RTH question / discussion

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I am planning a trip to Utah's Canyonlands where I will be flying a P4P to the limits of the drone's reception, and I expect to lose contact. Also, it is likely that the P4P might not be totally viewable due to turns in the canyon. If this happens and you lose drone communication wherein you HOPE the RTH has automatically triggered but you are not sure, (no controller confirmation) should you try pressing the RTH button OR if RTH had been triggered by loss of contact, would that CANCEL the RTH function if and when communication were reestablished?
Thanks for your thoughts.
---Skydriver
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That's some incredible scenery down there.

First of all, as a word of caution...
Do you realize that if you fly beyond visual line of sight, either by distance or by flying behind an object, that it is illegal? When flying, you must always have your drone in visual contact.

On to your questions:
  • If the drone flies beyond communication range and loses contact with the remote, it will initiate its RTH sequence within 3 seconds. If you hit the RTH button while it is without signal then nothing changes since the RTH button signal never got to the drone. If you regain signal and then you press the RTH button, it will cancel the RTH sequence.
  • If the drone is returning home and signal is restored, it will not cancel the RTH sequence until it either completes the sequence or you cancel it manually.
  • If you fly around a bend and lose sight of the drone, chances are very high that you will immediately lose signal. If the drone is below the lip of the canyon, you may also have weakened GPS signal. If you happen to lose both the comm signal and the GPS lock, then your drone will not be able to return home. This sort of scenario is a recipe for disaster.
My advice: stick to VLOS and keep everyone safe.
 
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OK--thanks for your reminder about VLS, but sometimes you might look away and then be unable to regain visual contact with the drone. Just saying.... Considering a strobe which can be another discussion.

In any case, I am a bit confused. You say: If you regain signal and then you press the RTH button, it will cancel the RTH sequence. You then say: If the drone is returning home and signal is restored, it (by "IT" I assume you mean the RTH button?) will not cancel the RTH sequence until it either completes the sequence (lands?) or you cancel it manually. (By using the RTH button or virtual button on your screen?)

Can you explain further?
 
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it (by "IT" I assume you mean the RTH button?)
In this case, 'it' = drone
If you think you'll look away and lose sight of the drone, you need that strobe you mentioned.
 
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I'm in my 70's and still have 20/20, 20/25 vision. But yes, at a distance where the drone is just barely visible against a light blue/grey sky, and it is increasing distance, I have looked down at the display, and looked back up not able to ID the drone. Bet I'm not the only one. Thanks.
 

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I am planning a trip to Utah's Canyonlands where I will be flying a P4P to the limits of the drone's reception, and I expect to lose contact. Also, it is likely that the P4P might not be totally viewable due to turns in the canyon. If this happens and you lose drone communication wherein you HOPE the RTH has automatically triggered but you are not sure, (no controller confirmation) should you try pressing the RTH button OR if RTH had been triggered by loss of contact, would that CANCEL the RTH function if and when communication were reestablished?
Rather than wondering, it would be best for you to do a little testing to get a good understanding of how Loss of Signal and RTH work.
The easy way is to find a large, open area with no obstructions to worry about, fly out 100 ft or so and turn off the controller.
Also try initiating RTH with the controller button and then press the RTH button after RTH has started to see what that does.

If ever you are uncertain about whether RTH is happening or if you might have cancelled it accidentally, switching the controller off is a good way to remove any doubt.
 
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If of use and bear in mind this is with a P3adv, the controller switches on quickly enough to regain control when I tried this with the done 100 -150 ft away and my RTH height was 20m.
One point, RTH speed is fairly slow and you can throttle up without cancelling or interfering with, the RTH process.
 
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OK--thanks for your reminder about VLS, but sometimes you might look away and then be unable to regain visual contact with the drone. Just saying.... Considering a strobe which can be another discussion.
That's all great and very true. However it does go against what you said in your original post. If you are preparing for loss of signal then you are outside of VLOS not because you lost sight of it against the blue sky, but because you flew out too far.

In any case, I am a bit confused. You say: If you regain signal and then you press the RTH button, it will cancel the RTH sequence. You then say: If the drone is returning home and signal is restored, it (by "IT" I assume you mean the RTH button?) will not cancel the RTH sequence until it either completes the sequence (lands?) or you cancel it manually. (By using the RTH button or virtual button on your screen?)
"It" refers to the object being discussed in that specific sentence:
  • If the drone flies beyond communication range and loses contact with the remote, the drone will initiate its RTH sequence within 3 seconds. If you hit the RTH button while the drone is without signal then nothing changes since the RTH button signal never got to the drone. If you regain signal while the drone is returning and then you press the RTH button, the drone will cancel the RTH sequence.
  • If the drone is returning home and signal is restored, the drone will not cancel the RTH sequence until the drone either completes the sequence or you cancel the RTH manually.
Heading out and flying in a manner where you fully expect to lose signal just isn't a good idea. Doing so without having a full grasp on exactly how the process works, and never having tested it in a controlled environment is even worse. Flying in a canyon where you could not only lose comm but also potentially lose GPS, is a really bad day of flying.



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You WILL know RTH is initiated because it will tell you. And it works. After contact re-established, press RTH to regain control. Sounds like an exciting trip, have fun.
 

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I expect to lose contact. Also, it is likely that the P4P might not be totally viewable due to turns in the canyon.
Post #9 brings up a highly relevant point.
RTH is impossible without GPS ... and flying in a narrow canyon blocks most of the drone's skyview which can mean no GPS.
 
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RTH is impossible without GPS ... and flying in a narrow canyon blocks most of the drone's skyview which can mean no GPS.
That raises a question, is there a known threshold at which too few satellite locks disable the RTH facility?

I ask because it has brought to mind the behaviour of my P3adv when I fly from my front garden.
I often set the home point when it's on the ground and there are maybe 4 satellites showing at that time (there are substantial tress around my garden).
When it takes off I often see a message about the homepoint when it has reached a few metres (2 or 3) off the ground, the number of satellite locks increases quite rapidly with height above my garden.
With the above quote in mind I am wondering if, as it climbs, it is passing through a number of satellite locks threshold and resetting the home point which might also apply to disabling the RTH facility?
I have never RTH'd all the way to a landing in my garden (the RTH's 'home point' is too inaccurate to bring it down safely ) but I have, several times, brought it back to overhead with the RTH function
 
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If the drone gets lost in this country, you are SOL.

I want to thank everyone for their responses. For whatever reasons, this area seems to do strange things to radio signals even though there are only buzzards, snakes and rabbits around for miles. Lat year I had a signal loss and RTH at about 3/4 of a mile.

Trust me-- I am a very conservative pilot but stuff happens and the best thing is to be prepared for a problem that you hope won't occur. As to canyon flying, I have no intention of going very low below the canyon rim; that IS looking for trouble.
For someone who might not be exactly sure how RTH works, I could see him/her pushing the RTH button after RTH is initiated not knowing that RTH would then be cancelled. If the drone were not in visual range, that could result in disaster.The suggestion to turn the controller off (if unsure) is a very good one.

Also, has anyone tried attaching a strobe like a Lime Cube for daytime use? If so, has putting it on the top of the case where it says DJI caused any reception issues?

Thanks again.
 
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I have put the small strobe (of Fireworks as I remember) on my P4P and in a low light environment it is visible far enough to see it even a mile or two away.
But in the bright sunny day it is visible only as long as in VLOS or maybe only few hundred m.
I attached it right between the front arms where is enough place to stick it. It would be better to put at least two of them (front and rear) but of different color so you can see where the drone is facing to. Putting something bigger on the top of the drone might interfere with GPS signal.
 
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Thanks Andy9--that's what I was afraid of. On large jets, even their wingtip strobes don't show up we'll in daylight.
Someone said that the GPS antenna is right underneath the DJI logo so you should not cover that area. I guess you could experiment by holding the strobe in place and looking at the GPS reception bars. Just trying to get a longer VLOS in daylight.

If you lost video feed, it would be nice to know which way the drone was facing.
 
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That's true. But light or no light I won't fly in a narrow places like canyons or so more than 300 m away because only camera orientation is not enough for safe flying. You can't see what is on both sides of the drone. And if you loose the signal... there you are. Flying ATTI is OK, but not in such places if there is even a slight wind.
 
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OK--thanks for your reminder about VLS, but sometimes you might look away and then be unable to regain visual contact with the drone. Just saying.... Considering a strobe which can be another discussion.

In any case, I am a bit confused. You say: If you regain signal and then you press the RTH button, it will cancel the RTH sequence. You then say: If the drone is returning home and signal is restored, it (by "IT" I assume you mean the RTH button?) will not cancel the RTH sequence until it either completes the sequence (lands?) or you cancel it manually. (By using the RTH button or virtual button on your screen?)

Can you explain further?
If you hear beeping from your remote it is in RTH mode. Just make sure your altitude for RTH is high enough in altitude to avoid obstacles, not a place you want to test your obstacle avoidance :)
 
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Thanks Andy9--that's what I was afraid of. On large jets, even their wingtip strobes don't show up we'll in daylight.
Someone said that the GPS antenna is right underneath the DJI logo so you should not cover that area. I guess you could experiment by holding the strobe in place and looking at the GPS reception bars. Just trying to get a longer VLOS in daylight.

If you lost video feed, it would be nice to know which way the drone was facing.
I put my strobes on each rear leg of the landing gear, facing outward. No problem seeing them a couple miles away.
 
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