[teqc] what does "invalid event flag" mean?

Lou Estey lou at unavco.org
Sun Mar 26 07:13:59 MST 2006

hi John,

> I hope you will excuse my very ill-informed question since I know little 
> about TEQC. I am trying to do a basic quality check on a potentially 
> ill-formed RINEX file which was generated by an experimental program.
> I know the receiver designation is wrong, but that's not my worry right 
> now. TEQC stops with a message about "invalid event flag" and I'm trying 
> to determine what that means. A google search for:
>   teqc "invalid event flag"
> returns just one link, which is actually the teqc binary file itself. 
> I'm the only one who's ever encountered this message?
> E:\Rinex>teqc +qc -O.int 1 0324-1240.06o
> ! Notice ! receiver designation "Antaris" does not match any in the IGS 
> standard table
> qc lite>
> teqc: failure to read " 21724091.864 6 114160976.090 6        40.000 6 
>  2943.449 6" on line 28 of "0324-1240.06o"
>         (invalid event flag: should be 2-6) ... exiting
> I assume it's bad form to post the actual rinex file to a mailing list, 
> but if you'd like to have a look, here is the file in question:
> http://www.bealecorner.com/D30/misc/0324-1240.06o.txt

There's a 40-kB limit on the size of emails posted to the list;
thus, emailing the whole file would have just gone to me and not the
list.  Emailing a snippet or posting the file on line is the best

The main problem with this file is that it's pseudo-RINEX, not proper
RINEX, i.e. it sort of looks like RINEX but doesn't follow all the
rules yet.  In particular (for this message), the SV list is
supposed to not have more than 12 SVs per line, e.g. from
http://www.aiub.unibe.ch/download/rinex/rinex210.txt :

  |             | - Number of satellites in current epoch         |     I3,    |
  |             | - List of PRNs (sat.numbers with system         | 12(A1,I2), |
  |             |   identifier, see 5.1) in current epoch         |            |
  |             | - receiver clock offset (seconds, optional)     |   F12.9    |
  |             |                                                 |            |
  |             |   If more than 12 satellites: Use continuation  |    32X,    |
  |             |   line(s)                                       | 12(A1,I2)  |

So the lines in this file like:

  06 03 24 20 40 30.0000000  0 13G03G07G14G15G16G18G21G22G26G29S22S34S35

should be two lines:

  06 03 24 20 40 30.0000000  0 13G03G07G14G15G16G18G21G22G26G29S22S34

(The "S35" in the wrong place is spilling over into the area reserved for
the receiver clock offset -- if it had been present.)
This error in the formatting is causing the teqc parser to get out of sync
with the pseudo-RINEX formatting of this file, causing it to read the
first data line of the second epoch as the EPOCH/SAT line of the second
epoch -- and you get the resulting peculiar message from teqc.

Hope this helps,

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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