Height estimation

[Gazp1961]

Hi all,
I'm a newbie the drone game so I guess like some I have a silly question, but I'd like to draw on the experience of the forum if possible...
So your in an unknown environment, you complete your flight checks and you come to set your RTH altitude... You look around for the tallest object in the vacinity and add maybe 20 metres as your RTH altitude, but clearly this is just guess work.. my question is ...are there any tips, tricks used to estimate the height of an object ...
Thanks in advance....

 

[msinger]

The easiest way to get close is to fly straight above the takeoff point (with the camera level) until all nearby obstacles appear to be below the horizon in DJI GO. For example, the trees are above the horizon here (when the Phantom is too low to clear them):

And below the horizon here (when the Phantom is high enough to clear them):

In this case, the RTH altitude would have to be set to at least 52 feet to clear those trees. Since the current altitude displayed in DJI GO is always an estimate, it would be better to set the RTH altitude to 102 feet instead (adding 50 additional feet to account for any error).

 

[Gazp1961]

Thanks alot, that's exactly the kind of tip I was looking for, so simple when you think about it...[emoji6][emoji6]

 

[jdharrin]

That makes sense but can you set the RTH altitude on the fly, i.e while it's up in the air, or do you need to land so it can reset and capture a new RTH position?

 

[msinger]

can you set the RTH altitude on the fly

You can set/reset the RTH altitude at anytime (even mid-flight). Keep in mind that it's always the altitude above the ground at the takeoff point.

 

[Gazp1961]

I just assumed that you would need to land, but if altitude can be set in flight that's a bonus....