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Calibration Question

Discussion in 'Phantom 2 Vision + Discussion' started by kymedic121, Jul 14, 2014.

  1. kymedic121

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    I need some serious input and advice. I am on my 4th flight this evening and all was going well until the unthinkable happened. I calibrated aircraft due to moving approx 20 miles from my last flight. Here are these steps that I followed.

    Placed the aircraft with battery facing me. Ensured S1 and S2 were in the up position. I then powered the aircraft, transmitter then Wifi. I then enabled my wifi on my my phone and the aircraft connected to phantom wifi. The aircraft flight control lights in the rear went from yellow flashing to immediate slow green flashing. I then proceed to conduct calibration. I toggle the S1 5 times and the flight control lights changed to steady yellow. I complete my first 360 degree rotation of the calibration and the flight control lights changed to immediate steady green, I then invert the aircraft in nose down position and then complete the second calibration rotation, flight control light changed to a "very short steady yellow" and then to an instant slow flashing green. My GPS meter was at 8. I start engines and wait one minute for more possible satellites and then lift off. I flew the aircraft out and back to me. I then send her up to an altitude of maybe 20' and away approx 15'. I placed her into a hover while I adjusted camera tilt and then all the sudden the aircraft took of on a hard bank to the right and straight toward me with no input from transmitter. I tried to climb and turn with no response. She continued hard right and headed straight for me. I am 6'7 so in a hale marry attempt to leap and grab her skids as she came overhead. Fortunately I grabbed her landing gear and immediately pull left stick down and hold until they stopped. after I gathered my composer I checked all controls and noticed that the GPS signal was bouncing from 4-7 intermittently. please know that i have read this manual from cover to cover enough times I can nearly repeat it verbatim. I watched every tutorial youtube has long before ordering this unit. I downloaded and read the manual several time before ordering this unit. I have very strict pre-flight check that I complete twice before I even turn on the unit. I am at a loss.

    What did I do wrong?
    Also on the second nose down clockwise rotation what color should the flight control lights be? Should it go to steady yellow for a second and then to the slow green? ( I Know that slow green indicates GPS mode) Am I missing something?

    I would truly appreciate any input or advice, I have had this unit for only 1 week and it does this.
     
  2. cahutch

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    I don't have an answer but I don't think you did anything wrong.
    It wasn't the wind blowing it toward you was it?

    What happens in GPS mode when you lose GPS lock? In theory it should know that it no longer has enough satellites for a fix.
    Does it just hover level and let the wind carry it? Seems to me like that's all it could do.

    From your description it sounds like it got bad data from the GPS, suddenly thought it was out of position and attempted to fly back to where it thought it should be.
    I don't think the compass could have caused it. The compass can tell it what direction is north and might cause it to change heading but shouldn't be able to cause a sudden position change like that.

    I've seen handheld GPS receivers show a very wrong location when you first turn them on and they haven't got a full lock on enough satellites yet.
    But you had a lock, and I would think the software would be able to ignore sudden large GPS location changes like that. If the reported GPS location changes too radically from where it was a half second before it should ignore it, especially if it can tell it doesn't have enough satellites anymore.
     
  3. kymedic121

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    I certainly had a good GPS lock well before i could even initiate the Calibration process, The flight control lights began the slow flashing green with mere second after turning the phantom on. My question is what color should the two rear flight control light be immediately concluding the second calibration (Nose down) rotation? Should it be instant green or does it turn solid yellow for a second before turning green? I am stumped.
     
  4. Mal_PV2_Ireland

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    If it was under 6 sats it would have gone into atti mode. Was the wind blowing it?
     
  5. EMCSQUAR

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    From your description it sounds like an interference "hit". You did nothing wrong in your compass calibration procedure. I'd hook it up to assistant and look at compass #'s (tools page) Those #'s should be between 1200 - 1800 (DJI say all the way up to 2200). If you took an RF hit or compass was off would make your bird do as you described. Do an advanced IMU cal & compass cal again see if that cures it.
     
  6. oldphantompilot

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    I have a post, 5 July, under fly away topic. Very similar thing. My V2+ is gone off into the trees, and never found.
    At this point I will not buy another. I have no firm idea what failed, me, the machine or both. Only hunches. Likely my fault, but having flown my V2 many times, watching the V2+ disappear first time was horrible.
     
  7. BlackTracer

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    The phantom will return to whatever non-compass-cal state it is in. For example, if it has >=6 sats at the time of compass cal conclusion, that's what you'll see. So if you're switches are both up, that would be Ready-To-Fly GPS, or slow flashing green in your case. If it has less than 6 sats, that would be Ready-To-Fly non-GPS, or slow flashing yellow in your case.

    The immediate GPS lock you got is a red flag to me. The phantom does not acquire >=6 sats instantly on power up no way.
     
  8. kymedic121

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    I really appreciate everyone's very sound hypothesis. I was up until 3am going over my procedures of yesterday,Winds were calm and I checked IMU Cal and was between 1490 and 1560, went ahead and did a IMU Advance Re-cal to be on the safe side. There is one thing that occurred yesterday just prior to my incident that didn't register with me until last night. Yesterday evening between 630pm and 745pm our Dish Network was up and down with complete signal losses and this was experienced by nearly half the country. I am wondering if this loss of Satellite Service for them could have actually effected my aircraft. What has me stumped is that when I lifted off I had slow green flashing lights and 7-8 sats and she flew with no problems for a few minutes and then utter chaos. I will never know the absolute cause but I am leaning toward some kind of RF Interference. The only electrical component with any proximity is my neighbors electric fence which bordered my property and which I did fly over at altitude in the onset.

    My next question is, Now that I am certain that the IMU values are within normal ranges should I slap the tracker on it and take it back to the same location and try again, chalk this area up as a No Fly Zone or not risk it, take it to another location and launch from there or send the unit back as it is brand new and get a replacement before it crashes which will void the warranty? This unit only has 6 flights including this last episode.
     
  9. happydays

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    No help on the 'fly-off' but you really should turn on the transmitter before the aircraft. I do transmitter, wifi extender, aircraft and then the app in that order.

    Glad you got hold of it, you certainly have been doing your homework over these past few weeks and it would be a real pity to be as prepared as you obviously are only to have it disappear.

    One tip that I would advocate, is checking on the waypoints screen that the home point (blue dot) is in the same place as the aircraft (red plane) so I know that the home point has definitely been set properly.

    Just a thought.
     
  10. kymedic121

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    Thanks so much. I am trying to be as a responsible and educated pilot as possible but I just hope I am not overdoing it and missing something. See I didn't think to check the map and see the home point location (I will for now on, just added to my preflight) but I did prior to lift off try and reset the home point to ensure it was in the correct location by toggling the S2 repeatedly up to 12 times and it never did reset the home point. I just assumed that this feature was not available in the phantom mode as the S2 switches are null in this mode. What is up with that?