When you lose controller signal and GPS at the same time?

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I've only ever lost GPS connection when I've tried to launch from an area surrounded by close hills or cliffs or flown into such an area. If I was already in the air, gaining elevation always fixed the problem.

Recently, I flew into a narrow canyon where I was concerned that I could lose both GPS and my controller signal at the same time. It occurred to me that I wasn't sure what my drone would do in such a situation. I suspect that it would just sit there, drift and eventually crash into something. However, if RTH was initiated (even without GPS), two things would happen that might still save the drone:

1. My proximity sensors would activate - I turn them off for normal flying.
2. The drone would ascend to my pre-set RTH elevation, pick up a GPS connection on the way, and then fly home.

Of course, it could easily crash into something on the ascent. But it would seem sensible to me to program the drone to activate RTH on loss of signal, even without GPS lock - as the first part of the RTH journey (ascending to RTH elevation) doesn't require GPS and could well save the drone. But is this what happens?

As to my flight through the canyon - it was uneventful. I stayed higher than I would have preferred, and the GPS lock held. The controller signal was surprising strong given that, ahem, I couldn't see the drone. There was a sheer rock wall blocking the direct line, which meant that the signal was bouncing off the sides of the canyon (like a game of pool) to get to the drone. I've only recently acquired Ocusync 2.0, and I continue to be impressed.
 
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Meta4

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I suspect that it would just sit there, drift and eventually crash into something.
DJI drones are programmed to land if they have no GPS signal and no control signal.
This is easily confirmed by blocking GPS reception with aluminium foil and tape, launching and flying further than 20 metres away and switching off the controller.
However, if RTH was initiated (even without GPS)
RTH cannot work without GPS.

Under normal flying situations, you should never lose GPS.
Flying in canyons etc, where a substantial part of the sky is blocked and you have no GPS, you need to make sure that you don't also lose control signal.
 
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DJI drones are programmed to land if they have no GPS signal and no control signal.
This is easily confirmed by blocking GPS reception with aluminium foil and tape, launching and flying further than 20 metres away and switching off the controller.
Thanks. I looked for an answer to that question online, but wasn't able to find one.

RTH cannot work without GPS.
I was posing a hypothetical. A smarter drone that lost both GPS and controller signal might try to ascend to the RTH elevation to possibly regain the GPS signal (if not the controller signal), and subsequently, return home.
 
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I like your way of thinking. It's logical but if no GPS signal how can the drone trigger RTH if have no data where to.
But loosing the signal could start elevation to preset hight becouse there is no need for GPS data to do that.
It would bve logical that it would ascend to preset level and then hoover if it has no GPS.
Well - this is only a speculation.
 

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I was posing a hypothetical. A smarter drone that lost both GPS and controller signal might try to ascend to the RTH elevation to possibly regain the GPS signal (if not the controller signal), and subsequently, return home.
It would only be in very specific flight environments that GPS would be lost and regained by gaining height.
In those environments, increasing altitude is not guaranteed to be a safe option.
Think crashing into tree cover or canyon walls.
But in most flying, if GPS is lost, climbing won't regain GPS and the drone could drift or be blown further away.

DJI kept their programming as simple as possible to provide the safest option for most flight situations.
Fortunately GPS loss in flight is very rare and most cases are due to where the operator chooses to fly.
In such cases, it's up to the flyer to recognise potential issues and fly accordingly.
 
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I like your way of thinking. It's logical but if no GPS signal how can the drone trigger RTH if have no data where to.
RTH is a state that is triggered by lack of remote signal. While RTH absolutely relies on satellite acquisition to return home, I see no reason why RTH would require satellite lock to trigger and ascend. I agree with the OP that it makes sense to trigger an ascension, as satellites are more easily acquired at higher altitudes. Many times I have launched in ATTI mode when I was too impatient to wait for satellite acquisition on the ground. Once in the air away from trees, buildings and other interference, the drone acquires satellites rather quickly.



But loosing the signal could start elevation to preset hight becouse there is no need for GPS data to do that.
Exactly.



It would bve logical that it would ascend to preset level and then hoover if it has no GPS.
Exactly.



Well - this is only a speculation.
Yep. As pointed out by another forum member, this is easily tested by blocking the GPS antenna, launching and then shutting off the remote.

D
 

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While RTH absolutely relies on satellite acquisition to return home, I see no reason why RTH would require satellite lock to trigger and ascend.
It doesn't ... but DJI have programmed the drone to land if the drone has lost control signal and GPS
 

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