Obstacle sensing and return to home height

[GiorgiD]

Hello,

The P4 tutorial says that when RTH is activated it will use Obstacle sensing and fly over and around objects. So my question is if Obstacle sensing will fly over obstacles why do I need to set return to home height in the software? Doesn't it use Obstacle sensing while flying home?

 

[msinger]

Doesn't it use Obstacle sensing while flying home?

It does if it's enabled in DJI GO. It would be better to set the proper RTH altitude though since obstacle sensing is not foolproof. It has a tough time seeing things like wires and small tree branches.

 

[yojo182]

Non owner here but from my understanding it tries to go up to get around obstacles. This would cause a problem when it flies under a tree and tries to lift so the give you the RTH height which if you are slightly off it will avoid tree tops.


Sent from my iPhone using PhantomPilots mobile app

 

[GiorgiD]

I see, thanks. Is the return to home altitude relative to home point or relative to ground? So if I fly it from a 100 meter building roof and descend it will it fly up above roof height when returning or will it calculate height above ground ?

 

[msinger]

Is the return to home altitude relative to home point or relative to ground?

It's relative to the takeoff point.

if I fly it from a 100 meter building roof and descend it will it fly up above roof height when returning

If you fly below the takeoff point, the altitude will show as a negative number in DJI GO. If your RTH altitude is set to 50m (for example) and the current altitude is showing -10m in DJI GO, your Phantom would first fly up to 0m and then up to 50m. So, it would ascend 60m in total before returning home.

 

[msinger]

This would cause a problem when it flies under a tree and tries to lift so the give you the RTH height which if you are slightly off it will avoid tree tops.

That should not happen in most cases since the Phantom should start ascending when it's 20m in front of the tree.