IMU and Compass Calibration Reading

[TCRay]

Before I fly, I always recalibrate my compass, not always the IMU's.

Question... when I do a calibration of the IMU's and/or the compass, there are some fields that show on the screen that will have decimal figures and colors that populate the fields; green, yellow, red. I have never seen those explained anywhere.

Should those fields be filled with green on both the IMU's and the compass 1 and 2? What decimal figures are the best? Thanks for any help!

 

[ChrisLX200]

There's no need to recalibrate unless the app tells you it is required. It may actually do more harm than good because if you get it wrong - i.e., calibrate in the presence of an anomalous magnetic field, then your aircraft could do strange things or even go AWOL.

 

[Fly Dawg]

Before I fly, I always recalibrate my compass,

For the sake of emphasis, DO NOT DO THIS! Compass calibration is very rarely necessary. It will cause more issues if you do this before every flight. Always check your directional icon prior to takeoff. If you notice a large directional deviation, then you may need to calibrate.

 

[TCRay]

What you both are telling me is different than what a drone training series instructed. They said to calibrate prior to each flight if I have gone even across town to fly (i.e. significantly changed locations).

Thank you both for your input.

But could you answer this. When I do calibrate, what values do I want to see in either the IMU fields or the compass fields? I notice for my compass 1 and 2 there will be different numbers showing, and they will change as I watch.

 

[msinger]

What you both are telling me is different than what a drone training series instructed. They said to calibrate prior to each flight if I have gone even across town to fly

Calibrating the compass prior to each flight won't hurt anything, but it's not necessary. Check out the Phantom Compass Calibration Guide for the best known practices.

When I do calibrate, what values do I want to see in either the IMU fields or the compass fields?

Anything in the green levels is good. I've never seen DJI quote specific values.

 

[TCRay]

Thank you for the article and feedback... very helpful!

 

[Meta4]

What you both are telling me is different than what a drone training series instructed. They said to calibrate prior to each flight if I have gone even across town to fly (i.e. significantly changed locations).

There's a lot of myth and superstition around the calibrating compass because so many people don't know what calibrating the compass actually does.
The source you used is only spreading these myths.
Check p57 of your manual to see when DJI think you need to calibrate your compass.
Under normal circumstances you should never need to calibrate your compass.

 

[$gambino$]

Yep I calibrated my compass one time when I first got my V2, and the last time I calibrated my mavic Pro's Compass was last year and I've traveled all over trust me you are okay. the only time you should worry is if the directional arrow is off on your map or if the app explicitly tells you to calibrate.

 

[Meta4]

... or if the app explicitly tells you to calibrate.

If you think the app is telling you to calibrate, look closer.
The wording will say Magnetic field interference - move the aircraft or recalibrate.
That wording is incorrect.
The correct action is to move the drone away from the magnetic influence the compass has dtetcted.
Recalibrating will not fix that.

 

[$gambino$]

If you think the app is telling you to calibrate, look closer.
The wording will say Magnetic field interference - move the aircraft or recalibrate.
That wording is incorrect.
The correct action is to move the drone away from the magnetic influence the compass has dtetcted.
Recalibrating will not fix that.

This is true I have never really see it say "calibrate" explicitly like I said I rarely calibrate my compass unless I know something is off.... also I think another scenario where you might want to calibrate is if you do move away from said interference and keep encountering the same message even in Wide Open Fields

 

[N017RW]

You can’t see mag interference. Wide open areas are no assurance of being clear or free of such ambient distortions.

Compass compensation can ONLY characterize and offset Hard and Soft Iron distortions created by items or materials IN/ON the aircraft.

This why it’s only necessary if you add, remove, or relocate items in/on you multi-rotor.

 

[$gambino$]

You cant see mag interf but if u look at compass values isnt that a tell tale sign? I know in certain spots it won't matter like if you are in your house or near your car but if you keep going to different locations free of metal ,ironsetc ....and your values are not going down then obviously something is wrong

 

[N017RW]

Sure. Your magnetometer may have become compromised requiring degaussing or replacing.

The point is compensation will not correct for distortions external to your aircraft. You must simply move to another location.

 

[Stevekris]

Well....that thing about never needing to calibrate, or one shouldn't calibrate unless told so by the app, has also turned into a "myth" of its own, but that is based on my personal experience. I frequently move relative long distances between places I fly, could easily be 40-70 miles, and not calibrating the compass between these moves very often results in strange or at least "nervous" behaviour of the P4P and/or compass errors showing up either in flight or in the logs after flight.

So, I at least, calibrate before each flight when coming to new places and doing this has solved these issues for me. Not sure exactly why, but calibrating fixes things for me at least.

 

[Meta4]

Well....that thing about never needing to calibrate, or one shouldn't calibrate unless told so by the app, has also turned into a "myth" of its own, but that is based on my personal experience. I frequently move relative long distances between places I fly, could easily be 40-70 miles, and not calibrating the compass between these moves very often results in strange or at least "nervous" behaviour of the P4P and/or compass errors showing up either in flight or in the logs after flight.

So, I at least, calibrate before each flight when coming to new places and doing this has solved these issues for me. Not sure exactly why, but calibrating fixes things for me at least.

Calibrating the compass doesn't "fix" anything.
If you understood what calibrating the compass actually did, you'd also understand when it's necessary (almost never).
I'm over 1500 miles away from home this week and my Phantom is flying perfectly without recalibrating anything.
But it should because distance from anywhere makes no difference to compass calibration.

Compass errors aren't the compass malfunctioning.
It's your compass warning you that its detected a problem in the area you are launching.
And re-calibrating the compass does nothing for the problem the compass is warning you about.
There's a reason that up-to-date DJI manuals don't tell you to calibrate the compass when:

• the Phantom is new
• you have travelled 50, 100, 1000 miles
• it's a day that ends in a Y

or any other time.

 

[Stevekris]

Doesn't really matter to me what is your belief - or what the Dji manual says for that matter. I've been flying quads since we put two sticks together with motors on, and the P4P since it was released, both privately and for commercial use.

I'm saying it does make a difference for me, and as I've seen and tested this over and over again with the same conclusive results, I stick with my method: Calibrating the compass on site, for me, prevents various behaviour issues, exit p-gps mode issues and from time to time - compass warnings mid air.

Calibrating the compass doesn't "fix" anything.
If you understood what calibrating the compass actually did, you'd also understand when it's necessary (almost never).
I'm over 1500 miles away from home this week and my Phantom is flying perfectly without recalibrating anything.
But it should because distance from anywhere makes no difference to compass calibration.

Compass errors aren't the compass malfunctioning.
It's your compass warning you that its detected a problem in the area you are launching.
And re-calibrating the compass does nothing for the problem the compass is warning you about.
There's a reason that up-to-date DJI manuals don't tell you to calibrate the compass when:

• the Phantom is new
• you have travelled 50, 100, 1000 miles
• it's a day that ends in a Y

or any other time.

 

[Meta4]

I'm saying it does make a difference for me, and as I've seen and tested this over and over again with the same conclusive results, I stick with my method:

What you are doing is nothing but a superstition.
If you understood what calibrating the compass actually did, you'd also understand when it's necessary (almost never).

Calibrating the compass on site, for me, prevents various behaviour issues, exit p-gps mode issues and from time to time - compass warnings mid air.

You'd also understand that calibrating the compass doesn't do a thing to prevent any issues.
You'd fly a lot safer with a little understanding and learning to avoid launching from reinforced concrete or steel surfaces.

 

[Stevekris]

I respectfully disagree. Simple as that. And, as for you domination techniques with concrete og steel, please.... save it

What you are doing is nothing but a superstition.
If you understood what calibrating the compass actually did, you'd also understand when it's necessary (almost never).

You'd also understand that calibrating the compass doesn't do a thing to prevent any issues.
You'd fly a lot safer with a little understanding and learning to avoid launching from reinforced concrete or steel surfaces.

 

[Meta4]

I respectfully disagree. Simple as that. And, as for you domination techniques with concrete og steel, please.... save it

I understand that you disagree ... and I don't care.
You're big enough to deal with the consequences of your decisions.
I'm only putting some facts out there so that less experienced flyers don't get mislead.

 

[N017RW]

I respectfully disagree. Simple as that. And, as for you domination techniques with concrete og steel, please.... save it

Can you explain, in a technical way, how this frequent compass compensation has prevented the behavior issues you referenced and how this is achieved?

Since one can’t prove a negative I’m curious about the technical aspect.