AW: [Paparazzi-devel] GPS precision

[Ethan Arnold]

Yes, but DGPS with that processing is much more complicated and expensive
than the experiment I originally proposed. We know that will work, even down
to a few centimeters (!!) accuracy. I however am aiming for something much
cheaper, even if with restrictions.

Assuming the ground receiver is on a big open field, I think the probability
that the airborne vehicle will see more satellites is rather small (if
within a few 100m range of the ground station). And if it does, one could
detect that from the GPS receiver status and be warned.

Regards,
Ethan

-----Ursprüngliche Nachricht-----
Von: address@hidden
[mailto:address@hidden Im Auftrag von
Tom Becker
Gesendet: Dienstag, 4. September 2007 20:54
An: address@hidden
Betreff: Re: [Paparazzi-devel] GPS precision

 > ... you need to determine the error induced by each satellite, and send
THAT information to the airborne station.

That is exactly what a fixed DGPS ground station does.  It determines the
pseudorange errors  from each visible vehicle and transmits those
corrections to moving receivers.  Surveyors and boaters use DGPS all the
time, and SBAS is just another form of it, distributed by InmarSats instead
of by LF beacons, broadcast FM subcarriers or Internet.