Re: Roughtly converting DOP to metric error

On 1 mar, 13:59, Sam Wormley <sworml...@xxxxxxxxx> wrote:
speleo...@xxxxxxxxx wrote:
Hi,

My cave survey freeware connects to a GPS for surface tracking. When I
connect to a Bluetooth GPS, the GGA and GSA NMEA sentences provide
various flavors of DOP values (PDOP, HDOP, VDOP). How can I provide
users with a rough error value in meters (as most GPS units do) from
these unitless numbers?

Luc Le Blanc
http://www.speleo.qc.ca/Auriga

   See:http://edu-observatory.org/gps/gps_accuracy.html

I found such info pages googling for a simple answer, but I can't help
but think that when I turn on my GPS 76, I don't have to input various
parameters to get a position error in meters. Can't I do the same
thing from the NMEA data I get from the GPS, or is the GPS basing its
precision estimation on data the DOP value doesn't convey?


Luc Le Blanc
.

Relevant Pages

  • Re: Roughtly converting DOP to metric error
    ... My cave survey freeware connects to a GPS for surface tracking. ... the GGA and GSA NMEA sentences provide ... Bad DOP does not always mean bad accuracy for example. ... Unfortunately, if you have only NMEA sentences, you usually don't have ...
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  • Re: Roughtly converting DOP to metric error
    ... but think that when I turn on my GPS 76, I don't have to input various ... thing from the NMEA data I get from the GPS, or is the GPS basing its ... I seriously doubt that anyone has actually tested one under a variety of conditions at accurately known locations for extended periods, so I don't think anyone knows how good the Garmin accuracy estimate is. ... If you run the DOP through a random weighting function or one based on astrological charts to create a nice looking number, I'll bet no one will ever be able to prove your result isn't as good as Garmin's. ...
    (sci.geo.satellite-nav)
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