Return to Home altitude . . . definition.

[emtor]

How does the system define the RTH altitude?
1) Altitude above sea level
2) above ground were the UAC is currently at
3) above the altitude the UAC is currently at
4) or the altitude where the RC is at?

If I stand on a 100 meter tall hill, my RTH altitude is set to 30 meters and I fly down into the valley below
I'll be having a hard time in all of the above instances except number 4 should RTH kick in.

 

[ryantrax]

The RTH Altitude is calculated from your home point elevation being ZERO.

 

[Steve7777]

How does the system define the RTH altitude?
1) Altitude above sea level
2) above ground were the UAC is currently at
3) above the altitude the UAC is currently at
4) or the altitude where the RC is at?

If I stand on a 100 meter tall hill, my RTH altitude is set to 30 meters and I fly down into the valley below
I'll be having a hard time in all of the above instances except number 4 should RTH kick in.

It's from the take-off point altitude. Fly down into a valley below and on RTH it would rise vertically at whatever place it was to 30 m above the takeoff point altitude and then return home and descend.

 

[emtor]

Thanks all,- been wondering about that for a while.

 

[Meta4]

How does the system define the RTH altitude?
1) Altitude above sea level
2) above ground were the UAC is currently at ...

All heights are relative to the launch point.
Your Phantom doesn't know where sea level is and it has no way to know how high above the ground it is.
The only height it knows is home = zero.