beren at beren at
Sun Jun 8 18:07:33 CEST 2008

On Sunday 08 June 2008 10:41:37 Brad Midgley wrote:
> Tim
> >> gpsd has a mode where it listens to both the gps and an online dgps
> >> source and produces corrected output. See the manpage for gpsd. I
> >> think you have to have the unit online continuously.
> >
> > Does gpsd have control over the various satelite signals? I thought
> > D-GPS only works before position calculation. If gpsd only gets the
> > composed position, then it's not possible to do D-GPS.
> I'm not an expert here, but maybe correction does require more raw
> data. It might depend on what the protocol is between gpsd and the
> gps. The gpsd docs don't shed any more light on it. It would be a good
> question for the gpsd mailing lists.

The problem here is not with gpsd but rather that we might not be able to get 
the required raw satellite measurements out of the Antaris chip due to some 
licence restriction :(
Not having a Freerunner at hand, I wrote a crude test program for accessing 
the required rxm-raw message of the GPS chip and sent it to Andy Green. The 
results were not encouraging - although I'd love to hear some official 
statement about the license status for the GPS chip before jumping to 
premature conclusions but currently it seems that DGPS will not be possible 
with the Freerunner.


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