Hi,

I have a phantom 3 standard that was stored for around 12 months without use, it now will not work correctly as the IMU unit will not calibrate and just shows an unknown error warning. I have updated the firmware via the go app, as far as I undertsand this updates the remote control at the same time, also checking the log file shows success for fw update.

I attempted to roll back to a previous firmware by formatting the SD card and installing the .bin file to the root directly, which worked but the IMU would still not calibrate. I have tried tapping the drone to see if the IMU unit is possibly stuck. However when looking at the sensor page it appears all values change as the drone is moved around pyhsically.

Thew only thing I noticed was that the Z section under acceleration seems to be -1.5 at rest, i'm not sure if this is correct?

From what I can see this may be a software problem because the values do seem to reading on the drone and it is aware of it's position/rotation. (picture attached of APP screen)

Please can you advise on what to do next?

Thank you,

Adam.

Was the ACC z axis always on -1.4 during moving the AC up and down or did it change? What temperture was around your AC during attempt to calibrate thie IMU?

Peterx Posted at 9-10 07:49
Was the ACC z axis always on -1.4 during moving the AC up and down or did it change? What temperture was around your AC during attempt to calibrate thie IMU?

Hi Peter,

The value changes when physically moving the drone, as do the other values. It just sits back to -1.4 ish at rest, so it seems to be registering movement correctly but it is unable to calibrate properly.

Have attempted calibration indoors and outdoors, various times of day with different temps etc, last one was around 10 degrees outside.

Any other ideas greatly appreciated.

Adam.

I´ll have a look to my P3S sensors parameters to see value of the z-axis ACC.

Peterx Posted at 9-11 10:16
I´ll have a look to my P3S sensors parameters to see value of the z-axis ACC.

Thanks Peter!

Any help from DJI greatly appreciated ????

The mod value in ACC-z axis must be 1.00 on the grond. This is the normal gravitation. 1.41 is a strange value. May be the ACC Z has a bug.

Peterx Posted at 9-12 06:10
The mod value in ACC-z axis must be 1.00 on the grond. This is the normal gravitation. 1.41 is a strange value. May be the ACC Z has a bug.

Yes I'm just trying to work out how to fix it ! Surely if it was a hardware fault then it wouldn't work at all or it would be stuck around -16 like people have had before.

Still no help from dji !

Ads1987 Posted at 2019-9-12 11:48
Yes I'm just trying to work out how to fix it ! Surely if it was a hardware fault then it wouldn't work at all or it would be stuck around -16 like people have had before.

Still no help from dji !

I'm fully aware of how old this is but I'm having the exact same issue!! Did you ever resolve it? Mod value and z also -1.4

What temperature had the AC during calibrations try? If it´s to warm then you´ll get a bad calibraton or you´ve been stuck in progress. Best way to see is cool down the AC without the battery and try the IMU calibration again.
I hope that brings you two to a success.

Hi,

Yes I read so many posts and internet info, tried coping battery and aircraft, tapping the aircraft, removing the imu and moving it around, tapping the imu but nothing would work. It looks like once the calibration goes over -1 it simply won't reset and allow the calibration. So I brought a drone for spares and repairs, swapped the IMUs over and reset it all, software updated and it worked , sold the other drone back on as spares and repairs.

Hope this helps,

Adam.

I flipped it upside down and calibrated then back right side up and calibrated again, all fixed till I crashed over water earlier today (
Luckily got a good deal on it, thinking some mavic variant next

Appreciate the quick responses though!

At least you got it working, mine would not go into the calibration at all, it just stuck at 2% and wouldn't budge whatever position I held the drone!

Do not hold,put the drone on an plain and even place to calibrate the IMU.