jake.Griffiths at noaa.gov
Tue Nov 29 11:37:01 PST 2011
Author: Jake Griffiths
Dear Colleagues,
The daily broadcast navigation (brdc) file at NASA/CDDIS is created by
concatenating nav records collected at a set of global (IGS and non-IGS)
tracking stations. The Analysis Coordinator (ACC) uses the brdc file for
various aspects of the orbit combinations. On three days in the past week,
spurious PRN24/SVN24 records have caused ACC processes to fail. The most recent
event happened today for yesterday's observations (i.e., brdc3320.11n).
Recall that PRN24/SVN24 was set unusable and stopped transmitting on September
30, 2011. It was then decommissioned on Nov 4, 2011.
A search of the IGS station-specific nav files at CDDIS for year=2011 and
doy=332 uncovered the following IGS stations (and receivers) reporting obs for
PRN24/SVN24:
SITE RECEIVER TYPE FIRMWARE VERSION
---------------------------------------------
ankr TPS E_GGD 2.6.1 Jan,10,2008
badg JAVAD TRE_G3TH DELTA 3.2.7 May,16,2011
bzrg LEICA GRX1200GGPRO 7.80/3.019
conz LEICA GRX1200+GNSS 8.20/4.007
darw LEICA GRX1200GGPRO 8.20/3.019
dlft JPS LEGACY 2.6.1 Jan,10,2008
hers SEPT POLARX3ETR 2.1
hofn TPS E_GGD 2.6.1 JAN,10,2008
hueg JPS LEGACY 2.6.1 JAN,10,2008
joz2 LEICA GRX1200GGPRO 8.20/3.019
joze TRIMBLE 4000SSI 7.29
mac1 LEICA GRX1200+GNSS 8.10
mad2 ASHTECH Z-XII3T 1L01-1D04
maw1 LEICA GRX1200GGPRO 8.01/3.019
nano LEICA GRX1200GGPRO 7.80/3.019
rcmn LEICA GRX1200GGPRO GSW
sass JPS LEGACY 2.6.1 JAN,10,2008
str1 LEICA GRX1200GGPRO 8.20/3.019
titz JPS LEGACY 2.6.1 JAN,10,2008
tow2 LEICA GRX1200GGPRO 8.20/3.019
wroc LEICA GRX1200GGPRO 8.20/3.019
yar3 LEICA GRX1200GGPRO 8.20/3.019
While there are common threads in this list, it is unclear to me what may be
causing the spurious records. If you operate a station with one of these
receivers, perhaps refreshing the almanac would eliminate the problem.
Otherwise, there may be firmware updates that could help. Unfortunately, I have
no other ideas. But any progress on solving these issues would be helpful to the
ACC.
Thanks for your time.
Best regards,
jake
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