I understand that MAV_FRAME_GLOBAL_RELATIVE_ALT
(https://mavlink.io/en/messages/common.html#MAV_FRAME_GLOBAL_RELATIVE_ALT) is defined as:
“Global (WGS84) coordinate frame + altitude relative to the home position. First value / x: latitude, second value / y: longitude, third value / z: positive altitude with 0 being at the altitude of the home location.”
I’m not sure what the rationale is, as this restriction means that you can’t use this frame to fly below the takeoff point.
But ArduCopter seems to do something bad - it accepts the waypoint with alt=0
, but ignores the altitude, and simply flies to it at its current altitude. This could mean crashing into something (imagine trying to fly under a bridge).
Do you think it’s a bug/undesired behavior? Should I open a ticket?