Getting most accurate derivative (velocity) from a discrete set of position data

I have a set of position values and time values. I need to obtain the velocity from this data. wht are the different ways i can use and which one will give the most accurate value of velocity from position and time data?

Answer 1

[Torsten]

Start with

velocity(i+1/2) = norm(position(i+1)-position(i))/(t(i+1)-t(i))

and see what you get.