Another Compass Calibration, Seriously?

msinger · Mar 28, 2018

Lake_Flyer said:
The biggest risk is interference DURING EACH CALIBRATION. You think it's calibrated OK but as soon as you take off the compass turns out to be faulty and there you have a 'fly away' as many people call it.

I think this one is very unlikely to happen too. The calibration should fail instead of completing.

The fly away incidents you noted were most likely all caused by powering on the Mavic and/or taking off near a magnetic metal object.

DroneTraveller · Mar 28, 2018

As with anything that is known to man 100 different people will give 100 different answers. As the old saying goes, 'Give a man a watch and he can tell you the time, give him two and you'll get an estimate.' Do what makes you happy.

dragonmuzz · Mar 28, 2018

Brian_MavicPro said:
My Mavic Air seems to require a compass calibration each time I fly. Indoors, seems to be mostly normal but outdoors is another story. I fly in rural areas over forest, lakes, waterfalls. Today I launched from a frozen lake. My Mavic Air needed the usual compass calibration dance (3X) and my DJI P3A did not...typical of the P3A, solid.

So, I am curious if anyone else has a Mavic Air with the same issue. My particular Mavic Air also had the shakes from an overactive IMU until the latest firmware. I am curious if this compass calibration is another firmware issue that will hopefully be fixed or do I have an odd Mavic Air.

My typical outdoor weather is 20F (-6C) to 41F (5C). Don't blame me, lol. DJI chose to put a new drone out in the middle of freaking winter and I live in Ottawa Canada. I bet all those lab tests were done in nice warm weather. Thoughts anyone?

only had to calibrate my Air compass once since getting it..im in UK so not that cold

Red Baron · Mar 28, 2018

InvisibleName said:
Please tell me that your 'LOL' means you don't really mean this!!

It means it works 99% of the time for me

Prismatic · Mar 28, 2018

The final and most important compass check you should always make happens just before takeoff: Verify that the actual heading of your drone, as it sits on the ground, matches exactly the heading shown in DJI GO 4. If it’s even slightly off, you’re flirting with catastrophe.

Brian_MavicPro · Mar 31, 2018

Doing the drone dance in 2 - 3 feet of snow while standing on uneven ground is not something to take lightly. It’s an absolute nuisance. My iPhone seems to know north from south and i’ve never recalibrated it. You would think location was GPS and Glonass dependent rather than compass but I digress. Again, my P3 only bugs me when I travel far. The Magic Air wants the drone dance nearly every time regardless of previous takeoff location.

PNWDronesolutions · Mar 31, 2018

The only times I been prompted to recalibrate is when I’ve walked off with the MavicAir still turned on. Swinging as you walk may affect it, particuarly if you pass something metallic or perhaps have a metal watch on the arm you’re holding it. I’ve never had to recalibrate if I turn the MavicAir on and off at the takeoff / landing location and just set it down on the ground.

jessegordondesigns · Apr 2, 2018

Sooooo we all have this problem...Does DJI have a fix for this?! I'm personally super over this as every time I fly it's up in the air what I will have to do to get my Air to connect, set home base, and maybe let me take off at some point.

I'm not really trying to stand here for 5-15min every time I wanna fly. I have to turn off the remote sometimes or turn off the drone sometimes...I never had any problems with the Spark.

joejaxvic123 · Apr 2, 2018

I love...Pro.

jessegordondesigns · Apr 2, 2018

joejaxvic123 said:
I love...Pro.

That helped a sh$% ton! Thanks....

droneworx · Apr 2, 2018

Really, it’s kind of annoying, but the air is so small, that it literally takes 15 seconds to do it, and it’s not like a phantom, where it’s such a big bird that it is a choir to rotate it in all the different directions. It’s annoying, but ive sort of resigned to the fact that I have to do it.

Spot25 · Apr 4, 2018

I have the Phantom 3Pro and the Mavic Air and the Air is constantly asking for the compass to be calibrated while I can’t remember the last time I calibrated the Pro....

KelloggKid · Apr 4, 2018

Once the drone begins to move, assuming good GPS data, the on-board computer should be able to determine (from the GPS) which direction the drone is traveling and it's physical orientation to that movement. From that data it should be able to determine with reasonable accuracy the drone's heading. I keep reading about fly aways caused by faulty compass calibrations and wonder why the on-board computer couldn't do it's own heading calculation and if it differs greatly from the compass issue a warning and/or RTH. BTW - my MA seems to require a new calibration every time I move my physical location more than about 25 miles. Perhaps because where I live the magnetic declination can vary quite a bit over a short distance.

Flywoody3 · Apr 5, 2018

Same, get the Calibration notification quite a bit. Very annoying.

Don

Prismatic · Apr 7, 2018

KelloggKid said:
Once the drone begins to move, assuming good GPS data, the on-board computer should be able to determine (from the GPS) which direction the drone is traveling and it's physical orientation to that movement. From that data it should be able to determine with reasonable accuracy the drone's heading. I keep reading about fly aways caused by faulty compass calibrations and wonder why the on-board computer couldn't do it's own heading calculation and if it differs greatly from the compass issue a warning and/or RTH. BTW - my MA seems to require a new calibration every time I move my physical location more than about 25 miles. Perhaps because where I live the magnetic declination can vary quite a bit over a short distance.

So far as GPS or GLONASS can tell, you’re a dimensionless point. You’re track means nothing; the aircraft orientation could be anything. “Wind” is the most reasonable assumption when it detects motion in an unanticipated direction (hovering or otherwise). If it’s compass isn’t true, flight corrections will exacerbate the problem.
Zoom zoom.

KelloggKid · Apr 7, 2018

Prismatic said:
So far as GPS or GLONASS can tell, you’re a dimensionless point. You’re track means nothing; the aircraft orientation could be anything. “Wind” is the most reasonable assumption when it detects motion in an unanticipated direction (hovering or otherwise). If it’s compass isn’t true, flight corrections will exacerbate the problem.
Zoom zoom.

Sorry but I somewhat disagree. Yes you are a simply a point in space. Until you begin to move. Then you are a series of points in space. If the flight computer looks at where it is now, where it was 1/4 second ago, where it was 1/2 second ago, etc. it can compute, with reasonable accuracy, a sense of what direction it is traveling. Then it should be able to tell from the gyro whether it is moving sideways, backwards, etc. Using those two pieces of information it should be able to make a fairly accurate assumption about heading. Not as accurate as the compass but hopefully good enough to prevent a fly away.

As an example, if after looking at the last 10 GPS data points the FC determines it is traveling due East, and the gyro tells it that it is traveling sideways toward the right side, one could conclude that the front of the drone is facing North.

If you have ever initiated a GPS trip in a car while it was stationary you will have noticed the system had no way of knowing which way the car was facing. However, the minute you start moving the car the system quickly figures it out. What makes it a little more difficult with a drone is that they don't always move nose first like a car.

moshik · Apr 7, 2018

Please take a look at this YouTube Compass explanation.

It helped me a lot to understand that I SHOULDN'T calibrate the compass every time that the Apps asked that I need to calibrate, just switched location (sometimes it is a few meters aside) and it helped.

The Mavic Air has a LUT (lookUp Table) that stores the Earth magnetic shift vs location (The other models doesn't have the LUT, even the Mavic Pro Platinum), so, once you unbox the MA and did the Compass calibration you do not have to do it again.
In case the GO4 app asks you to calibrate, look for Hi power line or metal in the area (even pips in the ground).

If you insists to calibrate the compass, leave the phone & the remote control away - Start the calibration process with the App and take the MA away from the remote, phone, car, building... and do the "twist".
You see the drone lights change to green after the horizontal 360d twist.

Moshik

swooshdave · May 21, 2018

I'm now being forced to do a CC before each flight. Before I just had done it once. Not sure what changed. I might be more cavalier with handling the drone while turning it on (moving it around) so I will try some things. Maybe a reset?

InvisibleName · May 21, 2018

swooshdave said:
I'm now being forced to do a CC before each flight. Before I just had done it once. Not sure what changed. I might be more cavalier with handling the drone while turning it on (moving it around) so I will try some things. Maybe a reset?

When you say "forced", do you mean that the caption at top left of DJI Go is red?

Mr Banks · May 21, 2018

New user here. But I too have been asked by the app to calibrate compass every single time I on my first three flights. The instructions on how to actually calibrate are not very clear in the app.

And I think of the three YouTube videos I have see, each have shown three totally different methods of how to do this. Nothing clear on DJI website either.

Check out these three videos. which one is the correct way to calibrate??

So I still don't know exactly how you are supposed to do it. And it is a pain to do it everytime. But I guess not as much of a pain than it would be if My Mavic Air flew off South all by itself!!!