I have been playing around with MP/Pixhawk for a while (3DR Iris+ and Aero). During planning (setting waypoints) you may use the different Altitude settings Relative, Absolute and Terrain. During flight or simulation the altimeter always starts with 0ft (at home point) independant on which setting (e.g. absolute) I have selected during the planning phase. In manned aviation this is called QFE reference setting.
Does anyone know if there is a plan to introduce an adjustable setting called QNH i Mission Planner?
QNH is the barometric pressure (e.g. 1020 hPa) at a specific geographic point at a specific point in time (e.g. NOW). The advantage is that this feature will always give the right altitude (according to the international standard atmosphere, ISA) at the altimeter all the time, given that the QNH is correct set.
It is a safety issue as well, because you may report the correct altitude (based on the AMSL reference) to other (manned) aircrafts. Of course this feature should also be a preconditionary function in the Pixhawk to be able to adjust the QNH reference and load the right altitude data in context with the waypoints.
QNH is also a mandatory setting for all aircrafts taking off or landing at airports worldwide. Hence I am a bit surprised that this is not a feature yet. Has anyone (programmers) discussed this issue?