3 ms·

I funded hoping for a couple. I imagine the centimetre accuracy will be hard yo achieve,but what sort of accuracy is required to calculate average speed over 20

• Someone 13y ago
  In general, assuming a perfect clock, t seconds over 200m with an independent measuring error of x/2 at both ends will measure as t seconds over (200 +/- x) m [1], for a speed of 200/t +/- x/t m/s So, for a given x, the error grows as 1/t. The longer t (= the slower your movement), the lower the absolute error. For a snail, you don't even need a GPS; just say "2 km/h" and you will be within 2 km/h. However, things are better, as measuring errors for GPS for nearby (in time and place) positions aren't independent. If your position is of by x meters in direction D now, chances are it will still be more or less of by x meters in direction D in a few seconds. Back to your question: I wouldn't know, but I think you want to rephrase it in terms of relative error or specify at what speed you want to know the answer. [1] the math is the other way around, but that doesn't matter much.