[teqc] teqc Digest, Vol 145, Issue 12

Guilherme Poleszuk gpoleszuk at gmail.com
Thu Jun 30 03:54:57 MDT 2016


Hello Mr. Lou, good morning!

Please, considering my point of view, all tips that you share with us are
relevant since they are not only a extract from a manual or recipe, but
they contains your experience with TEQC too.

I see importance in this tips because, in my point of view, is very good to
understand a tool, or a key in case of TEQC, knowing the reason that it is
developed for. I found your "survey" in the latest tip and I think it is
important to reply it. I remembered when you invited the TEQC users to
review the latest TEQC documentation in PDF (pre-release).

Congratulations, Mr. Lou for share with us a little bit of your knowledge
:-).

All the best regards
Guilherme Poleszuk
On 29 Jun 2016 15:01, <teqc-request at postal.unavco.org> wrote:

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> Today's Topics:
>
>    1. helpful tip of week 1903 (Lou Estey)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 29 Jun 2016 07:39:40 -0600
> From: Lou Estey <lou at unavco.org>
> To: "teqc at unavco.org" <teqc at unavco.org>
> Subject: [teqc] helpful tip of week 1903
> Message-ID: <e40f3cef-a741-3c7d-1b19-f147c0e8f1fc at unavco.org>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> This week's tip:  the '-no_orb[it]' and '-no_pos[ition]' options
>
> These options were added back in April-August 2011 and finalized (in their
> current
> form) on 1 Aug 2011.  I wanted to bring these up in last week's helpful tip
> on how to help check whether a strange qc result was due to problematic
> navigation
> messages -- rather than problematic observation data -- but that tip's
> writeup was
> getting rather long.  So recall from last week:
> (from http://postal.unavco.org/pipermail/teqc/2016/002113.html)
>
> -------
> If you are doing a full qc -- using navigation messages for orbit
> computation --
> weird problems might not be due to the observation data.  The problems
> might
> very well be with the navigation messages you are using:
>
> - Try a qc "lite" (without navigation messages).  Does the qc "lite" look
> good?
>
> - Look for unhealthy SVs; if any are found, try filtering them out.
>
> - Try using the combined broadcast RINEX nav files from CDDIS or another
> center
> (and filter out unhealthy SVs).
> -------
>
> The options '-no_orb[it]' and '-no_pos[ition]' allow you to do a qc lite or
> a partial qc full using only a subset of constellations very quickly.
> These two
> options are almost identical:
>
> [60] teqc +help | grep no_
>                    -no_orb[it] <list>       don't use orbits for listed
> constellations (G,R,S,E,C,J) in qc, e.g. <list> = R+E
>                    -no_pos[ition] <list>    don't use orbits for listed
> constellations (G,R,S,E,C,J) in qc's ppp, e.g. <list> = R+E
>
> Ok, what's the difference?  Specifying a constellation with '-no_orb[it]'
> during
> a quality check (qc) means that no orbit calculations whatsoever are done
> with
> that constellation; that constellation will be done in a qc 'lite' mode
> even
> if navigation messages for that constellation are present.  Therefore,
> elevation
> and azimuth calculations are not done for that constellation (e.g. no
> entries in
> the .ele and .azi compact3 files if '+plot' is used).
>
> The '-no_pos[ition]' option does the orbit calculation for the specified
> constellation
> (if navigation messages for that constellation are present), so elevation
> and azimuth
> calculations _are_ done for that constellation.  But now that
> constellation is not used
> in teqc position solution for the antenna.
>
> Deciding which to use depends on what you want or don't want.
>
> As you probably know, when qcing RINEX observation files, teqc
> automatically looks
> for name-matching RINEX navigation files in the same directory/folder,
> using the
> same filename prefix as the observation file) and reads any nav files
> found.
> The same thing happens when using either '-no_orb[it]' or
> '-no_pos[ition]', so the
> reading/formatting validity of any such RINEX nav files continues to be
> checked.
>
> Before these options were introduced, the only way to make teqc ignore a
> RINEX nav
> file during qc (assuming it was named with the same filename prefix as the
> RINEX
> observation file) was to move the RINEX nav file to a different
> directory/folder
> or to rename it in some non-canonical way.  However, if the RINEX nav file
> being
> eliminated in either of these two ways was for GLONASS, then teqc was
> probably not
> going to be able to do a qc 'lite' analysis.  Why?  One needs to be able
> to convert
> phase data, in units of phase cycles in RINEX, to units of distance and
> this conversion
> for GLONASS FDMA signals requires the GLONASS slot to frequency channel
> number (fcn)
> for each GLONASS SV with phase and pseudorange data.  This slot-to-fcn
> mapping can
> be provided without a GLONASS RINEX nav file (i.e. see the
> '-glonass_s2fcn' option),
> but normal teqc use extracts this mapping from the GLONASS RINEX nav
> file(s).
>
> Upshot: Using '-no_pos R' or '-no_orb R' allows you to shut off use of
> GLONASS
> orbits (to help see if the GLONASS navigation information is suspect or
> not),
> but still lets teqc read any GLONASS navigation information to obtain the
> slot
> to fcn mapping so that a qc "lite" can be applied to the GLONASS data.
> (But:
> problems in the qc with GLONASS data might still arise, however, if the
> fcn happens
> to be wrong in the navigation messages for one or more GLONASS SVs.)
>
> Can the '-no_orb[it]' and '-no_pos[ition]' options be used together in one
> command
> with different constellations?  Yes (... or at least this should work
> aok).  For
> example, using '+qc -no_orb R -no_pos E' should completely skip doing the
> orbit
> calculations for GLONASS (and therefore no elevation and azimuth values
> for GLONASS
> SVs in the .ele and .azi files if '+plot' is also included), whereas
> Galileo SVs
> should have orbit calculations done, but Galileo data should not be used
> in teqc's
> antenna position calculation in this run.  And both GLONASS and Galileo
> SVs should
> have a qc 'lite' done.
>
> A couple last notes: Multiple constellations can be specified with the
> '-no_pos[ition]'
> and '-no_orb[it]' options, as shown in the `teqc +help` usage.  You can
> include
> a delimiter character, like '+', or ',': '-no_pos R+E' or '-no_pos R,E' ...
> or just leave out delimiter characters: '-no_pos RE'.  So to switch to a
> qc 'lite' on all constellations, whether data for them are present or not,
> you could use, say, '-no_pos G,R,S,E,C,J' or '-no_orb G,R,S,E,C,J"
>
> Happy teqc-ing!
>
> cheers,
> --lou
>
> p.s. This is the 10th "tip of the week".  Are these really helpful ... or
> am I just boring most of you all to a near comatose state?
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 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
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Past helpful tips:
>
> week 1894: using teqc config files -
> http://postal.unavco.org/pipermail/teqc/2016/002067.html
> week 1895: qc of high-rate data -
> http://postal.unavco.org/pipermail/teqc/2016/002071.html
> week 1896: UNIX/Linux shells for Windows -
> http://postal.unavco.org/pipermail/teqc/2016/002072.html
> week 1897: '-' vs. '+' teqc options -
> http://postal.unavco.org/pipermail/teqc/2016/002076.html
> week 1898: auto-identification of formats -
> http://postal.unavco.org/pipermail/teqc/2016/002092.html
> week 1899: auto-identification vs. format flags -
> http://postal.unavco.org/pipermail/teqc/2016/002096.html
> week 1900: square brackets in options -
> http://postal.unavco.org/pipermail/teqc/2016/002105.html
> week 1901: using option '+mds' -
> http://postal.unavco.org/pipermail/teqc/2016/002108.html
> week 1902: qc results w/ problematic nav messages -
> http://postal.unavco.org/pipermail/teqc/2016/002113.html
>
>
>
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>
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>
> End of teqc Digest, Vol 145, Issue 12
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