Compass magnetic error keeps on coming

offtheback · Mar 1, 2019

After calibrations,takeoff in grass,no accessories on drone,and while in the air as well as before takeoff.No metal or car nearby.Any ideas?Thanks.BTW what does the compass actually do for the drone?If stupid question forgive me

GS40 · Mar 1, 2019

Time keeps on Slipping

SpinItUp · Mar 1, 2019

maybe calibration was off.
Why do you need to calibrate?
C.Columbus

Former Member · Mar 1, 2019

offtheback said:
After calibrations,takeoff in grass,no accessories on drone,and while in the air as well as before takeoff.No metal or car nearby.Any ideas?Thanks.BTW what does the compass actually do for the drone?If stupid question forgive me

Have you had any crashes?

Please be careful! Compass errors are one of the top reasons for flyaways.

According to a few experts here, if you are getting compass errors, try taking off from a different location, even if its just a few feet away. If I get a compass calibration error, thats the first thing I would do. If you do have to calibrate it, be careful for the first couple of minutes after the calibration.

BD0G · Mar 1, 2019

This may be a case of some part of the Mavic being magnetized and such would need to be demagnetized. Back in the days of the Phantom 2's and 3's there were some people that would swear the use of a demagnetizing tool was effective at solving compass errors. Others were more skeptical.

Here are some listings on Amazon if one wanted to try it out.

Amazon.com: demagnitizer

offtheback · Mar 1, 2019

BD0G said:
This may be a case of some part of the Mavic being magnetized and such would need to be demagnetized. Back in the days of the Phantom 2's and 3's there were some people that would swear the use of a demagnetizing tool was effective at solving compass errors. Others were more skeptical.

Here are some listings on Amazon if one wanted to try it out.

Amazon.com: demagnitizer

Thank you!

offtheback · Mar 1, 2019

Thunderdrones said:
Have you had any crashes?

Please be careful! Compass errors are one of the top reasons for flyaways.

According to a few experts here, if you are getting compass errors, try taking off from a different location, even if its just a few feet away. If I get a compass calibration error, thats the first thing I would do. If you do have to calibrate it, be careful for the first couple of minutes after the calibration.

Thanks Rob.I have tried moving the takeoff point and that didn't change the error.No crashes.Considering GPS and me controlling the direction what does the compass actually do?(serious question).It also says magnetic interference at times.

offtheback · Mar 1, 2019

SpinItUp said:
maybe calibration was off.
Why do you need to calibrate?
C.Columbus

While flying It says to move drone away from interference and/or calibrate.

DanMan32 · Mar 1, 2019

offtheback said:
Thanks Rob.I have tried moving the takeoff point and that didn't change the error.No crashes.Considering GPS and me controlling the direction what does the compass actually do?(serious question).It also says magnetic interference at times.

GPS can only provide heading if you are moving. All GPS can provide is "you are here". It can't tell you which way you are facing or before you actually started moving, which direction you would go once you started moving.
I've stated before though, a compass fail-safe could incorporated by using GPS delta to provide heading when the compass appears to have failed. Sure, from a standstill and during compass trouble the AC might go the wrong way, but within a few feet of travel, it should be able to compensate.

offtheback · Mar 1, 2019

DanMan32 said:
GPS can only provide heading if you are moving. All GPS can provide is "you are here". It can't tell you which way you are facing or before you actually started moving, which direction you would go once you started moving.
I've stated before though, a compass fail-safe could incorporated by using GPS delta to provide heading when the compass appears to have failed. Sure, from a standstill and during compass trouble the AC might go the wrong way, but within a few feet of travel, it should be able to compensate.

Thanks for the clear explanation.I am beginning to see the light!

Gray52 · Mar 2, 2019

Try a full IMU calibration sorted my compass error all the time!

GARealtor · Mar 2, 2019

Thunderdrones said:
Have you had any crashes?

Please be careful! Compass errors are one of the top reasons for flyaways.

According to a few experts here, if you are getting compass errors, try taking off from a different location, even if its just a few feet away. If I get a compass calibration error, thats the first thing I would do. If you do have to calibrate it, be careful for the first couple of minutes after the calibration.

I'm a newbie and I've had "mag interference" errors come up on my remote twice and had to calibrate the compass. No crashes and have only flown in my yard so far. Other than trying to take off from a different location, do you have any other advice? You mentioned being careful for the first couple of minutes after calibration...just curious...why? I'm still new at this and not sure what to expect. Thanks!

Former Member · Mar 2, 2019

GARealtor said:
You mentioned being careful for the first couple of minutes after calibration...just curious...why?

The answer is that if a compass is starting to give you problems in calibration, even if you are able to get it to calibrate, it doesn't mean that it fixed the problem. It might very well let you take off, and then as soon as it gets high enough, it can become uncontrollable. Its called the Toilet Bowl Effect. Its terrifying, and the best thing to do is land it asap, if you can.

That's why I say, if the compass is acting wonky, test it for a while in a hover before you venture off to parts unknown.

GARealtor · Mar 2, 2019

Thunderdrones said:
The answer is that if a compass is starting to give you problems in calibration, even if you are able to get it to calibrate, it doesn't mean that it fixed the problem. It might very well let you take off, and then as soon as it gets high enough, it can become uncontrollable. Its called the Toilet Bowl Effect. Its terrifying, and the best thing to do is land it asap, if you can.

That's why I say, if the compass is acting wonky, test it for a while in a hover before you venture off to parts unknown.

Thanks!

Canuk · Mar 2, 2019

One thing I do is point my drone north before lift off . then I look on my display and make sure the the drone icon in the radar display is also pointing north . I do this every time before takeoff .

msinger · Mar 2, 2019

Here's a list of things that should be done prior to taking off:

1) Find a takeoff spot that you know is not near any magnetic metal objects (e.g. rebar in concrete sidewalks).

2) Make sure your drone is never near magnetic metal objects after it has been powered on. It’s best to power on your drone in the exact location where you plan to take off.

3) Check the status message at the top of DJI GO and make sure it’s not reporting a magnetic interference error (like in the screenshot below). If you see this error, that’s a sign that your drone is near some type of magnetic metal object. Move your drone to a different location.

4) When your drone is on the ground at the takeoff spot, look at the map in DJI GO and verify that the red aircraft symbol is pointing in the same direction as the drone. If the drone and arrow are not both pointing in the same direction, that’s a sign that your drone is near some type of magnetic metal object.

5) Make sure the red aircraft symbol in DJI GO is not slowly rotating as your drone is sitting on the ground. If the red aircraft symbol is rotating, that’s a sign that your drone is near some type of magnetic metal object.

GARealtor · Mar 3, 2019

msinger said:
Here's a list of things that should be done prior to taking off:

1) Find a takeoff spot that you know is not near any magnetic metal objects (e.g. rebar in concrete sidewalks).

2) Make sure your drone is never near magnetic metal objects after it has been powered on. It’s best to power on your drone in the exact location where you plan to take off.

3) Check the status message at the top of DJI GO and make sure it’s not reporting a magnetic interference error (like in the screenshot below). If you see this error, that’s a sign that your drone is near some type of magnetic metal object. Move your drone to a different location.

4) When your drone is on the ground at the takeoff spot, look at the map in DJI GO and verify that the red aircraft symbol is pointing in the same direction as the drone. If the drone and arrow are not both pointing in the same direction, that’s a sign that your drone is near some type of magnetic metal object.

5) Make sure the red aircraft symbol in DJI GO is not slowly rotating as your drone is sitting on the ground. If the red aircraft symbol is rotating, that’s a sign that your drone is near some type of magnetic metal object.

Good info...thanks!

FormerMember07122019_2 · Mar 3, 2019

Thunderdrones said:
The answer is that if a compass is starting to give you problems in calibration, even if you are able to get it to calibrate, it doesn't mean that it fixed the problem. It might very well let you take off, and then as soon as it gets high enough, it can become uncontrollable. Its called the Toilet Bowl Effect. Its terrifying, and the best thing to do is land it asap, if you can.

That's why I say, if the compass is acting wonky, test it for a while in a hover before you venture off to parts unknown.

Hi Thunderdrones,

I am aware of the term toilet bowl effect for several different situations but this is the first time I have heard it used wrt to drones. What is your definition?

Ken