Obstacle Avoidance on RTH
3481 9 2018-1-2
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JohnnieTheCache
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Germany
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Hi!

I have had problems with the Obstacle Avoidance of my Mavic pro on several flight.
When the sun is low, or i am at a steep mountain, it wont come home. So my only choice was to deactivate it.

Now my question: I see that Obstacle Avoidance can be turnbed on separately for the RTH. This sounds very useful, but picture this situation:

- i loose contact with the Mavic Pro
- it goes into RTH
- sun is standong low and "blinding" the sensors

What will happen, will it come home?
I am afraid that it would not come back and potentially crash land or drop in the lake eventually.

Thanks!
2018-1-2
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rolling56
First Officer
Flight distance : 138310 ft
United States
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N/M i read your post wrong
2018-1-2
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Griffith
Second Officer
Flight distance : 98537 ft
United States
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If you're concerned about your flight, be sure to set your RTH height sufficiently to avoid a collision in a direct home path and disable RTH OA.  Try to avoid RC disconnect by keeping your flight sufficiently unobstructed and line-of-sight.
2018-1-2
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Ex Machina
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Flight distance : 1806362 ft
United States
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What will happen is the Mavic will rise to attempt to avoid the obstacle, and will eventually run the battery down to the point where it will be forced to land the AC.

One way to avoid this is to make sure the home point return path won't be aligned with the sun.

Of course, when flying in control of the AC, you can just fly home backwards when the sun triggers OA, or as Locoman states below, switch to Sports Mode if you've enabled that.

2018-1-2
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Locoman
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Flight distance : 748675 ft
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What kind of contact are you loosing, radio video, visual....Don't fly out of sight. Don't fly towards the setting sun, don't reduce your battery thresholds, watch for wind warnings, it will try to RTH, but will do a bunch of starts and stops. You should be able to notice this on your controls. Once I had to fly backwards all the way home, to avoid the sun. Some people go into  sport mode to turn off the sensors, but I don't since I am not a sport mode flyer. The best thing you can do is don't panic.
2018-1-2
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JohnnieTheCache
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Germany
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Locoman Posted at 2018-1-2 07:17
What kind of contact are you loosing, radio video, visual....Don't fly out of sight. Don't fly towards the setting sun, don't reduce your battery thresholds, watch for wind warnings, it will try to RTH, but will do a bunch of starts and stops. You should be able to notice this on your controls. Once I had to fly backwards all the way home, to avoid the sun. Some people go into  sport mode to turn off the sensors, but I don't since I am not a sport mode flyer. The best thing you can do is don't panic.

Hi,
i can assure you that i fly very responsibly. I have now flown 150 miles with my Mavic and no accidents. However, one single time i needed the auto RTH, because i lost signal. This may happen to any drone pilot, and thats why DJI gives us this very useful feature.

Not flying when the sun stands low is absolutely impossible for me. First of all im at 50° Latitude, which means i have quite low standing sun for the entire winter. But even more importantly, low standing sun is the best time for filming and photos. And thats what i use the Mavic for :-)

So, for me the Obstacle Avoidance as it is right now is not useful, seems i have to keep it fully deactivated even on RTH. :-(


2018-1-2
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JohnnieTheCache
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Germany
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Ex Machina Posted at 2018-1-2 07:06
What will happen is the Mavic will rise to attempt to avoid the obstacle, and will eventually run the battery down to the point where it will be forced to land the AC.

One way to avoid this is to make sure the home point return path won't be aligned with the sun.

Thanks, thats what i thought.

In many cases the auto-rise after the collision detection on RTH may re-establish radio control, and the problem is solved.

But there might also be a loss of signal due to other reasons, like some error on the remote or mobile phone. Then you fully rely on RTH, and if the sun is low behind you the AC will never come back.
2018-1-2
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DJI Thor
Administrator
Flight distance : 13602 ft
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When you disable the Forward Sensor, it can't avoid the obstacles during failsafe RTH. Please read the manual below. failsafe RTH oa.png
2018-1-2
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JustusLM
lvl.3
Flight distance : 1579888 ft
Germany
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DJI Thor Posted at 2018-1-2 22:17
When you disable the Forward Sensor, it can't avoid the obstacles during failsafe RTH. Please read the manual below.[view_image]

Does "vision system" in this regard equal "obstacle avoidance"?
They are not the same, but in the app, it is only one switch. Disabling the forward obstacle avoidance disables (as far as I know) the forward obstacle sensing, perhaps the whole forward VPS (or it doesn't, in that case it is still used for optical flow positioning); I'm obviously not 100% clear on that, but the more important issue is:
If obstacle avoidance is disabled, but the radar is enabled, obstacle sensing and the forward VPS are obviously enabled. Does this mean OA will work during RTH or will it still be disabled because the forward OA switch is still set on disabled, even though the radar is enabled?
2018-5-5
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Picanoc Jack
First Officer
Flight distance : 10321657 ft
Canada
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Locoman Posted at 2018-1-2 07:17
What kind of contact are you loosing, radio video, visual....Don't fly out of sight. Don't fly towards the setting sun, don't reduce your battery thresholds, watch for wind warnings, it will try to RTH, but will do a bunch of starts and stops. You should be able to notice this on your controls. Once I had to fly backwards all the way home, to avoid the sun. Some people go into  sport mode to turn off the sensors, but I don't since I am not a sport mode flyer. The best thing you can do is don't panic.

I agree locoman but it is so very nerve wrecking.
2018-5-8
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