RTH Logic in uneven grounds

leesmavic · Dec 25, 2016

My turn to ask a question to avoid pilot error. In the picture below I start my quad at home, set h1 as a RTH height to avoid trees, fly over to the point (to the right) where quad will probably loose signal. I over exaggerate on purpose. It might loose signal being in VLoS, earlier. Still, the question is whether the quad will measure height relative to original ground level to climb to RTH height or relative to the ground at the point where it looses signal and initiates RTH sequence (head straight to the left and struggle avoiding too many stuff and die in the end)

. Any ideas?

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msinger · Dec 25, 2016

When RTH is initiated, the Mavic will ascend from the current altitude to the set RTH altitude before returning back to the home point. If you fly below 0 feet, the Mavic will ascend back up to 0 feet and then up to the RTH altitude.

There are some other scenarios that can take place depending on the Mavic's current distance from the home point and whether or not you're moving the throttle stick at the time. You should review the RTH section of the Mavic manual for more details.

leesmavic · Dec 25, 2016

I probably know that manual by hard by now. I guess my real question was what is meant by 'current altitude'? Whether it's actual measured from ground below it or is it relative to home ground level. You've answered that, thanks!

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MavicKhan · Dec 25, 2016

The Mavic does not work with "altitudes", it works with "heights".

When you launch you drone, you'll see "0" entered as the the current height. From there on, all "heights" are referenced to that departure datum.

(I was flying it in a cliff zone, departed from the cliff and it was showing negative values while skimming the ocean)

In you scenario, the Mavic will fly with negative heights in the lower depicted region and, when you press RTH, it will climb through the "0" height datum and continue climb to the RTH set height, before returning.

MK