Finally figured out why my aircraft orientation indicator in DJI Fly is always wrong.  Interference from the RC throws the compass way off in the position the phone is meant to be placed in the holder (USB connection to the left).  I don't seem to get as much interference if the phone is rotated 180 degrees but I don't have an OTG cable long enough to test.  Hopefully that will fix this issue.

https://youtu.be/00RTrKwa4hY

Hello and good day Kevin Gregg. Thank you for sharing this video link you have created and for these informative information you have shared. Thank you for your valued support.

DJI Stephen Posted at 12-23 08:42
Hello and good day Kevin Gregg. Thank you for sharing this video link you have created and for these informative information you have shared. Thank you for your valued support.

Well, thanking the guy is nice of you but how'bout an answer to the actual problem?...... I'm using a totally different phone than him (iPhone 11 Pro) and the aircraft orientation is similarly broken, it's always at least 30 degrees off which kinda makes it useless.

As a side rant, I can't for the life of me understand why the DJI Fly app is hiding the orientation compass when showing the map in the lower left corner. There's plenty of space for both if you just move the little compass to the right a bit. Anyway, since it's not working anyway I guess that's not just a big issue right now LOL

Ice_2k Posted at 12-23 08:58
Well, thanking the guy is nice of you but how'bout an answer to the actual problem?...... I'm using a totally different phone than him (iPhone 11 Pro) and the aircraft orientation is similarly broken, it's always at least 30 degrees off which kinda makes it useless.

As a side rant, I can't for the life of me understand why the DJI Fly app is hiding the orientation compass when showing the map in the lower left corner. There's plenty of space for both if you just move the little compass to the right a bit. Anyway, since it's not working anyway I guess that's not just a big issue right now LOL

LOL, never fear, DJI will get to it and fix it, eventually!!!

I did some tests and, broadly speaking, the RC direction finder works correctly (+- 30°). If the RC has some magnetic/paramagnetic stuff in it, there is no workaround. One guess could be doing a compass calibration with the phone in place between the RC clamps. Of course afterwards you have to recalibrate to use the built in compass

JodyB Posted at 12-23 09:00
LOL, never fear, DJI will get to it and fix it, eventually!!!

Not much they can do if the issue is indeed the construction of the RC.....

Ice_2k Posted at 12-23 12:01
Not much they can do if the issue is indeed the construction of the RC.....

I don't seem to get much interference with the phone rotated 180 degrees.   I have ordered a longer OTG cable to test that so hopefully it helps.

Ice_2k Posted at 12-23 12:01
Not much they can do if the issue is indeed the construction of the RC.....

I would imagine that it could be possible to add some form of insulator. Be it external or, and this would require either a recall or voluntary send back of RC, internal to block the ingress. I've no experience with magnetic interference, but I do deal with RF interference with my work and we deal with RF ingress almost on a daily basis. Might be apples and oranges though.

JodyB Posted at 12-23 12:22
I would imagine that it could be possible to add some form of insulator. Be it external or, and this would require either a recall or voluntary send back of RC, internal to block the ingress. I've no experience with magnetic interference, but I do deal with RF interference with my work and we deal with RF ingress almost on a daily basis. Might be apples and oranges though.

I just did a quick test and it looks like if i calibrate my phone while it is in the RC, it is very close.  I will have to fly the mini later to make sure but I guess this might be a workaround.  Just need to calibrate the phone compass every time you use the mini and then again after you take the phone out of the RC.

If I have time this evening, I'm going to try my mount. From my earlier testing, I noticed that if I was very close to the mini, my compass would have the mini facing me while it was actually facing away from me but once my preflight was complete and I actually got a little distance away from me, it corrected itself. I want to see if I have the phone in the mount, up and away from the RC if it shows correctly or if it shows the opposite direction.

Just tested with my iPhone and I’m NOT seeing the same issue as with the Galaxy in the video above. So the issue must be something else for me.

Ice_2k Posted at 12-23 13:40
Just tested with my iPhone and I’m NOT seeing the same issue as with the Galaxy in the video above. So the issue must be something else for me.

Do you think maybe the iPhone is better insulated against that kind of ingress?

JodyB Posted at 12-23 13:43
Do you think maybe the iPhone is better insulated against that kind of ingress?

maybe. Or maybe it's just about the positioning of the sensor. Although I tried it in all possible positions and there was no effect on the compass reading, no matter how it was positioned compared to the RC. So thinking about it, yeah, I think Apple just did a better job of shielding the compass from outside interference than Samsung did.

Ice_2k Posted at 12-24 00:21
maybe. Or maybe it's just about the positioning of the sensor. Although I tried it in all possible positions and there was no effect on the compass reading, no matter how it was positioned compared to the RC. So thinking about it, yeah, I think Apple just did a better job of shielding the compass from outside interference than Samsung did.

Not all phone compasses are magnetometer based.  The electronic ones combine your movement using GPS and your recent "rotation" using the 3-axis accelerometer data to determine where you are, what direction the phone is pointing, and then calculates from this where magnetic North is.  These are not as accurate, and if you are just standing there flying a drone and not moving much, it could be pretty far off.  

To make matters worse, the Compass function really isn't activated in the phone until you start the App (DJI Fly).  If you do that when you are just about to take-off, the electronic based compasses don't have much information on which direction the phone is pointing, so it could be seriously off.  Perhaps this is the reason the Aircraft Orientation function with some phones seems to initially not work but then appears to work; the pilot moved around long enough for the algorithm to work.  The opposite could also be true, that if the pilot does not move around much while flying, the electronic compass drifts and therefore the Aircraft Orientation function drifts.  Either way, I'm right.

I was testing indoors, so it couldn't have been using GPS.

Ice_2k Posted at 12-24 02:02
I was testing indoors, so it couldn't have been using GPS.

My testing was also indoors. A mobile home with metal siding no less.

Last night I tried calibrating the phone GPS with it attached to the remote and the results were better but I was still between 15 and 30 degrees off (I tried multiple times).  Then I pulled out an actual compass to start comparing the phone against and found that the phone was in fact off by 15 or so degrees.  What I found was that

1) the 'calibrate' feature on the compass app must not be doing a full calibration because I found a way to get into the phone's configuration to check all the sensors and the GPS showed it needed calibration.  
2) calibrating the phone inside my house or even within 20 feet of the house resulted in the phone GPS being slightly incorrect

By moving far away from the house and going through the phone's full GPS calibration, it appears to match an actual compass.  Of course, I would have to repeat the whole thing with the phone in the RC now so testing will have to wait again.

djiuser_LBdAL64U0ZQC Posted at 12-24 06:07
Last night I tried calibrating the phone GPS with it attached to the remote and the results were better but I was still between 15 and 30 degrees off (I tried multiple times).  Then I pulled out an actual compass to start comparing the phone against and found that the phone was in fact off by 15 or so degrees.  What I found was that

1) the 'calibrate' feature on the compass app must not be doing a full calibration because I found a way to get into the phone's configuration to check all the sensors and the GPS showed it needed calibration.  

What kind of phone were you testing with?

have a look here:

https://forum.dji.com/forum.php? ... 948&pid=2039450

After doing some tests yesterday I managed to get correct reading of the compass.

Basically, with iOS Compass APP opened, the DI FLY APP did get the correct orientation, but as soon as I move the RC the arrow would go from Front to indicate the AC is behind me (which is wrong). Since the compass keep telling the AC is behind no matter what, I swapped my phone 180 degrees... and it works...

Now the USB connector of the phone is at the right, the orientation shows correctly as long I keep my body in the same position, that means let say I take off with my body facing north, I have to keep my body in that direction for the whole flight duration or the orientation is wrong.
Hope it helps!