Compass Calibration?

[Former Member]

That may be a different situation. On the M2 it reports magnetic interference and "cannot take off". Checking the compass interference level shows that there is no interference, and the DAT event stream shows that it was triggered by time or distance.

I think I see what you are getting at. Does this sound correct: Just because the error message comes up and says the compass needs calibration, it might not need to be calibrated, if there is no interference? Just moved to a different location to reduce interference?

 

[sar104]

I think I see what you are getting at. Does this sound correct: Just because the error message comes up and says the compass needs calibration, it might not need to be calibrated, if there is no interference? Just moved to a different location to reduce interference?

With the M2 it is pretty clear that the "magnetic interference" message is incorrect, in that there is generally no interference - it is being triggered by the firmware time/distance check. Moving the aircraft or restarting the aircraft makes no difference, because interference is not triggering it. On the MP, which I suspect still doesn't do that, "magnetic interference" means magnetic interference, and so moving the aircraft may fix the problem.

 

[kilomikebravo]

plus every thirty days if you don't travel.

SAR: FWIW, other than the first time I foolishly tried to takeoff from a concrete driveway and got the warning, I have not had one again and that has been since the release back in August. Go figure, huh?

 

[old man mavic]

since i took the MPP out of the box i have never had to do an IMU or compass calibration i do check them on the app and they always say no calibration needed and they are all in the green on the display my PH3S on the other hand has had a IMU and compass calibration before i could fly it i guess the latest electronics in the mav are better

 

[ddam]

I went on a cruise to the caribbean islands. When I went to fly my drone I had to calibrate the compass. When I returned home I had to calibrate the compass again

 

[crlmjohnson]

My Mavic 2 did let me know...I have done it twice since I own my drone....both times after an update.

 

[peros550]

With my old MP 1 I calibrated compass only once, when I bought it. I had it for 2 years and never needed to re-calibrate!

I sold my MP to buy the M2P. Now I get the 50Km triggers every time I move the drone 50km. It's very annoying for me! Especially when you know that in reality this isn't a necessary thing to do....

I hope DJI will either remove these triggers or at least explain the reasons behind this

 

[Starz]

I keep reading this and wondering why mine doesn’t do the nagging compass message. Trying to figure out if I should feel special?
Wonder if I could list it for sale as a white rhino type and make a buck?

 

[sar104]

I keep reading this and wondering why mine doesn’t do the nagging compass message. Trying to figure out if I should feel special?
Wonder if I could list it for sale as a white rhino type and make a buck?

If you look at a mobile device DAT file you will find the checks in the event stream.

 

[Cloudhopper]

Does anyone actually know what "compass interference" actually means?

Is it measured magnetic field strength too big? (if so, how much larger than the earth's magnetic field strength for the error to be triggered?)

Does it check for measured magnetic field strength too small? (such as when the earth's magnetic field is canceled out by a nearby magnetic anomaly of similar strength but opposite polarity)

Or does it check both?

If it doesn't check for field strength too low, then there's a real chance of the A/C initializing and taking off with a false magnetic bearing.

We can use an Android app to measure the magnetic field strength in micoTesla at the point of takeoff. Actually this would be an exceptionally useful thing to have built into the DJI GO app ...

 

[sar104]

Does anyone actually know what "compass interference" actually means?

Is it measured magnetic field strength too big? (if so, how much larger than the earth's magnetic field strength for the error to be triggered?)

Does it check for measured magnetic field strength too small? (such as when the earth's magnetic field is canceled out by a nearby magnetic anomaly of similar strength but opposite polarity)

Or does it check both?

If it doesn't check for field strength too low, then there's a real chance of the A/C initializing and taking off with a false magnetic bearing.

We can use an Android app to measure the magnetic field strength in micoTesla at the point of takeoff. Actually this would be an exceptionally useful thing to have built into the DJI GO app ...

That's a good question, and I've never seen a definitive answer. The app interference level can be low even when a local magnetic field is affecting the readings. My guess is that it is looking to see whether the x, y and z components of the field are within some expected bounds given the location of the aircraft.

 

[Cloudhopper]

The app interference level can be low even when a local magnetic field is affecting the readings.

This is my worry too. It's possible a lot of people are taking off with a compromised initial magnetic bearing, assuming the launch site was safe because there was no compass error warning.

if the field strength is "reasonable", but the field direction is wrong (possibly up to 180 degrees wrong!), the drone will still take off.

This would be an easy thing to eliminate if the DJI Go/Android magnetometer and A/C magnetometer were compared at A/C power-on (and the pilot were made to roughly align drone and A/C before takeoff. How many ATTI mode flyways/accidents could have been eliminated through this simple cross-check?!?

 

[sar104]

This is my worry too. It's possible a lot of people are taking off with a compromised initial magnetic bearing, assuming the launch site was safe because there was no compass error warning.

if the field strength is "reasonable", but the field direction is wrong (possibly up to 180 degrees wrong!), the drone will still take off.

This would be an easy thing to eliminate if the DJI Go/Android magnetometer and A/C magnetometer were compared at A/C power-on (and the pilot were made to roughly align drone and A/C before takeoff. How many ATTI mode flyways/accidents could have been eliminated through this simple cross-check?!?

That's correct, but there is a much easier pre-flight check - just ensure that the aircraft heading arrow is pointing the correct direction, relative to north, on the map.

 

[Cloudhopper]

That's correct, but there is a much easier pre-flight check - just ensure that the aircraft heading arrow is pointing the correct direction, relative to north, on the map.

Totally agree - and that's what I do at every launch.

But this is something so fundamental to safe flying that it should be enforced through the app at startup (or at the very least have a regular pre-flight nag similar to "please check it on the map". After all, a hard compass error is enough to halt launch, so a magnetic bearing cross-check should be taken equally seriously.

 

[sar104]

Totally agree - and that's what I do at every launch.

But this is something so fundamental to safe flying that it should be enforced through the app at startup (or at the very least have a regular pre-flight nag similar to "please check it on the map". After all, a hard compass error is enough to halt launch, so a magnetic bearing cross-check should be taken equally seriously.

I have never understood why the instruction manual doesn't include that advice. Perhaps DJI assumed that the "Please check it on the map" instruction refers to orientation as well as location.

 

[CanadaDrone]

I haven't had my M2P out of the country yet but I have driven it about 100km from my house and it has yet to ask me to calibrate, even when flying off giant rocks which presumably annoy the compass. I have been very pleased with how solid it's been in that regard. My Air needs a calibration much more often, but it's easy and takes 10 seconds.

As mentioned above you can see before you even fly if your compass is orienting correctly so it's mostly a non-issue.

The only thing that annoys me about compass calibration is DJI's graphic is not representative of the instructions. The instructions say to point the nose down, but the graphic has it horizontal. It doesn't matter either way, but I don't understand why they haven't bothered to correct that.

 

[SHRED]

You got it. It's usually not necessary unless DJI GO is forcing the calibration before a takeoff is allowed.

More details on when to calibrate can be found here.

There was a "300 mile" rule when traveling where calibration was done on my old P3A if I change locations 300 miles or more away.
Does this "rule" apply to the M2Pro?

 

[Bryce steiner]

My first Mavic 2 Pro I would get all kinds of interference errors, powerlines or not. I finally sent it back in because the camera would start to shake up in the air and get all kinds of overload errors. I would calibrate the gimbal and the compass but it never made any difference.

The one I got back worked perfectly and never had any errors like that. Never had interference errors and I never was asked to calibrate even when taking four hour trips. I just read on DPreview that if I take the drone up and fly around cities you pretty much have to calibrate the compass or you will have all kinds of problems around the tall buildings.

It got me thinking that I should probably just remember to do it once a month.

 

[msinger]

There was a "300 mile" rule when traveling where calibration was done on my old P3A if I change locations 300 miles or more away.
Does this "rule" apply to the M2Pro?

No. That rule doesn't apply to Phantoms either (even though DJI often mentions it). Follow this guide:

DJI Mavic Compass Calibration Guide

 

[sar104]

There was a "300 mile" rule when traveling where calibration was done on my old P3A if I change locations 300 miles or more away.
Does this "rule" apply to the M2Pro?

Most M2Ps trigger compass recalibration when moved more than 50 km or after 30 days. Not all though. Some have the "last calibration" date stuck years in the future and don't require it every 30 days. And some don't require it when moved more than 50 km, which I haven't yet figured out.