A couple of days ago I was out with my Phantom 3 Pro and I was having problems getting the compass to calibrate. It would go through the process but fail at the end. What was different was instead of just failing, I got a voice message saying that it was in ATI mode. Even though the controller was set to P-Mode. So instead of having the Phantom fly erratically in P mode, it switched automatically to ATI mode and was easily controlled. Am I dreaming or somewhere along the way was there an update that did this change? Being one who has suffered from a failed compass calibration and had the machine fly erratically in a ever widening circle, I welcome this change if it is indeed an update.

When the compass error is bad enough and the Phantom can't resolve conflicting data from the GPS and the compass, it will just drop the GPS input and switch to atti mode.
It's always been that way.

If you are having problems getting the compass to calibrate, that strongly suggests that you are doing it in a bad location.  Maybe somewwhere that is magnetically contaminated by a car, structural steel, a buried pipe or cable or reinforced concrete.

When you have trouble calibrating the compass, the correct action is to move to a clear location.
You'd be better off getting a good compass calibration and sticking with  it rather than unnecessarily recalibrating and risking getting a bad calibration.

labroides@yahoo Posted at 2016-5-26 21:37
When the compass error is bad enough and the Phantom can't resolve conflicting data from the GPS and ...

I was able to resolve the compass error but I had never experienced the change to ATI mode without actually flipping the switch. I guess I never had that big an issue before.

Hello Crowesnest, it is not a firmware issue. What labroides says is right and I'd suggest you to calibrate the compass in a clean place free of magnetic-field interference. It is also recommended to calibrate the IMU again.

DJI-Paladin Posted at 2016-5-27 15:27
Hello Crowesnest, it is not a firmware issue. What labroides says is right and I'd suggest you to ca ...

I actually wasn't commenting on the compass calibration error as I was able to correct that relatively quickly nor was I complaining about a firware problem. I was making a comment that it automatically switched to ATI mode when the compass calibration failed. I've never encountered that before. I was always under the impression that if I encountered a compass error I had to manually change it from P mode to ATI mode.

Crowesnest Posted at 2016-5-29 05:40
I actually wasn't commenting on the compass calibration error as I was able to correct that relativ ...

Did the app show P-Atti or Atti when the calibration failed? Which mode did you select when you calibrate the compass, P or A mode?

DJI-Paladin Posted at 2016-5-29 10:39
Did the app show P-Atti or Atti when the calibration failed? Which mode did you select when you ca ...

I believe that I was in P mode or at least that is what I thought that I was in. I didn't notice whether the app showed P-Atti or Atti. The compass failed just after it said that was setting the home point if that helps. It then said that it was in Atti mode. A vocal statement from the iPad.

Crowesnest Posted at 2016-5-29 20:58
I believe that I was in P mode or at least that is what I thought that I was in. I didn't notice w ...

It would be better to post a video or some photos of this issue here. It would be more intuitive.

I know this is 20 days old, but I'm just trying to understand this ... as I had a problem the other day:

From time to time, mine switches to ATTI mode after calibration for a few seconds, but there is no calibration failure message. Then I set it down and it switches back to P mode and I get the safe to fly.

I was just figuring it was still in the process of picking up enough satellites and so when it got enough it went back into P mode.

Are you telling me that getting the voice going into ATTI mode after a calibration is the sign of a failed calibration, even though there is no failure message?

Cause this happens to me from time to time and I was just figuring it didn't have enough satellites yet and when it got them it went back to P mode.

Thanks for any insight. And sorry if I'm bumping a thread that is too old.

Quint

quint7 Posted at 2016-6-19 12:43
I know this is 20 days old, but I'm just trying to understand this ... as I had a problem the other  ...

It was for me. I have tried flying it since then (after doing a compass calibration in a different location) and I am no longer getting the voice message or the dropping into ATI mode.

quint7 Posted at 2016-6-19 14:43
I know this is 20 days old, but I'm just trying to understand this ... as I had a problem the other  ...

There is magnetic influences in the ground.
I see a heap of users calibrate in their driveways and footpaths and then place it on the ground to take off. There metal in the concrete called rebar. The Phantom will switch to ATTI the moment it sees contradicting data.

It's best practice to do compass dances in open fields or places with minimal magnetic influences and then come back to the take off site to fly. You could be making things worse if you calibrate everytime you fly as you may be taking a bad compass snapshot. I've read the manual but I disagree with DJI's instruction on compass calibrations at every new location or take off.

quanthonytrang Posted at 2016-6-20 09:29
There is magnetic influences in the ground.
I see a heap of users calibrate in their driveways and ...

If I need to calibrate the compass I always go out to a field. There is a local high school and I use the football field.

I remove everything; watch, phone, wallet, steel bracelet and anything that has any metal in it.

I walk about ten feet away and do the calibration. I have never had a problem and I do not want one.