[teqc] Strange results with trimble file

Lou Estey lou at unavco.org
Wed Aug 11 07:40:44 MDT 2010


Pierre,

> Hi everybody, this is the first time I am posting. So please apologize
> if I didn't exactly follow the rules.

I suppose the only rule for members to know is that emails from members
larger than 40 KB are not automatically distributed to the list and
require approval.  Usually I discourage posting of data files to the list.

Your email had two attached files: a .t01 and a .10S.  I can't figure out
from your message below what the .10S is a qc of, but I suspect that it
based on the RINEX created by Trimble's Converttorinex.  Why?  Based on
your concern over the clock lines, the attached .10S shows that the RINEX
had millisecond jumps in the time tag and smooth phase and pseudorange
data.  This is one of two styles of RINEX that we long abandoned --
back in Oct 2006.  See http://ls.unavco.org/pipermail/teqc/2006/000414.html
and 2006 Oct 25 entry in http://facility.unavco.org/software/teqc/log.html

Or, to put it another way, Trimble's Converttorinex (run with whatever
options you had set with it) created RINEX equivalent to translation of
`teqc -smtt ...`, whereas the current teqc default is equivalent to
`teqc +smtt ...`.

(The translation to RINEX of 38621420.dat (from `rupkr00 -d 38621420.t01`)
using teqc, and then qc of the teqc-produced RINEX shows exactly what I
expect -- i.e. no strange results.)

The community at large agreed that RINEX with smooth time tags (i.e. the
epochs are +-0.5 ms within actual GPS time, and not a floating receiver
time) is the better approach.

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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> I received from the field a set of files related to static measurements
> observed with Trimble GPS receivers: 3861420.T01 (attached),
> 3861420.obs, 3861420.nav + 3861420.10S (attached) and the other files
> produced by running teqc.
>
> The T01 file has been converted by Trimble utility Converttorinex, as
> mentionned in the header of the .nav or .obs file
>
> The .10S file and the other ones has been generated by teqc (2010Mar17)
>
> To check what was done by contractor :
>
> Check1:
>
> I ran runpkr00 (from Trimble utility)to extract the files from T01, then
> dat2rin (from Trimble utility) and finally teqc +qc (2010Mar17).
>
> I got a .10S file that is different from the one mentionned above.
>
> The main differences are:
>
> In the SV symbol track, all the C and m symbols havebben replaced by o
> as displayed below (all SVs lines are showing the same change - from C
> to o):
>
> _ _
>
> _first file:_ 28|-CCCCCCCCCCCCCCCCCCCCCCCCCm--__ ____| 28
>
> _ _
>
> _check1:_ 28|--ooooooooooooooooooooooooo--__ ____| 28
>
> The clock reset line has changed as well:
>
> _ _
>
> _first file:_
> Clk|                                                                        |Clk
>
> _ _
>
> _check1:
> _Clk|------------------------------------------------------------------------|Clk
>
> Other figures related to clock receiver have changed too:
>
> _
>
> first file:
>
> _
>
> No. of Rx clock offsets : 0
>
> Total Rx clock drift : 0.000000 ms
>
> Rate of Rx clock drift : 0.000 ms/hr
>
> Avg time between resets : Inf minute(s)
>
> _ _
>
> _check1:_
>
> __
>
> No. of Rx clock offsets : 85
>
> Total Rx clock drift : -85.000000 ms
>
> Rate of Rx clock drift : -5.172 ms/hr
>
> Avg time between resets : 11.602 minute(s)
>
> So I did a second check:
>
> Check 2:
>
> with the .dat and .10n file got during check1, I ran the command teqc
> -tr d +nav ....... to get the .10o and then ran teqc +qc.
>
> The new .10S is different again from the two aforementionned ones.
>
> The SV symbol tracks are identical betwwen check1 and check2,
>
> _ _
>
> _check1:_ 28|--ooooooooooooooooooooooooo--__ ____| 28
>
> _ _
>
> _check1:_
> Clk|------------------------------------------------------------------------|Clk
>
> but the clock reset line has changed
>
> _ _
>
> _check2:_ 28|--ooooooooooooooooooooooooo--__ ____| 28
>
> _ _
>
> _check2:_
> Clk|                                                                        |Clk
>
> and
>
> _ _
>
> _check1:_
>
> __
>
> No. of Rx clock offsets : 85
>
> Total Rx clock drift : -85.000000 ms
>
> Rate of Rx clock drift : -5.172 ms/hr
>
> Avg time between resets : 11.602 minute(s)
>
> _ _
>
> _check2:_
>
> __
>
> No. of Rx clock offsets : 0
>
> Total Rx clock drift : 0.000000 ms
>
> Rate of Rx clock drift : 0.000 ms/hr
>
> Avg time between resets : Inf minute(s)
>
> I am really wondering how we can interpret these apparently
> contradictory results.
>
> Is one out of this sequence of commands errouneous ?
>
> Which .10S file describes at the best the behaviour of the GPS receiver
> during this session of static measurements ?
>
> Sorry to have been so long.
>


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