[teqc] Tow

Lou Estey lou at unavco.org
Wed May 25 08:01:23 MDT 2016


Thanks, Teresa.  A very good suggestion.

I should mention that a latent part of teqc's qc is, in fact, also screening
suspect navigation messages.  All (or most) of this screening also takes place
during translation and editing (splicing RINEX nav, header field editing, etc.).
Some parts of this screening you can control; other parts you cannot (like
this far out-of-bounds ToW issue).  This screening has been a work-in-progress
since teqc started and it is still evolving.

By the way, I had been planning a whole segment on screening of navigation
messages for one or more of my 'helpful tip of week' emails, which came to
mind because of two other recent qc email threads to me regarding "not normal"
navigation messages in RINEX.  One was an attempt to use a GPS SV that had
been set to 'unhealthy' (in fact, that SV had even been decommissioned) and
the other was an attempt to use navigation messages output from a synthetic
source which had, well, some interesting differences from real broadcast
navigation messages.

cheers,
--lou

On 24-May-16 7:13 PM, Teresa Vanhove wrote:
> If you throw out the bogus rinex nav files  you can run teqc on the
> rinex obs files either with no nav file or with a rinex nav file of
> the same date pulled from one of the archive center's ftp areas.    I
> run teqc on rinex obs files generated by the BNC RTCM tool all the
> time but we never generate any rinex nav files so there has never been
> any issue with getting the teqc +qc output we use.  We've never
> worried about screening the qc based on elevation angle or anything
> like that.
>
> Cheers,
> Teresa
>
>
> On Tue, May 24, 2016 at 8:15 AM, Lou Estey <lou at unavco.org> wrote:
>> No, the trouble is with the translator.  Having no ToW in the input is no
>> excuse for
>> putting in a useless and obviously wrong value (9.999000000000e+08).
>>
>> There is the same issue with some of the formats that teqc reads and
>> converts to
>> RINEX.  There are two options: 1) just put a value of zero for the ToW (as
>> Werner Gurtner
>> did in at least one of his early translators) or 2) use the time of the last
>> observation
>> as a proxy.  (And we also know that the ToW has a granularity of 6 seconds
>> in GPS.)
>>
>> If the input has no ToW, teqc uses option 2 when possible, i.e. when there
>> are observations.
>>
>> Hence, I don't except excuses for this.
>>
>> Plus, somebody needs to fix RTCM. :)
>>
>> --lou
>>
>>
>> On 24-May-16 8:00 AM, Dmitry Kolosov wrote:
>>>
>>> Lou,
>>> I am afraid the problem is not in BNC translator.
>>> It simply does not have this information to put in RINEX: ToW is not a
>>> part of RTCM ephemeris message.
>>> Dmitry
>>>
>>> ----
>>> Dmitry Kolosov
>>> Director, Global Application Software Development
>>> Topcon Positioning Systems
>>> DKolosov at topcon.com
>>>
>>>
>>>> -----Original Message-----
>>>> From: teqc [mailto:teqc-bounces at postal.unavco.org] On Behalf Of Lou Estey
>>>> Sent: Tuesday, May 24, 2016 16:49
>>>> To: Bonnes Gregory (TELESPAZIO FRANCE) <gregory.bonnes at cnes.fr>
>>>> Cc: teqc at unavco.org
>>>> Subject: Re: [teqc] Tow
>>>>
>>>> dear Grégory,
>>>>
>>>> Well, from teqc's point of view, the RINEX navigation files that
>>>> BNC-produced in this
>>>> case are garbage.
>>>> (Teqc needs the ToW in order to properly order the messages by receive
>>>> time.) There is
>>>> no work-around.
>>>>
>>>> Maybe you should contact the authors of the BNC tools and ask them to fix
>>>> their
>>>> translator.
>>>>
>>>> --lou
>>>>
>>>> On 24-May-16 7:41 AM, Bonnes Gregory (TELESPAZIO FRANCE) wrote:
>>>>>
>>>>> Dear Lou,
>>>>>
>>>>> I'm trying to make a qc on Rinex2.11 files providing by BNC tools
>>>>> (converting RTCM
>>>>
>>>> in rinex2 files). And it seems that on RTCM  the ToW is a bad value
>>>> (9.999000000000e+08) due to a non-transmission of this data. When I do a
>>>> qc with teqc
>>>> I have an error like this :
>>>>>
>>>>>
>>>>> ! Warning ! NAVSTAR GPS SV G02: magnitude of ephemeris ToE - ToW too
>>>>> large (-
>>>>
>>>> 16658640.0 min) @ ToC= 2016 Apr 28 10:00:00.000
>>>>>
>>>>>
>>>>> A long time ago with another version of teqc (I don't remember which
>>>>> version), the
>>>>
>>>> qc was possible. I would like to know if it's possible to avoid this
>>>> control.
>>>>>
>>>>> Thank you for your help
>>>>>
>>>>> Gregory
>>>>>
>>>>> -----Message d'origine-----
>>>>> De : Lou Estey [mailto:lou at unavco.org]
>>>>> Envoyé : mardi 24 mai 2016 15:23
>>>>> À : Bonnes Gregory (TELESPAZIO FRANCE)
>>>>> Cc : teqc at unavco.org; lou at unavco.org
>>>>> Objet : Re: [teqc] Tow
>>>>>
>>>>> dear Grégory,
>>>>>
>>>>> ToW control?  What exactly are you trying to work around?
>>>>>
>>>>> --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
>>>>
>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>
>>>>>
>>>>> On 24-May-16 1:17 AM, Bonnes Gregory (TELESPAZIO FRANCE) wrote:
>>>>>>
>>>>>> Dear All,
>>>>>>
>>>>>> Is it possible to desactivate the teqc control for the ToW in
>>>>>> navigation messages ?
>>>>>>
>>>>>> Thank you
>>>>>>
>>>>>> Best Regards/ Meilleures Salutations
>>>>>>
>>>>>> Grégory BONNES
>>>>>>
>>>>>> REGINA project
>>>>>> Tel :+33 (0)5 61 27 31 31  (office 7.56.10) / +33 (0)6 09 06 53 24
>>>>>> Email : _gregory.bonnes at cnes.Fr_ <mailto:thierry.lawrence at cnes.fr>
>>>>>> TELESPAZIO France support for CNES's operations



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