Re: DGPS / SBAS

[Greg Troxel]

"Gary E. Miller" <gem@rellim.com> writes:

>> After several days, cgps is still reporting DGPS fix (see attached 
>> screenshot) - you can see that SBAS SNR is zero and it's same for all 
>> SBAS satellites that I see shown.
>
> Oh, I see part of the confusion here. DGPS does not mean you see SBAS
> satellites.  They are independent values.
>
> Sadly no two firmware use the same definition for when to turn the
> DGPS flag on.

Agreed it's a mess but "DGPS" is obviously short for "Differential GPS"
and a receiver should only say it has that fixtype if it is applying
pseudorange corrections from either SBAS or some direct injection of
RTCM2, such as would happen with the old USCG beacons.

It seems pretty clear that either  this particular receiver is buggy or
that we're getting incorrect data about its behavior.