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Saved from FlyAway | Naza-M GPS bug???

Discussion in 'Phantom 2 Discussion' started by jplayer, Jun 1, 2014.

  1. jplayer

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    So I have had the phantom for about a month now and fly just about every day.
    Getting ramped up for a trip to Aruba (taking the phantom) and expect to encounter wind and wanted to get some practice in ATTI mode so I studied up and turned on Naza-M mode today for the first time...

    Most of my flights have been around the neighborhood as was the first flight in Naza mode.. Everything went well. It was cool being able to turn off the GPS and have it drift with the wind. It was also nice to see the extra "attitude" it has in ATTI mode... EXTREMELY NOTICEABLE!!

    After the test flight me and Fam decided to go for a walk at a local path that has a old historic train trestle(converted into part of the walking path) that goes over a huge river and I decided to take the phantom.

    Took it out and started getting some cool shots and within 2 or 3 minutes the thing started pulling away from me, HARD and uncontrolled!!! It was "steering" into some higher trees so I ramped up the gas to ascend and luckily it responded to that and started ascending but still pulling away HARRRRDDDDD despite NO directional input!! After It cleared the trees and they (the trees) were no longer a problem I reached down and flicked the switch into ATTI mode and THANK GOD it stopped pulling away. I got my bearings on the FPV and brought her back closer. I flew the rest of the battery much closer and as I flew I noticed a HUGE ISSUE... The day was clear.. we were over a wide open river but the GPS seemed to have a serious flaw... Before takeoff I let it lock on to 9 GPS'.. While in flight it would bounce betwen 13 / 12 AND........ 0 Thats right in the wide open it would lose ALL GPS signals (according to mini iosd).. 10 or so seconds later.. BOOM... 12/13 locked in again.. Then a few seconds later, same general area... 0 . The remainder of the flight the behavior continued. I decided to test another battery and the erratic GPS behavior continued that entire flight also.... As I monitored the GPS problem I would immediately pull it into ATTI mode as soon as the satellites dropped so no more "fly-away" behavior but still very unnerving!!

    SO... Is there a GPS bug in Naza-M mode??? This issue has NEVER HAPPENED in the month that I have had the phantom and I fly almost daily. I know that there was/is a theory the Naza-M and flyaways were linked and from my perspective this seems SPOT ON. Luckily I was able to save mine but definitely scary!!!
     
  2. AllanVB

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    Location:
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    Do you think it had anything to do with the Iron Bridge? I lost mine when I was filming a railroad bridge. It suddenly flew into the bridge and tumbled 200 yards to the bottom of the river canyon. Complete loss. DJI is blaming it on the bridge...
     
  3. ianwood

    ianwood Taco Wrangler
    Staff Member

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    If there was a GPS bug in Naza M mode that caused what you experienced, this forum would be awash in reports of flyaways. It is either something was causing strong interference with the GPS signal or there is an issue with your GPS unit/cable.

    Here's what you need to do:

    - Perform an ATTI flight in a totally different area and see if the GPS sat count results are similar.
    - If yes, open up the Phantom and check the cabling between GPS and the main board while looking at the OSD. It may be loose.
    - If no, go back to the site and try an ATTI flight to see if it happens again.
     
  4. jplayer

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    Allan, Ive thought of this but obviously I have NO CLUE???
    This is the first time I had flown around a structure like this and was also the first time that I noticed the intermittent and sudden loss/regain of GPS signal.
    Could a metal bridge cause this????? Doesnt seem to with my car GPS but maybe the GPS dependencies of the phantom are completely different than those of a Car GPS?



    Completely agree but seem to remember there being a theory that no one could every confirm a flyaway in Phantom mode...
    To be honest I don't know what would have happened in Phantom mode but I can assure you the only thing that stopped it dead int its tracks was me flipping it to ATTI mode. When I review the footage I was yet again astonished at how fast this thing was pulling away. The H3-3d couldn't even keep the picture level it was pulling away so hard (angled). As soon as I flipped to ATTI though.. Straightened up and regained full control.


    Obviously it was GPS signal. (Not cable.. Checked that!!) Especially since I kept losing GPS signal intermittently throughout the remainder of that flight and also the second flight that I did.



    Kind of already ahead of you. :D
    While the incident scared the *(&@ out of me I also realize that there is a chance something could happen with every flight so I didn't stop flying. As I flew the rest of the battery out (about 10 minutes) every time the GPS signal would get lost (know by looking at miniIosd overlay). I would immediately flip to ATTI and I never had one issue.

    I also flew at home previous to the incident and had no issues whasoever GPS or ATTI..

    Already checked just for sanity sake and this is not the problem.

    As mentioned above I flew for another 20 minutes after the incident. The problem with suddenly losing all GPS signals and then quickly regaining continued throughout the flights in the area but as I saw this happen I would immediately flip to ATTI so I never encountered a "flyaway" or any other "phantom has a mind of its own" problems.



    I really do not want to deactivate the NAZA-M (go back to phantom) mode but gosh its hard to fight the urge to just play it safe!! :?
     
  5. ianwood

    ianwood Taco Wrangler
    Staff Member

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    Can't say for certain, but I highly doubt the mode will have any effect on the GPS behavior.
     
  6. imprimatur

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    Hi pal, could you upload the video so we can review it? It will be pretty helpful. :idea:
     
  7. PhantoMax

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    Hi,

    I had the same GPS issue, from x sats to zero, and again, but...mine flown away...
     
  8. tom3holer

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    In Naza mode with both s1 and s2 in the up position it is the exact same as Phantom mode as I understand it.
    Have you checked the GPS antenna connection after opening it up? I would remove it and reconnect it and see if that helps.

    Tom
     
  9. jplayer

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    Tom, opened it up and connection is perfect!! flew 4 batteries full with at the house yesterday and no problems whatsoever!!
    Starting to strongly believe that the river and/or bridge where causing some odd interference!

    Phanto sorry for your loss!!!!

    Impri ill try to get the clip uploaded today.