Need your help in what this warrning means when I flew the other day:

Warrning:[IMU]heading exception (in flight) please switch to atti mode if craft behave abnormally (Using)

A little back story.  As of March 3rd I did the latested update on the craft and remote as the GOApp as well, took the aircraft out to an open field and did all of my calibrations, compass, remote, camera, etc. and then brought it back home and did a cold IMU calibration.  

I wanted to fly from a pier and I know that there is a tone of metal in pier's so that is why I did all of my calibrations away from there.  I was told that I can take off from a pier, BUT I would need to get the craft up ASAP to get it away from the metal.  I also went one step futher and launched off of a milk creat to aid in this.  I was able to do this twice w/o any issues and if flew awesome!  The third time was an issue.  I did take off and got it up and started to fly out about 10 to 15 feet and then it bacame a little erratic in flight, got the warranings, but if you look at the satilite status, it indicates 18 but only one bar and it is in the red.

Can any of you help out on this?  DJI-Ken or DJI-Jamie?

Thanks

Your first mistake was doing IMU. Never do it unless asked. You might have done a bad not so level IMU calibration.

i thought imu cal after every update?

Nees Posted at 2017-3-10 15:41
Your first mistake was doing IMU. Never do it unless asked. You might have done a bad not so level IMU calibration.

Nees,

I disagree with you.  I have always re-calibrated everything after a firmware update.  I also re-calibrated it on a flat and level surface as well as a "cold" recal.  This has been suggested many times in this forum on the Mavic, Phantom as well as the Inspire pages.  These suggestions come from the DJI-reps on here.  It is also a good idea to re-calibrate the IMU's to get it down to as close to zero as possible.

Now, what that said...it is possible that the IMU calibration I did, did not turn out the was is was suppose to.  I did not check it like I normally do after a calibration to see if it was as close to zero as possible.  This may have been my mistake.

The questions are...What does the warring mean exactly and why did it come up?

boostedford Posted at 2017-3-11 11:52
i thought imu cal after every update?

Boostedford,

Yes, you are correct.  Re-cal after every firmware update.  I have done this with every quad I have owned and have never had any issues...until this time around.  Still waiting for an answer.  Thanks for your impute.

I got this warning yesterday too. Mavic was flying fine, 19 satellites, i initiated RTH and immediately got a warning that Satellite positioning was off, then the IMU heading exception and RTH was cancelled. Mavic started to drift in Atti mode but GPS suddenly came back and was able to bring it back safely. A bit scarey!

DJI Ken has also said several times, IMU doesn't need to be calibrated, even after firmwareupdate unless it tells you to do it.

Guys, this is NOT correct. Whilst with the drones prior to the Mavic it was best practice to follow this procedure all the newer DJI drones use updated FC's and as such the IMU should only be calibrated if prompted to or should you be experiencing repetitive fight issues and need to troubleshoot.

EDIT: Irrespecive of what some 1st line support staff may say on here, this info comes from the DJI Mavic Project Lead Engineer. Not saying it is bad to calibrate the IMU especialy if done correcly, the message from them is simply that it is not necessary and should not be done after each f/w update or for the fun of it lol :-)

chippie Posted at 2017-3-12 08:44
Guys, this is NOT correct. Whilst with the drones prior to the Mavic it was best practice to follow this procedure all the newer DJI drones use updated FC's and as such the IMU should only be calibrated if prompted to or should you be experiencing repetitive fight issues and need to troubleshoot.

EDIT: Irrespecive of what some 1st line support staff may say on here, this info comes from the DJI Mavic Project Lead Engineer. Not saying it is bad to calibrate the IMU especialy if done correcly, the message from them is simply that it is not necessary and should not be done after each f/w update or for the fun of it lol :-)

chippie,

Thanks for the updated info.  Agree with sticking with the best practice.  I think I may have done it incorrectly somehow.  I flew it a few hours about 2 miles from that pier with out any issues after I did a new IMU calibration.

HOWEVER, this still does not answer my questions.  Any thoughts?

ProQuad Posted at 2017-3-12 12:29
chippie,

Thanks for the updated info.  Agree with sticking with the best practice.  I think I may have done it incorrectly somehow.  I flew it a few hours about 2 miles from that pier with out any issues after I did a new IMU calibration.

It is not necessary to calibrate after firmware update, firmware updates will have no effect on compass or IMU .
It also mentions in your manual Not to calibrate unless prompted, I'm sure there's a very good reason for putting this in the Manual, it's also in the Manual for P4P and I2.
After firmware updates you can check compass and IMU levels in you app.

Having said that if you feel your AC is not preforming the way it should , you are not going to damage it by calibration, you may add to your problems if you calibrate incorrectly, and I think this has a lot to do with it being added to new manuals.

If you just launch Mavic 8 feet let it hover 30 sec fly forward/backward left/right up/down yaw right yaw left all these manoeuvres should be done x 3 feet i.e. 3 feet left 3 feet right and so on. Each time if your aircraft comes back to horizontal and performs to your commands, you will know you have good gps compass and good IMU , it takes less than two minutes and I would recommend before every flight..

Good luck..

hallmark007 Posted at 2017-3-12 12:57
It is not necessary to calibrate after firmware update, firmware updates will have no effect on compass or IMU .
It also mentions in your manual Not to calibrate unless prompted, I'm sure there's a very good reason for putting this in the Manual, it's also in the Manual for P4P and I2.
After firmware updates you can check compass and IMU levels in you app.

Hallmark007,
Hummm...looks like I'm reading my manual...again.  I thought I remembered that, but thought it was compass calibration.  Yes, I also agree with your statement in letting it hover and left right forward back etc., I did that but not 3 feet in each direction. That may have been part of my problem as well. Thanks for the reminder.
I flew it since I had those issus and did not have any problems.

ugh so many conflicting answers

boostedford Posted at 2017-3-13 18:15
ugh so many conflicting answers

Right??  In the time I have been flying (since P2V+) I have learned to (as a best practice) re-cal everything after a firmware update.  This gives me some quality time with my quad so I can look at everything with a fine tooth comb.  Do one compass cal, then leave it unless it says to re-cal OR if I travel more then 100 miles (but others will argue with me on this).  

Since I have done it this way, this is, honesty, the very first time I have had any issues with any of my quads.  I am starting to believe that it was a bad IMU calibration I did the day before.

ProQuad Posted at 2017-3-14 04:19
Right??  In the time I have been flying (since P2V+) I have learned to (as a best practice) re-cal everything after a firmware update.  This gives me some quality time with my quad so I can look at everything with a fine tooth comb.  Do one compass cal, then leave it unless it says to re-cal OR if I travel more then 100 miles (but others will argue with me on this).  

Since I have done it this way, this is, honesty, the very first time I have had any issues with any of my quads.  I am starting to believe that it was a bad IMU calibration I did the day before.

same here except i was told compass cal if 20 miles (since p2v+)

boostedford Posted at 2017-3-14 15:09
same here except i was told compass cal if 20 miles

Yea, again...conflicting answers.  I did get that info from DJI-Ken or DJI-Jamie

ProQuad Posted at 2017-3-14 15:19
Yea, again...conflicting answers.  I did get that info from DJI-Ken or DJI-Jamie

Send happen to me 12march to march17

I’ve had it a few times. I have put it down to confusion from where I launch. Or even possibly radar from boats that where close at the time.

Recalibration will not cause problems if it's done correctly.   Problem is that it often is not done correctly - making a non-problem into a problem.

Back to OP's problem.  I'm assuming that you did not receive a Compass Error while flying or you would have mentioned it.  However,  this problem sounds like the GPS direction and the compass direction don't agree and the flight guidance system is confused.  This condition is common with initial "Magnetic Interferrence" or Compass errors, but I suppose it could also be caused by GPS problems.  It's been pointed out on previous posts that GPS signal strength is far more important than satellite count.  There is a field in the Mavic DAT file for gps_health which might shed some light.  I suggest you upload and share the DAT file (in DropBox) so we could take a look to see if anything makes sense.

Griffith Posted at 2017-7-5 11:21
Recalibration will not cause problems if it's done correctly.   Problem is that it often is not done correctly - making a non-problem into a problem.

Back to OP's problem.  I'm assuming that you did not receive a Compass Error while flying or you would have mentioned it.  However,  this problem sounds like the GPS direction and the compass direction don't agree and the flight guidance system is confused.  This condition is common with initial "Magnetic Interferrence" or Compass errors, but I suppose it could also be caused by GPS problems.  It's been pointed out on previous posts that GPS signal strength is far more important than satellite count.  There is a field in the Mavic DAT file for gps_health which might shed some light.  I suggest you upload and share the DAT file (in DropBox) so we could take a look to see if anything makes sense.

Griffith,
Thanks for your input and I agree with you.  This was a one time thing and have since learned how to correct any issues I come across.  So far, no issues and have traveled to a few places since I posted this...again no issues at any of those new locations.

ProQuad Posted at 2017-7-5 12:33
Griffith,
Thanks for your input and I agree with you.  This was a one time thing and have since learned how to correct any issues I come across.  So far, no issues and have traveled to a few places since I posted this...again no issues at any of those new locations.

It would still be an interesting learning experience to take a look at the DAT file and maybe get some insight from the Mavic perspective.

Griffith Posted at 2017-7-6 04:36
It would still be an interesting learning experience to take a look at the DAT file and maybe get some insight from the Mavic perspective.

Could be.  This flight was in March and since then I have flown countless flights...might take me a while to find it (if its still there) then upload it.  I am assuming that I can do this VIA DJI assistant 2?

ProQuad Posted at 2017-7-6 04:40
Could be.  This flight was in March and since then I have flown countless flights...might take me a while to find it (if its still there) then upload it.  I am assuming that I can do this VIA DJI assistant 2?

It's probably not there now.  I think the cache is small.  May only be the last flight.  Oh well!  Enjoy flying!

StephenGSY Posted at 2017-7-5 09:15
I’ve had it a few times. I have put it down to confusion from where I launch. Or even possibly radar from boats that where close at the time.

If you access the DAT file from one of the flights where this happened using these instructions, upload it to DropBox or a similar service, and provide a link to it somewhere here will look at it and may be able to give you more information on why it occurs.

DroneFlying Posted at 2017-7-6 08:36
If you access the DAT file from one of the flights where this happened using these instructions, upload it to DropBox or a similar service, and provide a link to it somewhere here will look at it and may be able to give you more information on why it occurs.

Theres a .dat with Exception error

StephenGSY Posted at 2017-7-6 12:26
Theres a .dat with Exception error

That doesn't appear to be the correct DAT file as it doesn't contain any flight time but seems to have been created by powering the Mavic on and then back off again. The correct file will probably be at least tens of megabytes in size.

Sorry pain trying to find right one. Will have another look.