[teqc] inexplicable value on Galileo Navigation Message

Bonhoure Bernard Bernard.Bonhoure at cnes.fr
Fri Feb 1 09:58:44 MST 2019


Dear Lou,

Considering the RINEX 2.12 which supports  the Galileo navigation message for RINEX2, it seems that this is similar to the RINEX3 for the source description.

So we expect the following decimal values wrt signal frequencies for the Galileo Data source in RINEX2.12:
- Decimal 258 = binary 0100000010 for FNAV transmitted in E5aI signal (reserved or non defined bits are set to 0)
- Decimal 513 = binary 1000000001 for INAV transmitted in E1B signal
- Decimal 516 = binary 1000000100 for INAV transmitted in E5BI signal
- Decimal 517 = binary 1000000101 for INAV merged from E1B and E5BI signals, since INAV ephemeris parameters are transmitted in these both frequencies

For example in RINEX3 source for Trimble receivers are 258 for E5aI, 513 for E1B, and 516 for E5bI.
I guess that the source value of '1' in RINEX 2.12 for Trimble Alloy receivers using Teqc are rather for INAV sources E1B or E5bI, since we already see 258 values (for FNAV). I don't know the Trimble format (this is a proprietary format), but I imagine the '1' source should be rather 513 (E1B source), 516 (E5bI source) or 517 (merged E1B or E5bI sources, or unknown frequency source but with INAV inside).

Best Regards,

Bernard

Bernard BONHOURE 
GNSS/Galileo Navigation Senior Expert 
  
CNES – French Space Agency 
DSO/NT/SN 
 +33 (0)5 61 28 14 62 
 bernard.bonhoure at cnes.fr  

-----Message d'origine-----
De : teqc <teqc-bounces at postal.unavco.org> De la part de Lou Estey
Envoyé : vendredi 1 février 2019 15:22
À : Mathieu Peyréga <mathieu.peyrega at gmail.com>
Cc : teqc support discussion list <teqc at postal.unavco.org>
Objet : Re: [teqc] inexplicable value on Galileo Navigation Message

dear Mathieu,

You've never seen what kind of message?  A Galileo I/NAV from E1-B?

--lou

On 01-Feb-19 07:15 AM, Mathieu Peyréga wrote:
> Hello,
> 
> my GNSS station 
> (http://rgp.ign.fr/STATIONS/logsheet.php?nom=magc_20181016.log) is 
> based on a trimble board (bd970, and the rt27 to rinex streaming is 
> done with teqc). It's tracking Galileo for a while now, but I've never 
> seen this kind of message. Station is in metropolitan France and so 
> probably not seing any IRNSS signals (and anyway, option is not 
> activated on the firmware)
> 
> I'm keeping all .rt27 files in case and can provide them if needed for specific times.
> 
> Best regards,
> 
> Mathieu Peyréga
> --
> tel : +33 (0)6 87 30 83 59
> 
> 
> Le 01/02/2019 à 14:56, Lou Estey a écrit :
>> No one has commented on this in the last two days, either to this list or to me personally.
>> If you have any thoughts or comments about it, I suggest you try to 
>> send me something very soon, or this particular bit of grizzle in the 
>> sausage (*) will remain as part of RINEX creation in the next teqc release and may be around for a while after that.
>>
>> cheers,
>> --lou
>>
>> * see https://postal.unavco.org//pipermail/teqc/2018/002589.html
>>
>> On 30-Jan-19 07:34 AM, Lou Estey wrote:
>>> dear Grégory,
>>>
>>>> Yes we track IRNSS SV also
>>>
>>> Then teqc's message of:
>>> .dat 27/0x57-6: unknown SV type= 9
>>> might be referring to the IRNSS constellation.  The last 
>>> documentation I received from Trimble on .dat/.tgd record 27 (or 
>>> streaming 0x57-6) does not have a type = 9 defined, so this is something new that Trimble has added (for at least the Alloy).
>>>
>>> I have an email in to our contact at Trimble to get some 
>>> clarification on this (and two other questions).
>>>
>>>> You saying "it's due to limited information", does it mean that the problem coming from receiver ?
>>>
>>> No, the receiver is almost certainly fine.
>>>
>>> This is one of those cases where the RINEX specification is asking 
>>> for something that's not available in the input "data" (the decoded 
>>> Galileo navigation message in the Trimble .tgd format, record 28) or 
>>> not clearly evident (at least to me) from the documentation on that "data" (the Trimble documentation on record 28).
>>>
>>> Where you're seeing a value of 1 for the "data sources", it's very 
>>> clear from Trimble's documentation that the source of that 
>>> particular Galileo navigation message is E1-B.  That much is 100% 
>>> certain.  But, from what I understand, that's all that can be known about this situation from the documentation.
>>>
>>> Then for RINEX, bit 8 or 9 of the "data sources" value could also be set, i.e.
>>> from the RINEX spec:
>>>
>>> bit 8 set: af0-af2, ToC, SISA are for E5a,E1 bit 9 set: af0-af2, 
>>> ToC, SISA are for E5b,E1 bits 8-9; exclusive (only one bit can be 
>>> set)
>>>
>>> So in this case does one set bit 8 or bit 9?  I have no idea. Both 
>>> bits cannot be set (that much is 100% clear from the RINEX spec), so 
>>> I didn't set either one.  And, technically, not setting either bit 8 
>>> or bit 9 is totally valid given the current RINEX spec for the Galileo data sources.
>>>
>>> --lou
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