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Height on Failsafe

Discussion in 'General Discussion' started by tapple, Apr 27, 2014.

  1. tapple

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    I was wondering guys, but setting the failsafe mode or RTH also recognizes the phantom height? that is, if you take it off from the terrace of a house, for example, how does the drone? I find him at the front door of the house?
     
  2. IrishSights

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    Returns to the point set as part of the pre flight startup where it gets the postion from GPS. Usually within a metre but will vary a bit depending on the number of satellites locked into. Not too sure what you mean by reference to height.

    Sent from my Galaxy Note 8
     
  3. XL-Studios

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    The Phantom will recognize the take-off height (should be 0m even if elevated over sea) but will keep descending slowly till it hits ground. Even if below take of height (0m)
     
  4. QYV

    QYV

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    I think he was talking about height specifically? I've been wondering about this myself... of course I understand that GPS is a 3 dimensional measurement so I've been assuming that it registers "ground" level as well when it done a home.. lock? whatever you call it.

    for example I launch off a rooftop often (urban) so I've been assuming it would come back and be trying to land at the same X/Y position AND height that it took off from... but how does it know? if it were trying to auto-land and didn't find ground where it expected it; say it missed the roof or the wind gusted and was heading towards the ground 50 feet below... how would that work? does it just descend at a certain rate until it touches ground via an accelerometer or something?

    [edit] aaand it looks like my question got answered as I was typing heh
     
  5. tapple

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    exactly .. give an example of fantasy for me to understand ... I'm on a building about 50 meters high ... I do fly and even drop below the take-off point to ... - then! what to do if at the end of an active flight RTH?
     
  6. XL-Studios

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    I often fly from my 10m high terass and it has auto landed (RTH) safely on the ground 10m below. If it attempted to land on my terass I would hand catch it to avoid a messy landing among furnitures, wine-glasses and what not :)
     
  7. XL-Studios

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    Ok, this is a very interesting scenario! I suppose the quad would then be thinking it´s -50m and ascend to +20m and then try to land. But this is something to still be tested/verified.
     
  8. ElGuano

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    Yes, if you take off at 50m and set your homepoint there, the quad will think 50m is ground level. So if you descend 45m, and hit RTH, it will rise up to 70m (50m + 20m) and then return to homepoint and slowly descend.
     
  9. QYV

    QYV

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    okay and what if it misses the rooftop by a meter or 2 (laterally) and keeps descending? will it keep going down? realize it's at negative height and go back up and try again?
     
  10. XL-Studios

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    It will keep going down slowly till it hits ground.
     
  11. davemcm

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    +1
     
  12. QYV

    QYV

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    alright cool thanks
     
  13. jayhas

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    I too have been wondering about this RTH aspect for some time. This for me is "topic of the day". Thanks a lot guys for a very useful and assuring info.
     
  14. Dirty Bird

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    Has anyone actually tested this? Curious because I have access to the rooftops of a few highrise office structures. I am mostly curious how the Phantom will handle a Failsafe/RTH if I am below the launch altitude. Will the Phantom first climb to 20 meters above its launch altitude, or will it decide, "Even though I launched from a 350' rooftop, I am currently at 100' above the ground." and then just fly laterally into the side of the building? I wish the Assistant allowed is to specify an Failsafe/RTH altitude.
     
  15. davemcm

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    I have tested and confirm it does what we already said.