[teqc] helpful tip of week 1972

Lou Estey lou at unavco.org
Wed Oct 25 09:35:50 MDT 2017


This week's tip: what shows up as metadata in RINEX headers

A common question is why teqc puts an antenna position of XYZ = 0 0 0 in the RINEX obs header, whereas
using the '+meta' option (see 'tip of week 1928', https://postal.unavco.org/pipermail/teqc/2016/002206.html)
on the same input clearly shows that teqc can find an antenna position.  Hopefully this tip answers this
question and related questions for the other metadata fields.

As a nominal one-pass filter, teqc will only output metadata in the RINEX headers that it finds in the input:

    - before the first GNSS observation (or external event, if '+event' is being used) in a RINEX obs file,
    - before the first GNSS navigation message for any of the GNSS RINEX nav files

unless that metadata is specified with one of the editing options, e.g. '-O.px' or '-O.pg' for the
antenna position for RINEX obs, and so on, and then the metadata in the editing options take precedence
and are used.

For example, if an antenna position is not found before the first GNSS observation and the user is not
supplying an antenna position with '-O.px' or '-O.pg', then teqc writes the position as XYZ = 0 0 0 which
basically means "unknown".  Mandatory text fields where nothing was found before the header is written
will be populated by blanks or perhaps by "-Unknown-".  Optional text fields where nothing was found
simply will not be output.

But when using the '+meta' option on a raw data file, teqc reads the entire raw file.  What is shown in the
'+meta' output corresponds to the last found metadata in the file, unless a corresponding editing option
is used to override that value.  (When using the '+meta' option on a RINEX obs file, teqc cheats a bit
by only reporting the XYZ that's in the header -- since in this case reading the bulk of the file is
skipped to speed things up somewhat.)

Happy teqc-ing!

cheers,
--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

"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
week 1903: '-no_orb[it]' and '-no_pos[ition]' options - http://postal.unavco.org/pipermail/teqc/2016/002115.html
week 1904: '-week' option - http://postal.unavco.org/pipermail/teqc/2016/002117.html
week 1905: using '+bcf' for XYZ/geodetic conversion - http://postal.unavco.org/pipermail/teqc/2016/002126.html
week 1906: the '+v[erify]' option - http://postal.unavco.org/pipermail/teqc/2016/002128.html
week 1907: '+C2', '+L5', "+L6', '+L7', '+L8', '+all' options - http://postal.unavco.org/pipermail/teqc/2016/002130.html
week 1908: getting RINEX doppler and L2 - http://postal.unavco.org/pipermail/teqc/2016/002131.html
week 1909: using paths w/ file names - http://postal.unavco.org/pipermail/teqc/2016/002132.html
week 1910: the (un)importance of file names - http://postal.unavco.org/pipermail/teqc/2016/002133.html
week 1911: notices, warnings, and errors - http://postal.unavco.org/pipermail/teqc/2016/002134.html
week 1912: the '-max_rx_SVs' option - http://postal.unavco.org/pipermail/teqc/2016/002137.html
week 1913: the end of '++igs' and '+igs' - http://postal.unavco.org/pipermail/teqc/2016/002140.html
week 1914: splicing together RINEX files - http://postal.unavco.org/pipermail/teqc/2016/002144.html
week 1915: using '-O.int' and '-O.dec' - http://postal.unavco.org/pipermail/teqc/2016/002145.html
week 1916: '+doy' option - http://postal.unavco.org/pipermail/teqc/2016/002146.html
week 1917: '-tbin' and '-ast' options - http://postal.unavco.org/pipermail/teqc/2016/002152.html
week 1918: mp12 RMS before/after Oct 2013 - http://postal.unavco.org/pipermail/teqc/2016/002158.html
week 1919: the global windowing options - http://postal.unavco.org/pipermail/teqc/2016/002159.html
week 1920: '-M.dec' and '-N.dec' options - http://postal.unavco.org/pipermail/teqc/2016/002163.html
week 1921: combining time filtering options - http://postal.unavco.org/pipermail/teqc/2016/002176.html
week 1922: helping me (or someone else on the list) help you - http://postal.unavco.org/pipermail/teqc/2016/002187.html
week 1923: the "build" line - http://postal.unavco.org/pipermail/teqc/2016/002190.html
week 1924: the qc '-w[idth]' option - http://postal.unavco.org/pipermail/teqc/2016/002193.html
week 1925: qc with explicit time windowing - http://postal.unavco.org/pipermail/teqc/2016/002194.html
week 1926: the '+rx_state' option - http://postal.unavco.org/pipermail/teqc/2016/002200.html
week 1927: the '-O.sum' option - http://postal.unavco.org/pipermail/teqc/2016/002204.html
week 1928: the '+meta' and '+mds' options - http://postal.unavco.org/pipermail/teqc/2016/002206.html
week 1930: more on '-O.sum' - http://postal.unavco.org/pipermail/teqc/2017/002207.html
week 1931: the '-O.s[ystem]' option - http://postal.unavco.org/pipermail/teqc/2017/002208.html
week 1932: leap seconds - http://postal.unavco.org/pipermail/teqc/2017/002215.html
week 1936: what you can (and shouldn't) do in a RINEX obs file - http://postal.unavco.org/pipermail/teqc/2017/002229.html
week 1938: the '+psp' option - http://postal.unavco.org/pipermail/teqc/2017/002231.html
week 1939: the '+diag' option - http://postal.unavco.org/pipermail/teqc/2017/002235.html
week 1951: '-n_<system>' and SV filtering options - http://postal.unavco.org/pipermail/teqc/2017/002277.html
week 1953: more with '+diag' option - http://postal.unavco.org/pipermail/teqc/2017/002287.html
week 1954: using '+diag' output to split raw files - http://postal.unavco.org/pipermail/teqc/2017/002290.html
week 1955: current qc notation - http://postal.unavco.org/pipermail/teqc/2017/002302.html
week 1956: the '+qcq' option - http://postal.unavco.org/pipermail/teqc/2017/002304.html
week 1957: using Trimble formats - http://postal.unavco.org/pipermail/teqc/2017/002305.html
week 1958: ToC != ToE messages - http://postal.unavco.org/pipermail/teqc/2017/002310.html
week 1959: receivers vs. formats - http://postal.unavco.org/pipermail/teqc/2017/002311.html
week 1960: when the '-week' option is very wrong to use - https://postal.unavco.org/pipermail/teqc/2017/002314.html
week 1961: "less" is usually best - https://postal.unavco.org/pipermail/teqc/2017/002315.html
week 1962: using GPS L2C with teqc - https://postal.unavco.org/pipermail/teqc/2017/002316.html
week 1964: the '+eds' options - https://postal.unavco.org/pipermail/teqc/2017/002317.html
week 1965: handling RINEX comment lines - https://postal.unavco.org/pipermail/teqc/2017/002324.html
week 1966: the '+dUTC_p' options - https://postal.unavco.org/pipermail/teqc/2017/002331.html
week 1967: the strange position from '+meta' - https://postal.unavco.org/pipermail/teqc/2017/002355.html

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