Speed in Sport Mode is incorrect in Go app

Discussion in 'General Discussions' started by Nathan Hoover, Nov 4, 2016.

  1. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Has anyone else noticed that the speed reported in the Go app when using Sport mode is exaggerated? The first time I noticed was on my second flight. I was amazed to see speeds of just over 60 mph in the app in Sport mode. I fly there all the time and know it was not that fast. I've flown several different Phantoms between 60-70 mph in that location and this didn't look like it, and the distance changes just weren't fast enough. Sure enough when I got home and loaded the flight log into healthydrones, the max speed for that flight was 41.41 mph. Almost zero wind that time.

    I flew again yesterday and had a sustained period where the speed in the app read between 58 and 59 mph into the wind obliquely. Luckily I captured the screen video and reviewing it I saw I traveled 1473' in 26 seconds -> 38.6 mph - and healthydrones had 39.28 mph as the max for that flight.

    On the other hand when in normal mode, I am not noticing speed problems. I hope DJI can fix this soon. I've seen reviewers on youtube who are crowing about how the Mavic delivers "50% more speed than DJI claims". Believe me, DJI knows how fast the Mavic goes. It's just a simple software bug.

    Anyone else noticed this?
     
  2. TommyJeep

    TommyJeep Member

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    Watching speed runs on YouTube, I had the same feeling as you. Seems like they are reporting KPH instead of MPH. Personally, I've never understood the need to do a speed run with a device that has its max speed capped in software.
     
  3. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Doesn't seem like it's quite as much of a factor as simply miles -> km. My guess is it's more like 1.5x off, not 1.6. For me it's great to have a high speed machine so I can fly out a long way and spend some time there shooting video, panoramas, etc. Loving the Mavic so far.
     
  4. TommyJeep

    TommyJeep Member

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    I can't wait to get mine, much like a few other people :)

    BTW, one video I saw the guy reached 63"MPH". That calculates to 39.1 MPH (if it truely is just a KPH-MPH error). Seems feasible to me.
     
  5. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Today I upgraded to the newly released 01.02.900 firmware and this problem is worse. Instead of just affecting Sport mode, it now seems to affect GPS mode as well. This is with collision avoidance off, units set to Imperial, Go 3.0.1 on Nexus 5x running Android 7. Didn't try other settings/devices.

    But, on the RC, the speed appears to be correctly displayed. I saw mostly 27-28mph on the RC on a distance flight I did whereas the App was consistently showing well over 40mph. This is in very light wind and we know GPS mode is not capable of that.
     
  6. Jamie

    Jamie Member

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    Pack it back in the box, and ship it to me in Australia where I will only use it in kmh and won't have an issue.
     
  7. Nathan Hoover

    Nathan Hoover Well-Known Member

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    I was wondering if it's a constant ratio and if so, what is that ratio? I took some shots today while flying in all 3 modes (GPS with and without collision avoidance) and Sport. In all cases the speed shown in the app was 1.47 times as much as the speed shown on the RC screen.

    Since 1.47 is no where near the conversion from miles to km, that's not the problem. Anyone have an idea what that number comes from (ie how could they make this mistake?)

    GPS wo/CA. 30.6/20.8 = 1.47
    P1090662s.jpg

    Sport mode 62.8/42.8 = 1.47
    P1090674s.jpg

    GPS w/CA 29.7/20.2 = 1.47
    P1090680s.jpg
     
  8. Raptorman

    Raptorman Well-Known Member

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    My guess is they will fix this soon -- can't be a hardware thing and must be a software f'up. Let's hope it's fixed in a month when I'm schedule to receive mine.


    Brian
     
  9. Dronebow

    Dronebow Well-Known Member

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    1 mph = 1.47 feet per second

    Now how DJI messed that up I do not know. Probably some calculation in the app.
     
  10. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Nice! That could well be it. Kind of a pathetic bug really. While it's no big deal really it does undermine confidence a little.
     
    #10 Nathan Hoover, Nov 11, 2016
    Last edited: Nov 11, 2016
  11. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Today on Android I see that Go 3.1.0 is released. The change list is:
    Mavic:
    - Added landscape and portrait display switch in the DJI GO app, available when the screen is unlocked
    - Added Manual Focus
    A2, N3:
    - Added a notification for flight controller assembly status
    General:
    - Improved the UI of the attitude indicator in Sport Mode
    - Improved the UI of notifications appearing when the aircraft approaches a No-fly Zone
    - Fixed occasional crashing when sharing flight records

    Maybe this means they've fixed it? I won't have a chance to try it until Wednesday.
     
  12. Alex Baxter

    Alex Baxter Well-Known Member

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    I suggest you've got the speed reading in kph, 60 kph = c.40 mph. Don't blame DJI...
     
  13. Nathan Hoover

    Nathan Hoover Well-Known Member

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    Hmm, sounds like you're kidding but I didn't see a smiley face.

    For 3 thousand words on the subject, take a look at post 7 in this thread Speed in Sport Mode is incorrect in Go app - you can clearly see MPH as the unit of speed in both the Go app and on the RC.

    Also post #5 above it explains that while the problem was initially in Sport mode only with the recent firmware update it is now a problem in all modes.

    The upshot is that the error is a constant ratio, but that ratio, 1.47, is not the conversion factor between miles and kilometers. I am sure DJI will get it right soon.
     
  14. Alex Baxter

    Alex Baxter Well-Known Member

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    OK, I retract that suggestion, my bad. Hard to believe that they'd get that wrong.
     
  15. The Editor

    The Editor Well-Known Member

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    Not hard at all - it's bug.
    DJI get a lot of things wrong and this is just one example
    Their engineers can be very innovative but their code writing is very buggy and always has been.
     
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