Subject: [IGSSTATION-3102]: ESOC] missing Rapid clock epochs
From: [email-masked]
To: [email-masked]
Cc: [email-masked]
Date: Wed, 3 Jun 2009 09:53:40 +0200

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IGS Station Mail          03 Jun 09:46:12 PDT 2009      Message Number 3102
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Author: Tim Springer

Dear Jim,

At ESOC we construct the data we use for our Ultra-Rapids from the hourly 
RINEX files. We wait 20 minutes after the full hour before starting our 
procedure. This should be more than enough time for stations to deliver 
the data of the last hour.

In our Ultra-Rapid processing we check the number of epochs for which we 
have clock epochs and this is almost always 288. However, this does not 
mean that for all stations the clocks are complete. Any missing clock 
epochs for a station will most likely be due to the fact that the station 
in question is "to slow" in providing the hourly RINEX data. 

Of course one should note here that at ESOC we do NOT generate a special 
rapid product. Our rapid product is the estimated part of our "00" hour 
Ultra-rapid submission. This is why the data submission for our rapid 
products is critical. We could make a seperate rapid solution that would 
run much later than we currently do. However, given the fact that our 
rapid orbits and clocks are already one of the best we consider that to be 
a waste of resources. Maybe the IGS station group (or infrastructure 
committee) could have a look into the delays of the hourly data files. I 
know that we have seen that at many stations the automatic procedure runs 
at a fixed local time meaning an increased delay when Summer/Winter time 
kicks in. So things can certainly be optimized.

Cheers,
Tim

---------------------
Tim Springer
Navigation Support Office, OPS-GN (nng.esoc.esa.de)
European Space Operations Centre
Robert Bosch Strasse 5
64293 Darmstadt
Germany
Tel: +49-6151-90-2029  Fax: +49-6151-90-3129

"Jim.Ray" <[email-masked]> 
Sent by: [email-masked]
01/06/2009 19:33
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Subject
[IGS-ACS-176] missing Rapid clock epochs

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IGS-ACS Mail      01 Jun 10:34:10 PDT 2009      Message Number 176
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Author: Jim Ray

Recently it seems that more and more IGS Rapid clocks are
missing the last hour of data each day.  For 5-min samples,
there should be 288 clock values per day.  If the last hour
is missing, then only 276 clock values will be available.

The table below shows all IGR stations with <280 clock values
for day 1534_0.  I suspect that the reasons for the missing
data are mixed.  Probably, ESA and/or JPL construct their daily
station RINEX files from hourly submissions and are sometimes
failing to build complete daily files for their IGR processing.
Please correct me if this is wrong, otherwise please consider
improving your procedures to eliminate these end-of-day gaps.

Since the IGS clock combination requires results from at least
2 ACs, the stations below analyzed by at least 2 ACs besides ESA
or JPL probably produce daily RINEX files with the last hour
missing, at least initially.  Those stations are:

NRCan -- CHUR, SCH2
BKG   -- HOFN, WTZR
GA    -- MAW1
SRC   -- BOR1

I do not have the time to research the data files & AC solutions
of each of these stations individually, so it is possible that
my interpretations are not correct.  Nevertheless, it is clear
that data epochs are being dropped someplace.

It is very difficult for the IGS time scale to handle such
recurring gaps, especially when they involve some of the best
clocks in the network.  So please investigate and try to
eliminate these data gaps, whether in the RINEX files or in the
AC analyses.

Thanks,
--Jim

  GPS week: 1534   Day: 0   MJD: 54982

       | RMS (ps) OF AC CLOCK COMPARED TO COMBINATION
       |   brd   cod   emr   esa   iga   igu   jpl   ngs   usn | NEpoch 
Agency
 
-----+-------------------------------------------------------+--------------
  ALGO |     -     -     7     7     -     -     -     -   111 |  276 
NRCan
  ALIC |     -     -     -     9     -     -    10     -     - |  276  GA
  ANKR |     -    15     -     7     -     -     -     -     - |  276 BKG
  ASPA |     -    21     -    10     -     -     -     -     - |  235 NGS
  BOR1 |     -    13     -     6     -     -     -     -    16 |  276 SRC
  BRFT |     -     -     -    15     -     -    18     -     - |  275 NGS
  CAGL |     -     -     -    43     -     -    50     -     - |  152 ASI
  CEDU |     -    15     -     7     -     -     -     -     - |  276  GA
  CHAT |     -     -     -    15     -     -    17     -     - |  263 GNS
  CHUR |     -    19    18    20     -     -     -     -     - |  276 
NRCan
  CONZ |     -     -     -    15     -     -    18     -     - |  276 BKG
  CRAO |     -     -     -     6     -     -     7     -     - |  276 
UNAVCO
  HARV |     -     -     -     9     -     -    10     -     - |  276 JPL
  HOFN |     -    67     -    32     -     -     -     -   123 |  250 BKG
  KARR |     -    16     -     8     -     -     -     -     - |  264  GA
  MAW1 |     -    49     -    14     -     -    20     -     - |  276  GA
  ORID |     -     -     -     6     -     -     7     -     - |  276 BKG
  RABT |     -     -     -    14     -     -    16     -     - |  279 
UNAVCO
  REYK |     -     -     -     5     -     -     6     -     - |  275 BKG
  SCH2 |     -     -    20    21     -     -     -     -    88 |  223 
NRCan
  WARN |     -     -     -     7     -     -     8     -     - |  276 BKG
  WTZR |     -    21     X    10     -     -     -     -    12 |  276 BKG
 
-----+-------------------------------------------------------+--------------