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Magnetic Interference in the Far North
934 35 2018-9-27
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fans5383f7b5
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Friends,


I'm shooting on a TV show up around the 62nd Parallel, and we are getting gnarly magnetic interference on all our drones, plus fly aways with these issues. The gimbal goes haywire, and the drones fly like they are drunk. This is the case with the Phantom 4 Pro, Inspire 1, and the Mavic Pro 2. I am curious as to troubleshooting, as well as technical explanations of what is happening. We tend to recalibrate each flight, and this solves nothing. Some areas are worse then others, but I suspect this has to do with the natural differences in magnetic fields here.


Thanks!
2018-9-27
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Hellsgate
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In which country are you refering to can you be a bit more specific as to your location if you are getting this interference on all your drones then quite possibly are either ontop of or very close to a magnetically unstable area you may be able to test this theory by using a standard hand held compass and see how it reacts as you walk around with it.
Unfortunately if this is the case then im not sure there is much you can do about it.
Its quite possible you may be ontop of a large iron ore deposit thats is messing with the drone compass.
You could try take off point from an elevated location thus or nay not help.
2018-9-27
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fans5383f7b5
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Hellsgate Posted at 2018-9-27 12:22
In which country are you refering to can you be a bit more specific as to your location if you are getting this interference on all your drones then quite possibly are either ontop of or very close to a magnetically unstable area you may be able to test this theory by using a standard hand held compass and see how it reacts as you walk around with it.
Unfortunately if this is the case then im not sure there is much you can do about it.
Its quite possible you may be ontop of a large iron ore deposit thats is messing with the drone compass.

I haven't considered that so thank you. I am in Canada, specifically the Great Slave Lake Region. I'll see if I can source a compass. It only seems to happen in specific flight areas, and rather consistently around those point which would lend credence to your theory.

Any other potential thoughts? Thank you sir.
2018-9-27
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Hellsgate
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Yes the best thing you can do is find a point that has normal magnetic field go to that point and then redo your compass calibration again on each drone once this is done dont i repeat DONT do another one on any of the drones even if the app asks you to do dont do it. If you do your are going to cause yourself even more problems
2018-9-27
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fans5383f7b5
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Hellsgate Posted at 2018-9-27 12:37
Yes the best thing you can do is find a point that has normal magnetic field go to that point and then redo your compass calibration again on each drone once this is done dont i repeat DONT do another one on any of the drones even if the app asks you to do dont do it. If you do your are going to cause yourself even more problems

Roger that. Do you have any idea why the gimbal and drone would also lose full function of the controls? What I mean is, when magnetic inference strikes, flying the drone forward doesn't actually do that, rather in a more 2'o clock direction. The drone gimbal also slops around like a drunk man on a boat. I've never seen anything like it.
2018-9-27
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Hellsgate
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Once you have a correct callibration on each drone they will keep that calibration unless you modify the drone in some way by adding accessories.
If you see a compass error come up heed the warning and move to a different location. If you see one come up during flight then you should imeadiatly stop what your doing and land the drone as soon as safely possible even if you have to walk to collect the drone just get it on the ground asap.
2018-9-27
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fans5383f7b5
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Hellsgate Posted at 2018-9-27 12:42
Once you have a correct callibration on each drone they will keep that calibration unless you modify the drone in some way by adding accessories.
If you see a compass error come up heed the warning and move to a different location. If you see one come up during flight then you should imeadiatly stop what your doing and land the drone as soon as safely possible even if you have to walk to collect the drone just get it on the ground asap.

Roger that. Are you mentioning the emergency landing due to the possibility of a fly away?
2018-9-27
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Hellsgate
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Yes correct but do it safely
2018-9-27
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fans5383f7b5
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Hellsgate Posted at 2018-9-27 12:47
Yes correct but do it safely

Thank you for your time, friend. Anyone else is welcome to join in on the conversation.
2018-9-27
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Mark The Droner
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I remember long ago DJI would warn us that we cannot operate these ACs in the polar regions.  Not sure if anything has changed since then.  

Here's a cached page I just found:  http://webcache.googleuserconten ... cache:6mkfZGsFjEoJ:[/url]

edit:  https://tinyurl.com/yafny8g2

It warns not to fly in P mode

2018-9-27
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Hellsgate
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A compass error can cause many different side effects but the main and worst of all is an uncontrollable drone known as a flyaway this can be a very dangerous situation.
The compass circuit works in conjunction with the imu circuit this in turn works with every other circuit.
When the compass deviates but the imu doesnt detect any movement of the drone it comes up with this error it will favour the compass reading over its gps reading and switch off gps you are now flying in atti mode but your directions are screwed up due to a bad compass reading. This causes ghe drone to fly off in a completly different dirrection than you intended it to go.
DO NOT INITIATE RTH this will cause the drone to fly off in some random direction and you will most likely loose the drone.
2018-9-27
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Nigel_
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fans5383f7b5 Posted at 2018-9-27 12:29
I haven't considered that so thank you. I am in Canada, specifically the Great Slave Lake Region. I'll see if I can source a compass. It only seems to happen in specific flight areas, and rather consistently around those point which would lend credence to your theory.

Any other potential thoughts? Thank you sir.

That's really not very far north, the northness shouldn't be an issue, although the horizontal strength of the earths magnetic field may be a lot less than you are used to if you are from a long way south so maybe your calibration is being affected by your other equipment more that it would be further south.

Make sure that when you calibrate the compasses that there is nothing possibly magnetic anywhere near, and that includes things like mobile phones, watches etc. as well as concrete, steel fences etc.   Once you have a good compass calibration, keep it, don't keep recalibrating.
2018-9-27
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Hellsgate
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The important thing we are try to say is currently your drones may have a bad or incorrect calibration of the compasses you should not fly them again untill you get a good reliable calibration done on each of the drones then once this is done dont do another one.
2018-9-27
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Hi. Thank you for reaching DJI Forum. We suggest trying to a different location so that we can confirm if this was caused by magnetic interference or not.
2018-9-27
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Geebax
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fans5383f7b5 Posted at 2018-9-27 12:39
Roger that. Do you have any idea why the gimbal and drone would also lose full function of the controls? What I mean is, when magnetic inference strikes, flying the drone forward doesn't actually do that, rather in a more 2'o clock direction. The drone gimbal also slops around like a drunk man on a boat. I've never seen anything like it.

The gimbal is not affected in any way by magnetic influences. Make sure you are launching from a safe site, not on concrete, not from the top of a vehicle or anything metal. Contrary to popular belief, re-calibrating the compass does not cure anything.
2018-9-27
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Labroides
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There's a lot of confusion and misunderstanding about the compass and compass calibration.
Calibration only identifies which magnetic fields are a part of the drone and the drone will know that everything else is the earth's magnetic field.
Calibrating the compass won't fix problems caused by outside issues.

You are working approx 3000 km south of the north magnetic pole so the issue probably isn't related to being too close to it?
I'm not sure that the app would warn you of magnetic interference anyway if you were.
The compass would just have trouble pointing to magnetic north.

If the app is warning you of magnetic interference, the usual explanation is that your drone is close to iron or steel.
The usual remedy is to launch from somewhere that puts the compass further away from the source of the magnetic interference.
What's the geology like there?
Try hand launching or something to get the drone above ground level.


2018-9-27
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fans5383f7b5
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Nigel_ Posted at 2018-9-27 12:57
That's really not very far north, the northness shouldn't be an issue, although the horizontal strength of the earths magnetic field may be a lot less than you are used to if you are from a long way south so maybe your calibration is being affected by your other equipment more that it would be further south.

Make sure that when you calibrate the compasses that there is nothing possibly magnetic anywhere near, and that includes things like mobile phones, watches etc. as well as concrete, steel fences etc.   Once you have a good compass calibration, keep it, don't keep recalibrating.

I'll keep trying to recalibrate away from everything that could interfere with it, but so far previous attempts with this haven't worked.
2018-9-27
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fans5383f7b5
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Hellsgate Posted at 2018-9-27 13:09
The important thing we are try to say is currently your drones may have a bad or incorrect calibration of the compasses you should not fly them again untill you get a good reliable calibration done on each of the drones then once this is done dont do another one.

Of course, but we are still flying regardless, because we have to. The issues still happen after we have calibrated, but perhaps we haven't done it well enough. I want to make clear that we also have the all-life ending "compass error" as well.
2018-9-27
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Geebax
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fans5383f7b5 Posted at 2018-9-27 17:56
Of course, but we are still flying regardless, because we have to. The issues still happen after we have calibrated, but perhaps we haven't done it well enough. I want to make clear that we also have the all-life ending "compass error" as well.

Maybe, but compass errors usually have nothing to do with encountering any magnetic anomalies in the landscape, this is a very common misconception. The single greatest cause of compass errors is launching the aircraft from a surface that contains ferrous material. Of these, concrete containing rebar is the most common, but another is taking off from the roof of a vehicle, or the bed of a truck, or even powering the aircraft up while it is in a car. Look to these before you look elsewhere. The cure is to move the aircraft elsewhere, not calibrate the compass.
2018-9-27
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Hellsgate
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fans5383f7b5 Posted at 2018-9-27 17:56
Of course, but we are still flying regardless, because we have to. The issues still happen after we have calibrated, but perhaps we haven't done it well enough. I want to make clear that we also have the all-life ending "compass error" as well.

Its your choice if you choose to fly with a compass error.
Regardless of have too or not i wouldn't fly in that area if i was getting a compass error.
I would try to find a location  that i could take off from that wasnt giving any errors then fly into the area from there, keeping the drone well above ground level at all times.
You may find that taking off from a non steel platform that lifts the drone up off the ground may help.
2018-9-27
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Labroides
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fans5383f7b5 Posted at 2018-9-27 17:56
Of course, but we are still flying regardless, because we have to. The issues still happen after we have calibrated, but perhaps we haven't done it well enough. I want to make clear that we also have the all-life ending "compass error" as well.

A compass error isn't a problem with the compass that needs fixing.
It's the compass warning you of a problem in the local area.
No amount of calibrating the compass will fix that.
The solution is to get away from the cause of the problem.

How big is the area where you have encountered the errors?
Have you driven back 1 mile/10 miles etc and is the error still there?
What's the geology there?
Are you sitting on a mountain of haematite or magnetite?
2018-9-27
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Bashy
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Be very interesting to see a 360º image of the launch site..... or exact location of google maps?
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Nigel_
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fans5383f7b5 Posted at 2018-9-27 17:54
I'll keep trying to recalibrate away from everything that could interfere with it, but so far previous attempts with this haven't worked.

The geological magnetic anomaly map for the area does have some big variations over fairly small areas so I wouldn't rule out ore deposits as a possibility, would be interesting to know more accurately where you are, but I've yet to see a case of compass problems that was proven to be due to geology.  Apparently there is a lot of magnetite in the area so when doing a calibration and take off, it might be a good idea to raise the aircraft off the ground by a meter or so more than normal.  Sit it on a plastic bucket rather than the ground.
2018-9-28
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RedHotPoker
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Edmonton here. Apparently not far enough N for it to matter...
848E02AE-2555-4ED6-80A0-E8B6DBF4E848.jpeg


RedHotPoker
2018-9-28
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ArcticPhoto
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I live further north, close to 70 degrees, above the arctic circle. I have two Phantom 4 Advanced, the first I bought gave me intermittent compass errors all the time. It switched to ATTI for 5-30 seconds, then returned to P-mode. This happened on almost every flight. Calibrating did not help. As a last resort I degaussed the compass and calibrated once, I have had no compass errors after that.
My second P4A has never had  compass errors, and I have not calibrated the compass.
I guess flying on or close to the north pole will confuse the Phantom since there is no north, and compasses don't work reliably there.
2018-9-28
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andy10
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I think that calibrating in such circumstances do even more problems to the compass and will result in compass errors on an "normal" locations after that.

I'm not sure if flying in ATTI eliminates compass issues? As the Phantom uses the compass for its heading orientattion it should not.
2018-9-28
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Labroides
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andy10 Posted at 2018-9-28 01:44
I think that calibrating in such circumstances do even more problems to the compass and will result in compass errors on an "normal" locations after that.

I'm not sure if flying in ATTI eliminates compass issues? As the Phantom uses the compass for its heading orientattion it should not.

I think that calibrating in such circumstances do even more problems to the compass and will result in compass errors on an "normal" locations after that.
Compass calibration must be the most misunderstood part of drone flying.
It's amazing how few flyers know what it actually does and how many myths persist.

Here are just a few little-known facts about your compass.
Calibrating the compass won't "fix" anything.
A compass calibration in one location works just as well at any other location.
You don't need to recalibrate your compass because you've traveled any distance from where you last flew.
2018-9-28
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ALABAMA
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The camera operators on "The last Alaskans" tv show use an Inspire 2 and are always flying in or near the artic circle.   If you have other contacts, maybe they can point you to these people and give you some tips.
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Labroides Posted at 2018-9-27 19:17
A compass error isn't a problem with the compass that needs fixing.
It's the compass warning you of a problem in the local area.
No amount of calibrating the compass will fix that.

Haha no moutains as far as I can tell, but there are plenty of rocky outcroppings and a few cliff bands. I should further note that I was mistaken earlier. The Mavic Pro 2 has no issues. The areas we are shooting in roughly encompass, with plenty of gaps, 10 to 15 square miles of mostly lake shore. It seems to be sporadic and unpredictable.
2018-9-28
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fans5383f7b5
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ArcticPhoto Posted at 2018-9-28 01:27
I live further north, close to 70 degrees, above the arctic circle. I have two Phantom 4 Advanced, the first I bought gave me intermittent compass errors all the time. It switched to ATTI for 5-30 seconds, then returned to P-mode. This happened on almost every flight. Calibrating did not help. As a last resort I degaussed the compass and calibrated once, I have had no compass errors after that.
My second P4A has never had  compass errors, and I have not calibrated the compass.
I guess flying on or close to the north pole will confuse the Phantom since there is no north, and compasses don't work reliably there.

Thank you for your time. Can you elaborate on what degaussed means?
2018-9-28
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Labroides Posted at 2018-9-28 02:23
I think that calibrating in such circumstances do even more problems to the compass and will result in compass errors on an "normal" locations after that.
Compass calibration must be the most misunderstood part of drone flying.
It's amazing how few flyers know what it actually does and how many myths persist.

Thank you for your time. If I may ask, what in your experience has caused compass errors? Or what might be causing me issues here?
2018-9-28
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ArcticPhoto
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fans5383f7b5 Posted at 2018-9-28 08:59
Thank you for your time. Can you elaborate on what degaussed means?

Basically degaussing is the process of reducing or eliminating an unwanted magnetic field. This is done with a degausser, a device with a controlled magnetic field.
I suspected that the compasses in my Phantom somehow had been magnetized, perhaps the aircraft had been stored or shipped close to strong magnetic fields, like speakers.
I bought a degausser from ebay (called cfixer), and it certainly helped in my case. No more compass errors. Other pilots also report that a degausser helped them. But of course, some people say that it's snake oil, a degausser can not fix a magnetized compass. Oh well.
2018-9-28
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Mark Weiss
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A rapidly alternating magnetic field will tend to randomize lines of magnetic flux in ferrous objects that have been magnetized. A bulk tape eraser is one such device will do the job. Just turn it on, bring the drone to it, move it around the alternating field, then remove the drone several feet from the demag coil of the eraser and shut off the eraser.
2018-9-28
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Geebax
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Degausing does nothing for the solid state compass chip in the aircraft. If it was a traditional compass, then degaussing it would destroy its function, because a normal compass relies on having a magnetised element in it. It is snake oil as suggested. Russian snake oil into the bargain, which makes it even sillier.
2018-9-28
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andy10
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Labroides Posted at 2018-9-28 02:23
I think that calibrating in such circumstances do even more problems to the compass and will result in compass errors on an "normal" locations after that.
Compass calibration must be the most misunderstood part of drone flying.
It's amazing how few flyers know what it actually does and how many myths persist.


That's for sure. What I'm talking about is calibrating the compass in magnetic interfered areas, such are near artificial or nature magnetic sources as it is described here. This would put the compass to a situation when such abnormal conditions are set as normal ones and it will fly accordingly. If such altered conditions are the same over the entire flight area then it's OK, but when you go or fly over the border into a normal earth magnetic field, such calibrated compass will act abnormally!         
2018-9-29
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Labroides
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andy10 Posted at 2018-9-29 10:26
That's for sure. What I'm talking about is calibrating the compass in magnetic interfered areas, such are near artificial or nature magnetic sources as it is described here. This would put the compass to a situation when such abnormal conditions are set as normal ones and it will fly accordingly. If such altered conditions are the same over the entire flight area then it's OK, but when you go or fly over the border into a normal earth magnetic field, such calibrated compass will act abnormally!

Even in magnetically contaminated areas, calibration should only be identifying which magnetic fields belong to the Phantom.
The other magnetic influencse that don't rotate with the Phantom should not matter.
calibrating the compass isn't about the measuring earth's normal magnetic field, it's about measuring the Phantom's own magnetic fields.


The problem is caused by powering the Phantom on in a magnetically "dirty" area and having the Phantom incorrectly establish where north is.
Then things go badly when the Phantom is flown away from the magnetic disturbance.
2018-9-29
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