AlansDronePics Posted at 3-9 07:13
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.

But that’s the great mystery, we all know it’s almost impossible to pick up Mag interference in the air, it’s even hard to detect with getting close to pylons cables etc, so the law of averages point back to the ground and many users giving information regarding TO point and conditions.

They’re many different components driving the drone IMU accelerometers gyros magnetometers compass gps FC ESC , so I’m certain at the first indication of interference that there is a program of events programmed to try halting the problem, but if the problem is bigger than program to combat it then you get an uncontrollable fly away .

hallmark007 Posted at 3-9 07:30
But that’s the great mystery, we all know it’s almost impossible to pick up Mag interference in the air, it’s even hard to detect with getting close to pylons cables etc, so the law of averages point back to the ground and many users giving information regarding TO point and conditions.

They’re many different components driving the drone IMU accelerometers gyros magnetometers compass gps FC ESC , so I’m certain at the first indication of interference that there is a program of events programmed to try halting the problem, but if the problem is bigger than program to combat it then you get an uncontrollable fly away .

Would it be fair to say that if the Mag Inf issue can't be reproduced, then it is unlikely to be an issue that can be actively avoided?

AlansDronePics Posted at 3-9 07:38
Would it be fair to say that if the Mag Inf issue can't be reproduced, then it is unlikely to be an issue that can be actively avoided?

While I cannot say it can be 100% avoided, a simple check of the small red triangle on your map while craft is on the ground will tell you if compass is aligned with the heading of the craft , thus showing that compass is correct.
Simple check put craft on steel manhole check triangle it will have moved , then switch off bring craft to safe launch start up triangle should have moved back into place.

It’s a pretty simple check and one I’m amazed dji don’t recommend anywhere. Maybe because it’s not fully 100% correct or they feel their system is better equipped to warn those of impending interference.

AlansDronePics Posted at 3-8 23:51
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.

I suspect you would have to get very, very close to the bridge for it to have any effect. IMO most times the aircraft never gets close enough to cause a problem. One way to test this is to use the compass built into your phone. Call up the compass app then see how close you have to get to a steel bridge structure for it to have any effect. When I did this several years ago I had to get extremely close to see any effect.

Geebax Posted at 3-9 13:06
I suspect you would have to get very, very close to the bridge for it to have any effect. IMO most times the aircraft never gets close enough to cause a problem. One way to test this is to use the compass built into your phone. Call up the compass app then see how close you have to get to a steel bridge structure for it to have any effect. When I did this several years ago I had to get extremely close to see any effect.

I was surprised how insensitive the phone system is to magnetic fields.
I use a Samsung J7 dedicated to the drone and an S9+ for other things.
If I type *#0*# as a phone number, it takes me to a smorgasbord of sensor and system values.
The IMU is always churning out values, the Compass is quiet, by comparison. The needle seems to ignore metal close up, although the graph shows a slight blip.
I think it is probably similar to the drone, you need to be up-tight and personal with metal.
Bridges made of iron or steel (not stainless) quickly take on the same magnetic flux of the earth in a very short time. That being the case, I wonder if the orientation matters. It is the same as the earth.

AlansDronePics Posted at 3-9 14:35
I was surprised how insensitive the phone system is to magnetic fields.
I use a Samsung J7 dedicated to the drone and an S9+ for other things.
If I type *#0*# as a phone number, it takes me to a smorgasbord of sensor and system values.

Yeah, I have an S6+ and it works very well as a compass, but shows little interest in steels structures.

I don't have much experience w/ iNav but the magnetometer is disabled and it can still do Navigation tasks (fixed-wing) not sure about the multi-rotor.  It can definitely loiter in and do WP w/ no magnetometer (no compass).  It uses just GPS.