Compass changing during take off
1270 17 2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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Hey guys.
I’ve been flying a lot the past weeks since I’ve been on vacation. Everything was working great. I flew to South Africa now and I am getting some problems with my compass lately.

I noticed the first times I wanted to fly in South Africa, I had a compass error. At first I did not want to recalibrate and fly because I have heard of problems when recalibration. So I searched for better positions, but I came to realize I had to recalibrate the compass, since it was never excellent, only good (yellow) when I was lucky, red if I wasn’t.
So I recalibrated and could fly. Still I was having awkward flights. It seems the spark is not as stable as it used to be in the air. I am having image transmission errors more often than before. Also the drone seems to turn slightly to the right over a period of time!
So i decided to recalibrate the imu as well, since it was also quite a lot higher than it used to be in the past (before of came to South Africa).

What is the most scary part for me is that the little compass on the bottom left is showing weird stuff.
Before I take off I always check if the drone orientation is correct, and it is (since the compass calibration), but as soon as I lift off, the orientation changes and is wrong. It’s off by 90degrees!!
Now it would not be a problem for me, since I can always fly back, in a very safe pilot, but I’m worried if I get an image transmission error and the aircraft goes into rth the it will fly in the wrong direction!!

Any help would be appreciated to try to find the problem...
2018-1-27
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Bright Spark
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Flight distance : 22129 ft
United Kingdom
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Well I say first obsevations are what I do, rather than advice.
It seems it must be change of locale here. Assume spark was with you or looked after in flight well.
If compass changes at lift off, ac may be moving out of field  where rc/phone is located.
If you have rc that is.
Which or how many of the three is the problem.
You could Link it straight to phone and see if rc is clear. You could swap out phone. You could 'fly' spark by hand and watch compass.
One could recalibrate all three in a large clean field if possible, if you're not in one already.
Weak transmission is no problem with rc since rc operates way past video/telemetry range, but very close in flights are the order of the day 'till you sort it.
Calibration may well be where the difficulty is.
2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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Thanks for your advice.
Yes the transport went well, nothing was damaged and I was carrying it with me at all time.

I am using the RC. And I’ve been far away from bigger populations for a while now (which doesn’t necessarily mean there are no interferences, but I would say there are less)

Just to be clear: I’m talking about the little direction compass on the bottom left off the Dji go app screen!
It’s always off by around 90degrees, after lift off. It doesn’t matter if it’s the map or the „compass“
2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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Oh and as far as I know I can only calibrate the compass and the imu of the aircraft... am I missing some calibration?
2018-1-27
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Bright Spark
lvl.4
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United Kingdom
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Your phone, and the remote can be reset with a long push till it beeps.
2018-1-27
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Bright Spark
lvl.4
Flight distance : 22129 ft
United Kingdom
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When you say always off, is this rotation as you take off? You can lock/unlock the map to the display - little compass icon  top right of screen. What matters is it points to the same compass point as the one in the centre of the screen, not if it looks visually the same distance.
If you take off, can you move remote close to ac as it hovers.what happens ro compass then?
2018-1-27
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Bright Spark
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Flight distance : 22129 ft
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And another thing.! Rear lights flash red/yell if compass calibration required, so keep a watch.
2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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Thanks.
To reset phone and RC a long push on what button?

I do connect to my iPad once in a while to transfer my videos through WiFi. To do that i need to reset the WiFi of the ac each time. I haven’t flown with the iPad though. This will be my next test.


No, I’m not talking about the orientation button(compass on map view), this turns with me, but it is off by 90degrees.

Im talking about the orientation of the aircraft itself (red) that is not pointing in the right direction..
2018-1-27
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hallmark007
Captain
Flight distance : 9827923 ft
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Ireland
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Nikp Posted at 2018-1-27 05:10
Thanks.
To reset phone and RC a long push on what button?

When you say is of 90 degrees , if your flying by small directional arrow is it correct when pointing at homepoint?

If it is then everything should be ok, if triangle suddenly changes from 90 degrees off then you might have a problem.
I have similar problem what I did to change and to correct was to calibrate my phone and I also use CS this is easy to calibrate, my phone no so easy and many phones you can’t, I also done a stick calibration, I’m not sure if this alone made any difference but when done alongside my CS calibration it worked fine.
The main thing is if it’s 90 degrees off all the time and not fluctuating it should be ok.
2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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Thanks for you reply!

The red arrow (ac) is not pointing in the right direction, no matter in what direction I fly. It’s 90degreees off. When I point straight ahead, it is going to the left... if I point home, it is going to the right.

Im guessing CS is crystalsky? Special flying device?

O have an iPhone and I think it calibrates itself (at least old versions had to be calibrated, haven’t seen the calibration in a long time!)
I do have a feeling it might be the phone though! The weird thing is it’s only wrong when in the air and not when on the ground!

One question though. Of the compass is pointing the wrong direction and I lose signal to the drone, will it rth to the wrong place? Or will it use gps and rth to the exact position I lifted off??
If the rth function works, I’m not so worried because I fly safe and always know in what direction my spark is. I’m just worried that I might lose connection and the spark will fly off in the wrong direction...
2018-1-27
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Bright Spark
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Flight distance : 22129 ft
United Kingdom
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Sorry, rc reset is long push on power button after it's turned on.
(Perhaps not worry about arrows until you have green compass sensor, and no shoft after take off). this is priority really.
2018-1-27
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Gunship9
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United States
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The directional arrow should point north if you point the nose of the aircraft to the north before take off.  It should not swing to a wrong direction.  If it is, then move to another location.  You never know what is buried around you.  
2018-1-27
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Bright Spark
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Flight distance : 22129 ft
United Kingdom
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I can't visualise it. Any screen shots? You must have green compass sensor.
(Crstal sky is a dji dedicated display using android)
2018-1-27
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Bright Spark
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Flight distance : 22129 ft
United Kingdom
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Spark must display green compass at take off, and in the air.
When you arrived in SA, if the initial error was the magnetic  difference between home and SA, then calibration was desireable. But if you were just in interference, the you calibrated that in to the compass as normal. When you leave the ground clean conditions are read as an error.
2018-1-27
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Nikp
lvl.4
Flight distance : 123947 ft
South Africa
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So I haven’t written anymore because I had no internet connection. I was on the wild

It’s weird, things got better and I can’t really explain why.
The next day the compass was much better, it was still sometimes off a little, but not the 90degrees anymore... I had the thought it might be the phone that does not compensate for turning the phone 90degrees to fit it into the remote control.. not sure.

Im not sure what changed, because I flew from the same positions and it was much better the following days..

Is the compass on the bottom left of the DJI go app related to 100% to the compass sensor?
So if the sensor is good (green), the compass showing the orientation of the aircraft will be correct and if the sensor is bad (red) the orientation will be wrong?

2018-1-31
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Bright Spark
lvl.4
Flight distance : 22129 ft
United Kingdom
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If the compass is red, spark finds its  heading as it travels at variance with gps data, leading  to switch to atti mode.
Green is always a must. It will tolerate some yellow, but I won't.
I don't know what it sends to the app, but when it meets the device's compass, it will be incorrect.
2018-1-31
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Locationscout_Bavaria
lvl.4
Flight distance : 62201 ft
Germany
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Maybe this is of interest for you.   https://forum.dji.com/thread-123368-1-4.html. Magnetic interference caused by RC. I do calibrate my smartphone compass before flying, but not AC. Not neccessary.
2018-1-31
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Nikp
lvl.4
Flight distance : 123947 ft
Austria
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thanks.
that link doesnt work though..

i dont think it was rc or phone interference, because i move away when i start. im always at least 1m away from the AC.
latley i tried moving my rc and phone close and far away from the AC to see how much it affects, and its not much.
2018-2-1
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