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Drifting to the Left.

Discussion in 'Phantom 2 Discussion' started by Xrover, Mar 6, 2014.

  1. Xrover

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    Location:
    Los Angeles, Ca
    Current Setup: P2 package W/Zenmuse H3-2D Gimbal, GoPro H3 Black. Mini IOSD, TS832 600mw FPV TX, Blue Beam Ultra FPV TX Antenna.
    Location is Los Angeles.
    Flying locations have been Deserts, Parks and various Country Clubs all over Socal.

    Since day One very first flight. (Pretty windy conditions on that one) I have been having this issue that when I fly forward in a straight line, the Phantom 2 begins to drift off course to the left. The nose will remain pointed at pretty close to the same initial heading but it as if I was adding a bit of left roll to the stick which i have made sure that I am not. I have tried it in NAZAM and Phantom 2 modes. II have tried different gain settings with no change. I have had the Phantom for 6 weeks now and it has done this since day One. I have flown it in 15-20 mph winds and I have flown it in 0-5 mph winds and there is no change. I had a hard landing with tip over once but there was no visible damage and the props were also untouched. It flew after that with no problems. except this drifting issue.

    All my firmware updates are good. Advanced IMU Calibrations have been done and those numbers are in the middle of the acceptable range. Sticks calibrated and pitch checked to make sure there is no roll input when adding pitch.
    Compass calibration gets done every new location I go to fly.

    I do not have anything in my pockets and my cell phone is turned off and in the car.

    I have been talking to the dealer about this and had one of the really knowledgable Quadcopter guys come and fly it yesterday. It was really doing it when he flew it and the shop he works at was up the street. We went back to the shop and called DJI. The tech at DJI couldn't come up with any ideas and said we already went through all the trouble shooting steps. He told me to send it in for repair.

    After negotiations with the owner of the shop I got him to replace the P2. We took the new one out in the back of the shop (without my Zenmuse, iosd and fpv gear installed) and flew it. It also had a slight drift to the left though not as bad. Another guy at the shop had a Phantom 1 with nothing installed on it and his Believe it or not his also had a slight drift to the left. Everybody is stumped.

    He then looked up at the sky and blamed the GPS Satellites for the problems. I know the gov't can through in any amount of error they want to the GPS system but that seems pretty unlikely as it would disrupt life as we know it.

    Anyone else experiencing similar issues?
     
  2. ianwood

    ianwood Taco Wrangler
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  3. Almmohd

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    I have some drift when hovering with gps lock. I have not really been paying much attention to it but I think it goes both left and right. If I go higher and there is some wind, it seems to do better at holding it's position in one spot.
     
  4. ianwood

    ianwood Taco Wrangler
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    Does it hook when you fly straight fast and then let go?
     
  5. dbot3000

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    Glad this was brought up. I've experienced the same thing with 2 different, brand new Phantom 2's. After acquiring GPS lock, I'll take off, and hover. It hovers a bit in a circle as though it's searching for where it's supposed to be. I'll then fly forward in a straight line (it exhibits some left bias even at this point) and after letting go of the stick, it just drifts to the left by roughly 10-20 feet. It then seems to slowly drift back to where it knows it's supposed to be. Upon flying straight backward, the same thing happens, only the drift is to the right.

    Colin has mentioned this symptom in a video and seems to attribute it to poor compass calibration. I've calibrated several times, holding the P2 in different ways, turning it at different speeds. Nothing seems to help.

    I've noticed that after flying it around for about 10 minutes, then coming back to run the same test, it does it less. It flies in a bit more of a straight line and the drift upon letting go of the stick is less, but it still happens.

    Again, I've witnessed this firsthand with 2 separate, both brand new units. One had the H3-2D installed (and nothing else) and the other had no gimbal or other accessories installed. I've verified this in suburban and rural locations.

    The dealer is sending me a replacement GPS antenna but I doubt this will fix it. It seems like more of a GPS receiver or firmware issue. I've opened up only one of the units so far and everything seemed to check out. The only oddity was that the GPS antenna appears to be covered with copper shielding, which is in turn covered by some sort of grey felt-like insulation, which is all well and good. But that insulation was pushed back and torn slightly revealing the copper shielding. And the part that seemed to be causing that is the plug from the GPS antenna.

    But, since the problem seems to lessen after a few minutes of flying, I'm wondering if that's inconsequential, and if it has more to do with total number of GPS satellites locked. I'll have a better idea of what's going on GPS-wise once my FPV and iOSD equipment arrive.

    If anyone else has experienced this or has some thoughts on it, I think we'd love to know about it/hear about them. It's more than a nuisance when you're trying to fly between obstacles or get some kind of calculated shot.

    Regards.
     
  6. Almmohd

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    It would seem so :?
    Every time I pushed forward and let go it would swerve off to the right. If I pull back and let go it would swerve to the left. Not really swerve... but move almost like a knight in chess.

    Like this but with the left with the left and right switched: viewtopic.php?f=19&t=9264
     
  7. Fink

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    I've flown my twice now and have yet to experience this, thankfully.

    Only thing I notice is sort of like what you get with cheaper quads without GPS where you'll be flying forward, let off and try to get it to hover and it will sort "rear up" in the opposite direction in which you were traveling, almost as if it were flying into a headwind and once you dropped back, the wind sort of pushes it back a little.

    I'm hoping to get four or so more flights in this weekend so I'll keep an eye on this and see if I can replicate.

    Fink[​IMG]
     
  8. ianwood

    ianwood Taco Wrangler
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    Are you on the East coast? Northeast perhaps?

    If you are in Florida, you won't see it very much if at all. The Naza M v2 is capable of up to +/- 5 degree adaption for compass alignment.
     
  9. Xrover

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    Yes..

    The forum did not send me a topic reply notification to the replies in this thread so I just stumbled across it now.
    I just read that thread and that is one of my issues..
     
  10. Xrover

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    Yes. Sometimes pulls up while doing it..
     
  11. Xrover

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    I'm in So Cal also and my symptoms including having the same problem with my second (Dealer Replaced) P2 are identical to yours!!

    I posted on the thread about the J Hook issue which I feel is what we are talking about here.
    I think I might now the issue. I think it has to do with the GPS compass data conflicting with the compass data. One must be calculating True North and the compass most likely reading Magnetic North.

    In Los Angeles we have a Magnetic Deviation of +12 degrees (East) Pretty damm close to how much it veers off course.
     
  12. Xrover

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    Hmm, Where do you live?
    That would be interesting if you had a - Magnetic Deviation in your area.
     
  13. Xrover

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  14. Almmohd

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    I'm just a little north of Venezuela and in line with Florida in the Caribbean - Trinidad.


    Sent from my iPhone using Tapatalk
     
  15. Xrover

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    You have a -12 Degree Magnetic Deviation and your P2 drifts to the Right. In Southern California we have a Positive 12 Degree Deviation from Magnetic north and our P2's drift to the Left.

    Sounds like the drifting issue is a firmware calibration issue which DJI has not corrected..