Alta 8 Poor GPS Mode Flight Performance

Discussion in 'ALTA 8' started by Bobby Watts, Feb 1, 2017.

  1. Bobby Watts

    Bobby Watts New Member

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    So we have been flying the Alta 8 for some time now and love its reliability, ease of setup, and overall performance. For the most part we couldn't be happier... But I just can't wrap my head around the performance of the Synapse flight controller in GPS mode. The Synapse controller flies GREAT in Manual mode/ Height Hold, but in GPS mode we find the flying performance so poor, it is almost completely unusable. As I have often found with Freefly's products, whenever it doesn't seem like something is working correctly then I am almost always doing something wrong. I hope this is the case here.

    NOTE: We just updated to the latest firmware and enabled Kinematic mode, which gave it a different feel overall but we still see the same poor performance.

    Setup:

    • Stock Alta 8 with Default Gains (After doing some digging it appears that most people seem to be running stock gains.
    • Movi Pro Gimbal
    • Red Epic/Zeiss lens
    • 6s 10,000mAh packs (x2)
    • Mostly flying at Sea Level and 75-90 degree weather (Orlando, Florida)

    All up flying weight ~ 36lbs +/- a few lbs depending on lens

    Some of the problems we commonly encounter in GPS mode:

    1) Sluggish performance around center stick- In GPS Mode, center stick feels almost dead, even with the velocity clamps raised all the way up.

    2) "Toilet bowl effect" in a hover- Straight out of the box, the aircraft wanted to do the "toilet bowl effect" in a hover in GPS mode. I reduced the Horizontal stiffness a few points but I have been told that most are running stock gains. It still does not hover as "locked in" as it does in Manual mode. We have calibrated the GPS multiple times but this does not appear to change the issue.

    3) A rocking back and fourth during straight and level flight- This is the biggest problem we are seeing... If I am in a hover and push forward on the Pitch/Elevator stick, the aircraft will slowly enter into forward flight, as it should. It will then begin to rock back and fourth a noticeable amount and never really track straight and level like it does in Manual mode. This rocking back and fourth motion continues as the aircraft continues to fly straight and level.

    4) Takeoff/Landing in GPS Mode- As many of you can attest, flying a drone on a movie set gets the heart pumping just a little more than an afternoon stroll through the park. Having to remember one more thing like not taking off/landing in GPS mode is just another thing that has to go through my head during every flight. Would it be possible for a future firmware release to allow the pilot to just leave it in GPS mode during all aspects of flight? (take off, flying, and landing)

    Even if there was a mode that flew exactly the same as manual (or Height hold) but then just allowed the aircraft to hover in one GPS position, that would be great! I realize that is not a true GPS mode, but just having the same performance as Manual mode + GPS hovering assist would be a great help.

    Have any of you had a similar experience with your Alta 8? Freefly's customer support has been a huge help to us in the past but I wanted to get a feel for what other Alta 8 pilots were thinking.

    Thanks a bunch,

    Bobby Watts
    Orlando, Florida
     
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  2. Humberto Barchini

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    Are you "The Bobby Watts"!!! Oh boy oh boy!!!!

    About GPS mode it is not that good as DJI GPS.... but it is usable.... try to raise your max gps speed to 10 ms at least, and clamps at max...
    That first move above center stick is tricky... but when you use to it is helpful to do straight shots... that's all I do in GPS mode... 90 % of my flight I do it in height mode...
    I have very bad experience taking off nd landing in GPS mode with DJI products...

    About the toilet bowl, that's weird it sounds like calibration problems or maybe declination... never have that issue with my A6 or A8 and I'm in South America with a -13.8 declination...

    Cheers from Paraguay!!!



     
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  3. Bobby Watts

    Bobby Watts New Member

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    Hi Humberto,

    Yes, I believe it's me! lol thanks for the reply.

    I can try to increase the max speed, but if the performance is this poor at only a few mph, I don't really want to push it faster than I have to. I feel much more comfortable doing fast shots in Manual mode but I would love to eventually just put it in GPS mode and leave it there all day.

    Comparing to DJI- I can't say I have had the same results as you. On our previous machine, we must have logged over 1,500 flights with a DJI Wookong- taking off, flying, and landing in GPS mode almost every single flight without a single issue. But.... I do realize that getting a flight controller "right" is not an easy task!
     
  4. Dave Ketelhut

    Dave Ketelhut Member

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    Bobby,

    I am in the same boat as you are. I think i have flown in GPS a couple times for less then 30 seconds and hated it. I fly in Height mode 99.9% of the time. If i had to guess, Freefly pilots are also not flying in GPS mode, so they dont have to much interest in making it fly much better then it does now. hopefully they will invest some time on it because there are some benefits of GPS over height mode if done right.
     
  5. Bobby Watts

    Bobby Watts New Member

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    Hey Dave, nice to hear from you!

    You may be right! Who knows... Hopefully they see this and want to make it better. I really believe that GPS mode is a must for filming accurate, repeatable shots especially on windy days or when the director wants you to hold a shot 300' in the air. Take it easy- hope all is well.
     
  6. Dave Ketelhut

    Dave Ketelhut Member

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    Nice to hear from you too! we will have to catch up sometime. and I agree, there are some major benefits for GPS and it would be nice to actually use it!
     
  7. Chris Fanning

    Chris Fanning Member

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    Hey Bobby
    Hope all is well. Try the following settings. Didn't make it perfect but much better. This should only be used when lifting a heavier setup like Red or Alexa. I came the the settings below while working through the same issues with the freefly team.

    To fix waddle inflight:
    Vertical stiffness: 5
    Default: 11
    Vertical hold: 50
    Default: 80

    To fix wind instability:
    Under Position setting: Bring down a little
    Horizontal Stiffness: 30
    Default: 30
    Hold Strength: 35
    Default: 40

    Tell Jordy I said hi.
    Cheers
     
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  8. Chris Fanning

    Chris Fanning Member

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    Also turn max gps angle & speed all the way up.
     
    Humberto Barchini likes this.

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