Altitude correction while flying auto missions

Mission Planner with arducopter in mission flights
It´s know the barometer has certain drift that could be between 5 and 15 meters so long as the fligh time flows. Also, when doing long missions 30 to 60 mins the barometric conditions may change and so will the real altitude vs the displayed one.
If there is no option to land in midflight to reset the baro altitude, which one is the best way to adjust the flying altitude? .
I need to do long flights at 20 meters altitude only and the possible drift is 50% of this margin. It´s easy for me to see from the fpv cam images when the altitude has been changed beyond an acceptable ammount and a correction is required but no idea about the best way to do it. Options:

  1. While flying the mission, simply change the altitude of the remaining waypoints and upload the mission again? (no idea what will the copter do : accept, crash, reject … )
  2. Pause the mission, modify the altitude of the remaining waypoints , upload the mission and resume the flight? (will the copter accept it and having the default MISSION RESTART value will it resume the mission or will it start from wp1 because it consideers that like a new mission)
  3. Add a negative value on the Altitude Offset field to slowly correct it according with the visual references in flight.
  4. Any other option you can suggest?


If a LIDAR or Sonar is available on the copter, it would be nice to have the possibility to program, in an auto mission, a special waypoint that would consist in descending the copter to an altitude that is compatible with the Lidar/Sonar range and calculate the baro offset at that moment by comparing the baro value and the Lidar/Sonar value. For long missions, this auto baro offset recalibration could be repeated.
That would be really nice as a feature indeed.

As a suggestion it is nice but I dont have a lidar. What options do we have right now?

There is no solution at the moment in Ardupilot for the baro drift issue. Solution can only come with extra hardware unfortunately

I see, in any way do you consideer none of the options I posted could be used?