Etrex Summit Speed/Velocity Accuracy

[whitepjs]

Hi

I'm trying to find out how accurate my Etrex Summit is at calculating speed or velocity over land (in a car). My car speedo seems to be acting strangely, and I want to check how accurate or inaccurate it is before faffing around taking it to a garage.

I know that the Summit is meant to have an accuracy of +/- 0.1 Knots RMS in steady state, but don't really understand what that means. If the Etrex is showing accuracy to 33ft on the satellite setup/info page when the unit is placed on the dashboard, how accurate is it likely to be mph wise (+/- what roughly?)

Many thanks

David

[Skippy]

Hello and

What it means is that a GPS receiver will report your speed to within about .1 Knots (roughly .1 MPH) when traveling on flat ground in a straight line at a constant speed with a 3D GPS fix.

If you are concerned that your car speedometer is reading too fast then remember that the law is that a speedometer must read 0% to 10% fast. In my experience, the accuracy can be anywhere in this range.

Lots of people are surprised to find that their speedo is not reading accurately! There have been a few discussions about this in the past.

Do a search or have a read of this thread:

http://www.pocketgpsworld.com/modules.php?name=Forums&file=viewtopic&t=13472&highlight=accuracy
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