Help with setting negative altitude for LAND command in MP (using AP 4.0.9)


Any help would be appreciated. I have search and searched and not received a satisfactory solution. I have a simple issue.

I would like to use the Auto Land command in Mission Planner to land airplane 5m BELOW my home take-off elevation. It seems that only values greater than zero are allowed in the landing altitude parameter in mission planner with Arduplane 4.0.9. Is this really true?

Another way would be to manually, set the home altitude in the mission file to 5m below the actual elevation. In this case, I worry that the barometer would still set the zero altitude at the true home elevation. Any thoughts on how to accomplish this simple thing?

ps. It seems one CAN enter negative values in AP dev 4.1 but I do not want to upgrade at this point.

thank you all (in advance).

Have you tried setting your altitude reference to terrain? You can set it for the whole mission, or just specific points.

I have not. Does this mean, that I have to fly with a SD card (logger)? Thanks.

I’m not certain. (I fly with SD cards for data logging so I don’t know if you can do it without)

I think that if you plan the mission using the terrain reference in Mission Planner the waypoints should have the data, but I’d want to test that to be sure.