ADS-B question
I'm an ADS-B newbie. Can someone tell me: Is the "Groundspeed" reported on ADS-B output the speed across the ground? or, the indicated airspeed? If the airplane is in a very steep dive (like near vertical) the "airspeed" and "groundspeed" will be very different values, which is reported in the output? (is it ASI based? or GPS based?)