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first auopilot flight

Discussion in 'DJI Ground Station' started by Suwaneeguy, Aug 30, 2014.

  1. Suwaneeguy

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    Finally got to the flyiing field this morning and did a trial run.
    On the first run I set 3 waypoints and launched.
    Each waypoint was set to 10 meters.
    However, the bird flew at 1 meter. I tried it a second time, same thing, but this time it crashed on a little pile of grass.
    Third try, I set the height to 25 meters.
    This time the bird flew just fine. Reached point 1, and flew to point 2 just fine.
    Took manual control and landed the bird.

    When entering the height, should you enter as 10 point 0?
    I think this may be why it flew at 1 meter instead of the desired 10 meters.

    A few others were there flying their birds and one asked, "Who was flying it?"
    So I explained how it worked and he kind of liked that.
     
  2. Buckaye

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    You shouldn't have to type the "point zero". Did you look to see what altitude your phantom was reading on the ground? Is it possible it's reading you at some height close to 10 meters high before you even take off?
     
  3. Buckaye

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    Hey... I just had the same thing happen to me today and it caused a crash (I am so lucky it crashed in soft grass... I missed things that would have messed up the phantom by like 6 inches.

    Anyway - I put in 25 ft... and it flew much closer to 2.5 feet off the ground... I am going to hook it back up and see what height it thinks it is at before I take off....
     
  4. Buckaye

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    ok... so yeah... I'd say that putting anything less that 50 or so ft in the GS is a crap shoot. Here's what I observed.

    1. Before it even takes off... GS thinks the phantom is 5 ft off the ground.
    2. Flew it up to about 10 ft.. and it was reading more like 20 ft on GS
    3. Brought it back down to like 7 ft and GS was reading between 18 and 20 ft.

    My thinking is that the altimeter on the GS is pretty unreliable... I don't think I will enter anything less than 50 ft from now on. I'll post the video later... scary as heck to watch it... seriously missed a utility pole by like 6 inches - that would have sucked. Bad enough I lost sight of the Phantom because it was so low to the ground and had to basically run around looking for it. I got lucky.
     
  5. Buckaye

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  6. cmturn0

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    Yeah the altitudes are all based on whatever your height is when you power on you quad. It doesn't account for any changes in ground level, so if your flying towards higher ground, you WILL fly into the ground if you don't account for the altitude change when you plan your route. Add that to the fact, as you noted, its not exactly super accurate in measuring its altitude.
     
  7. ChuckMRN

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    Sorry if this was already mentioned, but suggest your first point is very close to take off position. Other wise my experience is that it tries to fly a rather straight line to the first point. This makes it look like is flying across the ground. I have learned to fire up the bird and elevate before pushing the GO button. This has been the best practice for me.
    Good luck, Chuck
     
  8. Buckaye

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    Yeah that's true. though when I push go it goes up to about 15 ft and hovers for 5 seconds before it starts to first point (so it was well over my head when it started to point 1) But still as CMturn0 mentioned... it also occurs to me that there is some very slight elevation change on the flight path... so between the inaccurate height to begin with... the slight elevation change (I am in Florida so very slight elevation changes) and the bleed of altitude off of highspeed turns... all led to this crash landing.

    I appreciate the help folks :)

    On the lighter side... I took her for a test flight this morning at 100+ altitudes and she flew like a champ! Beautiful sunrise shots :)
     
  9. Timsytanker

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    I agree with Chuck, set first waypoint close to take off point to allow the quad to reach desired hight before heading off on it mission. I nearly always take off myself, hover at about 15m then hit go. I use UK Ordanance Survey maps to check the contour lines along the mission route just to see what altitude I need to set to clear obstacles.
     
  10. tbwester

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    I'm pretty sure the altitude is based on a ground height terrain model. Has anyone flown in steep terrain, and seen if the phantom adjusts to keep a standard height above ground?