Those Shadow Box gps must have a clever way of handling altitude.
As I understand it gps altitude readings are generally unreliable. The Navi readings certainly are. The Garmin cycling gps use a barometric doodad for altitude and they are are still considered unreliable by some.
SB records acceleration and attitude too and reports a bunch of derived data. I wonder if it uses some clever gps analysis or maybe it has an inertial recorder, a gyro or some such?
) Looks like the chop we get here in Yeppoon 
