Re: DGPS / SBAS

[Greg Troxel]

Nick Taylor <nicktaylor@dataskill.uk> writes:

> If the SBAS satellite signal is lost, I would expect fix to revert to
> basic GPS after the cached DGPS data expires?

I would expect that too.

> I have run a test where I move antenna so that SBAS signals not seen
> (with antenna in this location I never get DGPS fix)

Can you post s summary of statistics for 24h with SBAS and then 24h
post-move?  Besides the fix indicator, I would more or less expec the
SBAS statistics to be tighter.

> 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.
>
> We are using the SIM68 chip:

Obviously you should kill and restart gpsd to make sure that this is a
case of the GNSS receiver still reporting DGPS when it isn't.

Then, it sounds like you should follow up with your receiver
manufacturer, starting with reading the documentation and filing a bug
report about that if it doesn't clearly explain the loss-of-SBAS
behavior.  Good luck!