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Random GPS Failure causes panic and crash

Discussion in 'Phantom 2 Vision + Discussion' started by paulsheaves, Jan 14, 2015.

  1. paulsheaves

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    Hi Guys,

    I'm afraid I have had countless problems with my PV2+ from the off... but I just love the thing so much I am determined to learn and try and fix everything!!

    The latest thing that happened was this - we were in the desert (huge open space), did the pre-take off calibration, had slow flashing green lights and 10 satellites/blue symbol on the app. Ready to go we thought...

    Once in the sky, for around 5-6 minutes of "checking its ok" which is what I normally do, we were about to do a fly over of us on a dune (pretty cool shot haha), as we were about to do the sweep, the machine then went from slow flashing green to red flashing. The stable GPS had gone!!

    The only thing (other than a GPS failure) that I can think of that could have caused this is the 4x4 car that was parked nearby, but the car was turned off and stationary so I find it hard to believe it could have been this.

    This caused mass panic, the machine was facing the opposite way to the controller so forwards was backwards etc, but also there was a slight breeze (nothing major, but it had an effect) so the PV2+ was spazzing out in all kinds of ways, and drifting very very fast towards out of range. I could not regain control to bring it home in the non-gps mode.

    As I understand it, I had no choice (I think, but do correct me if there was something i could have done to bring her home?) but to push down on the trigger to crash land it before it drifted (and thus continued to drift forever before battery died) out of range. In non GPS mode, there is no way it will auto return home correct? The machine crash landed in soft sand, not ideal but better than a hard landing, but on the face of it there appears to be no damage, all the props and motors are working, the lights are working as normal, and all appears fine.

    After this, the dealers that I bought it from said to do an advanced calibration. I have now done this, but am seriously scared to re-fly the machine.

    Firstly what caused this to happen?

    Secondly, will the advanced calibration have had any affect whatsoever?

    Thirdly, what if i fly the machine and it repeats the problem and i cannot get it back or i have to crash land and this time break it?!

    Many thanks for all your help and happy flying!!
     
  2. justin00

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    If im understanding correctly... lost gps and was drifting in wind... but one of the problems was because it was backwards you had troublw controlling it because controlls were reversed??

    if thats part of the problem... practisw more in controlled conditions with it backwards. I've had 130 flights which isnt alot compared to many and I still get very confused when its backwards... def a skill to master.

    also does course lock only work with gps?? That may have helped if its not reliant on GPS.. shouldn't be... but probs is??

    Apologies if ive misread.

    btw do you have a v3 or older model?
     
  3. MacCool

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    My guess is that, for whatever reason (not the car parked nearby), you lost your GPS lock. If you had enough control to do a CSC and shut the motors down then you likely had enough control to bring it back, but I suspect that you got flustered and were unable to bring it back in ATTI mode. I agree...you should practice keeping your orientation and controlling the Phantom no matter where it's pointing.
     
  4. paulsheaves

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    Thank you for your help guys.

    Sorry if i sound like a newbie (which i am!) but what is CSC? I have probably flown my PV2+ maybe 50 times or so, I would still say that i am not confident at all in flying it unless i am facing the same way as it!! I agree i need more practice at reverse controls.

    UPDATE...

    I've just come back from testing the bird after its calibration, and believe i have found the problem.

    The bird was working perfectly in GPS mode, normal flying. When taking a photo it was also fine. However, when you push video camera mode on the app, the satellites slowly go down. I then grounded the bird and tested this on the grass, and sure enough with video camera off the GPS was working fine, put it back on and there is a loss in satellites.

    What could be causing this?
     
  5. happydays

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    If the light signals went from slow flashing green to flashing red, this would indicate something else - if you lost satellites and it went into Atti mode, the lights would have started flashing yellow instead of green.
     
  6. paulsheaves

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    It would appear that my problem is also experienced by many others from looking at this thread: viewtopic.php?f=27&t=28924&p=305421#p305421

    I can't believe that DJI are selling faulty products, and/or not recalling them or accepting there's a problem and exchanging the product.

    This fault alone will cause a crash sooner or later and could cause serious damage to a building, car or worse a human - you can see it now, someone loses GPS, loses control in ATTI mode, crashes into a building or tree 50-100 metres in the sky, the drones propellers stall and it drops out of the sky and onto someone's head.
     
  7. Meta4

    Meta4 Moderator
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    The parked car had no effect. If you are losing sats when videoing, you NEED to do the foil mod.
    Your Phantom is not safe without it and it will fix your satellite problems for ever.
    You need more practice.
    Flying backwards should be second nature.
    If not you should be able to turn the Phantom any direction you like and fly home.
     
  8. IrishSights

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    I know after the fact comments are annoying, however I try to encourage folks to take planned time to go to an open field with light winds in a safe controlled environment and practice solely flying in ATTI mode until it becomes 2nd nature. This is so important. I know the urge is always there to just get out and fly and depend on GPS - been there too, but being comfortable in ATTI will save many a 'flyaway'. Just be disciplined about it before rather than after an incident.

    I sound like a grandad, but I'm not! Lol

    Edit: also if you lose GPS you have no homepoint so all the more reason to stay LOS
     
  9. AHill

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    Another safer option to learn flying in reverse is to use a flight simulator on a computer. I use Real Flight 7.5 but others in this forum have different programs they prefer, search for thread. RF 7.5 has a quad that is very similar to the Phantom. It is slightly harder to fly because when moving horizontally it will lose some altitude but you will be surprised at how fast your flying skills improve when you are not afraid to crash a $1300 Phantom. You can also pick Quads that are harder to fly to hone your skills even more. After you gain confidence in your flying ability then practice some more using the real Phantom.

    If Phantom starts flying away put S1 to ATTI mode to regain control without GPS. If transmitter is still connected it will give you back control in ATTI mode, if transmitter is not connected it will not make any difference.
     
  10. MapMaker53

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    Do you know if the RF 7.5 Wireless SLT Transmitter Interface Edition will work with the P2V+ remote control? http://www.realflight.com/products/gpmz4524.html In other words, does anyone know if the Phantom's remote is an "SLT transmitter"?
     
  11. TeeJayN

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    As others have stated you need to do the GPS antenna foil mod.
    But sadly, the end result of loss of control with a forced crash could likely have been easily prevented.
    Many don't like to hear this, and I won't sugar-coat it, but you need to read and follow the provided DJI manuals! Yes, plural, there are two of them. The one that's overlooked, and in my opinion is critical for any newbee, is the Phantom Pilot Training Guide. Get that sucker out, read it, and then follow every step - repeatedly. In doing so you will learn to control its movement regardless of its orientation. The more you train with it, the birds orientation will become second nature. Then try additional maneuvers like flying in a smooth circle with the camera always pointed to the center of the circle. This will seem impossible at first but you will be amazed, what practicing this will accomplish. Ok, I still can't do absolutely smooth circles but I am getting pretty good! :D Then if your doing clockwise circles, switch to counter clockwise circles. I promise you, the need for you to keep your bird always orientated the same way as your transmitter will melt away. And then at least two other great things will happen - your chances of surviving a similar mishap will go up tremendously, as will the overall Fun Factor of flying these wonderful machines!
    Enjoy!
     
  12. AmazingRando

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    Best thing I ever learned if your aircraft is off in the distance, you have some sort of directional control (no GPS necessary) but have no idea what direction it's facing...

    Press your right stick up to make it go forward no matter what direction it's in. If it flies to the right start pressing your left stick to the right and she'll slowly stop drifting that direction while she turns... Keep pressing the right stick forward and she's heading back to you. Same thing if you press forward and it heads to the left. Bend your left stick to the left and she'll aim her head back in your direction.

    Practice this a lot! Great way to save your bird in ATTI mode or with GPS loss if you still have control. I know this may seem trivial to a veteran, but this has been invaluable to me.
     
  13. jasonb777

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    If you have already set your bird to naza mode in the phantom assistant software, then all you would have to do is toggle the top left switchS2) all the way down and then pulled back on the stick and regardless of orientation the phantom will fly back to you with no sats. I never really used it because I have been flying helis for a while but I taught my father how to use it and he can rest easy if he loses orientation. But still PRACTICE, PRACTICE, PRACTICE, and enjoy :D
     
  14. AHill

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    Don't know, I use the included RF USB control box.
     
  15. Mopar Bob

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    If you want to learn to fly without the worry of losing a ton of dough in the process, get a Hubsan x4. It costs about $35 from amazon and it will teach you to fly in ATTI mode. You can crash it a hundred times and it will still fly. When you finally learn to fly it under your control, you will be ready to fly the Phantom.
     
  16. MapMaker53

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    I believe you need to be in GPS mode with 6+ sats in order for home lock to work. Without sats, your bird has no idea where home point happens to be. AmazingRando's advice is the best tip I've heard to solve orientation confusion, especially when navigation signal is lost but the quad is still in sight. Thanks.
     
  17. TeeJayN

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    I don't think that's true. The bird still has the Home Lock coordinates but it won't know how to get there without the GPS. No?
     
  18. IrishSights

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    Homelock will not work if you have no GPS lock. But it will pull it back to you if you purely loose orrientation. Remember to give it some height first in case there are any trees or other obstacles between the craft and you. Has to be in NAZA mode and IOC ticked on of course.
     
  19. BlackTracer

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    Just want to clarify, it will only pull it back if you have sat lock and are in gps mode.
     
  20. yorlik

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    Newbie question: what is LOS???? I can't 'stay' in it if I have no clue what it is! thanks.