[teqc] inexplicable value on Galileo Navigation Message

Lou Estey lou at unavco.org
Wed Jan 30 07:34:55 MST 2019

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.


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