compass error mid-flight.. now what??

[ishboo4343]

I had a P3S that kept getting the yaw error. I changed the compass and that seemed to fix the problem.

 

[itechnology]

Do you mean that you recalibrated the compass?

 

[ishboo4343]

Do you mean that you recalibrated the compass?

No took it apart and replaced the compass in the leg. Did a calibration after I put it back together.

 

[cinclodes]

Another common magnetically dirty area that people are always tempted to use is their car hood. That never works well for me lol

I have never launched from the surface of my car, but I once set the controller on the roof of my car during a Litchi mission. It seemed that the video feed came in from much longer range. I tried this for a few more flights, and it really seems to enhance the reception.

 

[cinclodes]

Why would a compass error occur in the middle of a flight? It would seem that the drone would have to approach wires or some metal object that distorts the local magnetic field. Or perhaps a problem could occur at high latitudes where the magnetic field may have anomalies. Some of the replies mention causes on the ground, but the original post states that the problem occurred during the flight. One possibility would be that the compass was confused by something on the ground just before launch. Then it sensed the ambient magnetic field after the launch and detected the difference. That would be expected to happen very quickly after launch. I would think that the only way to lose a drone due to a compass error would be if it's out of sight. Return to home wouldn't work, but it ought to be easy to bring it in manually.

 

[Nightwolf]

I once set the controller on the roof of my car during a Litchi mission. It seemed that the video feed came in from much longer range.

interesting

 

[solentlife]

I have never launched from the surface of my car, but I once set the controller on the roof of my car during a Litchi mission. It seemed that the video feed came in from much longer range. I tried this for a few more flights, and it really seems to enhance the reception.

Its possible that the metal roof acted like a reflector but its debatable because the slope of car roof is convex instead of concave as would be needed ...

 

[Shoot4fun]

Ground based anomalies could be explained by any number of things, as has been mentioned so far. I would think the in-flight anomalies would be caused more by, say, solar activity. Perhaps a stray microwave transmission? The earth's magnetic field does fluctuate a little here and there. I looked again at the flight log. I'm not sure of his exact location, as far as which island that is, but I would consider possible sub-surface volcanic activity as one possible explanation.. ? Molten lava can create magnetic fields, if the iron ore content is high enough. Doesn't necessarily have to be from an earthquake even. And, I may be completely off base. Wouldn't be the first time. Just a thought that occurred.

Brad

 

[sar104]

Why would a compass error occur in the middle of a flight? It would seem that the drone would have to approach wires or some metal object that distorts the local magnetic field. Or perhaps a problem could occur at high latitudes where the magnetic field may have anomalies. Some of the replies mention causes on the ground, but the original post states that the problem occurred during the flight. One possibility would be that the compass was confused by something on the ground just before launch. Then it sensed the ambient magnetic field after the launch and detected the difference. That would be expected to happen very quickly after launch. I would think that the only way to lose a drone due to a compass error would be if it's out of sight. Return to home wouldn't work, but it ought to be easy to bring it in manually.

There are a couple of reasons for the error occurring mid-flight. The most common that I've seen is that the compass is not properly calibrated, which generally leads to a yaw-dependent discrepancy between the actual heading and the heading indicated by the compass. In other words in some directions the compass reads correctly, while in other directions doesn't.

 

[cinclodes]

Its possible that the metal roof acted like a reflector but its debatable because the slope of car roof is convex instead of concave as would be needed ...

There are two received propagation paths whether the reflecting surface is concave, convex, or flat. I believe it's the additional reception that enhances the signal, not a focusing effect like a parabolic mirror.

 

[xrider]

hello..

sorry for my late response but there is A LOT of work to do this period.. im a professional photographer and as you can imagine i was tryin to understand what the heck is goin on with my drone.. i talked to dji support.. they ve told me to recalibrate everything.. which ive done several times in places without metal etc over near and underground.. compass is brand new.. dji changed it on february.. and one month later errors - compass related - started to showin up.. yesterday i faced my worst nightmare one more time.. so.. im asking DESPARETLY for advise.. look up my log.. there are yaw errors etc.. there was absolutely nothing magnetic close by to mess with its compass.. in .dat file the compass mod is around 1500 all the time.. even during yaw error.. i really want to understand.. why it was tryin to flyaway?? is this compass faulty?? is something that am i doing so wrong?? so fricking complicated.. it tried to flyaway in several flights from the same error.. this thing must stop.. and i need some advice from the experts here.. no calibration work even if calibration has been accepted..

here is the log..

 

[xrider]

note that before the old compass replacement.. before it dies.. there were no problems at all.. i am flying in this place from the beggining without ANY error - compass related.. and now this.. i really want to understand why it was trying to fly away.. there was absolutely nothing metallic where it took off from.. i really want to understand why yaw error occured.. what is goin on and what do i have to do.. i dont wanna lose it.. im fricked out.. i want to fly error free again.. ive already checked the connection between compass and mainboard.. connection was fine.. i feel desparate.. ?

 

[sar104]

The discrepancies between the IMU and compass that led to the yaw errors are clearly visible in the comparison between position and velocity data:

However, to try to determine the cause will require the DAT file, FLY142.DAT.

How to retrieve a .DAT

 

[xrider]

The discrepancies between the IMU and compass that led to the yaw errors are clearly visible in the comparison between position and velocity data:

View attachment 112983

However, to try to determine the cause will require the DAT file, FLY142.DAT.

How to retrieve a .DAT

so.. which one is giving me the nightmare? compass or imu?? which one is faulty?? im confused sorry for my stupid questions.. ?
give me some time to upload the .dat file.. as its a bit huge..

 

[xrider]

here is the .dat file..
thank you for helping me

FLY142.DAT

drive.google.com

 

[xrider]

no updates??
im so worried...

 

[sar104]

no updates??
im so worried...

Stand by.

 

[RodPad]

no updates??
im so worried...

As far as I can tell, its been 17 days since you gave us an update, now you have had another issue.
Nobody replied, 17 Hrs since you shared your data.

Yep, Just my view.....

Anyways, let see what @sar104 (Search And Rescue) shares with us.

If you think his results are correct, send him PM with a Donation.


Rod

 

[xrider]

As far as I can tell, its been 17 days since you gave us an update, now you have had another issue.

nope its the same issue and i d apologised as i work a lot and i couldnt have time to see what you ve posted..

Nobody replied, 17 Hrs since you shared your data.

Yep, Just my view.....

i know people have work to do and families to take care of.. and maybe they are on vacations and they re having fun with their flyin buddies.. its july..

Anyways, let see what @sar104 (Search And Rescue) shares with us.

If you think his results are correct, send him PM with a Donation.

cannot understand this one.. are you making fun of me or he s a tech guy so.. thats why the donation?? youre confusin me

Rod

so.. im facin a trouble.. and i cannot find help anywhere.. thats what i see.. my job is especialising on aerial photography and videography.. and i really dont know what else i can do.. i cannot send it in as techs are on vacations.. so i need to know the faulty component to proceed myself with the replacement.. job is getting slow because of this thing.. which i cannot understand why is happening.. when its sitting on the earth everything is fine.. when up in the air.. compass error and a lot of drift occur.. dont know what is causing it.. no metals nearby during take off.. meh..

 

[sar104]

The DAT file doesn't indicate any compass problems. Looking at the IMU and magnetic yaw values:

And the event stream doesn't mention any yaw errors - just the RC-commanded switch to ATTI at 187 seconds:

187.058 : 11632 [Ctrl<1>] REQ_RC_NORMAL ATTI ctrl_atti
195.558 : 12057 CTRL reset all by rc mode switch
195.598 : 12059 CTRL reset all by rc mode switch
195.918 : 12075 CTRL reset all by rc mode switch

However, the IMU velocity does start to disagree with the GPS velocity starting at around the time of the errors:

So it doesn't really look like a compass problem - have you calibrated the IMU recently?