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Vision 2 Plus GPS issues revealed

Discussion in 'Phantom 2 Vision + Discussion' started by lizard, Jun 9, 2014.

  1. lizard

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  2. platonas1

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    I will test it today with video and post the result.Stay tuned.
     
  3. varmint

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    That the test failed to use the same shielding present in the Phantom itself (or any shielding at all for that matter). OF COURSE the electronics in the Phantom produce noise, which is exactly why there's a shield in the shell between the GPS and the mainboard. The test would have been much more informative if the phone was placed where the GPS lives and was shielded in the same way. I'm not really sure this particular test proves anything except the for the well-known fact that electronics produce noise.
     
  4. lizard

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    Unfortunately, at these wavelengths, the "shield" as used inside Phantom 2+ have zero efficiency, and actually acts as improvised ground plane.
    How can you explain the situation where the Phantom struggles to get 5 satellites, nor even 6 for long 15 minutes and the phone placed just by side gets easily 12 GPS satellites immediately plus 10 more other satellites? I can confirm this from my own experiences.
     
  5. varmint

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    You missed my point entirely. Please read the post again.

    I'm not debating the effectiveness of the GPS shield, I'm debating the validity of the "test". I have no clue how effective the GPS shield is, nor have I seen that argument made in any of the points that were bulleted; It was never even mentioned. As I said, for that reason, the test is completely bogus and proves nothing.

    Futher, you have provided no evidence whatsoever that the existing shield is "useless", and unless you're planning to do that, perhaps you should quit while you're ahead. Nobody, especially DJI spends money on shielding that does nothing, and just common sense.

    As to "how I can explain " X number of satellites, it's fairly easy, really:

    1) It's a cheap UBLOX, averaging about $15-$20 retail at any supplier. If you think I'm defending the use of a cheap chip, think again. That was not my point. It is however a very high data rate model offering 75Hz updates as opposed to the more common 5Hz. The probably chose to save money on the battery backup in order to recoup the cost of the additional bandwidth.

    2) It has no persistence whatsoever because it has no flash and no battery for maintaining offset data. Fixes take a long time to achieve and can't be maintained because DJI wanted to save $1 per unit.

    3) DJI has already publicly declared that they use filtering, which by definition reduces the number of useable satellites under the premise that the ones they're throwing out are unsuitable in their opinion, probably due to excessive declination.

    4) DJI chose to mount the GPS within the shell, in close proximity to other electronics. The RFI/EMI shielding works none the less, no thanks to this stupid "test". If you want perfection, then move the GPS outside the shell: http://www.canadadrones.com/Universal-F ... s-mast.htm or buy some high-grade shielding: http://www.ebay.com/itm/like/171173026902?lpid=82
     
  6. XL-Studios

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  7. ToThePoint

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    Yeah shhhhhh "I am recording " LOL and your having eggs for breakfast LMAO. Its funny meant XL-Studios and yes i draw my own conclusion.
    I see no difference !
    What app are you using ?
     
  8. ToThePoint

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    Found 2 app's that do the job.
    Obvious i did the test also with the 2 app's in the same condition as the test video.
    I can't see any difference between ALL the phantoms systems on or off.
    The Phantom sees the same amount as the 2 app's and there is no noticeable loss of sat signal.
     
  9. Dozer

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    I put the phantom vision plus near my dick, and immediately my **** flopped. I think these things emit some sort of impotence signal. DO NOT USE YOUR PHANTOM 2 VISION PLUS WHILE HAVING SEX. It will only cause impotence and embarrassment.
     
  10. yawnalot29

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    I apologize for cross posting, but wanted to see if anyone's got an idea about this:

    I was wondering about maybe replace the GPS Antenna with one that has a higher gain.

    I think this one below can be used to replace the P2V+ GPS antenna. However, am looking for something with more gain.
    http://www.digikey.com/product-search/e ... .25.2.A.02

    http://www.taoglas.com/images/product_i ... 190410.pdf


    Like these, but not sure if these are too thick..
    http://www.taoglas.com/antennas/GPS-GLO ... h_Modules/


    These are Glonass Antennas
    http://www.digikey.com/product-highligh ... ennas/3704

    This one is slighly thicker (by 2mm), but am thinking might work:
    http://www.digikey.com/product-detail/e ... ND/3927214


    Anyone have experience with this?
     
  11. CapnBob

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    I tried the shielding exercise described, but it had little effect for me. On a hunch, I tried some 2" copper tape that has conductive adhesive. I put 2 strips in an "X" pattern extending out onto the motor struts, and then filled in the "web" areas in between to the parting lines of the shell. I squeegeed the tape down tight wherever it overlapped, to ensure good contact. The resulting shield is shown in image below.

    I have always put the bird on my bed when working on it at home, and have NEVER seen more than 4-5 satellites in that position. Immediately after doing this mod, I can now see 7-8-9 sats consistently.

    I attribute it to possibly the conductive adhesive making electrical contact with the DJI shielding, as well as the filling in of the "web" areas. My theory, anyway.

    Again, I have never seen as many sats indoors before.
     

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  12. job2310

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    Wait, you get GPS lock indoors?!?! How does that work? Big windows? :lol:
     
  13. CapnBob

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    Not particularly big windows, no. I have always been able to receive a few sats inside (3-5), but never 7 and a lock, never mind 9.

    I haven't had the chance to fly her since I did this earlier today, but if I can get 9 inside, I should have no trouble at all outside. ;-)
     
  14. job2310

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    Excellent. I can't get 1 indoors! :)

    Sounds like you'll have no problems outside.

    One question, did you cover the copper tape with clear packing tape as well?
     
  15. CapnBob

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    No, I did not cover the tape with anything. There are no issues with contact to the electricals. I suppose if you were concerned, you could spray it with a clear acrylic such as Krylon, etc. The adhesive on the copper tape is quite aggressive, I have no worrys about it staying put.
     
  16. OutdoorEd

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    I bought a new phantom about a month ago. It locks on to 7 sats in my house. The computer is in the center of the house and not near any windows. I have no trouble locking in to as many as 11 sattelites and almost always get a lock in as little as a minute. Lucky??
     
  17. job2310

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    Ok good to know. I've read about potential shorts so always concerned about that.

    Maybe my problem is living in a pre-war brick house. It survived the Blitz so maybe it's just to solid for sats to get through, haha.

    Thanks for your input.
     
  18. job2310

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    Showoff! :D
     
  19. CapnBob

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    Good God, man. Do you live in on a mountain top? ;-)
    I usually got 3-4-5 before I did this. Also, I live in a single story home.
     
  20. OutdoorEd

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    Live in south LA along the coast. Flat land here.....Ive been flying a little bit (about 5 hours total) and learning a lot by reading the forum. Getting a signal here is really easy. House is a one story, but when I plug in the bird to the computer and power it on, it sets a home point lock in about 2 minutes. Using the PV2 for wildlife management purposes. Hope the hawks don't bring her down!