Welcome to PhantomPilots.com

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

Descending while in hover (approximately 20 feet)

Discussion in 'Phantom 2 Discussion' started by ITSAPHANTOM, May 28, 2014.

  1. ITSAPHANTOM

    Joined:
    Feb 13, 2014
    Messages:
    18
    Likes Received:
    0
    Hey guys, I just took my phantom 2 out for a flight and 2 times during the flight it randomly descended about 20 feet on it's on. It then slowly found it's way back up to it's original position. It did this while it was hovering and the battery was between 75%-100%. What could be causing it to suddenly lose altitude?
     
  2. KG4MXV

    Joined:
    Mar 29, 2014
    Messages:
    198
    Likes Received:
    1
    Sounds like it lost connection to some of the satellites and self corrected.,
    during the decent did you try to correct and did it not respond?
     
  3. damoncooper

    Joined:
    Mar 20, 2014
    Messages:
    747
    Likes Received:
    51
    Location:
    Boston, MA
    That or VRS
     
  4. Ejazzle

    Joined:
    May 7, 2014
    Messages:
    44
    Likes Received:
    0
    This same thing happened to me 3 times during 3 separate flights (one time per battery) If i was hover lower above the water I wouldve been screwed
     
  5. EMCSQUAR

    Joined:
    Sep 5, 2013
    Messages:
    1,692
    Likes Received:
    6
    Location:
    N 44.895 W 93.354 Minnesota
    That usually happens when humidity is up. NAZA uses barometric pressure to hold hover and since everything is internal on a Phantom, sometimes it's slow to react. I find that to be the case when flying early mornings. As it warms up it corrects itself.
     
  6. ianwood

    ianwood Taco Wrangler
    Staff Member

    Joined:
    Jan 7, 2014
    Messages:
    4,929
    Likes Received:
    1,800
    Location:
    Lost Angeles
    That and actual pressure gradients, changes in wind speed, temperature, etc. I would have thought the Phantom uses the IMU to smooth barometric anomalies but who is to know for sure.
     
  7. sar104

    Joined:
    Mar 22, 2014
    Messages:
    1,265
    Likes Received:
    245
    Location:
    Los Alamos, NM.
    I'm confused. Are you suggesting that external pressure changes are not immediately detected by the barometric pressure sensor inside the craft?
     
  8. EMCSQUAR

    Joined:
    Sep 5, 2013
    Messages:
    1,692
    Likes Received:
    6
    Location:
    N 44.895 W 93.354 Minnesota
    In some instances - YES. The NAZA IMU attempts to make changes for weather conditions, but in high humidity and/or wet winter conditions it seems to not be able to hold a hover as it does in warm dry conditions. Winter also adds it's own variables but it does amplify the effect. It's really evident when you start loading up your Phantom with gimbals, IOSD, etc...
     
  9. AmosMoses

    Joined:
    Mar 22, 2014
    Messages:
    597
    Likes Received:
    161
    Location:
    Illinois
    Just curious, did you happen to notice if the altitude was reading correctly on the app when it was doing this?

    Sent from my SM-P900 using Tapatalk
     
  10. The Editor

    Joined:
    Aug 7, 2013
    Messages:
    568
    Likes Received:
    7
    Or of course you could try raising the vertical gain by 10% or so!

    If your Phantom has been loaded up with baggage you may need to tweak the vertical gain a little just so it can maintain hover.
     
  11. hoagie0101

    Joined:
    Nov 18, 2015
    Messages:
    5
    Likes Received:
    0
    Location:
    Massachusetts
    My P3 has the same problem. I just got it back from the shop after a crash. The last few times out I noticed it loses altitude while hovering but the altimeter doesn't change. If I bring the copter back up, The altimeter goes up. so now it reads 50 ft when I'm actually at 30 ft. Could be a problem If I hit return home.
     
  12. AmosMoses

    Joined:
    Mar 22, 2014
    Messages:
    597
    Likes Received:
    161
    Location:
    Illinois
    A cold IMU calibration on a perfectly level surface took care of the problem for me.