Unexpected results

Understanding Home Position Better
I have a mission that is tried and true again and again and then suddenly be off on altitude and drag on the ground as a result of where I plugged in the battery and it started flashing green.
I’m assuming that home position is at fault but I don’t fully understand how it works.

Home position is used in mission planner to determine how far above sea level you are so that if you have verify height selected it will adjust the default height that you pick on your mission points that are added.

Say you are 100m above sea level and your default height is 20m. If the point on the map you pick is at 120m above sea level then it will at 20m to your default height for that waypoint provided you picked the verify height check box.

Otherwise when you plug the copter in and it takes off that is the home position of the copter and will always fly relative to that height. Now that being said it is possible for the barometer to be off at take off time which could cause it to fly higher or lower than expected. In addition when it flies into or out of the wind it will miss interrupt the height and rise or fall.

Also temperature effect the height as well. If you have mission planner or droid planner connected you can verify that the copter is as 0 meters before take off so you will be close to flying at the correct height.

I have taken my copter from my house which was at 21 degrees and placed it on the ground outside that was at -3 degrees and left it there for a few minutes and when I went to fly it thought it was 10 meters in the ground and shot up very quickly into the air.

Be careful when relying on the height of the copter.