Delivery Mission with Ardupilot

Hello. I am planning a demo flight to deliver some goods between two locations. The takeoff location is at a higher altitude than the landing location. I am wondering if I need to use any special hardware or plan the missión using terrain following or verify height option to have a good landing.

Takeoff altitude is 122 meters above sea level
Landing altitude is 72 meters above sea level

I will fly 50 meters above the home position (takeoff altitude).

Any help will be more than appreciated.

Thank you

I guess there are two risks:

  1. the mission causes the vehicle to crash into the terrain on it’s way to the delivery location
  2. the vehicle doesn’t slow down to the LAND_SPEED before landing which would cause it to land very hard (i.e. 1.5m/s instead of 0.5m/s)

For (1) you can set the altitude type in the mission command to Terrain and the vehicle will follow the terrain on it’s way to the destination. Note that it probably won’t fly the most direct route… i.e. it won’t be a straight line from the origin to the destination, it will instead climb and descend on its way to the destination. As mentioned on the terrain following wiki page you don’t need a rangefinder for this to work, it can use the SRTM data provided by the ground station even if the ground station isn’t connected for the entire flight.

For (2) you might want to increase the LAND_ALT_LOW param value from 1000 (meaning 10m) to 2000 (meaning 20m) to account for inaccuracies in the SRTM data.

I think it would be a good idea to use Mission Planner’s built in simulator to test the mission before trying it on a real vehicle.


Thank you very much for your answer.

I will read about the terrain following option during the flight.

The main question that I have is for the landing phase. The home / takeoff ground altitude is 50m above the landing ground altitude. The flight altitude is 50m above home position. So, my question will be: what is going to happen when the Hexacopter arrives to the landing point, will it descent the 50m ”thinking” that this vertical distance is enough to touch the ground? In reality it will still be 50m above the ground. Or Will the hexacopter descent all the way to the ground without taking into account the home altitude?

I think that if I use terrain following option for the entire mission, I will not have this problem. Am I correct?

Thank you very much for your help.