GPS Error Measurement
An empirical estimation of GPS precision (in the sense of giving measures
consistent with themselves).
I placed my Holux GR-213 (SirfSTAR-III GPS mouse) on a fixed position,
and captured its NMEA output during two intervals separated by some
2005/11/20 22:55 to 2005/11/24 14:56;
2006/02/19 01:21 to 2006/02/27 14:41;
There's a total of 955468 measurements in the sum of both intervals.
I then wrote a program to process that NMEA
data and produce a gnuplot script
that will in turn produce a graphic chart of the GPS position variations
(i.e, "errors") found on the collected data, using colors to
diferentiate the measurements by their reported
Dispersion of Precision).
Beware of GPS measurements with HDOP > 2.0 (especially > 4); you
could easily be off a few hundred meters... :-/
Measurements with HDOP <=2.0 (especially <= 1.0) tend to be
very precise, in the range of less than 50 (20) meters.
Last modified: Mon Feb 27 20:32:16 EST 2006