"Mogens Beltoft" writes:

We use GPS receivers in our gliders, and most of them can find the wind
direction and speed automatically by detecting that you have made a full 360
degree turn (happens often for gliders when searching for thermals), and
analysing the 360 degree turn you have made for drift direction and speed.

And I'm certain that the information is used to display a wind-corrected
heading.

So which GPS receivers do this for you?

We use Pocket-Nav http://www.cambridge-aero.com/pocketNAV.htm and others.

That seems to be an application that runs on an external computing device,
not something that a GPS receiver itself provides. Interesting, but
different.

Dave