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Avoid Crash due to Compass Interference
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AntDX316
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A J Posted at 5-30 23:47
It's all in the manual. You'll do well reading it

You're right.  Atti mode is pretty much the failsafe method probably installed after the mass Wookong DJI A2 S800 crash study.
2019-5-30
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A J
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AntDX316 Posted at 5-30 23:56
You're right.  Atti mode is pretty much the failsafe method probably installed after the mass Wookong DJI A2 S800 crash study.
[view_image]

There you go - now keep reading and hopefully the need to post rhetorical questions will stop...
2019-5-30
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AntDX316
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A J Posted at 5-30 23:58
There you go - now keep reading and hopefully the need to post rhetorical questions will stop...

I mean, I thought it would only not work when it's dark but being too bright and angled surfaces is interesting.. though I should look into how terrain follow mode works in detail.  I never really trust the systems like that as it doesn't always work as it should.
2019-5-31
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hallmark007
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Labroides Posted at 5-30 20:08
there are a lot less compass problems with these aircraft, so hopefully for whatever reasons dji has managed to tweak problems with compass for the better
Actually the compass has always been trouble free.
The problems have always come from operators not understanding the compass or compass calibration.

While i agree with all you say, there is a notable decrease with compass problems in fact almost none in MavAir and M2, or at least extremely rare, whether it’s down to something as simple as better sealing or position of compass in these craft I’m not sure, but I would not think it’s down to better educated users, so while everything you say is correct, it doesn’t explain why we see so few problems with compass in new craft .
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hallmark007
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AntDX316 Posted at 5-30 21:15
"1/ Never calibrate Compass unless prompted to."

This is wrong.  The compass interference rises at times, no idea why.  I get interference in the hundreds.  It gets reset back to a low single or 2 digits green number After calibrating.  The weirdest thing is when you calibrate when it has interference that the numbers are really low.  Now, I'm wondering if you calibrate in an open field, is that better than calibrating in a hard interference area because if you can get low numbers in a hard interference area then the open field calibration should be even lower.  If you calibrate in an open low interference area the interference tolerances would be A lot word when being in a high interference area.  It would be easier if we had a compass engineer tell us what is truly going on so we can make an optimal decision on when and where to calibrate.  Right now, we are all pretty much guessing and those unfortunate ones who do it wrong, lose their drone and worse.

I’m afraid none of what you say makes any sense, so it leads me to believe your comments are not genuine, they are so far off the mark, they could have been written by someone in preschool.
I think most people like commenting back and forth when there is something to Be learnt from one or other.
What your saying is tantamount to pure drivel .
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AntDX316
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hallmark007 Posted at 5-31 01:19
I’m afraid none of what you say makes any sense, so it leads me to believe your comments are not genuine, they are so far off the mark, they could have been written by someone in preschool.
I think most people like commenting back and forth when there is something to Be learnt one or other.
What your saying is tantamount to pure drivel .

Don't calibrate your compass then.  I don't even calibrate mine with the Mavic 2 Zoom even when it says calibrate it but I do w/ my P4P V2.0 as I'm worried the system design of 2016, I can get away with cheating the system as the Compass 2 on the Mavic 2 is VPS.  I think it could be ok though.  All the sense I have is from real-world information and engineering.  The people are talking from a level above that (surface wise not the deep core essence) which is flawed.  It involves rapport and sometimes extreme rapport to learn and trust who to believe.

I look at the numbers after calibration and they drop significantly.
2019-5-31
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Labroides
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hallmark007 Posted at 5-31 01:06
While i agree with all you say, there is a notable decrease with compass problems in fact almost none in MavAir and M2, or at least extremely rare, whether it’s down to something as simple as better sealing or position of compass in these craft I’m not sure, but I would not think it’s down to better educated users, so while everything you say is correct, it doesn’t explain why we see so few problems with compass in new craft .

Compass problems?
We don't see any compass problems, we see operator problems.
A compass error is not something wrong with the compass that needs to be fixed.
It's a properly working compass that's warning that it's detected a magnetic problem in the local environment.
Calibrating the compass doesn't "fix" anything and will never fix the issue the compass is warning about.
Better sealing?  The compass has to be sensitive to small magnetic fields or it's not useful as a compass.
I suspect there is no change in what you are perceiving as compass problems.
I still see plenty of users having troubles and blaming their compass.
There's certainly no significant improvement in user education and no shortage of people totally ignorant of how the compass works.



2019-5-31
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Labroides
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AntDX316 Posted at 5-30 21:15
"1/ Never calibrate Compass unless prompted to."

This is wrong.  The compass interference rises at times, no idea why.  I get interference in the hundreds.  It gets reset back to a low single or 2 digits green number After calibrating.  The weirdest thing is when you calibrate when it has interference that the numbers are really low.  Now, I'm wondering if you calibrate in an open field, is that better than calibrating in a hard interference area because if you can get low numbers in a hard interference area then the open field calibration should be even lower.  If you calibrate in an open low interference area the interference tolerances would be A lot word when being in a high interference area.  It would be easier if we had a compass engineer tell us what is truly going on so we can make an optimal decision on when and where to calibrate.  Right now, we are all pretty much guessing and those unfortunate ones who do it wrong, lose their drone and worse.
This is wrong.
What's wrong is almost every stupid word you type.
You have very little knowledge of anything related to your drone or how it operates and even less understanding of how little you know.
No-one should pay any attention to the garbage you post.

You'd do well to stop posting for a month and just read.

It would be easier if we had a compass engineer tell us what is truly  going on so we can make an optimal decision on when and where to  calibrate.  Right now, we are all pretty much guessing and those  unfortunate ones who do it wrong, lose their drone and worse.
I'll tell you but you probably won't pay any attention and won't learn anything.
Calibrating your compass has nothing to do with where you are as long as there's no spurious magnetic fields very close by).
Once your compass is calibrated (and it probably was before you opened the box), there's no need to do it again.
Unless you :
1.  Modify your drone  .. or
2.  You bought one of those Mavic 2 drones that DJI forces you to unnecessarily recalibrate from time to time.

Understanding what compass calibration actually does is the key ... and you have no idea of that.

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AntDX316
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Labroides Posted at 5-31 17:55
This is wrong.
What's wrong is almost every stupid word you type.
You have very little knowledge of anything related to your drone or how it operates and even less understanding of how little you know.

I understand your issues but even the Note 9 and other Samsung phones ask to calibrate for some reason even after calibrating.  You can get away w/o calibrating at all, it being off and still being ok.  We all can.  People probably crash because of something not compass related.
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Labroides
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AntDX316 Posted at 5-31 19:32
I understand your issues but even the Note 9 and other Samsung phones ask to calibrate for some reason even after calibrating.  You can get away w/o calibrating at all, it being off and still being ok.  We all can.  People probably crash because of something not compass related.

Like I said, once your compass is calibrated, it's not necessary to ever calibrate it again.
It's done and that's all there is to it.
Your compass doesn't go out of calibration, it doesn't go off.
It's always OK.

But you'd have to understand what calibrating the compass really does and how it doesn't "fix" anything.
But you don't.
2019-6-1
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AntDX316
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Labroides Posted at 6-1 00:04
Like I said, once your compass is calibrated, it's not necessary to ever calibrate it again.
It's done and that's all there is to it.
Your compass doesn't go out of calibration, it doesn't go off.

I will calibrate in a super open field and leave it but the only way to tell if you are not near anything interfering is to have some sort of magnetic interference sensor.  If you calibrate over an open field that is over a fault line like some people did, they would lose their drone but I'm not sure how the compass even matters.  There is no such thing as a compass on some DIY multi-rotors.

Would this work as I assume you portray yourself as the compass expert here?
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Labroides Posted at 6-1 00:04
Like I said, once your compass is calibrated, it's not necessary to ever calibrate it again.
It's done and that's all there is to it.
Your compass doesn't go out of calibration, it doesn't go off.

I agree!
Calibration is unnecessary until DJIGO4 requests.
The real problem with Spark is that there is only one compass, so it is not possible to determine whether the disturbance is real or just the malfunction of the cheap compass ...
If you have 2 compasses (eg mavic, phantom, inspire) then the firmware is simple:
- 1 compass error, 2 compass fine = internal fault, no action
- 1 compass error, 2 compass error = interference, ATTI mode
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AntDX316 Posted at 3-25 15:13
If you don't calibrate the compass you can get drift and a tilted quadcopter when doing nothing.  I didn't calibrate out of the box for a while but was noticing how the horizon is Always tilted and it drifting.  After calibrating it fixed it.

It was "normal" all the time unless it's on something metal like a hood or on the ground

The inclination of the horizon is not caused by the compass. IMU is responsible for controlling the drone movement.
In this situation, the IMU should be calibrated and not the compass.
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hallmark007
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Labroides Posted at 5-31 17:51
Compass problems?
We don't see any compass problems, we see operator problems.
A compass error is not something wrong with the compass that needs to be fixed.

What your talking about is more to do with the semantics of the whole thing, most users are well aware if they put their drone on a ton of steel the compass will have problems, and if the take it off compass problems will be gone, so I’m certain most users can figure out what’s causing the problem, not the compass but the steel, maybe give users some credit.
I’m not to sure where you seen I said calibrating compass will fix anything , but if you own a MavAir or a Mavic 2 you won’t fly unless you calibrate.

While you still see users having problems with their drones as I do, I still say there is a marked improvement in those who own M2 and MavAir, you can go through the forum and you will see this for yourself , and I don’t think it’s just a coincidence, but more likely improvements in building newer craft, if you know something to the contrary then maybe show us .

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AntDX316 Posted at 6-1 00:28
I will calibrate in a super open field and leave it but the only way to tell if you are not near anything interfering is to have some sort of magnetic interference sensor.  If you calibrate over an open field that is over a fault line like some people did, they would lose their drone but I'm not sure how the compass even matters.  There is no such thing as a compass on some DIY multi-rotors.

Would this work as I assume you portray yourself as the compass expert here?

but the only way to tell if you are not near anything interfering is to  have some sort of magnetic interference sensor.
If only the drone had some sort of magnetic sensor built-in.
Something that could detect magnetic fields and the identify the direction of their force lines.

but I'm not sure how the compass even matters.  
Of course .. there's so much you aren't at all knowledgeable about.
But that doesn't stop you trying to lecture everyone with half-baked theories.

Would this work as I assume you portray yourself as the compass expert here?
Do you know what a compass is and what it does?


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Labroides
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hallmark007 Posted at 6-1 01:27
What your talking about is more to do with the semantics of the whole thing, most users are well aware if they put their drone on a ton of steel the compass will have problems, and if the take it off compass problems will be gone, so I’m certain most users can figure out what’s causing the problem, not the compass but the steel, maybe give users some credit.
I’m not to sure where you seen I said calibrating compass will fix anything , but if you own a MavAir or a Mavic 2 you won’t fly unless you calibrate.

What your talking about is more to do with the semantics of the whole thing, most users are well aware if they put their drone on a ton of steel the compass will have problems, and if the take it off compass problems will be gone
Except in the rare situation where the magnetic field associated with the steel is aligned exactly the same way as the earth's magnetic field, that's a very good way to come to grief with a yaw error.
The greater the difference between the directions of the magnetic fields, the bigger the problem and the more likely the drone is to crash seriously when the drone departs the mag field of the steel object and turns to face another direction.
I see this sort of mistake every week and the result is usually quite bad.
Never powerup or launch from close to steel objects or reinforced concrete, it's about the worst thing you can do with your drone.

you can go through the forum and you will see this for yourself, and I  don’t think it’s just a coincidence, but more likely improvements in  building newer craft, if you know something to the contrary then maybe  show us
I haven't carried out any kind of survey but from the forums I read, my perception is the opposite.
My guess has been that it's due to the large number of new users coming in since the M2 series was released.
I don't believe there's any fundamental improvement in the compass technology.
It's hard to imagine how there could be, but I'm not aware of any inherrent problems with compasses, old or new.

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hallmark007
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Labroides Posted at 6-1 06:02
What your talking about is more to do with the semantics of the whole thing, most users are well aware if they put their drone on a ton of steel the compass will have problems, and if the take it off compass problems will be gone
Except in the rare situation where the magnetic field associated with the steel is aligned exactly the same way as the earth's magnetic field, that's a very good way to come to grief with a yaw error.
The greater the difference between the directions of the magnetic fields, the bigger the problem and the more likely the drone is to crash seriously when the drone departs the mag field of the steel object and turns to face another direction.

I’m not sure how you manage your perception, but I’m telling you if you compare for instance Mavic Pro to M2 , you will find that fall in craft crashing because of “compass” related problems is vast , and one thing we do know is there was a change in compass system from Mavic Pro to M2, change consisting of two compass in Mavic Pro one in M2 and Only a blind man couldn’t see the clear difference in compass associated problems between these two craft, I would hazard a guess that Mavic Pro with compass problems would have been almost 1/2 a week showing up here, M2 I would say that since it’s release less than a handful showing up here. So yes I would say something changed .
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Labroides Posted at 6-1 05:48
but the only way to tell if you are not near anything interfering is to  have some sort of magnetic interference sensor.  
If only the drone had some sort of magnetic sensor built-in.
Something that could detect magnetic fields and the identify the direction of their force lines.

but the only way to tell if you are not near anything interfering is to  have some sort of magnetic interference sensor.
If only the drone had some sort of magnetic sensor built-in.
Something that could detect magnetic fields and the identify the direction of their force lines.


As has been mentioned before, you can download free (or nearly free) Android and iOS Apps that will show magnetic force lines of a SmartDevice's compass.  Compass is composed of three magnetic field sensors for X, Y, Z axis.  Apps will show deviations from Earth's normal magnetic field.  Which can be an increase (source of magnetic field) or decrease (source acting as shield) in magnitude.  Some of Apps have ability to show individual XYZ sensors strength vs. simple combine value for XYZ sensors.



Mavic Pro uses two electronic compasses (primary & backup) for total of six magnetic field sensors (Xp/Xb, Yp/Yb, Zp/Zb).  You can use drone's magnetic field sensors to detect sources of magnetic field interference.  Raising drone or moving drone should not result in significant change to GO-4 App's magnetic interference bar.  Bar(s) should be green and short in length.  Mavic Pro with two electronic compasses has advantage in that a source of magnetic interference is generally closer to one of it's two compasses, unless drone is directly over or under source of magnetic field interfernce.  By rotating drone, you can get idea of where source is.  Understanding moving drone as little as several inches can result in Good-to-Go or Warning of Magnetic field interference.


** Assuming SmartDevice's compass or drone's internal compass(es) have been properly calibrated.











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hallmark007
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Labroides Posted at 6-1 00:04
Like I said, once your compass is calibrated, it's not necessary to ever calibrate it again.
It's done and that's all there is to it.
Your compass doesn't go out of calibration, it doesn't go off.

I do fully agree with you once compass is calibrated correctly it never needs to be calibrated again including when moving large distances, as someone who owns P4Pro Mavic Pro , I have calibrated P4Pro once since I got it and Mavic Pro twice, and have had only one warning to calibrate Mavic Pro, I don’t have any need or urge to calibrate either again.

With MavAir and Mavic 2 compass calibration is forced on these two craft and yes unnecessarily, but there is no way around it .

We have also seen change in the Mavic pro manual where it now advises calibration every 50km which I have and will completely ignore .
2019-6-3
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Bluehook
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hallmark007 Posted at 2017-7-11 13:40
Tip To Help Avoid compass interference and crash.

I read this before my first flight and I have done it every time without exception.  Also, I follow the rule also suggested (I believe) by @Hallmark007, to lock no less than 11 sats before take-off.

And (knock wood) so far I haven't had any issues.

Thank you, sir.

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What happened to the tip?
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Have read through the whole thread, learned a couple of things about how the compass works. Did get alot of Compass and Yaw errors a couple of days ago, and now I'm not sure if I should calibrate the compass or not. The app has not asked me to do so, , so shouldn't be necessary. I've noticed that I get a interference number of about ~2-300 in different locations, where I'm sure there is no metal. Could a "bad calibration" cause that? I haven't calibrated it myself, bought it as a used unit, but I guess it has been on repair at Dji, since it looked brand new, stickers on camera and positioning lens. And it activated as brand new, elegible for Dji refresh care.

Not sure though, but if someone calibrated the compass in a not-so suitable area or way, could that explain why I get around the same amount of interference, even in different remote locations?

Have a thread up, describing the errors. Hope to get it sorted out somehow.

I will try to check interference levels in a different location later today, if the weather clears up that is
2019-8-18
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Flygmaskin Posted at 8-18 06:02
Have read through the whole thread, learned a couple of things about how the compass works. Did get alot of Compass and Yaw errors a couple of days ago, and now I'm not sure if I should calibrate the compass or not. The app has not asked me to do so, , so shouldn't be necessary. I've noticed that I get a interference number of about ~2-300 in different locations, where I'm sure there is no metal. Could a "bad calibration" cause that? I haven't calibrated it myself, bought it as a used unit, but I guess it has been on repair at Dji, since it looked brand new, stickers on camera and positioning lens. And it activated as brand new, elegible for Dji refresh care.

Not sure though, but if someone calibrated the compass in a not-so suitable area or way, could that explain why I get around the same amount of interference, even in different remote locations?

I'd say:

"I haven't calibrated it myself, bought it as a used unit, but I guess it has been on repair at Dji, since it looked brand new, stickers on camera and positioning lens. And it activated as brand new, elegible for Dji refresh care."

Since YOU have never calibrated your compass, you should do it once and right, like it is described in a lot of topics and videos.

After that,you know it is done!
Edit: Aside that there can be a need, if it WAS in repair (Netherlands for europe?) and is NOW in Sweden?
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S-e-ven Posted at 8-18 07:55
I'd say:

"I haven't calibrated it myself, bought it as a used unit, but I guess it has been on repair at Dji, since it looked brand new, stickers on camera and positioning lens. And it activated as brand new, elegible for Dji refresh care."
Yeah, I’m starting to think that as well.. Performing a good calibration “once and for all” would probably be a good thing to do. Since I actually don’t know who actually did it and where.

I wonder what kind of environment Dji centers calibrate in..

The retailer that sold it at discount price, said that the unit had been on service but couldn’t say where it went (or why it needed service).

Since it’s a Dji product, my guess is that it most likely would have been in Dji center in Holland or in Germany which are the two service centers I’m aware of in Europe.

Now it’s in Sweden, waiting for better weather ;)

Do you think that a calibration performed in a “bad place” can make the compass show interference in another location even that there might be none?

I guess I might go ahead and calibrate it, but I have stainless steel plates and screws inside my hand, pretty hard to avoid proximity of metal then.. Guess it shouldn’t be magnetic though, but not sure.
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Flygmaskin Posted at 8-18 22:33
Yeah, I’m starting to think that as well.. Performing a good calibration “once and for all” would probably be a good thing to do. Since I actually don’t know who actually did it and where.

I wonder what kind of environment Dji centers calibrate in..

I think that too:"Guess it shouldn’t be magnetic though, but not sure."


Check with your doctor, use the other hand, dont forget the Phone, keys, money, zipper, .... ;-)


I think that you are good, as long you not doing the calibration close to "real", known metal sources.


Check a couple of the videos on youtube or elsewhere
2019-8-19
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Bluehook Posted at 6-3 09:26
I read this before my first flight and I have done it every time without exception.  Also, I follow the rule also suggested (I believe) by @Hallmark007, to lock no less than 11 sats before take-off.

And (knock wood) so far I haven't had any issues.

The 11 satellite rule is a good one.

2019-8-20
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DAFlys Posted at 8-20 01:38
The 11 satellite rule is a good one.

don't remember but somewhere says min 14 satellite which is mostly hard to catch if you are in  a city heavily covered by the skylines or deep valleys , forest fields.
Good to know >11 is OK to go
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moral of the story is, if all else fails,  open the book that it came with. repeat step one again.  lol
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This post-take off bee-dance saved me at least two times. Without it, if I flew off right away, I would have discovered the drift and the subsequent BATTI too late.
With the bee-dance you see right away that something is wrong and can land without any issues.
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BumblerBee Posted at 11-4 07:38
This post-take off bee-dance saved me at least two times. Without it, if I flew off right away, I would have discovered the drift and the subsequent BATTI too late.
With the bee-dance you see right away that something is wrong and can land without any issues.

More haste less speed .
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FatherXmas Posted at 2017-7-16 17:31
I would like to point out, these are only valid points when flying outdoors. I fly a lot indoors, seldom get a good GPS lock and it's constantly complaining about magnetic interference, especially when I get close to the refrigerator. Just make sure the prop guards are on and you take it easy. One other thing - not a good idea to fly into the bathroom when the wife is in there - good way to get it slapped out of the air.

Mrs. Claus would to that? ;)
2019-11-24
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Phuong Do Posted at 2017-7-12 23:19
Hi Captain, I do not mean to say right or wrong here, but just open for discussion.
I saw this page today from DJI, seems like they advise to "calibate compass before flight". You have any comment on that?
https://store.dji.com/guides/dos-donts-drone-flying/

I don't want to start a bun fight, but you did ask for comments.

Many people have opinions. You heard the general saying about that. Opinions should be backed by concrete scientific evidence, or at least some basic logic. The "I haven't had a problem yet" is not sufficient. There is much evidence that people do in fact have problems.

Here is my "Opinion" with evidence.

It is best practice to calibrate your compass if you change your flight location by more than about 50klm.

This is due to the fundamental issue with Magnetic North changing in relation to MAP True North, based on your location.

The 50 klm is considered to be sufficiently, insignificant.

The issue is with GPS map programmed, (Waypoints) or RTH flights.

It does not effect manual flights.

If the true north configuration error is great enough to where you originally calibrated the compass it can miss the programmed waypoints or RTH location on a RTH.

The impact of this is determined by the actual logic programmed into the Flight controller Firmware. As can be seen by recent incidences of Compass heading flips and the non recovery of the FC logic causing the drone to fly away.

DJI need to provide much more defensive logic in their FW for compass issues.

Magnetic north also drifts with time You can calculate the drift by using the NOAA reference site below.

DJI have updated their firmware I believe on the M2 to force Compass recalibration at regular intervals. (It should be noted that the M2 supports programmed waypoints) This will catch some, but not all incidences.

If you are flying outside of a 50 klm radius of where you calibrated the compass you should recalibrate.

If you are traveling, particularly international travel you should recalibrate at your new flight location.

Travel can change the Magnetic Deviation angle to True North from approx +13 degrees to -12 degrees. Just across the continental USA. So this is significant.

Now, as recalibration has no ill effects its better to be safe than sorry and follow the manufacturers recommendation. You can check your deviation from true north at the following websites.

NOAA Magnetic Fields over Specific Dates Calculations.

Calculate your Magnetic Declination.

Here is a fundamental example of the issue. This is a 25 degrees difference just across the USA.

New York -12 degrees 51 minutes. West.
San Fran +13 degrees 19 minutes. East.

AFAIK the deviation is calculated and stored at the time you do your compass calibration. It is done then, and not on the fly, as on the fly, it cannot rotate itself by 360 degrees in all 3 axis and cannot determine that it is clear of all magnetic interference.

It assumes that you are obeying the instructions and do the manual calibration away from any magnetic interference.

As stated earlier this is not an issue for normal flight, as everything is relative to the compass heading.

It is only an issue when the drone has to hit a GPS coordinate from its current GPS coordinate. That calculation is based on True North so it must reference its current magnetic heading and adjust for the magnetic deviation at the flight location.

Adjusting compass's for geographic deviation is a routine procedure for all flight crews on long hall flights.

Drone manufactures generally have this documented in their User Manuals. The distance recommendation is in the Walkera manuals. Walkera have had Pre programmed waypoint flights available for their Arducopter based Flight Controllers for some time.  
2019-11-26
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siowxsen
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thanks....
1-12 02:51
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siowxsen
Second Officer
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Thanks for the information
1-21 20:07
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AlansDronePics
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Szwedu Posted at 2017-8-2 14:28
yes , but that sill don't explain that DJI sell this as a first time drone and for some reason DJI did't do this check list , only you , a normal spark user like me and him.. So if a NORMAL person "stick" to what see in the ad's and read in the manual he is kind of ... on the lost position . Even if he will NOT do any calibrations if not needed , he still can lost his drone from no reason KNOWN and will don't have a AC ( far flyaway or water) AND no log on the device (if palm launch). Potential user is not in the way of KNOWING THIS .

A normal person will understand the dangers and uncertainties of a drone and will have understood the manual. Not just read it.
I can understand a person unboxing and switching on a TV, computer or simple household appliance without understanding the product, but what sort of person believes a flying a drone is without risk? Even the military have mishaps with drones and aircraft.
Everything Hallmark has said is good advice and common sense.
Thank you Hallmark for the clear, simple tips.
2-20 05:12
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AlansDronePics
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Zaheed Posted at 2017-9-14 13:54
There is absolutely no logic to this 2 min routine. You're better off spending time to learn to fly in ATTI. Just go about flying as usual and be ready to takeover in ATTI whenever the AC behaves odd. Saved me every time. I learned it the hard way by waiting for it to fix itself the very first time I had a odd AC behavior due to compass issue, and sure enough it didn't. That was some 3-4 years ago in a NAZA FC when things were a lot less stable. This stupid routine might seem to be useful but trust me it's of no use. It can all go well in the beginning and you can still have issues mid flight, in fact ALL my incidents have been like that. And of course if you've a motor, ESC, or battery failure, nothing in this world, not even 2x of this stupid 2 min routine will do you an ounce of good. If anything those 2 mins every time will leave your AC further used and warmer, which eventually can only increase the chances of such failures, specially if you're doing consecutive flights. Instead if you even leave the AC off for those 2 minutes, it will be way more useful.

Please don't waste 2 mins in every flight because someone, who clearly doesn't know what they're talking about, told you so. I hate it when people pretend to know something they have zero idea about.

As Hallmark made quite clear amongst the replies, it is for the user to decide if they want to test out the drone before flying. To that, no more need be said.
Regarding to point and logic of the proceedure, it is quite simple.
See #85 Nemroig That post is an example where a test might have revealed a fault while the AC was recoverable.(Recoverable, nearby, like just overhead)  In that example, even if no sticks functioned, eventually, the aircraft would have landed when the battery ran low.

The issue about magnetic influences on the AC is just one factor that can affect the drone. I personally believe a simpler failure in the drone is the more likely reason for a drone flying off.
If you have a simple compass, hold it near the motor of your drone. The drone should be switched off when you do this. You will find each motor has a strong magnetic field. In addition, when the drone is in flight, the current in the wire from body to motor will generate a detectable and varying magnetic field. These fields must be stronger that the earth's field, from the drone's perspective, or the compass needle wouldn't deflect from North. The point is, the Magnetometer in the drone is not so sensitive or fussy as people think.
The real worry is the software that controls the workings of the drone. When the drone is switched on, the system boots up and everything that happened on previous flights (like working perfectly) no longer applies. The drone is effectively rebourne. A glitch is always possible and if and when the code encounters it, then some sort of error occurs.
This is the likely reason for flyaways when the operator did everything right.
Most times the operator is at fault.
I expect someone will want to argue, but we all know that things made by man (or woman) do develop faults.
2-20 05:54
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AlansDronePics
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I have carried out some practical experiments regarding magnetism and its effect on the drone system.
Although the video is thrown together, the content clearly shows this preoccupation with the compass is misguided.



No doubt you will discover drones being used to carry magnets in fishing. There is at least one video where the drone has a powerful magnet attached in flight.
Look to a glitch in the smooth running of the software for fly aways , or more likely, operator error. Remember, it is operator error, even if you haven't flown and haven't understood the manual.
I close by reinforcing the words of wisdom from Hallmark and other respected members here.  My magnet experiments do not detract for their sound procedures.
2-20 10:14
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maticture
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Wow, this is very useful! Thanks for sharing with us
2-26 09:19
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hallmark007
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maticture Posted at 2-26 09:19
Wow, this is very useful! Thanks for sharing with us

Your welcome safe flying .
2-26 09:23
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AlansDronePics
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hallmark007 Posted at 2017-7-11 13:40
Tip To Help Avoid compass interference and crash.

I personally believe this to be sound advice. Newbies should make this the first lesson.
3-11 05:03
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