Compass error

Eyeonyou · Aug 4, 2017

Should you always recalibrate when you get a compass error or just move it to a different location?

DanMan32 · Aug 4, 2017

Use your judgement based on your surroundings.

Meta4 · Aug 4, 2017

Eyeonyou said:
Should you always recalibrate when you get a compass error or just move it to a different location?

Don't think of a compass error as something wrong with the compass.
It's almost always a perfectly working compass telling you that something is wrong.

Any time your Phantom brings up the calibrate warning, there's 99% chance that the reason is that you have placed the Phantom somewhere close to a lot of iron or steel or electrical cables.
Your compass is telling you that it has detected a magnetic field that's significantly different from the earth's normal field - you are close to a bunch of steel etc.
You should NEVER calibrate the compass in that sort of environment and you should never launch from there.
The correct thing to do whenever you see that message is to move away from the source of the magnetic interference.

Richard R · Aug 4, 2017

Since the compass is a very stable subsystem, I would always assume that there is some locale issue when I get a compass error message before I would think that the compass is the fault. Anything on or in the ground could be confusing the compass. I would move and restart (perhaps even move a couple of times) and only recalibrate if moving doesn't remove the message. Be willing to bet that it would clear up 99 out of a 100 times.

Eyeonyou · Aug 4, 2017

That's good advice, thanks[emoji106]

Eyeonyou · Aug 4, 2017

I may have jumped the gun and recalibrated it. I took off by a river bank in the middle of nowhere and it popped up a error. So I landed it and recalibrated it right there (oops) and it went away and I flew it and never came up again. Nothing was around, other then river rocks. My phone was in my pocket cause I was flying with my iPad and I decided to take it out of my pocket and lay it away from me. Not that it would make any difference, just trying to eliminate any possible problems. Maybe I showed go back out to a grass field and do another compass cal?

With The Birds · Aug 5, 2017

It's probably good practice to be familiar with what your compass mod value is with a known good calibration in a clean magnetic environment (available in the sensor screen in the go app). I usually check mine as part of my pre flight check, particularity when flying in a new area or one where I expect I might have issues. Often hand launching can allow you to take off from structures that would otherwise prove problematic- in these circumstances I will look at the mod value when holding the AC above my head. If it's within normal values I fly without issue.

Eyeonyou · Aug 5, 2017

I think I will start fresh and go to a open field and do another calibration and check the mod value and keep an eye on it before I fly. And if it does it again I'll just move locations instead of doing one right there and flying again. Thanks

Eyeonyou · Aug 5, 2017

Oh and one last thing. What's this whole degaussing procedure all about and if I need to do it what's the easiest way? Couldn't find that much about it on-line.

Richard R · Aug 5, 2017

Some materials, through long term use or as a result of exposure to high strength magnetic fields, can developable residual magnetism that affects how they perform. Degaussing is the process of removing those residual fields using another powerful magnet. As long as your compass holds its settings or recalibrate so on those rare occasions when you really need to, don't worry about it. It's not likely that you would ever have to do a degaussing of the compass on your bird.

Fester · Aug 7, 2017

I've made this suggestion several times, but bears repeating here. If you are showing compass errors from you Phantom in a particular area, most have an alternate means of checking for magnetic abnormalities...your iPhone/iPad or other device. Most have built-in Magnetometers and a free app to use it can be found easily. Do a walk around and see if the spot you're in is indeed showing something is skewing the local magnetic field. This gives you an independent means of checking.