GPS Error rates

Well, the laptop still will not boot but in the mean time, I’ve got a cheap netbook that will be my development environment from here on in.  I’ve recovered the data off the hard drive and in there was the GPS error data.  I wanted to produce a physical geo-plot of the data but did not have time, so have the distance from a fixed point instead.  This picture shows about 900 distance measurements (in meters) based on readings from the GPS module (em-406a with WAAS enabled) at 3 second intervals.  This was sort of a worst case scenario - no pre-locking on satellites, with lots of trees and houses around. 

Note - it is not until about 25 minutes in that the signal seems to get tighter.  I’m assuming by that point it has locked onto 4+ satellites.  Also note the GPS drift on about a 3 minute cycle.

This entry was posted on 8. April 2010 at 02:28 and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or trackback from your own site.