Consistent need to recalibrate...Cause?

[BokiFly]

A lot of the phone compass problems come from the magnetic interference emitted by the controller.

I presume DJI is aware of this and that there is no technical way to make controller with less magnetic interference?
That is the reason why I asked are other Mavic drones have the same problem, because I have just Mini and can't compare this behaviour to another drone.

 

[scro]

I also only own a MM so don't know how much of a problem this is on other controllers in the mavic series. I get the impression that the MM is worse than the others though.

DJI could use stick position sensors that don't use magnets (eg potentiometers or optical encoders), or they could build in better magnetic shielding... they could also add active tracking....

 

[Zbip57]

There is a speaker built into the controller on the right underside. The speaker has a magnet in it which can affect the compass in your cellphone. There are lots of Youtube videos documenting this. See at 1:20 in this one.

 

[scro]

Nice informative video @Zbip57 . I'd had a go at identifying the location(s) of magnetic interference, but without disassembling and it seemed to be centered around the sticks, though difficult to really pinpoint

 

[sar104]

Interesting. I admit that I didn't know about that.
But it's strange. First, in situations that position of the arrow on the arc of the indicator became wrong during the flight, why Mini asks for his compass calibration after that flight? And for the next flight, or part of it, position of the arrow is fine. Apparently that lead me to wrong conclusion about compasses.
Second question is why phone compass (if he is to blame) became out-of-calibration so often, even if it's fine in Google Maps, but not so fine for DJI Fly app.

Are other Mavic drones equally too sensitive with phone compass? Do they also require drone compass calibration often? Do they also have wrong orientation icon in half of the flights ?

The aircraft and control app don't care about the phone compass, even though the app uses the phone compass data to try to show the relative orientation of the controller and aircraft. And it will never request calibration of the phone compass - that's up to you to do if you need to.

 

[sar104]

Nice informative video @Zbip57 . I'd had a go at identifying the location(s) of magnetic interference, but without disassembling and it seemed to be centered around the sticks, though difficult to really pinpoint

There are noticeable magnetic fields from both the stick assemblies and the speakers. And the magnetic field directly in front of the speakers on the Mini RC is much stronger than on the MP or M2P, which may account for the greater number of issues reported with the Mini.

 

[BokiFly]

Considering that drone orientation on the map is fine why they don't use the same thing on main position orientation icon? That way we will have position orientation independent of the phone compass.

 

[scro]

Considering that drone orientation on the map is fine why they don't use the same thing on main position orientation icon? That way we will have position orientation independent of the phone compass.

The same info IS used on the orientation icon, but that isn't the problem with it. The map always points north, whereas the orientation indicator points whichever direction you are facing, and so needs a second compass to know what direction you are facing relative to the drone.

On the orientation indicator if the little arrow is pointing away from the centre of the arc the drone is pointing away from you. If the arrow points along the arc it is side on to you. This bit is usually correct, and tallies with the map/red line to "home". The bit that often doesn't work on the orientstion indicator is the position of the little arrow along the arc, as that relies on the phone compass.

 

[Franco7]

I think the most logical explanation is that he typically wears the Apple watch which is the potential cause of interference. I conveyed your comments to him. I should hear in a couple days if the problem goes away as he won't be wearing that watch when he flys. I have to wonder if drone's close proximity to the watch upon startup is the cause of his issue?

I use a magnetic bracelet (a gift from my daughter) and have compass calibration problems until I figure out that the bracelet may be the problem and yes it was!! I am not using the bracelet anymore when flying, I just want to share my experience in case it is helpful to anybody.

 

[mjstott]

If I wear my apple watch with magnetic strap, mine asks for calibration. If I take my watch off and re-start it, no issues. Check for any magnetic sources very close to the drone.

 

[tiparoch]

For what is it worth... I have several DJI craft. I have traveled to a number of overseas places , sometimes with different craft. I find it odd that on the same trip, and location 1 drone prompts for calibration more than others. It seems to me that: P-4(pro) almost no calibration, same for M-pro , and M-Pro2. The Mavic-Air (1) seems to constantly need calibration, even if I have not traveled far from the last flight. I even had a replacement (totally new craft) after a compass issue, and...yup... same thing, almost constant prompt for calibration, yet at the same locale, the MP-2 is fine. I also am lucky enough to have a Mavic -Mini. It seems to ask for calibration 1/2 the time that the M-A does... So... I have gotten used to it ...but weird that 2 different MA craft had the same issue. Yet at the same site/day etc. other craft are fine. I do check the compass and IMU status EVERYTIME... out of habit. I have heard others complain/comment about the MA always needing calibration. Obviously I cannot comment on the MA-2, but its dad is quite 'needy'.

 

[BokiFly]

Well...maybe DJI want as to have another reason to buy more premium drones.
Better camera, OccuSync, better wind resistance, tracking,......,compass that is more stable.

 

[tiparoch]

very good point... Strange though how different the models can be.