Compass Error?

[Brojon]

I wouldn't fly it with a bad compass. It should calibrate fine over grass. If you see issues from many locations, then the compass is bad. I have a bad one myself and changed it. It was so bad that when I took off and tried to fly straight, it would start curving off to the left and go sideways. Very hard to control if the compass is bad.

It's that little board in front of the nose right?
I repaired my gimbal on my crashed MP and now sometimes it wants to slowly turn while hovering. Odd thing is it seems to only happen when pointing SW - it will slowly rotate towards west.

 

[CyberNate]

It's that little board in front of the nose right?
I repaired my gimbal on my crashed MP and now sometimes it wants to slowly turn while hovering. Odd thing is it seems to only happen when pointing SW - it will slowly rotate towards west.

It's usually the rear compass/GPS that causes issues for me. I've had 2 go bad. The rear one is the main compass

 

[BudWalker]

Go ahead and take off and hover to see if it goes away.
Compass is only used for heading so it won't hurt to go straight up and down.

Actually, this can still be a problem. In order to achieve stationary hovering small corrections are required. If the Yaw is incorrect the corrections will be made in the wrong direction which then will result in a fly away. This is usually what happens as the pilot hasn't made any inputs other than throttle. Here is an example of an incident like this

Compass error

 

[Brojon]

Actually, this can still be a problem. In order to achieve stationary hovering small corrections are required. If the Yaw is incorrect the corrections will be made in the wrong direction which then will result in a fly away. This is usually what happens as the pilot hasn't made any inputs other than throttle. Here is an example of an incident like this

Compass error

Once removed from the source of magnetic influence things return to normal. It only has relevance to where it occurred.
I think it's quite a stretch to assert this as a definitive cause of flyaway...

 

[BudWalker]

Once removed from the source of magnetic influence things return to normal. It only has relevance to where it occurred.
I think it's quite a stretch to assert this as a definitive cause of flyaway...

It's not so much of a stretch as it's counter intuitive. What actually happens is that shortly after battery on the Yaw value gets initialized with the magYaw value (the heading determined by the compass). After that Yaw is determined mostly by the IMU with magnetometer data being used at low gain to make small adjustments to the Yaw value. Depending on the platform and separation size it can take anywhere from 10 secs to more than a minute for the Yaw to be fully adjusted to the correct value. In the example I cited

Compass error

it took 50 secs or so.

In this example

Looking for Trouble ??

it took even longer.

The Mavic, and I suspect the other platforms that came after the P3, will often try to reconcile a magYaw/Yaw separation by holding the Yaw value constant and then rotating the AC until that constant Yaw value agrees with the magnetometer data. Kinda tricky and it sometimes works.

 

[Brojon]

I feel an experiment coming on.
My poor Mavic

 

[BudWalker]

I feel an experiment coming on.
My poor Mavic

Please provide the .DAT for any experiment you have in mind. You could also take a look at the two examples I cited.

 

[JohnnieWalker]

Congratulations on getting your unit. Many of us are still waiting. Would you mind stating when you ordered it and when it arrived? As to the situation your described, I can tell you that I have been given that error when launching my P3S from on top of concrete, probably because of all the metal in the foundation. This happened to me at home over my driveway and also in town at the edge of a shopping center parking area. In fact, I went into atti mode when I launched, had to land quickly as a breeze was moving the unit close to power poles. I moved over about 25 feet to a gravel road and had no issues then. Perhaps this is your problem, too. Let me know if this solves it.

This exact thing happened to me near the lake in Chicago! I almost died seeing my brand new drone go crazy so close to the water! Lesson learned...dont take off from the concrete path!

 

[JohnnieWalker]

Had a bad compass on my Mavic Pro standard as well. Had it for 2 weeks and starting getting errors right away. Did the IMU calibration, compass calibration, firmware...everything! Luckily I was able to return it yesterday for a full refund.