That is correct Murray Cod.
They do work on baro pressure, one "click" on the AP's ALT knob and you climb (or descend) 10ft. It is alot more planning with programming waypoints into the GPS but the end result is less "noise" compared to a humans input.
I should point out this is for gravity data which needs very smooth air (and control inputs
) and normally done quite high - 1000ft
DStar
