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Lost my drone...for 15 minutes

Discussion in 'Pro/Adv Discussion' started by J0ck0, Jul 5, 2015.

  1. J0ck0

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    I started up my drone and got the fairly common imu calibration error. Calibrated it and it still said error. A minute later it said everything was good, so I took off...straight left. I pushed it up as high as I could to make sure it didn't hit anything, and hit return to home. It began to hook back to me but kept going right about a mile and a half before I lost connection. I thought for sure it was gone, but I jumped in the car to go to the last spot it reported just in case I could get the scraps. I turned into the drive of a gated community of townhouses and got the weak rc signal! My heart leaped for joy! I jumped out of the car and flew it back to me with 36% battery left. Some drunk guy in the yard next to starts yelling at me about shooting my drone out of the sky for invading his privacy as I'm nervously flying it back to land. I tell him to shut up as it finally touches down and I kill the motors. I'll pull the video and logs later, but this flying off to the left issue has to be fixed.

    edited - changed "typical" to "fairly common"
     
    #1 J0ck0, Jul 5, 2015
    Last edited: Jul 5, 2015
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  2. PaulMuns

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    ****, sounds like you were very lucky. Drunk probably couldn't hit the floor if he fell. I wish people didn't get so upset about our hobby. Glad you got your bird back.
     
  3. J0ck0

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    My question now is am I safe to fly again? Should I wait and open a ticket with DJI? I'm supposed to film a charity event at my church next week, and I'm scared to death to even try.
     
  4. tvckz

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    DJI will tell you - pilot mistake sorry - f@ck off. It is so cheap - that it is a miracle that it is flying. Get yourself a second one and only this way you will feel safe. I am in wedding video - so I understand you well.
     
  5. J0ck0

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    Here is a screenshot of the flight. Weird thing is the straight leg at the end of the curl shows as an instant jump from one spot to the next (several hundred feet ) when watching the replay. The arc begins near home because I had hit RTH. It just turned toward home and then flew sideways the rest of the arc while pointing home. image.jpg
     
  6. Meta4

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    I'd be concerned that you say you got the typical imu calibration error.
    I know there are some false error messages coming up lately (Gimbal Motor Overload and No Signal) but I haven't heard of one for IMU calibration.
    I'd be wanting to sort that one out because it's not typical for most flyers.

    If that arc was trying to fly straight, that looks like what you get with a compass needing calibration.
     
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  7. J0ck0

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    There were many reports of IMU calibration errors for quite some time now. It's why people have been putting them in the fridge. I calibrated last week roughly 10 miles from here, so I don't think a compass calibration would be necessary.
     
  8. PaulMuns

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    I thought the refrigeration before IMU calibration was to reduce the warm up time before flight. Did I miss something? Maybe the calibrate compass before every flight crowd is right. I don't always, but I fly from the same spot. Maybe a strong magnetic field corrupts the calibration between flights.
     
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  9. Chuck Young

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    I have only had my machine 10 days now but have never seen IMU calibration error, not once. I do get some whacky problems but have a pretty RF unfriendly home base. I probably have 12 to 14 devices that operate in the same frequency band as my Phantom, I expect a problem every single time I start the machine up, I watch for it and try to work around it. It is not the birds fault it all the junk I have in and around it's frequency band.
     
  10. tvckz

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    Yes, you d better calibrate compass every time you fly
     
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  11. J0ck0

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    If you do a search on IMU error, you'll find several posts about it. Here is just one:

    http://www.phantompilots.com/threads/imu-error-recalibrate.41563/

    Weird thing is it acted like normal once I reconnected to it after losing it. I think that straight line jump from the end of the arc is the drift it did after I lost signal. The end of that straight line is where I reconnected when I find it.
     
  12. Gyroplanes

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    Are these error messages on a POV (FPV) screen? If so, do all the POV / FPV screens have that feature?
     
  13. sdharris

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    You don't need to calibrate every time.

    I would say though that you shouldn't fly if you receive an error on startup and power off / on before taking off.

    Can you post the video of the flight log playing with the stick inputs so we can see the mode switching when it flew off?
     
  14. cjmwales

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    I'd suggest using some strong fishing line to make a tether for your next 'flight'. Tie one end to the phantom, and the other end to a stake in the ground. If you can replicate this error I'm sure DJI (and other P3 pilots like us!) will be very interested.
     
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  15. BenDronePilot

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    To me, "Typical IMU Calibration error" is not normal. You have either not been calibrating the IMU correctly (such as people doing a compass calibration thinking they're doing an IMU) or you may have a hardware fault with your Phantom or a problem with the firmware in which case you should reflash.

    When the IMU has been properly calibrated it literally never should need to be done again unless you get into a crash or you see your bird not flying as straight and level as it normally should be.
     
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  16. BenDronePilot

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    IMU too hot warnings has been a consistent resinous error in the Phantom 2 line and I believe so wouldn't surprise me if the same problem persists it it's temp senors with the P3.

    Storing your Phantom 3 in a refrigerator is a BAD BAD BAD idea. It's not a suitable environment to store your Phantom and could potential hard the electronics in your bird.

    If you're starting an IMU calibration after the Phantom has been stored in a safe place that's not overly hot but NOT a refrigerator you should be fine, regardless of any temp warnings.

    IMU and Compass calibration are COMPLETELY DIFFERENT and IMU will never really need to be done unless you see a problem specifically pertaining to it. Where as a Compass Calibration will need to be done more often and when you do large changes in your geographical location before flying and or add equipment to the Phantom.
     
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  17. JonasHess

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    I believe it is recommended to do a IMU calibration after each firmware upgrade and if you crash/drop the bird.
    I second that you shouldn't put it in the fridge due to moisture. Besides the only reason to cool it down before calibration is to reduce IMU warmup time when you power on. Has nothing to do with strange flight behavior.
     
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  18. J0ck0

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    The forums are full of people reporting the IMU error message after the firmware upgrade just after 1.1.9. That is why people recommended placing the Phantom in a refrigerator (I never did, btw). I've received it a few times in the past, recalibrate it, and flew fine.
    I also don't belive the compass needed to be calibrated because it flew fine once I reconnected to it. If the compass or IMU were at fault, it would have continued to be at fault even after I reconnected. They don't just randomly fix themselves in the air. I'll record the flight path video now and upload it so you can see the stick movements, etc.
    Had anyone switched to ATTI mode when this had happened to them and pulled out of it? I forgot about trying it due to sheer panic as I watched my bird fly away. I wonder it that would have helped.
     
  19. J0ck0

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    Here is the flight log video. I apologize in advance for my real bird squawking in the background. As you can see, it is in P-GPS and Home mode for the entire flight.

     
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  20. BenDronePilot

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    Yes switching to ATTI mode can and has helped people recover control of the aircraft when GPS and compass had conflicting data. It's always worth a shot to use if something goes awry
     
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