HedgeTrimmer Posted at 3-5 10:41
Big question is :  why did this compass was offset ?  due to magn interference or due to ??
Or was the compass OKE and the yaw reference signal out of tune in the IMU?

Hi HedgeTrimmer,

True about powering up holding in the air etc.

I have done this with my MM.

1/ keep it upside down, switch on and move around  put in on the ground
2/ find a good spot, drone few inches above spot, powering up and put MM on the ground,.

1/ compass data and reference data not that close to each other
2/ compass data and reference data line close to each other

Don`t know if it helps, but i have had not one error on my MA and MM  doing like this

** knock knock on wood **

cheers
JJJB

AlansDronePics Posted at 3-5 10:04
I read the OP again and also some links Hallmark pointed to.
OP said, "so I take off, but after few second of upward moving, made by me, mini start to go left very rapidly and then I've lost signal, then the drone start the Go Home procedure and come back straight forward, than I've got signal back and I've rapidly landend."

What may be happening is during initial takeoff, drone is flying using Optical positioning input coupled to IMU input when it is close to ground, essentially ignoring internal Compass(es).  Compass can be slightly off or way off during initial takeoff, and not cause drone flight problems.  


At some point, drone's Optical positioning input becomes invalid due to distance above ground, ground terrain, or lack of ground patter, etc.  Resulting in drone relying on internal Compass(es).  Compass(es) is close to correct N/S/E/W direction, drone can correct for for slight difference.  When Compass(es) is slight off (more than say 15-degrees), drone can not correct for differences.

DJI should be able to clarify all of this...

hallmark007 Posted at 3-5 10:48
Wow it’s incredible how others put up wit this continuing trolling by this guy. He is even on this thread lying to the op and in yellow I clearly point to his blind lying.
Now it’s time for this guy who only came to this thread to troll me, to try destroy what was a normal but at sometimes heated debate, and he is fully responsible for this kind of ridiculous outburst on many threads, particularly if I’m on them.

Hi all,

I am not in favour of anybody on this forum, just try to help other if i can.What i do not like in general is that often threads are exploding beacuse we have different opinions.....
Happy we do, so we can learn from each other. As long as we use normal language i am pleased to be here.

Hallmark checklist is oke ofcourse, if all users would take the time to start a flight like this, much beter and why better?

1/ no rush, so you could check more and see more looking at the app.
2/ checking the compass is the only thing we can do to prevent a fly away like this in this thread

Is it a 100% fail safe check to have a good flight regarding IMU and other defects/errors ect?  does it help 100% for good flight? nope.
*** in my country we say that only 100% quaranty is given on vacuum cleaners ***

But flying fwd, aft, left, right, yaw and see the reaction of the drone to RC inputs = not too bad to do.

See my checklist, MENTAL part issue is so important!  do we all land or fly back after a first error ??

cheers
JJB

hallmark007 Posted at 3-5 10:48
Wow it’s incredible how others put up wit this continuing trolling by this guy. He is even on this thread lying to the op and in yellow I clearly point to his blind lying.
Now it’s time for this guy who only came to this thread to troll me, to try destroy what was a normal but at sometimes heated debate, and he is fully responsible for this kind of ridiculous outburst on many threads, particularly if I’m on them.

Any excuse hallmark007 to keep from re-wording you very miss leading post-takeoff checks.

You have never provided evidence of your Raise, hover, and fly checks being tested, let alone verified.  Only thing we have gotten even remotely close to evidence was some blathering about others having used it.  Ironically, you continually trash others when they have put for the work and testing, trying their best to provide evidence.

We know your Raise, hover, and fly check does NOT work as you gone on to state afterwards.  Being you like to call out others, I am calling you out.  Call it Karma!
Provide evidence of testing and verification your Raise, hover, and fly check actually does what you go on to state afterwards.

Until you provide verified evidence, your Raise, hover, and fly checks  are nothing more than Joysticks input test, which can lead a Pilot into a  False sense of safety.

HedgeTrimmer Posted at 3-5 10:56
What may be happening is during initial takeoff, drone is flying using Optical positioning input coupled to IMU input when it is close to ground, essentially ignoring internal Compass(es).  Compass can be slightly off or way off during initial takeoff, and not cause drone flight problems.  

Hi HedgeTrimmer,

In logs you can see when the system uses the VPS vision as an input.

During normal takeoff (good GPS #and reception) VPS vision is not used.
Vision height is used and signal is additional to the baro height signal.
So AFAIK ; to hover at position in P-GPS mode GPS data and Compass data is used.

cheers
JJB

JJB* Posted at 3-5 11:07
Hi all,

I am not in favour of anybody on this forum, just try to help other if i can.What i do not like in general is that often threads are exploding beacuse we have different opinions.....

No not 100%, because there would never be any problems if there was a 100% check, but it’s a precheck that checks all it can before taking off to the sky, and it’s one that comes highly recommended from the IAA and what is thought to all commercial drone pilots throughout Ireland .
I would say for those who try to insult it put up or shut up and that’s what would be said in my country .

HedgeTrimmer Posted at 3-5 11:14
Any excuse hallmark007 to keep from re-wording you very miss leading post-takeoff checks.

You have never provided evidence of your Raise, hover, and fly checks being tested, let alone verified.  Only thing we have gotten even remotely close to evidence was some blathering about others having used it.  Ironically, you continually trash others when they have put for the work and testing, trying their best to provide evidence.

i think it’s clear you are in a majority of 1 here, once again way way out of your league and continuing to hit the self destruct button with every post, some of the stuff you are posting on this thread would be more at home in the twilight zone .

JJB* Posted at 3-5 10:53
Hi HedgeTrimmer,

True about powering up holding in the air etc.

last couple of flight i've been taking off from hand. hence powering off in the air, checking headings and taking off. So far didn't see much difference in headings and changes. I also hover in place at height and check general movement to confirm all is fine in the first couple of min...also to restart dji fly app, cause usually it stops working properly.
i do that mainly because of uneven terrain or dogs running around, also birds.

hallmark007 Posted at 3-5 11:17
No not 100%, because there would never be any problems if there was a 100% check, but it’s a precheck that checks all it can before taking off to the sky, and it’s one that comes highly recommended from the IAA and what is thought to all commercial drone pilots throughout Ireland .
I would say for those who try to insult it put up or shut up and that’s what would be said in my country .

I would say for those who try to insult it put up or shut up and that’s what would be said in my country .

Honestly do you even hear yourself as you type out insults and taunts?  Go back and read your posts.

We are all still waiting for you to Put up your own evidence you said you had.  Thus far, all we have gotten is Jack.  

Perhaps it is time you followed your own country, and Shut Up?!

hallmark007 Posted at 3-5 11:24
i think it’s clear you are in a majority of 1 here, once again way way out of your league and continuing to hit the self destruct button with every post, some of the stuff you are posting on this thread would be more at home in the twilight zone .

Lame, really Lame coming from someone who thought GPS satellites setup barriers (aka force-fields) around NFZs!   Drone can't penetrate NFZ, drone will bounce off...   ROFL!
  
Perhaps Mr. Compensated-Bias for DJI - would like to tell everyone here why you Troll-n-Trash threads which touch upon or hint at DJI problems?

HedgeTrimmer Posted at 3-5 11:29
I would say for those who try to insult it put up or shut up and that’s what would be said in my country .

Honestly do you even hear yourself as you type out insults and taunts?  Go back and read your posts.  

So here you go , now let’s see Hedgetrimmer preflight lists he seems to know more about them than the rest of us, I for one would like to see his, I don’t expect he will post anything because you probably don’t need a preflight for a kite . LMAO

HedgeTrimmer Posted at 3-5 11:35
Lame, really Lame coming from someone who thought GPS satellites setup barriers (aka force-fields) around NFZs!   Drone can't penetrate NFZ, drone will bounce off...   ROFL!
  
Perhaps Mr. Compensated-Bias for DJI - would like to tell everyone here why you Troll-n-Trash threads which touch upon or hint at DJI problems?

I see nobody agrees with you so maybe go somewhere else and troll someone else, you have well an truly trashed this thread as you usually do .

hallmark007 Posted at 3-5 06:42
I suppose you will have based this on some fact and will be able to tell us what happened ?

No, I don't have the faintest idea what's going on. Take a look here: #20 https://forum.dji.com/forum.php? ... p;page=1#pid2080540
DJI surely knows more ...

DaMa Posted at 3-5 11:40
No, I don't have the faintest idea what's going on. Take a look here: #20 https://forum.dji.com/forum.php?mod=viewthread&tid=208519&page=1#pid2080540
DJI surely knows more ...

That’s not what was the point here, I know what happened here,

HedgeTrimmer Posted at 3-5 10:20
Hello Luca6686:

Heads-up about following:

Well you obviously were completely out of your league again when you posted that rubbish, it’s a real comedy show with you around here .

AlansDronePics Posted at 3-5 06:52
None-the-less, it is always wiser to avoid the problem. I admit I am paranoid about minimising risk when flying.
1/ I avoid people and building, but not ruins.
2/ I avoid radio transmitters, coms dishes and navigation beacons. They will disrupt drone stability in a repeatable way. Nav beacons are plentiful on the small island I live on and flying through the beam, away from the source or receiver will cause a moment of unstable flight. Hovering is worse than ATTI mode, particularly on a P3P.

Good points. For my part, I do not pay attention to such things and do not know compass, IMU or any other abnormal behavior.
I used to fly with the Spark: iPhone, iPad, Goggles and BT300 – image dropouts excluded – no abnormal behavior.
At the moment I only have 2 MPs and the Mini (phone, pad and BT300 (BT not Mini) – no abnormal behavior.
Last flown 11000 km with the MP and the MM in my carry-on baggage – no abnormal behavior on site.

JJB* Posted at 3-5 11:17
Hi HedgeTrimmer,

In logs you can see when the system uses the VPS vision as an input.

During normal takeoff (good GPS #and reception) VPS vision is not used.

Wondering if flight logs are giving correct information about VPS at takeoff?  

Anyway, it was only reason at time, I could think of which would explain a drone being able to takeoff and initially fly with a compass indicating wrong direction.

We know GPS in small drones (at least at this time) can not provide the direction a drone is pointing, only direction drone is actually moving in.  

Don't know if Mavic drones have capability to determine the direction a drone is pointing too; based on radio transmissions from R.C. and phase of signals or differential in time.   Which would requre Mavic drones having two internal antennas with ample seperation between antennas.  


Is it possible IMU (with its 3-axis detection of rotation and 3-axis detection of in-line movement) could initially provide data needed for drone to know which way it is pointing.  Testing that would be difficult.  Need a magnet on drone causing complete internal compass interference, then over at least several minutes - hovering, hovering at altidue while turning, hovering at altitude with forward/back side-to-side movment, and lastly slow flights???  

hallmark007 Posted at 3-5 11:36
So here you go , now let’s see Hedgetrimmer preflight lists he seems to know more about them than the rest of us, I for one would like to see his, I don’t expect he will post anything because you probably don’t need a preflight for a kite . LMAO[view_image][view_image]

Bragging and braying about a checkoff list isn't proof in regards post-takeoff checks (Raise, hover, and fly).

Provide verified evidence of your post-takeoff checks (Raise, hover, and fly) being tested and proven to do what your statement afterwards claims.


Still waiting on you to provide your own video showing verified evidence to back up what you stated you could.

Bullocks

In meantime, once again, how about following your own country's advice, and Shutting Up; so rest of us can politely discuss this without your Trolling?  

HedgeTrimmer Posted at 3-5 12:11
Bragging and braying about a checkoff list isn't proof in regards post-takeoff checks (Raise, hover, and fly).

Provide verified evidence of your post-takeoff checks (Raise, hover, and fly) being tested and proven to do what your statement afterwards claims.

You obviously missed it but that’s about right for you, but jjb and Alan drones got it, no point in you getting it, you wouldn’t understand, your better at cutting and pasting trashing everyone’s threads, and it’s very easy to see nobody agrees with anything you say, again making yourself look like the fool you really are. You don’t know anything so trash it .

From a bystander: It seems like all this useless banter effort could be better used to develop a test to prove or disprove the theory. It should be one to which all agree.

And while we are on this topic, my landing pad has a steel ring around the perimeter inside to keep it opened. Should I not be using that for takeoff?

GaryDoug Posted at 3-5 13:31
From a bystander: It seems like all this useless banter effort could be better used to develop a test to prove or disprove the theory. It should be one to which all agree.

And while we are on this topic, my landing pad has a steel ring around the perimeter inside to keep it opened. Should I not be using that for takeoff?

You don’t need a test the logs don’t lie and the problem is those who have seen so many of these in all drones are watching exactly the same thing repeating itself, only difference is extent of interference which can have much more disastrous outcomes.
I have only seen others arrive a decisions that they don’t agree this is what happens, they never offer any reasonable reasons .
But I think if others want to try test, put your drone on a steel cover start it up and fly .
I think just like everything else if you use your manual as a reference as to how best to fly your drone you won’t go far wrong.

Regarding the metal ring, it’s been brought forward before, haven’t seen one that caused interference although that could be wrong , I’d say if you use the Centre check the small blue arrow on your map in the lower left corner of telemetry, if that’s on the same heading as your drone you won’t have a problem with compass .

People... you've managed to make an UTTER and COMPLETE MESS of this topic. Thank you for making something so simple now UNREADABLE.

CONCLUSION: if you want to talk about COMPASS interference problems,  OPEN ANOTHER THREAD. Thank you professors...

I think someone should definitely open another thread to explain HOW to properly read log.txt files in FRAP.

Now... what I see and I don't know if my guess is good is a big delta in HDG at about 44 seconds into the flight, values differ greatly between HDG and YAWr, at that point the toilet bowl spiral was almost complete and the OP was about to trigger RTH.

JJB quote:
Because of this connection loss MM into an automatic RTH. I cannot explain but i have seem more compass fly aways where hitting the RTH button the craft heading and yaw signals come together again. In this flight the same, RTH in a straigh line towards home. So not because of OP doing the right action, but because of the OutOfControl initiated RTH.

Correct me if I am wrong: I assume that during RTH compass heading is ininfluential... the compass is used initialy during RTH start up to correctly orientate the drone (to give the user a more apprpriate video feedback), but as if you were orienting the AC during RTH, this has no influence on the direction it is traveling to which is completely guided by GPS.

m80116 Posted at 3-5 15:20
People... you've managed to make an UTTER and COMPLETE MESS of this topic. Thank you for making something so simple now UNREADABLE.

CONCLUSION: if you want to talk about COMPASS interference problems,  OPEN ANOTHER THREAD. Thank you professors...

Hi m80116,

Good spotted about the yaw changing, see also that the pitch and roll angles after the change are changing as well. (ofcourse, as the FC has to deal with new compass heading.)

This sudden change of compass yaw indicates a compass or yaw error, depends wich value is given in he log ; the actual compass hdg as input value to FC, or the value after being processed by the FC.

My first guess is this sudden change did bring back the compass to its value it should have been at takeoff. But than the TBE move should stop too, wich it did not.
Wich signal is used for aligning to the HP in a RTH? This signal was good as the aligning to home the compass was good.With a faulty compass it is not possible to align the craft to the correct home direction, but it did align to HP.
So somehow, seen that before, is that RTH brings yaw (reference) signals in line...
About this sudden compass change in flight ; a hardware glitch??  or SW  or ??   DJI ??

AFAIK compass data and GPS data is used for RTH, first compass data to align craft towards home, during RTH compass data is needed for correcting drift.

cheers
JJB

Thanks to some to conclude something useful...
I agree all this waste of space, time and energy could be better spend in something else...

JJB* Posted at 3-6 00:40
Hi m80116,

Good spotted about the yaw changing, see also that the pitch and roll angles after the change are changing as well. (ofcourse, as the FC has to deal with new compass heading.)

"About this sudden compass change in flight ; a hardware glitch??  or SW  or ??   DJI ??"
Right ! And to a very "small" extent – pilot errors...

m80116 Posted at 3-5 15:20
People... you've managed to make an UTTER and COMPLETE MESS of this topic. Thank you for making something so simple now UNREADABLE.

CONCLUSION: if you want to talk about COMPASS interference problems,  OPEN ANOTHER THREAD. Thank you professors...

Compass is always used. The drone at all times must know the heading so it maintains the flight path. Even during a hover, it must use the compass to make sure it does not rotate at one spot without user command. The movement heading is determined by knowing where the phone is (phone GPS) and where the drone is (drone GPS) and where the drone is pointing at (drone compass).

Guorium Posted at 3-6 20:56
Compass is always used. The drone at all times must know the heading so it maintains the flight path. Even during a hover, it must use the compass to make sure it does not rotate at one spot without user command. The movement heading is determined by knowing where the phone is (phone GPS) and where the drone is (drone GPS) and where the drone is pointing at (drone compass).

Hi Guorium,

Not sure if this is completely correct.

During a RTH when mobile device gets disconnected, drone still know where to fly to.

AFAIK HP is set using GPS data from drone at takeoff and set in memory, to fly back home it uses this stored data and the current GPS data of the drone, plus compass data drone to steer towards home.

Only in the app you can set a new HP using GPS location of the mobile device (Go4 app) and in the fly app you can point a position onthe map as new HP (or use current mob device location)

cheers
JJB

JJB* Posted at 3-7 01:13
Hi Guorium,

Not sure if this is completely correct.

Of course, for RTH it is related to HP. But if you need to figure out the drone orientation relative to the phone when RC is connected, the compass should still be used.  It doesn't change my point which is saying compass is needed at all times.

Guorium Posted at 3-7 02:22
Of course, for RTH it is related to HP. But if you need to figure out the drone orientation relative to the phone when RC is connected, the compass should still be used.  It doesn't change my point which is saying compass is needed at all times.

I believe you are correct I don’t know of any dji drone operating without a working compass . You need compass for direction .

Guorium Posted at 3-7 02:22
Of course, for RTH it is related to HP. But if you need to figure out the drone orientation relative to the phone when RC is connected, the compass should still be used.  It doesn't change my point which is saying compass is needed at all times.

True, for use of the aircraft orientation indicator (AOI) for a MM (or compass ind in the Go4 app) you need a working (calibrated) mobile device compass.
If you just use the arrow in the map view you don`t need a mobile device compass.

So for a good working DJI drone, drone compass is always needed, if not than drone into ATTI.
Mobile device compass is nice  to have for AOI and for setting new HP in the app.

cheers
JJB

This is an update regarding my attempt to explore magnetic Interference and its effect on Mavic Pro. I would expect other models will produce the same results.
As the leading lights here know, I am not convinced, but am open-minded about the effects of taking off from surfaces that have steel mesh in them, flying near bridges or similar magnetic influences.
I am not saying you should take any chances by ignoring the good advice the leading lights recommend and you should follow the manual and the checklist mentioned in earlier threads.
I personally believe that the few genuine flyaways that happen and are mentioned on the forum are the result of software errors and hardware glitches. Let's just call them both glitches.
No one can prove these glitches, because unlike a computer on a test bench, a drone is flying. Test equipment cannot be attached. All I can show is what happens when a reliable drone takes off from a magnetically influencing surface or passes close to mass steelwork. There can be three outcomes. 1/ Nothing happens. 2/ the drone becomes erratic and becomes uncontrollable. 3/ the drone is temporarily impaired but restores itself quickly.
If nothing happens, and this must be repeatable, then it could be deduced that the influence is negligible. This would be great news for operators who unwittingly take off from or fly close to mass metal, but are unaware it is there.
If something bad happens, and this should also be repeatable, then it proves the influence is to be avoided, even if you can't see it.
In support of my theory that the problems are glitches, consider this link. https://www.bbc.com/future/artic ... at-lead-to-disaster You would be naive to suggest glitches can't happen to a DJI drone.
I see Hallmark suggested taking off from a sheet of metal. I suggest the roof of a car might be worth a try, However, I had in mind the WW2 bunkers here on the island. I can try them as well. We have no steel bridges, but we do have steel-reinforced bunkers rising high out of the ground. Mass wise, they hold more steel than a bridge per square metre.
I am still waiting for safe flying weather at the moment, so please be patient.
I see much reliance is placed on interpreting logs. My only doubt with them is that IF the issue is a glitch and not magnetic, the values would be generated by the glitch. A bit like asking a murderer if he did it. In those cases, the drone will quite rightly respond to the dodgy data.
I am planning how I can best deliver the evidence, (when I can get it) so we can all be happy with any conclusion that the forum chooses.

Tbh I also think so... never claimed ATTI mode doesn't use compass like someone's accusing me of writing (which is clearly a LIE), but you're talking from a Mavic Pro perspective I imagine, a drone I think it's programmed to reset the compass and IMU heading in case of high variance mismatch. MM and many other drones (especially more basic models) don't have this redundant check. And even the claims citing other sources of some of the most arrogant participants here lead me to think compass data isn't used in ATTI, hence the flyaways when GPS is aquired or the drone leaves interfered area.

Because in ATTI the drone already has HDG probably calculated with a gyroscope and/or accelerometer, and indeed the direction is deeply influenced from where you are. I have a Gentex mirror with digital compass and you have to manually set it for the world zone it operates into before the heading direction becomes accurate. Repeating a calibration every 50 Km although I feel excessive makes sure the offset is right... I don't believe the calibration often required by the Fly app is done to calibrate and offset internal drone interference... that could be done once and stored there for good, much a like a gimbal calibration... if you don't have crashes or hits you shouldn't really need to calibrate it.

Shall we go on to discuss this in a more appropriate thread ?

AlansDronePics Posted at 3-5 05:18
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.

Firstly, I tried to read through this whole thread, but it seemed like it just devolved into the normal bickering.  I'm sure there was some good information hidden somewhere in there, but I can't make myself suffer through all of it to try to see what everybody was trying to say.

Okay, having said that, here are my comments on the 3 videos that you provided as proof that magnetic interference isn't an issue..


#1 - Just having magnetic interference does not cause a fly away.  It can cause the drone to drop into ATTI mode which many GPS camera drone operators are not skilled or experienced in handling and thus cause a "fly away".  


#2 - The main issue with magnetic interference comes from the fact that it can cause 2 different systems to have different readings.  This creates a situation where the algorithms don't know which system to trust and thus stops controlling the system algorithmically and drops into ATTI mode allowing the operator to have full control over positioning.


#3 - the videos...

• The first video "Magnetic influence on Mavic Pro" only shows how magnet interference can be grossly detected by the system, but does not illuminate any details in regards to the behavior during flight.
• The second video "DJI Drone trying to pick up a magnet 1st try" seems to be completely unrelated because it never shows a source of magnetic interference anywhere close to the drone.
• The third video "Mavic AC -- Induced Magnetic Interference during Flight" is the most interesting of the 3 videos supplied.  It does show some interesting scenarios, but I don't think he put together a test scenario that would help to come to any sort of conclusion.
  

• In the first experiment, the drone was already on and had already initialized its compass and all of its systems.  This means that at this point, the compass and the IMU were on the same page and assuming that straight ahead was a given direction.  Then he introduced the magnetic interference by placing a magnet near the back of the drone.  Of course the drone immediately detected this sudden shift and gave immediate errors and warnings and verbally said it changed to ATTI mode.  This is because (as I described above), now the compass and internal accelerometers have a disagreement on the direction the drone is facing.  The accelerometers say it hasn't changed headings, but because of the magnetic interference, the compass now is showing a vastly different heading.  At this point, the operator launches the drone.  We can see that it is in OPTI mode and using the downward based vision sensors for its positioning algorithms and keeping it in its current location instead of actually being in ATTI mode.  After the drone is up in the air away from the magnetic interference, the compass and the accelerometers now agree again and can thus switch back to GPS positioning mode.  Also, in this test scenario, the drone never got higher than about 3ft, so the vision sensing system would still be able to assist with its positioning if it was choosing to ignore the GPS system.  In my opinion, everything worked just like I would have expected and doesn't help to come to any sort of conclusion to say that magnetic interference is not a problem.
• In the second experiment, the operator had the drone turned on for a period of time, then taped a magnet to the drone. Once the magnet was taped to the drone, the system immediately detected the magnetic interference and gave on screen errors as well as a verbal message it was switching to ATTI mode.  He talks (but doesn't actually show) the fact that the software now thinks his drone is pointed the wrong direction from where it is actually physically pointed at.  As soon as he starts the motors, you can see that the system switches to OPTI mode to use the vision system for positioning.  If you look closely, you can also briefly see in the DJI GO 4 interface that there are no GPS bars shown.  This gives us insight into the fact that it is not using GPS positioning at all.  He also mentions that it is drifting around a little bit. This is likely also an indication of using the visual optical flow for positioning instead of GPS.  The problem with this test scenario is that it was still using the OPTI system for positioning.  Had he gone higher than the visual sensing system could work, then it likely would have dropped into ATTI mode.  Again, in this test scenario, everything worked just like expected and doesn't help us to come to any sort of conclusion to say that magnetic interference is not a problem.
  

Not sure anyone will take the time to read or understand that wall of text, but if you did, then thumbs up to you!  

Cheers!

KlooGee Posted at 3-8 12:12
Firstly, I tried to read through this whole thread, but it seemed like it just devolved into the normal bickering.  I'm sure there was some good information hidden somewhere in there, but I can't make myself suffer through all of it to try to see what everybody was trying to say.

Okay, having said that, here are my comments on the 3 videos that you provided as proof that magnetic interference isn't an issue..

As a starting point in the search for answers, I fully agree with all your comments.
As you rightly say, all of it is inconclusive.
As I outlined in my post that you answered, more needs to be done. I hope to try multiple flights from obvious magnetic hazards where the start point influences the drone compass to an incorrect reading. As you rightly say, if the drone compass is aligned with north at takeoff, then it is unlikely to throw a wobbly.
I hope good weather will allow me to try things out pretty soon.
If you have any scenarios you think are worth trying, please let me know.
Thanks

AlansDronePics Posted at 3-8 13:02
As a starting point in the search for answers, I fully agree with all your comments.
As you rightly say, all of it is inconclusive.
As I outlined in my post that you answered, more needs to be done. I hope to try multiple flights from obvious magnetic hazards where the start point influences the drone compass to an incorrect reading. As you rightly say, if the drone compass is aligned with north at takeoff, then it is unlikely to throw a wobbly.

I have been looking through this thread, trying to ignore all the pointless arguing going on, to find one very important point, and I finally found it in Kloogee's post # 113.

Adding a magnet to the aircraft while it is sitting on the ground then taking off does not simulate the scenario that often causes compass errors. you must have the source of interference in place BEFORE switching on the aircraft. And you do not need to tape it on the aircraft and fly with it. Just monitor the compass settings, then place the magnet on the ground close to the aircraft. Switch the aircraft off, then turn it on again, let it initialise then try flying it. That is the situation that best simulates the problem that many people experience.

Geebax Posted at 3-8 14:25
I have been looking through this thread, trying to ignore all the pointless arguing going on, to find one very important point, and I finally found it in Kloogee's post # 113.

Adding a magnet to the aircraft while it is sitting on the ground then taking off does not simulate the scenario that often causes compass errors. you must have the source of interference in place BEFORE switching on the aircraft. And you do not need to tape it on the aircraft and fly with it. Just monitor the compass settings, then place the magnet on the ground close to the aircraft. Switch the aircraft off, then turn it on again, let it initialise then try flying it. That is the situation that best simulates the problem that many people experience.

Yes, I agree with you about aircraft on the ground then adding a magnet.
Do you have any view about a normally flying AC (that some claim) becomes unstable close to something like a bridge? Presumably, everything was fine at TO but when the bridge (Magnet) was introduced, things went wrong.

KlooGee Posted at 3-8 12:12
Firstly, I tried to read through this whole thread, but it seemed like it just devolved into the normal bickering.  I'm sure there was some good information hidden somewhere in there, but I can't make myself suffer through all of it to try to see what everybody was trying to say.

Okay, having said that, here are my comments on the 3 videos that you provided as proof that magnetic interference isn't an issue..

Hi KG,

I tap on my shoulder, read your text from start to end  ;-)

About #1

Not all magn interference will set craft into ATTI.

Few times on this forum we see crafts where the compass heading is not the same as the actual heading on the ground. If in this case the craft starts flying, the moment it needs a correction to hold postion things go wrong....a fly away ; as the software does sent the good correction the the motors but beacuse heading craft is not actual heading the wrong motors are getting the correction signals.

This is hard to detect if only the flightlog is there as you read only heading value in the log and not knowing if that is the actual heading.

Great example is this link > https://forum.phantomhelp.com/t/mavic-mini-flew-away-on-me/4477

This pilot had his flight on video ; take off South and MM hdg in the log 055.

For this scenario it is important to check before take-off if heading = actual heading.

BAD is that sometimes in flight, after many minutes normal flying, the compass heading value will change rapid in a large different value! ; thus fly awayI have no clue how this is possible?  1/ magn interference picked up at start [ not i think...] .... /2 magn interference in air? [ no way...] /3 ??



cheers
JJB

AlansDronePics Posted at 3-8 13:02
As a starting point in the search for answers, I fully agree with all your comments.
As you rightly say, all of it is inconclusive.
As I outlined in my post that you answered, more needs to be done. I hope to try multiple flights from obvious magnetic hazards where the start point influences the drone compass to an incorrect reading. As you rightly say, if the drone compass is aligned with north at takeoff, then it is unlikely to throw a wobbly.

I think if you look at this video, when craft goes to atti mode, you will see compass trying to get craft back on track, controller turning craft to get his orientation and eventually gets all back on line and gps returns.
Some people think that craft drops compass but you can see from video this is not the case.

JJB* Posted at 3-9 02:57
Hi KG,

I tap on my shoulder, read your text from start to end  ;-)

Woohoo!  It looks like at least a couple of people read through it all.  That is quite impressive!  Lol!

I agree that not all magnetic interference will cause it to go into ATTI.  That is why I stopped short of suggesting specific scenarios to test.  I largely just wanted to point to the videos that were provided to try to explain the behavior I saw and why I thought the systems behaved in a predictable manner and don't provide any conclusive evidence that magnetic interference is not an issue.

There are going to be some scenarios where the behavior is quite predictable and others where the behavior is not predictable because in the real world we can't know all of the variables at play.  This is especially key for something invisible like magnetic interference.  But there is also going to be a certain percentage of situations where there are just straight up hardware or software bugs/problems that just can't be taken into account from our limited viewpoint.

Cheers!

hallmark007 Posted at 3-9 04:38
I think if you look at this video, when craft goes to atti mode, you will see compass trying to get craft back on track, controller turning craft to get his orientation and eventually gets all back on line and gps returns.
Some people think that craft drops compass but you can see from video this is not the case.

Interesting for several reasons.
1/ Screen recorder running at same time as GO4. I had considered this, but my dedicated J7 is unlikely to keep up. Perhaps it is worth a try, though.
2/ A most unlikely TO point to have Mag Int. There was no sign of it after calibration. I would have expected it to be repeatable/there.
3/ If no Mag Inf at TO, why did it show up so far into flight? The drone reported Mag Inf. but why there?
4/ The IMU readings were blank. I have never looked at them during flight, so do they switch off? Was this the result of a glitch? Curious...
5/ Like you (Hallmark) said once about someone's video claim of a flyaway, it actually proves nothing. I don't know what this one proves if anything at all. Well spotted though.
6/ What a miracle the recordings were made at that time. I just hope I can catch the drone in the act of going haywire.
Was there a flight Log analysed by someone who knows how to read one?