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Litchi fail safe behaviour with phantom 3 advanced

Discussion in 'Pro/Adv Discussion' started by David Hagen, Sep 10, 2016.

  1. David Hagen

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    Hi Can someone advice if the phantom 3 advanced does not return to home if the transmitter signal is lost in Focus/orbit/Course lock/Home lock ?

    I understand in waypoint mode it will complete the mission but not to return home in the other mod sounds dangerous.

    I have seen a warning re the standard phantom 3 and the 3/4k but have not seen anything on the 3 professional/3 advanced or phantom 4

    Thanks
    David
     
  2. koop

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    good qeustion

    Sent from my SM-P905 using Tapatalk
     
  3. DragonsBack

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    Orbit seems pretty clear on the litchi help page - with signal loss it will orbit continuously then land on critical battery warning. Though I've never experienced this to verify for sure:
    Help - Litchi

    The other modes you mention don't seem to be covered. But as they all control the orientation of the aircraft and gimbal rather than being autonomous flight path modes, I would assume the RTH functions as normal. Can anyone verify that in practice?
     
  4. David Hagen

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    Thanks for your advice. Keen to find out answer to your question above
     
  5. DragonsBack

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    Like you, I don't like the no RTH behavior on Orbit - wish there was an option to turn it back on. or even RTH on low battery rather than land at current location on critical battery. For wide radius orbits I actually program them in as waypoint missions with deep curves just to be sure.
     
  6. sonof40

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    I thought you could switch tp P mode and then RTH.
     
  7. DAVEJF

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    If transmitter signal is lost..I somehow
    Doubt it


    Sent from my iPhone using PhantomPilots
     
  8. sonof40

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    Could you not then switch to the GO App?
     
  9. DAVEJF

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    But switching to P mode won't work if you have
    No transmitter connectivity


    Sent from my iPhone using PhantomPilots
     
  10. Mocho

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    And be careful with waypoint missions as well. Especially if set to return along same path. Loose your connection and your bird will just sit there and hover, you manually control the return along the same route using the sticks.
    I'd like to see Litchi add a switch that allows RTH on signal loss, regardless of the mission your running. Then we can choose how the bird reacts to a signal lose.
     
    DragonsBack likes this.
  11. DragonsBack

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    Agree. I make all my waypoint missions 'circular' - i.e. the final waypoint is back at the starting location - and fly them forwards only. As always - you have to know the behavior under each setting and plan accordingly. Speaking of which, does anyone know the answer to the OP's question on signal loss RTH in focus and lock modes...?
     
    TLeTourneau likes this.
  12. David Hagen

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    Fully agree. The failsafe in Go App seems fare safer.
     
  13. DragonsBack

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    I think that concern only relates to running waypoint missions in reverse as the speed has to be manually controlled. Obviously if you lose signal then the the speed will be zero and it will just hover.

    But a waypoint mission running forward should have no more/less risk of getting back to the intended destination than relying on RTH - both rely on GPS and will function fine so long as there is a GPS signal.
     
  14. warmbooter

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    I was seriously thinking about buying litchi, but after reading some comments about people loosing their drones when using it, I start to wonder if I should buy it.

    I usually fly in mountain region with lots of tall trees, so sometimes I get signal lost and having the RTH working automatically is a must for me. I would use litchi mostly for setting waypoints flights to areas where usually I can't do a normal (FPV) flight due to loss of signal.

    What do you guys think? Should I take the risk?

    PS: I have a P3 Advanced.
     
  15. David Hagen

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    Asked the question on the litchi facebook page

    RTH will activate with loss of transmitter signal in all modes except waypoint if the "loss of signal behaviour" setting is set to RTH on the Phantom 3 advanced. This is what I need confirmation of

    David
     
  16. Mocho

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    Thanks for the update David.
    Maybe I'll give it another try now, with the bird in sight and just turn off the controller to test RTH.
     
  17. David Hagen

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    It will be good to find out for sure

    David
     
  18. L3thalB3ard

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    I use litchi.. I have no problems with any of the failsafes except orbital... if I lose signal in orbital the bird just hovers. Everything else seems fine. I've even done range tests with litchi so I could record the screen. Never had a problem.


    Sent from my iPad using Tapatalk
     
  19. DragonsBack

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    I fly waypoint missions in mountainous terrain a lot and I would suggest you think about the situation and risk a little differently... waypoint missions are designed to follow the waypoint path regardless of signal loss. Sounds like this is what you are looking for and this is a good thing (if it didn't work like this then your mission would be aborted as soon as you lost signal - pointless). You can set it to RTH at the end of the mission if you want to and it will do that fine, regardless of signal loss.

    So 'non-auto RTH during waypoint' is how it's supposed to be and is not a reason to worry about losing your drone. I would say the top risks that could lead to loss are...

    1) Risk of hitting terrain
    2) Risk of weak/lost GPS signal, meaning that neither waypoint mission nor RTH would work

    How to manage these risks...?

    1) Terrain
    My strong recommendation is not to fly 'desktop' missions - i.e. ones that you plan at home based only off google maps. In mountains it is much easier to accidentally program a mission that flies straight into something. It is hard to account for elevation and, though there are ways to do it off google earth, the margin for error in mountains is way smaller than in other areas and it's difficult to be sufficiently accurate. Secondly, in mountains the google maps satellite images are not super-accurate. They are actually taken at an angle rather than straight down - so the image of the top of the mountain is not directly over the true GPS location - this negligible on low gentle slope hills, but a big discrepancy on tall steep slopes.

    Instead, I do plenty of reconnaissance flights and create the mission waypoints in the air whilst flying at the real location (easy to do, just set up one of the buttons on the back of the remote to drop a waypoint). That way you ensure that the location and altitude are definitely safe (also a good chance to check out camera angles, check for obstacles etc). You can then go back and edit points of interest, behaviors etc. You can do this over multiple flights. ( And you can do it from different take off points but be very careful there to adjust the waypoint altitude for any difference in takeoff altitude.) I usually use 1 or even 2 batteries to plan and set the flight then put in another fresh one to execute it.

    2) GPS signal
    The risk is that mountains or cliffs suddenly obscure satellites as you go behind them. Same method as above covers this also - if you've flown successfully FPV in P mode at the location then you will know that the GPS signal is OK there (remember that satellite counts differ slightly over time so keep a margin of error).

    A couple of other recommendations... firstly, avoid relying on RTH to get the drone home at the end of the mission - again, mountainous regions carry more risk of the RTH altitude accidentally being insufficient. I make all missions 'circular' - i.e. the final waypoint is back at the takeoff location. That way I know the path that the drone will follow and know it is safe. I still put RTH as the endpoint behavior, but I intend it as a failsafe in case i somehow got my mission plan wrong. Secondly, 'hands off controls during autonomous flight' - especially if out of range. The risk is that you think it is out of range, panic, hit the throttle, switch back to p mode etc and it turns out that it is in fact not out of range and the signal reaches the drone with unintended consequences.

    Hope that's of some help... so in answer to your question: I recommend you get litchi, learn in detail how it works, and manage the risks... happy mountain flying!
     
  20. WayneMHK

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    Have you ever tried waypoints using Google Earth? https://www.youtube.com/watch?v=4nEhjHukM3k