[teqc] helpful tip of week 2024

Lou Estey lou at unavco.org
Wed Oct 24 09:56:35 MDT 2018


This week's tip: qc: main "filtering" possibilities

The goal of this week's tip is merely to summarize the main "filtering" possibilities
while running teqc's '+qc' (or '+qcq') process, which can be used individually or in
combination with each other and/or other qc options.  And I'm using the term "filtering"
in the broad-brush sense that these options modify the default qc output in some way.
These options have been covered before, so hopefully there are no major surprises.

---------------------

Explicit global time windowing: These are the '-st', '-e, and/or delta time options
(like '+dd 1'), and are applicable for either qc 'lite' or qc 'full'; see tip of week 1919,
https://postal.unavco.org/pipermail/teqc/2016/002159.html.  Using any of these during
qc will result in a "windowed" summary line labeled "SWN", which will be just after
the normal "SUM" summary line, as discussed in tip of week 1925,
https://postal.unavco.org/pipermail/teqc/2016/002194.html.

Main uses:

- To force a specific time window, like 24 hours, for each file, regardless of the
actual time span of the actual data (thus giving a qc of the specified time window,
rather than the time span between the first and last data epochs)

- To zoom in on a specific time window for data debugging

---------------------

'-w' width for the ASCII time plot: The default is a "width" of 72 time columns for the
indicators over the time span of the time plot, but this can be changed to be a value
from 1 to 255 if you so desire.  Applicable for qc 'lite' or 'full'.  See tip of week 1924,
https://postal.unavco.org/pipermail/teqc/2016/002193.html.

Main uses:

- To adjust the desired number of epochs in each column (esp. if used with time windowing)

- If zooming in for data debugging, the width can be adjusted so that there is no more than
one epoch of data in each column

---------------------

'+/-[constellation]' filters for all SVs or specific SVs of a constellation: Applicable
for qc 'lite' or qc 'full'.  These filters were covered as part of tip of week 1951,
https://postal.unavco.org/pipermail/teqc/2017/002277.html.  Probably the most common
application would be to use '-R' to eliminate all GLONASS, to use '-E' to eliminate all
Galileo, and so on.  But you can also remove one or more specific SVs, like '-R12,24'
to eliminate GLONASS SVs with slot numbers 12 and 24 -- although using '-R12,24' is
exactly the same as using '+R1-11,13-23'.

Main uses:

- To quickly eliminate one or more constellations of SVs for the qc

- To quickly eliminate one or more specific SVs for the qc

---------------------

'-no_orb[it]' to not do orbit calculations for the specified one or more constellations:
Usually for qc 'full' only (but see below).  If used with GLONASS, teqc will read
GLONASS navigation messages for slot-to-fcn mapping.  See tip of week 1903,
https://postal.unavco.org/pipermail/teqc/2016/002115.html.

Main uses:

- To test whether the ephemerides of one or more constellations are having a degrading
impact on teqc's antenna point position (PP) determination

- Using '-no_orb G,R,S,E,C,J,I' -- regardless of which constellations are actually present --
is a quick way to switch to a qc 'lite' and, if GLONASS is present with GLONASS ephemerides,
still have a slot-to-fcn mapping for the qc of the GLONASS data

---------------------

'-no_pos[ition]' to do orbit calculations for the specified one or more constellations,
but not include the SV positions for the specified constellations in the antenna PP
calculation:  This is also applicable for qc 'full' only.  Also note that the elevation
and azimuth of SVs in the specified constellations are computed, i.e. if generating
compact3 plot files with the '+plot' option, then the .ele and .azi files are created
(assuming an antenna PP is determined or specified).  See tip of week 1903 for this as well,
https://postal.unavco.org/pipermail/teqc/2016/002115.html.

Main use:

- The SV elevation and/or azimuth information is needed for one or more constellations,
but you don't want the selected constellations to be used in the antenna PP calculation
(i.e. might be done as part of a data debugging procedure)

---------------------

Elevation limits on PP solutions, qc 'full' only:  No need to worry about these options unless
you are doing qc full from a platform (e.g. aircraft, LEO satellite) which is at an elevation
higher than 9000 meters above the WGS84 reference ellipsoid.  See tip of week 2023
https://postal.unavco.org/pipermail/teqc/2018/002556.html

-pos_h_min[m] #    to set a minimum elevation threshold value #, in meters, above the ellipsoid
                     (the default is -500 meters)

-pos_h_max[m] #    to set a maximum elevation threshold value #, in meters, above the ellipsoid
                     (the default is 9000 meters)

Main use:

- Ignore any PP solutions, due to faulty or very incomplete observation data, which are yielding
PP solutions with unrealistic elevations.  Epochs where PP solutions are ignored due to these
limits will be designated with a 'K' (= "solution convergence problem") in the ASCII timeplot.

---------------------

'-unhealthy' (the default) to not use any SV's ephemeris if the SV is set as unhealthy:
This is only applicable for qc 'full' only.

'+unhealthy' to override the above default and use all ephemerides, whether an SV's ephemeris
has the SV set as healthy or unhealthy: This also is only applicable for qc 'full' only.  Be
advised that including unhealthy SVs is generally not a good practice.

These two options were not discussed previously in a tip of the week, but were discussed
in https://postal.unavco.org/pipermail/teqc/2017/002369.html.

Main use:

- '+unhealthy' to see if using the SVs with an unhealthy setting in their ephemeris
has a degrading effect of some aspect of the qc and, if so, how much of an effect

---------------------

'+O.px or '+O.pg' options to exactly specify the antenna point position to be used
during qc full:  Again, this is only applicable for qc 'full' only, and forces teqc
to use the specified antenna PP instead of trying to compute the antenna PP, with the
specified position is then be used for things like the .azi and .ele compact3 plot files.
Discussed in tip of week 1987, https://postal.unavco.org/pipermail/teqc/2018/002422.html.

Main uses:

- To force an absolute consistent antenna PP from dataset to dataset (e.g. day to day)
instead of relying on teqc's PP (although doing so sacrifices the PP calculation aspect
of teqc's qc)

- To construct an alternate teqc qc result with a known and specified antenna PP to compare
with teqc's qc with its antenna PP calculation

---------------------

'-O.px or '-O.pg' options to edit the antenna point position: Using the '-' instead of the '+'
on these two options does something different.  With '-', the antenna point position is set,
but if qc full is being done, the qc antenna PP will be done and compared to this edited
antenna PP.

Main use:

- To override whatever metadata value for the antenna point position might be found in the input,
e.g. the APPROX POSITION XYZ values in a RINEX observation header

---------------------

The '-set_*' options for various elevation angles:

-set_hor      horizon angle
-set_mask     cutoff mask angle
-set_comp     "comparison" angle (roughly, defining a low-elevation angle regime and
               a high-elevation angle regime)

Discussed in tip of week 1979, https://postal.unavco.org/pipermail/teqc/2017/002383.html.

Main uses:

- '-set_mask #' to adjust the cutoff mask angle, probably to match that set in the receiver

- '-set_hor #' to adjust the horizon angle, especially if qc-ing data from a satellite;
if from a moving antenna, like a satellite, remember to also use the '-ap' option =
"don't compute average position during qc"

---------------------

'-O.obs' or '-O.-obs', the "include" or "exclude" options for modification of which
observables are to be qc-ed:  But just remember that you can't ask for, get, and qc observables
that aren't already present in the input.  (And remember that pseudorange observables
are needed in order to do a qc full with point-position solutions.)  The "exclude" option
'-O.-obs' was introduced in 2009: https://postal.unavco.org/pipermail/teqc/2009/000931.html.

Main use:

- To quickly modify the observable list without the need to create an intermediate file
with the desired observables, e.g. if Galileo E6 observables are present, '-O.-obs l6+c6+s6'
can be used to eliminate Galileo E6 data from being qc-ed

---------------------

Filters for indicators in the qc ASCII timeplot:

I won't exactly call these some of the main qc filtering options, but since these were covered
just a few weeks ago in tip of week 2020 https://postal.unavco.org/pipermail/teqc/2018/002535.html
All have a filtering capability of the indicators in the ASCII timeplot:

  '-data' to not show the normal data indicators above the cutoff mask angle
  '-lli' to not show the loss-of-lock indicators
  '-mp' to not do multipath combinations; therefore no multipath slip indicators
  '-ion' to '-iod' to not do the ionospheric combinations and their time-rate-of-change, respectively;
     together, no ionospheric slip indicators

Main use:

- To have the ASCII timeplot focus on just slips or just data

---------------------

Individually or used together, these are a fairly powerful set of tools for modifying
your qc results -- sometimes needed for digging in to find out what is really going on.

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 - https://postal.unavco.org/pipermail/teqc/2016/002067.html
week 1895: qc of high-rate data - https://postal.unavco.org/pipermail/teqc/2016/002071.html
week 1896: UNIX/Linux shells for Windows - https://postal.unavco.org/pipermail/teqc/2016/002072.html
week 1897: '-' vs. '+' teqc options - https://postal.unavco.org/pipermail/teqc/2016/002076.html
week 1898: auto-identification of formats - https://postal.unavco.org/pipermail/teqc/2016/002092.html
week 1899: auto-identification vs. format flags - https://postal.unavco.org/pipermail/teqc/2016/002096.html
week 1900: square brackets in options - https://postal.unavco.org/pipermail/teqc/2016/002105.html
week 1901: using option '+mds' - https://postal.unavco.org/pipermail/teqc/2016/002108.html
week 1902: qc results w/ problematic nav messages - https://postal.unavco.org/pipermail/teqc/2016/002113.html
week 1903: '-no_orb[it]' and '-no_pos[ition]' options - https://postal.unavco.org/pipermail/teqc/2016/002115.html
week 1904: '-week' option - https://postal.unavco.org/pipermail/teqc/2016/002117.html
week 1905: using '+bcf' for XYZ/geodetic conversion - https://postal.unavco.org/pipermail/teqc/2016/002126.html
week 1906: the '+v[erify]' option - https://postal.unavco.org/pipermail/teqc/2016/002128.html
week 1907: '+C2', '+L5', "+L6', '+L7', '+L8', '+all' options - https://postal.unavco.org/pipermail/teqc/2016/002130.html
week 1908: getting RINEX doppler and L2 - https://postal.unavco.org/pipermail/teqc/2016/002131.html
week 1909: using paths w/ file names - https://postal.unavco.org/pipermail/teqc/2016/002132.html
week 1910: the (un)importance of file names - https://postal.unavco.org/pipermail/teqc/2016/002133.html
week 1911: notices, warnings, and errors - https://postal.unavco.org/pipermail/teqc/2016/002134.html
week 1912: the '-max_rx_SVs' option - https://postal.unavco.org/pipermail/teqc/2016/002137.html
week 1913: the end of '++igs' and '+igs' - https://postal.unavco.org/pipermail/teqc/2016/002140.html
week 1914: splicing together RINEX files - https://postal.unavco.org/pipermail/teqc/2016/002144.html
week 1915: using '-O.int' and '-O.dec' - https://postal.unavco.org/pipermail/teqc/2016/002145.html
week 1916: '+doy' option - https://postal.unavco.org/pipermail/teqc/2016/002146.html
week 1917: '-tbin' and '-ast' options - https://postal.unavco.org/pipermail/teqc/2016/002152.html
week 1918: mp12 RMS before/after Oct 2013 - https://postal.unavco.org/pipermail/teqc/2016/002158.html
week 1919: the global windowing options - https://postal.unavco.org/pipermail/teqc/2016/002159.html
week 1920: '-M.dec' and '-N.dec' options - https://postal.unavco.org/pipermail/teqc/2016/002163.html
week 1921: combining time filtering options - https://postal.unavco.org/pipermail/teqc/2016/002176.html
week 1922: helping me (or someone else on the list) help you - https://postal.unavco.org/pipermail/teqc/2016/002187.html
week 1923: the "build" line - https://postal.unavco.org/pipermail/teqc/2016/002190.html
week 1924: the qc '-w[idth]' option - https://postal.unavco.org/pipermail/teqc/2016/002193.html
week 1925: qc with explicit time windowing - https://postal.unavco.org/pipermail/teqc/2016/002194.html
week 1926: the '+rx_state' option - https://postal.unavco.org/pipermail/teqc/2016/002200.html
week 1927: the '-O.sum' option - https://postal.unavco.org/pipermail/teqc/2016/002204.html
week 1928: the '+meta' and '+mds' options - https://postal.unavco.org/pipermail/teqc/2016/002206.html
week 1930: more on '-O.sum' - https://postal.unavco.org/pipermail/teqc/2017/002207.html
week 1931: the '-O.s[ystem]' option - https://postal.unavco.org/pipermail/teqc/2017/002208.html
week 1932: leap seconds - https://postal.unavco.org/pipermail/teqc/2017/002215.html
week 1936: what you can (and shouldn't) do in a RINEX obs file - https://postal.unavco.org/pipermail/teqc/2017/002229.html
week 1938: the '+psp' option - https://postal.unavco.org/pipermail/teqc/2017/002231.html
week 1939: the '+diag' option - https://postal.unavco.org/pipermail/teqc/2017/002235.html
week 1951: '-n_<system>' and SV filtering options - https://postal.unavco.org/pipermail/teqc/2017/002277.html
week 1953: more with '+diag' option - https://postal.unavco.org/pipermail/teqc/2017/002287.html
week 1954: using '+diag' output to split raw files - https://postal.unavco.org/pipermail/teqc/2017/002290.html
week 1955: current qc notation - https://postal.unavco.org/pipermail/teqc/2017/002302.html
week 1956: the '+qcq' option - https://postal.unavco.org/pipermail/teqc/2017/002304.html
week 1957: using Trimble formats - https://postal.unavco.org/pipermail/teqc/2017/002305.html
week 1958: ToC != ToE messages - https://postal.unavco.org/pipermail/teqc/2017/002310.html
week 1959: receivers vs. formats - https://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
week 1972: what shows up as metadata in RINEX headers - https://postal.unavco.org/pipermail/teqc/2017/002362.html
week 1973: GPS L2C navigation messages - https://postal.unavco.org/pipermail/teqc/2017/002363.html
week 1974: the '+ion_p' options - https://postal.unavco.org/pipermail/teqc/2017/002370.html
week 1975: the '+event' options - https://postal.unavco.org/pipermail/teqc/2017/002372.html
week 1976: options '+smtt' (default) vs. '-smtt' - https://postal.unavco.org/pipermail/teqc/2017/002374.html
week 1977: the reported interval with '+meta' for a RINEX obs file - https://postal.unavco.org/pipermail/teqc/2017/002377.html
week 1978: the '-N.dUTC' options - https://postal.unavco.org/pipermail/teqc/2017/002378.html
week 1979: the various qc elevation angles - https://postal.unavco.org/pipermail/teqc/2017/002383.html
week 1980: avoid in RINEX: Transit data - https://postal.unavco.org/pipermail/teqc/2017/002385.html
week 1981: avoid in RINEX: epoch flag = 6 - https://postal.unavco.org/pipermail/teqc/2017/002389.html
week 1982: avoid in RINEX: RCV CLOCK OFFS APPL = 1 - https://postal.unavco.org/pipermail/teqc/2018/002392.html
week 1983: don't count on in RINEX: receiver clock offset per epoch - https://postal.unavco.org/pipermail/teqc/2018/002393.html
week 1984: requirements for multiple target files/stdin - https://postal.unavco.org/pipermail/teqc/2018/002410.html
week 1985: default output for various input - https://postal.unavco.org/pipermail/teqc/2018/002412.html
week 1986: the '+latency' options - https://postal.unavco.org/pipermail/teqc/2018/002419.html
week 1987: the 'O.px and 'O.pg' options - https://postal.unavco.org/pipermail/teqc/2018/002422.html
week 1988: the '+relax' option - https://postal.unavco.org/pipermail/teqc/2018/002423.html
week 1992: the '+x_tilt' options - https://postal.unavco.org/pipermail/teqc/2018/002452.html
week 1993: GLONASS: slot and freq. chnl. numbers - https://postal.unavco.org/pipermail/teqc/2018/002453.html
week 1994: GLONASS: slot numbers > 24 - https://postal.unavco.org/pipermail/teqc/2018/002454.html
week 1995: GLONASS: signals - https://postal.unavco.org/pipermail/teqc/2018/002456.html
week 1996: GLONASS: broadcast ephemeris - https://postal.unavco.org/pipermail/teqc/2018/002457.html
week 1997: GLONASS: system time and broadcast time parameters - https://postal.unavco.org/pipermail/teqc/2018/002458.html
week 1998: qc: 'lite' vs. 'full' - https://postal.unavco.org/pipermail/teqc/2018/002470.html
week 1999: qc: the 'full' point-position and the antenna 'height' - https://postal.unavco.org/pipermail/teqc/2018/002474.html
week 2000: qc: what's a "complete observation"? - https://postal.unavco.org/pipermail/teqc/2018/002475.html
week 2001: qc: percentage of actual to expected complete observations - https://postal.unavco.org/pipermail/teqc/2018/002483.html
week 2014: qc: interpreting slips - https://postal.unavco.org/pipermail/teqc/2018/002521.html
week 2015: qc: loss-of-lock - https://postal.unavco.org/pipermail/teqc/2018/002524.html
week 2016: qc: observations per slip - https://postal.unavco.org/pipermail/teqc/2018/002526.html
week 2017: qc: multipath rms - https://postal.unavco.org/pipermail/teqc/2018/002527.html
week 2018: qc: signal-to-noise - https://postal.unavco.org/pipermail/teqc/2018/002532.html
week 2019: qc: the ASCII time plot - https://postal.unavco.org/pipermail/teqc/2018/002534.html
week 2020: qc: little known (but sometimes useful) options - https://postal.unavco.org/pipermail/teqc/2018/002535.html
week 2021: qc: qc full: the '-dn' and '+dn' ASCII time plot lines, part I - https://postal.unavco.org/pipermail/teqc/2018/002544.html
week 2022: qc: qc full: the '-dn' and '+dn' ASCII time plot lines, part II - https://postal.unavco.org/pipermail/teqc/2018/002554.html
week 2023: qc: point-position elevation restrictions - https://postal.unavco.org/pipermail/teqc/2018/002556.html

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