what caused the compass errors?

[redserv]

Hi guys i haven't flew my Mavic Pro Platinum for about 45 days. I woke up Saturday trying to out a Sunrise Timelapse that failed. This is the first time that i have launched my MPP from my office where i work. its like a two story building with flat concrete. everything was ok when i first launched no compass errors and all of a sudden i started to get lots of compass errors although I was already airborne. I am trying to understand what caused the compass errors was it the obvious that i was on top of a two story building? or was it something else. I don't know how true this is but i read that if you don't fly your bird for more than a month you should do a compass calibration. I am looking for answers, can you experts help me on this, so I can make the necessary corrections? Thanks in advance, see logs below.

 

[Deleted member 3792]

The concrete is filled with iron armour that will disturb the compass.

 

[redserv]

The concrete is filled with iron armour that will disturb the compass.

wow that was some quick analysis. I suspected it may be obvious, how can you guys tell from the log file that the environment was a factor? and If i hand launched and hand catch from the same location will it eliminate the compass errors? Thanks again for your feedback, apprecaited

 

[Deleted member 3792]

It says in the manual that avoiding concrete and other metal constructions is recommended.

 

[Meta4]

Hi guys i haven't flew my Mavic Pro Platinum for about 45 days. I woke up Saturday trying to out a Sunrise Timelapse that failed. This is the first time that i have launched my MPP from my office where i work. its like a two story building with flat concrete. everything was ok when i first launched no compass errors and all of a sudden i started to get lots of compass errors although I was already airborne. I am trying to understand what caused the compass errors was it the obvious that i was on top of a two story building? or was it something else. I don't know how true this is but i read that if you don't fly your bird for more than a month you should do a compass calibration. I am looking for answers, can you experts help me on this, so I can make the necessary corrections? Thanks in advance, see logs below.

I've looked through some of the 8 flight logs and only found compass errors in one of them.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

If you are posting flight data, try to just post the data relevant to the problem you are asking about.

A compass error is not a faulty compass and calibrating the compass won't "fix" a compass error.
It's a compass warning you of a magnetic problem in the local area.

In the flight above, you get compass errors on landing the drone.
Did you land on reinforced concrete?
Reinforced concrete is full of steel reinforcing (but you can't see where the steel is in the concrete.
If the drone's compass is close to steel, it will warn you.
That's likely to be the issue.
Reinforced concrete is not a safe surface for launching and landings.

Hand launching etc will keep the compass far enough away from the steel in concrete.

 

[redserv]

Hi Meta thank you for your advice. I will remember to check the logs and upload the appropriate ones with the errors, I really thought i saw compass errors on multiple logs when I uploaded to air data but i could be wrong. Thank you for clearing this up for me. I will try a different location just to make sure that i don't get any compass errors. I will also try to hand launch and Hand catch alot more

 

[Meta4]

Hi Meta thank you for your advice. I will remember to check the logs and upload the appropriate ones with the errors, I really thought i saw compass errors on multiple logs when I uploaded to air data but i could be wrong.

You might have.
I gave up after opening four.

 

[redserv]

You might have.
I gave up after opening four.

LOL ok np i got the information required, thanks again man.

 

[old man mavic]

being near any steel rich enviroment will cause compass errors, get a small hand held compass and hold it at waist height then lower it to the ground and you will see it deviate from north if there is any magnetic material in the ground,also move it close to your car and watch the affect it has on magnetic north, it causes the same issues in the compass in the mav

 

[redserv]

being near any steel rich enviroment will cause compass errors, get a small hand held compass and hold it at waist height then lower it to the ground and you will see it deviate from north if there is any magnetic material in the ground,also move it close to your car and watch the affect it has on magnetic north, it causes the same issues in the compass in the mav

wow very interesting. I never thought of that. neat trick I will look for a cheap compass on amazon to keep with me. I am very paranoid when anything goes wrong with my drone, this is the reason i try to educate myself and eliminate as much pilot errors as i could. thanks for this information.

 

[redserv]

It says in the manual that avoiding concrete and other metal constructions is recommended.

Thanks i actually forgot about that until i got the compass errors, thanks for the reminder

 

[DanMan32]

If your mobile device has a compass, you can get a compass app or metal detector. Most do have compasses though Samsung Tab E does not, believe it or not, and WiFi only iPads.

Sometimes you will have compass interference on launch but not enough to trigger an error. Once you're in the air, the interference goes away, but the compass is now offset which will likely cause flight issues

 

[redserv]

If your mobile device has a compass, you can get a compass app or metal detector. Most do have compasses though Samsung Tab E does not, believe it or not, and WiFi only iPads.

Sometimes you will have compass interference on launch but not enough to trigger an error. Once you're in the air, the interference goes away, but the compass is now offset which will likely cause flight issues

I am actually using a crystal sky monitor to fly. I think there is a also a calibration for the monitor built in. however when my drone and Cs is facing north i always feel that the compass displayed on go4 app is like 15 degrees off. it don't matter how mant times i calibrate both the drone and the cs. I just live with it.

 

[DanMan32]

It's not uncommon for Androids to have compass inaccuracies and needing frequent calibration. CS is a glorified Android tablet.

 

[JAW]

True vs. magnetic north variance?

 

[redserv]

True vs. magnetic north variance?

Yes I was reading about this last night and there is like a 5 degree variance between North and true north. This may explain the slight variance on my crystal sky monitor and the drone

 

[JAW]

Yes I was reading about this last night and there is like a 5 degree variance between North and true north. This may explain the slight variance on my crystal sky monitor and the drone

Where I fly in NC the declination (variance) is -10 degrees. On Long Island it's -14 degrees.

 

[sar104]

Yes I was reading about this last night and there is like a 5 degree variance between North and true north. This may explain the slight variance on my crystal sky monitor and the drone

No - both those devices correct automatically for declination, and display true, not magnetic.

 

[redserv]

No - both those devices correct automatically for declination, and display true, not magnetic.

Ah ok so you are saying that the CS monitor compass should align to North when the drone is facing north?

 

[Thomas B]

Ah ok so you are saying that the CS monitor compass should align to North when the drone is facing north?

Yes