So how does the wifi iPad know its location?

Sorry if this has been covered already - but - our wifi iPad, which I understood NOT to have GPS like the 3G version, somehow still can self-determine its position in Maps. In fact, it can pin it down surprisingly accurately. It does the same thing in the SkyVoyager astronomy app.

I thought I was pretty well read about the iPad but this one has me baffled. Not that I am complaining...

Anyone?

It uses the Skyhook wifi positioning system, just like the iPod touch.
http://www.skyhookwireless.com/

Cool, Skyhook is a new one on me. Seems to work, at least from my house!

Thanks for the reply, Aptmunich!