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Beta Testers requested to fix Compass Issue

Discussion in 'Phantom 2 Discussion' started by terry.one, Apr 4, 2014.

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  1. terry.one

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    Hi, Everyone,
    This is Terry from DJI HQ. I've read our phantom users have compass issues like TBE, not flying in straight line in certain areas. This is very strange to us and engineers are very concerned about it. We believe it is related to magnetic interference locally. To find out the cause and solve the problem, I'd like to request for beta testers in this forum who:

    1. own Phantom 2 or Phantom 2 Vision.
    2. suffer compass issue and compass calibration does not help with latest 2.0 0 firmware.
    3. have iOSD Mark II installed and provide flight data for analyse.
    4. experienced in flying.

    We will try our best to fix this issue and very appreciate your help as testers. If you are interested, pls reply the thread and I will contact you shortly. Thanks. :)
     
  2. ianwood

    ianwood Taco Wrangler
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    Terry, thanks for getting in touch. You can certainly put me down for beta testing. I can most certainly say that local interference would be one big huge coincidence as there are 74 people on this site all reporting very similar issues and everyone of them is in an area where the declination is +/-10 or higher. Anyway, I am glad you guys are here to help. That's great news. I'll help in any way I can. I'm sure we can figure it out! Thanks.

    EDIT: One problem I just realized. I don't think very many here have an iOSD Mark II. Maybe 1 or 2 people. Most everyone including me have the iOSD mini.
     
  3. Cor Brink

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    Ahh, there's the keyword, locally. Now that makes sense. There are 100's of owners where the declination is +-10 degrees or more, of which I am one, who have no issues whatsoever.
    In fact, I fly my drone with me wherever I go and have now flown it on 4 different continents without any problems.
     
  4. Almmohd

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    Yup, not mark II just the mini.
     
  5. rodemic

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    Like others I only have an iOSD Mini, but I have a Flytrex module on the way - will that provide enough flight data?

    Great to see DJI getting involved here.
     
  6. FASTFJR

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    EXCELLENT! Like many others I have the mini
     
  7. landonkk

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    Hi Terry -

    I assume this is related to the problem ianwood identified and many have confirmed. As I posted in his thread, I live in Santa Barbara, CA (not sure specifically but a high degree of positive magnetic declination). I own both a P2 and a P2 Vision. Both exhibit identical issues - a leftward drift. When I push straight on the stick both crafts will fly to about 11 o'clock - offline 10 or so degrees. Also, after a 'straight' forward thrust, both crafts will drift drastically to the left. Also as exhibited in ianwood's video example, my crafts likewise show the same behavior when in reverse (to the right). And lastly as in his video, the problem seems to get better as I get towards the end of a single flight, but returns when I start a new one.

    I have not yet updated to 2.0 as I have just returned from a trip out of the country but will be doing so this weekend. From what I gather, I don't expect an update to resolve anything. I would love to offer to volunteer for your testing as I have been intrigued (and upset) by this issue for sometime and would love to help with a fix. The only issue as mentioned is that I only have a mini iOSD and not a Mark II (and of course nothing on the Vision).

    I also have a new P2 with H3-3D gimbal on order that I assume will have the same issue.

    If I can be of any help, please let me know.
     
  8. C-Mac13

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    Great news. Thank you DJI. I would like to help but I too only have a mini. Look forward to the results.
     
  9. C-Mac13

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    Good for you. Some of us, more than just a few are having issues so I'm not getting your persistence in being troll. Your not helping the situation.
     
  10. C-Mac13

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    By the way Terry. I have 2 P2's and one has the new firmware and has the same issue and I would have no problem sending it to you guys. If your at the LA location I'm just down the freeway from you in the OC.
     
  11. PhuturePhantomPhlyer

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    Hope everyone finally finds a fix for the Phantoms. I am eager to buy one, but have been waiting to read a resolution to the fly offs.

    The good thing is, I have spent many hours reading up on them....instead of making one of my typical impulse buys.

    Good luck all.
     
  12. C-Mac13

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    You do realize this has nothing to do with fly offs correct. That's not an issue with the P2 IMO.
     
  13. poostik

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    iOSD mini here as well.

    Will keep checking in here and the other thread for updates.
     
  14. John Shaw

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    I would like to help - I have a P2V with latest software but I don't have iOSD.
    I ask Terry to be cautious as I don't think this is local. There are a lot of people seeing similar results.
    Prior to seeing ianwood's video I had noticed the JHook, the self correction with time, and especially that in Course Lock the course was offset significantly.

    After seeing ianwood's videos I figured a good test area would be a local soccer field as there are lines to line up on and reference. In preparation I zoomed in with Google Earth and measured the field. By handy coincidence if I start in one corner of the field the opposite corner is about at twice my local declination (my local declination is 17 degrees) from the near sideline.

    I flew a number of flights with IOC off and after carefully lining up with the sideline I got results nearly identical to ianwoods video. Repeating them every few minutes the JHook kept decreasing until finally it was gone and the Phantom flew straight as one would expect and is shown in ianwoods videos.

    I then lined up with the sideline and put it in Course Lock, and pushed the stick forward. It immediately headed for the opposite corner of the field in a perfectly straight line. I repeated this a number of times and it never changed. This would be close to twice the declination - as ianwood estimates in his video. This did not seem to go away with time. I thought I could reset course lock in flight but was not successful. So for me Course Lock has about a 35 degree error - which makes it tricky to use.

    I have a long background in aviation as a light plane pilot and a career in navigation and flight control systems for big airplanes. I was impressed with ianwood's analysis and many of the comments in this thread. Since we don't know the nature of DJI's "learning" process I can guess but don't know why the JHook disappears with time but Course Lock doesn't etc.

    So I am glad Terry and DJI are on it with ianwoods being the focal. I will be following with great interest, looking forward to periodic updates, and of course hope for a solution. If I can help with something that doesn't require iOSD let me know.
     
  15. ianwood

    ianwood Taco Wrangler
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    John, great summary and it's good to see that you were able to duplicate the course lock compass error pretty much exactly as I did. I think that further supports the theory of this potentially being a signing issue. If I had to put money on, I'd bet there is one line of code that looks like this:

    Code:
    true_compass_heading = compass_heading + (-declination(gps_lat, gps_lon)) + adaption(compass);  
    instead of this:

    Code:
    true_compass_heading = compass_heading + declination(gps_lat, gps_lon) + adaption(compass); 
    Terry, I think we may have a challenge in using the Mark II OSD unless you can supply some. I know the logging function was supposed to be available in an upcoming firmware version for the iOSD mini. I assume that's not going to be available soon enough for this?

    rodemic, I don't think the Flytrex is going to give Terry what he needs. He needs the CAN bus messages that contain the raw and computed values for the various flight control inputs. That's what OSD Mark II records.
     
  16. sar104

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    There is one curious aspect to the course lock behavior though. Conventional wisdom seems to be that course lock mode does not involve GPS - it simply tries to fly in the direction in which it was pointed when course lock was activated. In that case it really shouldn't matter whether the calculated bearing is correct - it should simply attempt to maintain a heading equal to that bearing. In other words it should go where it was pointed, even if it doesn't correctly know what that direction is in degrees true.

    So this would seem to imply that there are mixed, and conflicting, declination corrections in the control code - specifically that it incorrectly calculates its orientation (by -2 x declination) when course lock is activated but correctly navigates to that incorrect heading when in flight. That would lead to a constant left drift on course lock in areas of positive declination.
     
  17. onfourblades

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    I qualify for all above accept #3 i have iOSD MINI, Which i thought could log data.... Let me know if i can help.
     
  18. ianwood

    ianwood Taco Wrangler
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    It's a fair point but I look at course lock as being "compass priority" and that GPS is used to account for wind. Otherwise course lock would act like ATTI and maintain only a heading while drifting on a different course. In the case of the Phantom, it is actually maintaining heading and course by adjusting for drift.

    The idea of inconsistent declination corrections in different places in the control code, I totally agree with. It fits with my belief that real-time compass adaption doesn't have the bug which is why the compass being shimmed to twice the local declination ultimately screws up and skews the other way.
     
  19. ianwood

    ianwood Taco Wrangler
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    I hope everyone is cool with this. It is just a compiled list of all the people who have reported the issue so far on this forum and rcgroups. Terry, this is all the people who have identified that they have the same problem and the local declination where they fly.

    Code:
    Forum              Nickname             Location                 Equipment   Declination
    PhantomPilots.com  ianwood              Los Angeles, CA          P2Z         12
    PhantomPilots.com  GMANNZ               Wellington, NZ           P2V         22
    PhantomPilots.com  dbot3000             Ontario, CA              P2Z         12
    PhantomPilots.com  shartiza             Orange County, CA        P2          12
    PhantomPilots.com  Madkeen              Brisbane, Australia      P2          12
    PhantomPilots.com  Xrover               Los Angeles, CA          P2Z         12
    PhantomPilots.com  Almmohd              Trinidad and Tobago      P2Z         -15
    PhantomPilots.com  nhoover              Northern California      P2V         14
    PhantomPilots.com  kmgibbs              Seattle, WA              P2V         17
    PhantomPilots.com  dcozad               Redlands, CA             P2V         12
    PhantomPilots.com  JWDrone              Central California       P2Z         13
    PhantomPilots.com  mcmax20              Norther Alberta, Canada  P2          16
    PhantomPilots.com  C-Mac13              Orange County, CA        P2          12
    PhantomPilots.com  BigBadFun            ChristChurch, NZ         P2          24
    rcgroups.com       tom3holer            Cape Cod, MA             P2Z         -15
    PhantomPilots.com  SkyView              Nova Scotia, Canada      P2V         -17
    PhantomPilots.com  horsepowerphoto      Skyview                  P2V         ??
    PhantomPilots.com  flight-of-eye        Northern California      P2V         14
    PhantomPilots.com  CouesWhitehall       Globe, AZ                P2          11
    PhantomPilots.com  DesertFlyer          Ridgecrest, CA           P2Z         12
    PhantomPilots.com  britchris1           New Hampshire            P2          -16
    PhantomPilots.com  Fdnyfish             Northeastern PennsylvaniaP2          -12
    PhantomPilots.com  neil21               ChristChurch, NZ         P2          24
    PhantomPilots.com  Hiway                Washington, DC           P2          -11
    PhantomPilots.com  Frankflash           Lyttelton, NZ            P2          24
    PhantomPilots.com  Spunrdneck           Santa Cruz, CA           P2          14
    PhantomPilots.com  Tripnman             Northern California      P2V         14
    PhantomPilots.com  scotch               Los Angeles, CA          P2          12
    PhantomPilots.com  layertone            Northern California      P2V         14
    PhantomPilots.com  cougar               Nova Scotia, Canada      P2V         -17
    PhantomPilots.com  efoot77              Santa Barbara, CA        P2Z         13
    PhantomPilots.com  driodi               Sacramento, CA           P2Z         13.5
    PhantomPilots.com  Harold1966           Grahamstown, South AfricaP2V         -27.8
    PhantomPilots.com  paw252               Greenland                P2V         26
    PhantomPilots.com  tanstafl             Southern California      P2V         12
    rcgroups.com       westwood21           Santa Barbara, CA        P2V         13
    PhantomPilots.com  skeeter              Imperial Valley, CA      P2Z         12
    PhantomPilots.com  jedi88               Cape Town, South Africa  P2V         -24
    rcgroups.com       landonkk             Santa Barbara, CA        P2          14
    PhantomPilots.com  BenDronePilot        New York, NY             P2V         -13
    PhantomPilots.com  CliveC               Dunden, NZ               P2Z         25
    PhantomPilots.com  Slapface             ??                       P2V         ??
    PhantomPilots.com  EyeUpHigh            Northern California      P2V         14
    PhantomPilots.com  sahair1              Utah                     P2Z         12
    PhantomPilots.com  Quadro               New York, NY             P2Z         -13
    PhantomPilots.com  kmggibbs             Mill Creek, WA           P2          17
    PhantomPilots.com  itomas58             San Francisco, CA        P2          14
    PhantomPilots.com  John Straw           Pacific Northwest        P2V         17
    PhantomPilots.com  cruiser607           Auckland, NZ             P2Z         19
    PhantomPilots.com  japaneezy            Honolulu, HI             P2Z         9
    PhantomPilots.com  Byroman              Northwestern Montana     P2V         17
    youtube.com        Martin Eichenberg    New Zealand              P2Z         20
    PhantomPilots.com  wkf94025             Napa Valley, CA          P2Z         13
    PhantomPilots.com  riblit               Blacktown, NSW           P2V         12
    PhantomPilots.com  xybe                 Montevideo, Uruguay      P2V         -10.5
    PhantomPilots.com  BillGrant            South Carolina           P2          -8
    PhantomPilots.com  dbot3000             Southern California      P2Z         12
    PhantomPilots.com  onfourblades         Long Island, NY          P2          -13
    PhantomPilots.com  poostik              New Jersey               P2Z         -12
    PhantomPilots.com  cliveg               Hamilton, NZ             P2V         19
    PhantomPilots.com  aussiepilot          Sydney, OZ               P2V         13
    PhantomPilots.com  bigthai              Orange County, CA        P2Z         12
    PhantomPilots.com  nzvideoguys          ChristChurch, NZ         P2Z         24
    PhantomPilots.com  Peteresha            Bertie County, NC        P2Z         -8
    PhantomPilots.com  ivieje               Southern California      P2Z         12
    PhantomPilots.com  droneranger          Los Angeles, CA          P2Z         12
    PhantomPilots.com  PhotomanJ            Seattle, WA              P2Z         17
    PhantomPilots.com  gecary               Northern California      P2Z         14
    PhantomPilots.com  Bigbells             New Jersey               P2Z         -12
    PhantomPilots.com  xplorer              Cape Town, South Africa  P2Z         -24
    PhantomPilots.com  wworrall             Anchorage, AK            P2V         -18
    PhantomPilots.com  Highflight           New Zealand              P2          20
    PhantomPilots.com  Jeff_S               New Hampshire            P2V         -16
    PhantomPilots.com  phantomguy           ???                      P2V         ???
    
                                            Total P2 Reports         19
                                            Total P2Z Reports        28
                                            Total P2V Reports        27
                                            Total Reports            74
    
                                            Average Positive Declination         15.23
                                            Average Negative Declination         -15.12
     
  20. PhantoMax

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    Hi,

    this is Max, Phantom Vision (flown away...) and Phantom 2 pilot.

    Are you going to solve even flyaways?

    Kind regards.
     
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