compass calibration and satellites question..

JAG1 · Nov 30, 2016

hi, sorry i know these are basic questions but i would just like to clear a few things up...

when it comes to calibrating the AC (doing the funny dance) the first step on the screen tells me to hold and rotate the aircraft horizontally 360 degrees, the 2nd step on my screen tells me to hold the AC on its side and go 360 degrees BUT IN the manual it says to hold the aircraft vertically with nose pointing downward, and rotate it 360 degrees. Why is the DJI go app telling me to do it different to the manual??

Second question, how many satellites must you have before take off?

many thanks

Lesmess · Nov 30, 2016

I have always done it as per the manual. I only do it once after a firmware upgrade. 10 or more for me usually around the 18 mark though.

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JAG1 · Nov 30, 2016

so as anyone noticed that the calibration is different on the iPad compared to what it says in the manual...

Farnk666 · Nov 30, 2016

They changed it a couple of app versions ago - Manual hasn't been updated yet

JAG1 · Nov 30, 2016

so which is the correct way then?

Lesmess · Dec 1, 2016

It doesn't matter which way, always done it as per manual. No issues at all.

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Highrpm955 · Dec 1, 2016

I bet I've done 2 Compass calibrations in 400+ flights. After every FW update, I do an IMU calibration. Before every flight, I check the mods. IF they are in check.. fly. I've only had 1 known mod out of whack, and I moved locations. Otherwise, I feel its best to leave the magnetic fields alone. The one time I skipped the checklist, I had a bird out of control. (recovered without incident). Never, ever lift off without checking your Mods. This is the most important check you can do before launch, other than the obvious, prop locks, 12-17 sat locks, frame inspection, prop inspection, etc. I think, (and I think The Editor will agree), that over calibrating the compass is asking for trouble.

The Editor · Dec 1, 2016

I agree...I agree !!! ^^^^^^^^

Dave Smith · Dec 2, 2016

Highrpm955 said:
over calibrating the compass is asking for trouble.

Out of curiosity, how's it possible for the compass to become over calibrated?

Lesmess · Dec 2, 2016

Dave Smith said:
Out of curiosity, how's it possible for the compass to become over calibrated?

It's not a case of over calibration, calibrating multiple times increases the chance of a bad calibration. This can confuse the inspire if the compass & GPS are not in sync which can lead to unusual flying characteristics often termed as toilet bowling do a search on here.

Dave Smith · Dec 2, 2016

Lesmess said:
It's not a case of over calibration, calibrating multiple times increases the chance of a bad calibration. This can confuse the inspire if the compass & GPS are not in sync which can lead to unusual flying characteristics often termed as toilet bowling do a search on here.

Cheers, will check it out.

rmb · Dec 3, 2016

The Editor said:
I agree...I agree !!! ^^^^^^^^

Wow. I confess I have been doing wrong for 3 years now! I have been calibrating the compass before every flight. I guess I should stop doing that? I do think that callibrating is important if you are flying more than 20 miles away from where you last calibrated. Or is that silly as well? What say you oh-wise moderator?

The Editor · Dec 3, 2016

rmb said:
Wow. I confess I have been doing wrong for 3 years now! I have been calibrating the compass before every flight. I guess I should stop doing that? I do think that callibrating is important if you are flying more than 20 miles away from where you last calibrated. Or is that silly as well? What say you oh-wise moderator?

Let's put it this way - I regularly travel around 250 miles south of my home and sometimes circa 300 mile NE and I can't actually remember the last time I calibrated my compass.
I do however always check my mod values prior to every single take off. If they are out of that sweet spot of 1400-1600 (+/- 50 or so fluctuating) then I do not take off. I move the aircraft a few feet and check again.
I have however had the odd compass error when I have put the Inspire on the ground ready for take off, so I simply moved around 20 feet and the mods were back in line. Had I have calibrated from that error area I would have got a skewed calibration which could well have caused issues once I was airborne and clear of whatever was causing the error on the ground.
Even DJI have changed their advice now on their newer platforms to calibrate only when the app tells you to. The problem is the app can be wrong in the instance I gave above.