[R] Derivative of nonparametric curve

[FMH]

Dear All,

I'm looking for a way on computing the derivative of first and second order of a smoothing curve produced by a nonprametric regression. For instance, if we run the R script below, a smooth nonparametric regression curve is produced. 

provide.data(trawl)
Zone92   <- (Year == 0 & Zone == 1)
Position <- cbind(Longitude - 143, Latitude)
dimnames(Position)[[2]][1] <- "Longitude - 143"
sm.regression(Longitude, Score1, method = "aicc", col = "red",  model = "linear")

Could someone please give some hints on the way to find the derivative on the curve at some points ?

Thank you.
Kagba