[teqc] teqc spliced 1sec RINEX bug ... ?

Lou Estey lou at unavco.org
Tue Nov 2 11:52:18 MDT 2010


Dear Ant,

On 11/2/2010 9:18 AM, Sibthorpe, Ant (335H) wrote:
> Hi Lou,
>
> OK, I get the same issue with the attached sub-set of files when using:
>
> teqc -E +relax +out new.08o -igs -C2 -O.obs L1L2C1P1P2 -O.dec 1s -L2C_L2
> -n_GPS 64 -st 2008-11-18_21:00:00 -e 2008-11-20_03:00:00 -phc artu325c45.08o
> artu325d00.08o artu325d15.08o
>
> After checking again, it seems that the problem starts with the *d15* and
> onwards files in my larger set, because the first two files on their own
> work as expected. That's why there are three pairs of lines at the end in my
> initial email (one for each of *d15*, *d30* and *d45*). But I can¹t see
> anything obvious [visually] in *d15* that might do this. A start/end time
> issue...?

Yes, so it's a windowing bug in conjunction with -phc.  (nothing to do with
1-sec input).  The start/end times for your test input files are:

[3605] teqc +mds art*.08o
2008-11-20 02:45:00  2008-11-20 02:59:59    810492  artu325c45.08o
2008-11-20 03:00:00  2008-11-20 03:14:59    776379  artu325d00.08o
2008-11-20 03:15:00  2008-11-20 03:29:59    784928  artu325d15.08o

and the minimum command that causes the problem with these 3 files is:

teqc +out new.08o -e 2008-11-20_03:00:00 -phc art*.08o

and then the end of new.08o looks like:

  08 11 20  2 59 59.0000000  0 10G08G19G25G03G07G28G10G15G27G26
<data for epoch>
                             4  1
RINEX FILE SPLICE; other post-header comments skipped       COMMENT
  08 11 20  3  0  0.0000000  0 10G08G19G25G03G07G28G10G15G27G26
<data for epoch>
   1
other post-header comments skipped                          COMMENT

So teqc correctly inserts the minimum splice comment between the data
of artu325c45.08o and artu325d00.08o, correctly outputs the first epoch
of artu325d00.08o (because that's the end time specified with the '-e'
option, and then _incorrectly_ outputs a partial splice comment (i.e.
the missing whitespace and '4') at the end.

With a little experimenting, it looks like this bugs manifests itself
for each file boundary after the time window end time when '-phc' is
in use.  So:

teqc +out new.08o -e 2008-11-20_03:15:00 -phc art*.08o

new.08o is OK

teqc +out new.08o -e 2008-11-20_02:45:00 -phc art*.08o

new.08o with two sets of the partial splice comment at the end

although:

teqc +out new.08o -e 2008-11-20_02:59:59 -phc art*.08o

new.08o with one good and one bad splice comment at end (although
neither is needed)

teqc +out new.08o -e 2008-11-20_02:59:58 -phc art*.08o

new.08o with two sets of the partial splice comment at the end

So the full statement of the bug is: manifests itself
for each file boundary after the time window end time if window
end time < file end time when '-phc' is in use.

You've come across a strange one, that's certain. :)

cheers,
--lou


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