Re: gpsd_json(5) and cgps seem to differ

[Gary E. Miller]

Yo Greg!

On Fri, 09 Jun 2023 19:56:44 -0400
Greg Troxel <gdt@lexort.com> wrote:

> > I expected the PRN for SB satellites to be in the range 100-164  
> 
> What is SB?  SBAS?

Yes.  SBAS sats come from many different countries, but they all use
the same secret ITU data protocol.  Not the same one that GPS sats use.

Ssome newer receeivers do not even bother with SBAS anymore.

Since there is no standardization, gpsd uses the numbers that u-blox uses.
From include/gps.h:

    /* gnssid:svid:sigid, as defined by u-blox 8/9:
     *  gnssid        svid (native PRN)
     *  0 = GPS           1-32
     *  1 = SBAS          120-158
     *  2 = Galileo       1-36
     *  3 - BeiDou        1-37
     *  4 = IMES          1-10
     *  5 = QZSS          1-5       Undocumented u-blox goes to 7
     *  6 = GLONASS       1-32, 255
     *  7 = NavIC (IRNSS) 1-11       ZED-F9T

There are way too many gnssid:svid conversions to NMEA PRN to be
documented.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

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