[teqc] Request information about software "TEQC" after receiving message from Carey Noll (RE : Problems with recent CNES GNSS data)

Lou Estey lou at unavco.org
Mon Jul 7 07:43:05 MDT 2008


Dear Jean-Paul,

> I have received an email below from Carey Noll to delete comment lines in Rinex files.
> Is there from "teqc" software an option to put only one comment line in Rinex files?

The short answer is no, but some explanation might be in order.  Carey's email (below)
seems to be specifically about RINEX comment lines like:

teqc  2006Jul20     administrateur ccgps20080618 23:06:15UTCCOMMENT

which she says is occurring over 300 times in some files.  The real question is: how
are so many lines like this getting into the RINEX header?  If these are really being
put in by teqc, I doubt they are exact duplicates: the times are most likely different.

In any RINEX file output by teqc, it puts out a PGM / RUN BY / DATE header line showing
the current version of teqc and the current date & time, e.g. (on a test file I happened
to create two days ago):

teqc  2008Jul5      Lou Estey           20080705 20:23:02UTCPGM / RUN BY / DATE

If you are using teqc as a RINEX-to-RINEX filter (decimation, header editing, windowing,
file splicing, ...) then there is at least one original PGM / RUN BY / DATE header line
in the input -- which is converted into a comment so that the user still has a record
of the original program that created the RINEX file.  For example, if I run the file
mentioned above through teqc, then in the header:

teqc  2008Jul5      Lou Estey           20080707 13:14:23UTCPGM / RUN BY / DATE
...
teqc  2008Jul5      Lou Estey           20080705 20:23:02UTCCOMMENT

and if I run _that_ file through teqc again, there will be in the header:

teqc  2008Jul5      Lou Estey           20080707 13:14:27UTCPGM / RUN BY / DATE
...
teqc  2008Jul5      Lou Estey           20080707 13:14:23UTCCOMMENT
teqc  2008Jul5      Lou Estey           20080705 20:23:02UTCCOMMENT

(These all say that _something_ was done by teqc, but they don't specify _what_ was done.
A long time ago, there was some discussion about doing that, but this would lead to
even more comments in the header.)  Of course, once something is a comment in a RINEX
header, there's not much that can be done with it automatically unless you specifically
know what you are looking for.

So, assuming teqc alone is responsible for putting in these comments, what is
being done to a RINEX file 300+ times by teqc?  It seems to me that there is
some unintentional misuse of teqc going on, like a runaway script process, that
is responsible for so many of these types of comment lines showing up in the
RINEX headers.

--lou

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Louis H. Estey, Ph.D.              office:  [+001] 303-381-7456
UNAVCO, 6350 Nautilus Drive           FAX:  [+001] 303-381-7451
Boulder, CO  80301-5554            e-mail:  lou  unavco.org
    WWW:  http://www.unavco.org   http://jules.unavco.org

"If the universe is the answer, what is the question?"
                                                -- Leon Lederman
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> -----Message d'origine-----
> De : Carey Noll [mailto:Carey.E.Noll at nasa.gov] 
> Envoyé : mardi 1 juillet 2008 22:14
> À : Bruno Garayt; Cardaliaguet Jean-Paul
> Cc : Maurice P. (GSFC-690.1)[SSAI] Dube; Carey Noll
> Objet : Problems with recent CNES GNSS data
> 
> 
> Dear Bruno and Jean-Paul,
> 
>     We just noticed that data from several of the CNES GNSS stations (GRAS, HARB, NKLG, THTI, TLSE) for days 08167 onward have odd header sections in the RINEX files. The line:
> 
> teqc  2006Jul20     administrateur ccgps20080618 23:06:15UTCCOMMENT
> 
> is repeated many times (e.g., for GRAS day 170, the line appears in the header over 300 times). Can you look into this problem and replace the files?
> 
> Thanks,
> Carey.
> -----
> Ms. Carey Noll
> Manager, Crustal Dynamics Data Information System (CDDIS) Secretary, ILRS Central Bureau NASA GSFC Code 690 Greenbelt, MD 20771 USA
> 
> E-mail:  Carey.Noll at nasa.gov
> Voice: (301) 614-6542
> Fax: (301) 614-6015
> WWW:  http://cddis.gsfc.nasa.gov


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