[teqc] latest development version of teqc on-line (16 Mar 2009)

Lou Estey lou at unavco.org
Tue Mar 17 11:48:42 MDT 2009


Lou Estey wrote:

> The latest development version (16 Mar 2008) of teqc is on-line:
> http://facility.unavco.org/software/teqc/teqc.html#executables
> As usual, save a copy of your current executable in case there
> is some unexpected problem with the new executable.
> 
> The main fixes and changes since 2 Oct 2008 are fairly extensive
> and are given in detail in:
> http://facility.unavco.org/software/teqc/log.html
> but I'll give a very brief summary here:

<snip></snip>

> * default removal of duplicated SVs in RINEX output; this is
> a rare but possible result in raw data

This change also effects and correctly normalizes qc results if there
are repeated SVs in epochs.  Since this had been rare, I never bothered
with looking for and removing SV duplication, but occasional SV duplication
in epochs is now showing up with increased regularity -- far more than
I imagined it would. (I won't say where I've seen it, but let's just
say this is now occurring in several widely used formats.)

The problem, when it occurred, was inflating the qc full observation count.
In one sample file that was sent to me, the qc full with the 2 Oct 2008
version of teqc yields:

[2712] teqc.20081002 -notice +qcq 20010281.09O 2>&1 | tail -2
       first epoch    last epoch    hrs   dt  #expt  #have   %   mp1   mp2 o/slps
SUM 09  1 28 15:30 09  1 29 16:29 25.00  30  25951  27075 104  0.07  0.16    444

In other words, the no. of "observations" in the input RINEX exceeds
the possible expected number by 4%.  With the 16 Mar 2008 version of
teqc, which by default removes the duplicates:

[2713] teqc -notice +qcq 20010281.09O 2>&1 | tail -2
       first epoch    last epoch    hrs   dt  #expt  #have   %   mp1   mp2 o/slps
SUM 09  1 28 15:30 09  1 29 16:29 25.00  30  25951  25924 100  0.07  0.17    425

where now the no. of observations  < no. expected, and is 99.896% =
25924/25951.  As a check, you can leave the duplicates in with new
'+sv_dup' option in the 16 Mar 2009 version:

[2714] teqc -notice +sv_dup +qcq 20010281.09O 2>&1 | tail -2
       first epoch    last epoch    hrs   dt  #expt  #have   %   mp1   mp2 o/slps
SUM 09  1 28 15:30 09  1 29 16:29 25.00  30  25951  27075 104  0.07  0.16    444

getting us back to the older wrong result.  The actual no. of
duplicates in this file?

[2706] teqc +qcq 20010281.09O 2>&1 | grep "duplicate SV" | wc -l
1292

whereas 27075 - 25924 = 1151 < 1292, so 141 of those duplicate SVs
must have incomplete data (i.e. incomplete phase+pseudorange on both
L1 and L2).

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
    WWW:  http://www.unavco.org   http://jules.unavco.org

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