Okay, facing doing some long missions and am concerned about baro drift, which we have seen in the past but are of larger concern with these longer flights.
It seems that it would be easy, and consistent with manned aviation, to tie the GND_ABS_PRESS or GND_ALT_OFFSET to an altimeter setting, so that over the course of a long flight or over long distance, you could compensate for drift by getting an updated altimeter setting. Possibly, even doing so automatically using the aircraft’s location to pull data from the nearest wx station within a user defined radius.
thoughts?