From: Bruce Griffiths <[EMAIL PROTECTED]> Subject: Re: [time-nuts] GPS PRN vs SV...?? Date: Sat, 09 Feb 2008 21:57:57 +1300 Message-ID: <[EMAIL PROTECTED]>
Hej Bruce, > > > 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#. Yes, but SVID isn't SVN, which may be the cause of confusion. Actual SVNs isn't meaningfull for normal GPS users and bears no meaning to the receivers, where SVID and PRN# is the important things. > 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). It would appear that during normal operation PRN# is set to the SVID. There is actually a SVID to PRN# mapping provided, but the SVID range isn't free enought to hold SVN numbers. > 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). Looking into IS-GPS-200D I am inclined to agree. > 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? Requesting data for PRN# 1-32 and hex-dumping the result would be of interest. Cheers, Magnus _______________________________________________ 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.
