My em-406 unit says its travelling anywhere between 0 and 7 knots while it is stationary. This is an error of nearly 10km/h or 6miles/h
Am I doing something wrong here or is this error value normal?
What have been other peoples experience with the speed over ground reading, thanks.
With a half decent view of the sky I typically see <1 km/h speed reported when stationary. I’ve noticed it go up to ~5km/h in poor reception areas (car park buildings etc) but I’ve never seen much more than that.
Can’t say I have paid that much attention though sorry 
There are other ways of measuring speed using the GPS if you’re looking for better resolution. eg - http://nujournal.net/HighAccuracySpeed.pdf
Parked in an underground carpark complex today and am seeing up to 17km/h reported. Must be some freaky reflections going on 
SiRF III constantly amazes me where it will manage to get a signal at all.