Re: Roughtly converting DOP to metric error

speleoluc@xxxxxxxxx wrote:
On 1 mar, 22:14, Sam Wormley <sworml...@xxxxxxxxx> wrote:
speleo...@xxxxxxxxx wrote:
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
I've never known what algorithm Garmin uses to estimate error.
If the receiver knew its true error... it could correct for the
same.

Isn't this reported error a maximum uncertainty around the displayed
position?


Luc Le Blanc


Error is usually reported as 1-sigma or 2DRMS oe similar.... it not
in the form of worst case.

.

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 ... precision estimation on data the DOP value doesn't convey? ...    I've never known what algorithm Garmin uses to estimate error. ...
    (sci.geo.satellite-nav)
  • Re: Roughtly converting DOP to metric error
    ... the GGA and GSA NMEA sentences provide ... users with a rough error value in meters (as most GPS units do) from ... 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? ...
    (sci.geo.satellite-nav)
  • 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 ... Luc Le Blanc ... thing from the NMEA data I get from the GPS, or is the GPS basing its ...
    (sci.geo.satellite-nav)
  • Re: Roughtly converting DOP to metric error
    ... My cave survey freeware connects to a GPS for surface tracking. ... connect to a Bluetooth GPS, the GGA and GSA NMEA sentences provide ...
    (sci.geo.satellite-nav)
  • Roughtly converting DOP to metric error
    ... My cave survey freeware connects to a GPS for surface tracking. ... the GGA and GSA NMEA sentences provide ... various flavors of DOP values. ...
    (sci.geo.satellite-nav)