I have two questions. Really more directed to DJI but, feel free to comment.

1: The manual says, only calibrate the compass when told to do so by the app. Normally, when you start the app and turn everything on, you get this screen that slides over from the right giving you system status. For compass, it states "Normal" but, to the left of it, there is a "Calibrate" button. Is that just optional? Or. Suggest action? If it is optional then, what does it look like when it really wants you to calibrate because I have never seen anything different then what I described above. I know on my P3P, on occasions I would get compass error during startup and ask me to calibrate but, at that point, I could not takeoff until I completed the calibration. Would this be the same on the I2?

2: The I2 has a lot of redundant hardware but, I'm curious as to why the Compass is not one of them? If you do a search for DJI drone problems, the number one would be compass errors.

Regards,
Tom

I noticed that myself on the Inspire 1 and I think it is confusing .  To me neither one should be  "circled" or maybe the term  "Elongated circle Highlight " is in order.  

The way I understand the DJI system , the elongated highlight does NOT indicate calibration is necessary , there are several things on the app that you need to Accept as just Normal . ( NOT saying it is correct , It is just the design )  I  for one always look at the way the Radar on the lower corner of the app is Indicating North and then make sure that it is correct .  I  have  only once been told to calibrate the compass on the Go app, so It will tell you if action is needed.

I calibrate my  compass about once a month or maybe longer, just to play it safe, I certainly don't do it every flight like some pilots do .  I will also do it after any updates to the system as well.  I also wish there was some type of "Success" after you do the calibration .  There is a  GREEN  light flash on the AC  that I have come  to rely on ( after I do the second circle dance ) and a camera little movement at the 180 degree mark .  BUT would like a small message on the screen that told me it was "SUCCESSFUL " as well. ( If the light on the AC goes solid red  after calibrating ,then you must re do calibraion ) I DONT LIKE THE LIGHTS, I WOULD LOVE TO SEE A MESSAGE ' SUCCESS '

Not sure why the compass is not redundant like the other systems .... maybe they feel the other sensors (GPS) etc make up for that , not sure .

Happy flying .....also great minds think alike because I wondered this same thing.  Maybe one of the DJI folks can chime in if they know something.

***The AC will also flash Red and Yellow if the Compass does indeed require calibration ......just remembered that .

donnie

Tom,

The app will make it clear when it wants you to calibrate the compass, it flashes up on screen that it needs to be done, you can't miss it. It cannot, however, tell the difference between needing a compass calibration and needing to be moved away from some hidden metal object so if you do ever get this message, before trying a compass calibration (probably right where the metal object is) ensure you are not anywhere near any metal, move the bird 6 feet or so away from the car, if you are on a concrete surface there may be steel rebars affecting the compass, get a friend to hold the drone aloft while you take off.
ONLY perform a calibration if all else fails.
The more you perform unnecessary calibrations, the more you risk getting a bad cal. If you don't calibrate when you need to, you may experience some lateral drift whereas bad calibrations are notoriously linked to flyaways, I know what I'd rather.
Those of you who prefer to calibrate whenever you are unsure, just to be, "on the safe side", are not actually, "on the safe side".
For those who insist on calibration whenever they fly in a different postcode, take look at this map. This should give you an idea where and how far you can go without compass deviations making a scrap of difference.

I'd rather be, "on the safe side"

Thanks for the input guys. I agree that only doing a calibration when the app instructs you to is good practice. The only time I had any issues with compass was on my P3P. Took off from my backyard and at about 100 feet in the air I got a compass error and the it started to drift. I put it in Atti mode and was able to bring it back but, I was always a little nerves after that. I think it is important to note that you should change to Atti mode when a compass error occurs because the UAS may decide to take off in a direction because it thinks it should be somewhere else then it's current location.

Regards,
Tom

dldp-sp Posted at 2017-2-25 03:24
Thanks for the input guys. I agree that only doing a calibration when the app instructs you to is good practice. The only time I had any issues with compass was on my P3P. Took off from my backyard and at about 100 feet in the air I got a compass error and the it started to drift. I put it in Atti mode and was able to bring it back but, I was always a little nerves after that. I think it is important to note that you should change to Atti mode when a compass error occurs because the UAS may decide to take off in a direction because it thinks it should be somewhere else then it's current location.

Regards,

That is good advice Tom  to switch to Atti mode when  you get a compass error  .  I made a Note of that in my book .

thanks

donnie

Mark Guille Posted at 2017-2-24 07:57
Tom,

The app will make it clear when it wants you to calibrate the compass, it flashes up on screen that it needs to be done, you can't miss it. It cannot, however, tell the difference between needing a compass calibration and needing to be moved away from some hidden metal object so if you do ever get this message, before trying a compass calibration (probably right where the metal object is) ensure you are not anywhere near any metal, move the bird 6 feet or so away from the car, if you are on a concrete surface there may be steel rebars affecting the compass, get a friend to hold the drone aloft while you take off.

Oh, that is a very cool chart Mark !

Thanks for sharing that , more stuff to add to my book as well. ( the book or notebook rather is little hints , charts and ideas that I refer to from time to time  for reference )

donnie