Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Reasons for non stable hovering [gpsmode]

Discussion in 'Pro/Adv Discussion' started by t2adze, Jan 10, 2016.

  1. t2adze

    Joined:
    Jan 3, 2016
    Messages:
    556
    Likes Received:
    39
    Hey all

    What can be reasonS for phantom not hovering stable while in gps mode.

    A little wind.
    What else?
     
  2. msinger

    Approved Vendor

    Joined:
    Oct 30, 2014
    Messages:
    18,863
    Likes Received:
    5,557
    Location:
    US
    Try calibrating the IMU again. It's important to make sure the Phantom is on a completely level surface when calibrating it.
     
  3. Meta4

    Meta4 Moderator
    Staff Member

    Joined:
    Jan 8, 2014
    Messages:
    7,722
    Likes Received:
    3,440
    A little wind shouldn't make much difference
    You'll have to describe what you are seeing.
    Non-stable could mean anything.
     
  4. Mako79

    Joined:
    May 16, 2014
    Messages:
    3,410
    Likes Received:
    567
    Location:
    Sydney Australia
    Outdoors - turn VPS off.
    Indoors - turn VPS on.
     
    Dounin Front likes this.
  5. Energy Guy

    Joined:
    Oct 4, 2015
    Messages:
    86
    Likes Received:
    100
    If GPS signals are weak due to a canopy of trees. I can't fly gps mode down our road consistently because of this. Also, once I calibrated my compass while standing between to big steel picnic tables and had some trouble until I realized what I'd done and recalibrated.
     
  6. Ken Hanks

    Joined:
    Dec 28, 2015
    Messages:
    164
    Likes Received:
    34
    A CME or Coronal Mass Ejection which is a solar flare will cause havoc on satellites thus causing erratic signals to the GPS system. There are several free apps that monitor these events that are reported as "K" index. The higher the K, the stronger the interference. K's of 5 or greater will mess the GPS system for hours.
     
  7. Mako79

    Joined:
    May 16, 2014
    Messages:
    3,410
    Likes Received:
    567
    Location:
    Sydney Australia
    Compass:
    Check your compass mods while hovering about 12-15ft.
    They should be around 1500. If they are +/- 200 while hovering then you may have influence (buildings/metal structures) or maybe a bad compass dance.

    IMU:
    Have you done a COLD IMU on a perfectly levelled surface?

    VPS:
    The VPS works by "remembering" what pattern it sees at heights less than 10ft. If the image keeps changing then it may be hard for it to "remember". Eg, on a windy grassy field or on water. Its best to turn off outdoors unless you rely on it.

    Generally:
    If you are at low altitudes, there is less sat counts as they are being blocked by mountains/trees/buildings. The P3A/P acceptable sat count is 8. Prop wash also causes stability at low altitudes.
     
    #7 Mako79, Jan 10, 2016
    Last edited: Jan 10, 2016
    Dounin Front likes this.
  8. t2adze

    Joined:
    Jan 3, 2016
    Messages:
    556
    Likes Received:
    39
    IMU cali was done cold and on perfect surface.
    Vps is off.
    Gps signal is ok, its an open field in the middle of the city though.
    Ill check compass tomorrow when hovering.

    Its not very catastrophic but it kinda movesaway when hovering on 2 meter height. It was a little windy also.
     
  9. Shammyh

    Joined:
    Apr 4, 2015
    Messages:
    325
    Likes Received:
    154
    No it will not. Solar activity has neglible impact on the P3. Or any other GPS system. This has been discussed at length.

    OP, try with a regular imu cal, not a cold one. And by "perfect surface" you mean leveled with a spirit level? Both front to back, side to side, and across?

    Also, a video of the errant behavior might help others diagnose.