Magnus Danielson wrote: > > Bruce, > > > > > >> >> Although it is labelled as SV number, my version of the documentation >> >> clearly states that the meaning of byte 4 is the SV PRN#. >> >> >> > > > > It actually does not clearly states that in my documentation. It > > contradicts itself! > > > > Byte Item Type Value Meaning > > 2 Sat PRN # UINT8 0 Data that is not satellite ID-specific > > 1 to 32 Satellite PRN number > > > > Byte Item Type Meaning > > 4 SV number UINT8 SV PRN number > > > > The field SV number (which is what we are looking for) is said to have the > > meaning of SV PRN number. > > > > > Perhaps Trimble's SV number = GPS SVID (as defined on page 8 of the GPS Interface control document) for SVs: SVID = PRN#.
>> >> However as you say since the PRN# is given in the common 4 byte header >> >> this would seem somewhat redundant. >> >> >> > > > > With the above writing, you can almost assume it is a documenation miss, > > but it > > needs to be confirmed. > > > > If you look at the Item numbers, they match what is in the ICD-200 so it is > > likely they have propper meanings. > > > > Also notice how the PRN number field is limited in the range 1-32 where as > > no > > such limitation is given for the SV number. > > > > > >> >> The documentation is certainly inconsistent and confusing. >> >> >> > > > > Inconsistent and confusing yes, but there is only 4 characters too much that > > cause that confusion. If you assume they should not be there it makes > > perfectly sense. > > > > > >> >> I guess the operational test is: >> >> Does the displayed SV number contain values greater than 32 (current >> >> values for SVN can be as high as 61, the maximum value for PRN is 32)? >> >> If so then its very likely to be the SVN and not the PRN. >> >> >> > > > > Rather, when dumping this, we can verify that the PRN numbers in byte 2 > > and SV number in byte 4 matches the PRN and SVN mapping available. > > To help confuse things, I noticed that there is still birds having the same > > PRN and SVN numbers. > > > > Cheers, > > Magnus > > > > > Hej Magnus Perhaps all is explained, if one notes that the SVID's described in the GPS Interface Control document are identical to the SV PRN# except when SVID is used to differentiate between data pages. PRN# can be as high as 37 (but not for SVs which are limited to a maximum of 32). I didnt find any mention of the SVN # in the Interface Control document so maybe it isnt broadcast (or at least it isnt publicly available via GPS messages). The Motorola M12+ user manual indicates that the SVID is used in some messages. Has anyone dumped Thunderbolt report packets 0x58 to a text file? Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
