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Vision Positioning System and Water

Discussion in 'General Discussion' started by Charles R., Jun 7, 2016.

  1. Charles R.

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    Hello, I have recently acquired a Inspire 1 and have read that the vision positioning system should be turned off over water. I have not flown my inspire 1 over water as of today. In the DJI manual it says "operate with caution" over certain surfaces water is mentioned. Does any one have any recommendations or experience. Appreciate your comments.
     
    #1 Charles R., Jun 7, 2016
    Last edited: Jun 8, 2016
  2. Dobmatt

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    Simply turn off the VPS and don't fly too low. Some DJI aircrafts has the tendency to slowly decrease the altitude at bigger speeds and compensate (climb back) at stops. It's known issue, so just keep your flights with 25 ft. headroom at least.
     
  3. The Editor

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    Because the surface of water changes height and angle (waves) the VPS can be fooled into thinking the 'surface' is lower than it actually is during the trough phase of the wave. If the aircraft lowers then when the peak comes it can be disastrous!
     
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  4. Charles R.

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    Thanks for the recommendations, I'll check for the setting for disabling it when the time comes. Oh when i'm landing ill I have to manually lower the gear as i get closer the ground if the VPS is off?
     
  5. Dobmatt

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    That is obvious. As a rule of thumb the VPS system is intended for flying indoor above well patterned and well illuminated floor. It doesn't work at altitudes higher than a few meters, so it really matters only during low flying or automated landing. Just fly high enough and leave VPS active until you gain some confidence with your piloting skills ...
     
  6. Charles R.

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    Got It
     
  7. Charles R.

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    Point well taken, thanks for the information
     
  8. emtea

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    I fly over the ocean all the time and sometimes quite low, it's pretty common to see my inspire slowly drop in altitude while hovering and then suddenly coming back up a few feet. I always leave VPS on, it's a bit worrying as it almost looks like your bird is losing power and can't support itself.
     
  9. Dobmatt

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    Emtea, this is exactly the reason why flying over water with VPS active is NOT recommended.
     
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  10. emtea

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    Ah I see...I did not see that in the manual to be honest.

    To those of you who are like me and fly off of boats a lot, I suppose turning VPS makes landing a bit easier too :D Will definitely turn it off next time.

    Question for everyone: has anyone actually found VPS to be very helpful? I never fly indoors so I'm wondering what I would really lose by ditching the entire system altogether.
     
  11. Eric

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    Lately... No. I've noticed my VPS doesn't seem to be locking into patterns at all! I've kept the lense clean and reset it multiple times to no avail. Both with and without auto landing gear on and off (mines usually off). As everyone should be, be ready to fly In Atti indoors or out.
    I've flown over water quite a bit, never really thought about turning VPS off. Will do next time.
     
  12. WBTRC

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    I fly over water (Lake) a good bit of the time and I have tried on and off and do not see the difference so I leave it on. As long as you are in line of sight you can always correct if it does something strange. I fly RC Helicopters so it is natural for me to compensate if needed.
     
  13. Dobmatt

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    Inspire (and Phantom as well) manual is actually quite precise about VPS limitations, and flying over water with is one of several big NO's. Once again, VPS is sensing surface below at very low altitudes, within a meter or two range. Naturally with assumption that it is able to sense and scan the surface, and water is NOT a good medium. It doesn't really maters when flying at 25' higher altitude, the system is short sighting. If you enjoy watching landing gear raising and lowering automatically, that'll be perhaps the only benefit flying outdoor with VPS. Once my bird happen to hover just above tree branch, VPS kicked in, lowered the gear and get it neatly anchored. With $400 penalty for fixing the gimbal I've never kept the VPS active since...
     
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