Re: [gpsd-dev] 'status' field in TPV JSON to include DGPS and RTK solution indicators

[Gary E. Miller]

Yo Max!

On Wed, 15 Jun 2016 00:37:08 +0200
Max Schulze <address@hidden> wrote:

> Hey Gary,
> 
> I totally respect the choices you make, just let me maybe clarify the
> use cases, as I consider them to be more generic than vendor-specific.
> 
> As I do get it, statuses 1 is for normal gps, 2 is when you use a
> wide-area augmentation systems (SBAS via satellite) that lets you do
> differential gps, and for 4,5 you need an earth-bound base-station
> (then comes the distance to the base-station into play, the base
> vector) and lets you do another, more-precise form of DGPS, either
> with fixed or float integers.

So I used to think, but I just spent a lot of time on RTCM for the
Skytrazq.  The data in WAAS, is sesentially the same as the data in
NTRIP.  And gpsd processes them the exact same.  If either WAAS or other
DGPS status is indicated by the GPS the DOPs are reduced by the same
amount.

I'll believe there is a difference when I can see a difference.

> > Sadly, GGA is not evern very common, or even standardized.  Which
> > is why gpsd tries to abstract all the variants into something mostly
> > consistent.
> >
> > And RTK is essentially identical to DGPS, so I just lumped them in
> > together.  The data fields are identical.  
> On the internet I found the NMEA 0183 Standard V3.01 and V4.0
> (searching for its exact title: "National Marine Electronics
> Association NMEA 0183 Standard" ;-) ) that does indeed specify all
> these indicators.

Oh, there is a standard, just not impmented the same way by different
vendors.  And not all GPS speak NMEA in their high rez modes.

So I'll wait for a valid use case, then hopefully things will be clearer.

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

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