OK Forum...

Today I was flying in an open field, no metal other then my truck and a livestock fence in front of my truck where I took off and landed.  I flew 4 full battery's worth, the last two I put into sport mode and was just flying around.  On the last battery, towards the end of the charge, I received the warrning "Warning:[IMU]heading exception (In Flight) please switch to atti mode if craft behave abnormally (Using)" as well as "Warning:Satellite Possitioning Off.  Fly with caution"  I did receive this several times and my satellite icon clearly shows 17 but the bars are down to one (in red).

I landed, then took off again after I got the green light with satellites.  I then went up about 20' then flew straight and noticed that it was vering off to the left...stopped and pulled the right stick straight back, this time it vered off to the right as it was coming back.  When I did this I received many of both of these errors/warnings and all of the LED lights on the craft when solid red.  The craft was NOT responsive to my commands.  I then switched it to atti mode and was able to regin control and bring it back to land...as I hovered over my landing site, the back LED's went from solid red to flashing yellow.

There were some high powered power lines around but they were about 5,000' away and I have flown in this general area many many times before with out any issues.

Even though it does NOT say to calibrate the IMU or the compass, I feel that I should because I have read many times the if the craft is vering off left or right from your command of straight forward then it would be best to do a re-cal on the IMU and compass.

Any suggestions or thoughts on this?  Any help woudl be awesome.  Thanks.

The screen shot is just one of the few incidences that I had today (3-29-17)

Please sync you flight records through DJI GO 4 and provide me your app account (e-mail address)
Also please connect the drone to a PC with Assistant 2 installed then export the flight data which showing the issue, then upload it to Dropbox and post the link here.
We'll check it for you.

DJI Natalia Posted at 2017-3-31 02:15
Please sync you flight records through DJI GO 4 and provide me your app account (e-mail address)
Also please connect the drone to a PC with Assistant 2 installed then export the flight data which showing the issue, then upload it to Dropbox and post the link here.
We'll check it for you.

DJI-Natalia,
Thanks for helping out on this.  My email is:  bill@celtinn.com
I have synced my flight records via DJI GO4 app
I think this is the link you need.  I have never done this before or used Dropbox.  I am not sure which flight record it was so I sent you what I have.  The dates of all of the flight records is March 30, 2017 and I think what you need is the latest two records.

https://www.dropbox.com/sh/zbmvw ... UEGptGgCUh4lja?dl=0

I've seen several threads on this issue and I had exactly the same problem on my first real flight today. Identical messages twice. FIrst after 2 min flight, second time after 4 min, warning stayed on for 30 seconds then back to normal (GPS).

15-20 satellites throughout. Very rural area. Latest firmware.

Would also appreciate help on this.

Maybe I'm far off, but has anybody checked the solar activity level? Solar "wind" can do things to satellites...

Antonio76 Posted at 2017-3-31 10:15
Maybe I'm far off, but has anybody checked the solar activity level? Solar "wind" can do things to satellites...

Good point...and I just check now and the KP index is at 3.  

On the 30th it did get up to 5 so maybe that had something to do with it.  However when I flew yesterday at around 4PM it was a 4.

ProQuad Posted at 2017-3-31 12:14
Good point...and I just check now and the KP index is at 3.  

On the 30th it did get up to 5 so maybe that had something to do with it.  However when I flew yesterday at around 4PM it was a 4.

ProQuad and Antonio76, be careful. You are going into the dark zone, and in a short time you will receive an answer from Australia.....................

Sry OT but how do you get notifications when someone answer a thread?

Still looking for an answer for IMU-problems and GPS lost momentarily.

I had the exact same issues along with the loss of control. Sent to DJI and they replaced this with a new unit.

ProQuad Posted at 2017-3-31 04:48
DJI-Natalia,
Thanks for helping out on this.  My email is:  
I have synced my flight records via DJI GO4 app

Thank you, we could access to the link but failed to download the file.Please double check whether you uploaded it correctly, or you can try google drive, thanks.

Bullflyer Posted at 2017-3-31 12:58
ProQuad and Antonio76, be careful. You are going into the dark zone, and in a short time you will receive an answer from Australia.....................

OK with me. Love strine...

bajen Posted at 2017-3-31 13:22
Sry OT but how do you get notifications when someone answer a thread?

Still looking for an answer for IMU-problems and GPS lost momentarily.

Top of your page small bell will have a red dot with number.

hallmark007 Posted at 2017-4-1 06:08
Top of your page small bell will have a red dot with number.

I thought that only works when someone clicks reply to one of your posts.  That is not the same thing as what he asked.

DJI Natalia Posted at 2017-3-31 20:24
Thank you, we could access to the link but failed to download the file.Please double check whether you uploaded it correctly, or you can try google drive, thanks.

Natalia, let's try this again.
Also, I uploaded these files directly from the assistant 2

https://www.dropbox.com/sh/i5l70 ... gEPmFZMjhkafSa?dl=0

also, try this link.  I'm not sure whice files you want or need.

https://www.dropbox.com/sh/qqbog ... hkeHuVQt9i2O5a?dl=0

DJI Natalia Posted at 2017-3-31 20:24
Thank you, we could access to the link but failed to download the file.Please double check whether you uploaded it correctly, or you can try google drive, thanks.

DJI-Natalia,
What did you find out with this issue?  I have not heard from you or any other DJI rep either here or via email.

ProQuad Posted at 2017-4-4 16:03
DJI-Natalia,
What did you find out with this issue?  I have not heard from you or any other DJI rep either here or via email.

Ah,,, you posted a message and the screen shot I promised to post but never got down to doing. Thanks +++
Please refer to this thread http://forum.dji.com/thread-88071-1-1.html

I the exact same problem some weeks ago.

The solution is to do a cold recalibration of the IMU. (Cold means to do this straight after you power on the aircraft for the first time that day - you MUST do the recal with a cold craft or it will FAIL to remedy the problem).  

My craft was totally loco and intermittently so. I don't like to criticise people openly but in this case, 'Natalia' simply is following a script and doesn't have the requisite technical knowledge. I almost sent my craft in thinking it was a hardware fault but decided to IMU recal.

This is categorically not a solar flare issue. There are a whole slew of people who fervently believe this but while it can give rise to transient GPS glitching, the GPS error message is a red herring in this case. (again see my thread about this)

Upvote this post if it works for you.

I've had no problems since. Still don't know what triggered the problem but if you see it, take down the bird early and fix the problem.

Another thing, it is NOT a GPS issue. Notice that in your screen shot you have a FULL slew of satellites. YET, the messages say that GPS signal is weak.

I think DJI should review this case and edit its error messages to avoid flyaways. My case would have definitely resulted in a flyaway if there was a strong wind and if I panicked.

ProQuad Posted at 2017-4-4 16:03
DJI-Natalia,
What did you find out with this issue?  I have not heard from you or any other DJI rep either here or via email.

I'm still waiting the data analysis result from the engineers, it's a 3-day public holiday in China, sorry for the inconvenience, will let you know once it's done.

Mike-the-cat Posted at 2017-4-4 17:26
Ah,,, you posted a message and the screen shot I promised to post but never got down to doing. Thanks +++
Please refer to this thread http://forum.dji.com/thread-88071-1-1.html

Thank you very much for your detailed information, and nice to know your aircraft performs fine after a cold IMU calibration, enjoy the flight!
For this situation, it would be best to analyze the data since the OP did calibrate IMU and compass already, then we will know the reason why it acted like that.
Appreciate your feedback again, we'll keep improving.

DJI Natalia Posted at 2017-4-4 23:58
Thank you very much for your detailed information, and nice to know your aircraft performs fine after a cold IMU calibration, enjoy the flight!
For this situation, it would be best to analyze the data since the OP did calibrate IMU and compass already, then we will know the reason why it acted like that.
Appreciate your feedback again, we'll keep improving.

To be clear, the OP only asked for advice re: whether to recalibrate the IMU. He did not actually report doing so.

We should wait for his response....

I have posted this thread to Ed Tahoe who has forwarded the message up the chain. Hopefully we'll hear from the OP soon. If his problem resolves, then there are at least two well documented cases of this type of event.

Mike-the-cat Posted at 2017-4-5 00:20
To be clear, the OP only asked for advice re: whether to recalibrate the IMU. He did not actually report doing so.

We should wait for his response....

Had a rather similar case yesterday: P4P, windy conditions. Wife asked me why I tried to fly in her face - I would never do such things of course. My way out: Atti, full climb to approx 50 m and manually "pray" the bird down. I'm an experienced RC-Heli pilot, maybe that saved me from crashing.
4 red lights continously.
- reboot bird and rc: at first normal behavior.
- lift off again: error-behavior, flashing yellow LEDs in the back of the bird, switched to continously red LED
- atti-landing again on solid ground, no damages

The result: I don't trust it any more. Obvious to say that the latest FW is installed properly.
Northern Germany.
Greetings to all - wish you never have accidents and stay safe.

Falcon Eye Posted at 2017-4-5 00:53
Had a rather similar case yesterday: P4P, windy conditions. Wife asked me why I tried to fly in her face - I would never do such things of course. My way out: Atti, full climb to approx 50 m and manually "pray" the bird down. I'm an experienced RC-Heli pilot, maybe that saved me from crashing.
4 red lights continously.
- reboot bird and rc: at first normal behavior.

adddition: My gimbal showed abnormal behavior also. It went straight downwards with an error message that disappeared too fast for me (I was in emergency mode that moment).

Falcon Eye Posted at 2017-4-5 00:58
adddition: My gimbal showed abnormal behavior also. It went straight downwards with an error message that disappeared too fast for me (I was in emergency mode that moment).

IMO this is not the same issue that the OP or I posted on.

All red lights suggests a serious issue with hardware integrity (flight control problem). The IMU cal issue gives rise to flashing yellow lights when one is kicked from GPS to Atti mode but no continuous red. (Yeah, I know I'm contradicting myself a little here with my advice to the OP with regard to the continuous red lights)

If this matter persists, you should send your craft for an inspection.
If the IMU recal does not work (and I suspect it won't in your case) the most likely issue is a loose connection somewhere. Opening the craft could void your warranty but if you are willing to do this check it out. The only time I've seen this is when 1) I had a cracked motherboard from my old P2 that once replaced sorted out the problem and 2) from another P2 with GPS cable not properly secured after some internal work.

As you are an experienced pilot, I'm sure you'll work your way to a solution. Good luck

Mike-the-cat Posted at 2017-4-5 01:18
IMO this is not the same issue that the OP or I posted on.

All red lights suggests a serious issue with hardware integrity (flight control problem). The IMU cal issue gives rise to flashing yellow lights when one is kicked from GPS to Atti mode but no continuous red. (Yeah, I know I'm contradicting myself a little here with my advice to the OP with regard to the continuous red lights)

Yep, the solution for me is simple:
- as this is a brand new drone, I'll send it in for a try to repair. Normally nothing will change.
- I'll send it in for the 2nd try, I don't hink that something changes.
- I'll get me money back.

I won't launch this model again until I don't trust it any more.
I used to fly non gyro-rc-helis that I built on my own. I think I'm going back to the roots

Falcon Eye Posted at 2017-4-5 02:11
Yep, the solution for me is simple:
- as this is a brand new drone, I'll send it in for a try to repair. Normally nothing will change.
- I'll send it in for the 2nd try, I don't hink that something changes.

Good luck. Hope you'll have a better experience next time

Mike-the-cat Posted at 2017-4-4 17:26
Ah,,, you posted a message and the screen shot I promised to post but never got down to doing. Thanks +++
Please refer to this thread http://forum.dji.com/thread-88071-1-1.html

Mike the cat,
Thanks for your responses on this and some of what you posted is off a little bit.  This post you say to do a recal of the IMU (yep cold, flat surface, etc.).  I did read your other post and due to weather and work I have NOT had a chance to take him out and test fly to see if it corrected itself.  Falcon Eye said he received all red lights and in my original post, I too had all red lights.  You also said it is NOT a satellite issue, which I have a tendency to believe, but worries me that it flys erratically against my RC commands...even when I put it into ATTI mode.  (I'm just glad I have been flying for a few years and have learned NOT to panic at the first sign of trouble and can fly in ATTI mode w/o freaking out...lol)

I will have a chance to test fly him later this week and see if I get the same issue again AND if he flys straight or not.
Also, I know that you are referring to me as the "OP" but I'm not sure what "OP" means.  I do thank you for moving this on to Ed Tahoe, and again, don't know whom that is, I can only assume he is a DJI rep that is high in the ranks?

After I do a test flight, I will repost here and let everyone know.  Thanks for your advanced advice.

DJI Natalia Posted at 2017-4-4 23:42
I'm still waiting the data analysis result from the engineers, it's a 3-day public holiday in China, sorry for the inconvenience, will let you know once it's done.

DJI-Natalia,  Thanks for letting me know AND thanks for moving the data to that analysis for review.  As I said to Mike-the-cat, I will repost here after a recal of the IMU and test flight.  Thanks again for your help.

ProQuad Posted at 2017-4-5 03:51
DJI-Natalia,  Thanks for letting me know AND thanks for moving the data to that analysis for review.  As I said to Mike-the-cat, I will repost here after a recal of the IMU and test flight.  Thanks again for your help.

Thank you, and please keep us posted.
Besides, OP means "original poster".

DJI Natalia Posted at 2017-4-5 03:55
Thank you, and please keep us posted.
Besides, OP means "original poster".

OP....I really was trying to figure that one out, feel kinda dumb, but thanks.  You never know unless you ask, right?

In the mean time, please continue to have the data analyzed.  Thanks again.

ProQuad Posted at 2017-4-5 03:50
Mike the cat,
Thanks for your responses on this and some of what you posted is off a little bit.  This post you say to do a recal of the IMU (yep cold, flat surface, etc.).  I did read your other post and due to weather and work I have NOT had a chance to take him out and test fly to see if it corrected itself.  Falcon Eye said he received all red lights and in my original post, I too had all red lights.  You also said it is NOT a satellite issue, which I have a tendency to believe, but worries me that it flys erratically against my RC commands...even when I put it into ATTI mode.  (I'm just glad I have been flying for a few years and have learned NOT to panic at the first sign of trouble and can fly in ATTI mode w/o freaking out...lol)

Hi,

I too did have the erratic flying problem. This is because with attitude evaluation failure, orientation is messed up. (think of being drunk - your brain can think 'walk straight' but you can't). Atti just means GPS is off in this case. To fly straight, the flight controller needs attitude information from the IMU and compass and if these are not functioning properly, then the craft flies erratically.

Ed is a US based senior advisor and is the chief moderator of this forum. He has heaps of experience with these craft.

Will wait to hear from you.

ProQuad Posted at 2017-4-5 03:58
OP....I really was trying to figure that one out, feel kinda dumb, but thanks.  You never know unless you ask, right?

In the mean time, please continue to have the data analyzed.  Thanks again.

Our engineer reviewed your flight records, but they need more details to locate the issue.
Please sync all your flight records to the server through DJI GO.
Then let me know the exact flight records which the notification appears, thank you very much.

DJI Natalia Posted at 2017-4-6 00:39
Our engineer reviewed your flight records, but they need more details to locate the issue.
Please sync all your flight records to the server through DJI GO.
Then let me know the exact flight records which the notification appears, thank you very much.

All flight records have been synced to the server.
Please look at:
29/3/17 18:35:10 @ the 10 min. left received several errors

29/3/17 18:46:28 no GPS, IMU issue (received MANY of these errors.  I think this was when it first started)
29/3/17 18:47:34 does NOT fly in a straight line
29/3/17 22:01 does NOT fly in a straight line
30/3/17 15:14:26 does NOT fly in a straight line
30/3/17 15:18:41 does NOT fly in a straight line
30/3/17 15:21:33 does NOT fly in a straight line
30/3/17 15:23:45 does NOT fly in a straight line
30/3/17 15:37:21 does NOT fly in a straight line
30/3/17 15:39:50 does NOT fly in a straight line

Did a COLD IMU calibration, RC calibration, camera calibration and GPS calibration

5/4/17 19:07:53 does NOT fly in a straight line
5/4/17 19:11:26 does NOT fly in a straight line


Also posted this to my other feed:
http://forum.dji.com/forum.php?m ... mp;page=1#pid756141

ProQuad Posted at 2017-4-6 04:00
All flight records have been synced to the server.
Please look at:
29/3/17 18:35:10 @ the 10 min. left received several errors

Thank you, I've asked them to review your flight records again.

ProQuad Posted at 2017-4-6 04:00
All flight records have been synced to the server.
Please look at:
29/3/17 18:35:10 @ the 10 min. left received several errors

Looks like you have a persistent issue and may have to send your craft in.... Anyway, you have the engineer's attention now so good luck.

ProQuad Posted at 2017-4-6 04:00
All flight records have been synced to the server.
Please look at:
29/3/17 18:35:10 @ the 10 min. left received several errors

I hear from our engineers.
According to the flight records, the compass was interfered. It might be caused by the environment you calibrated it or flew it.
Please try to calibrate it in an open place without the interference and fly it again to see whether the error appears frequently or not.
If still the same case, the drone needs to be sent in for further evaluation.

Mike-the-cat Posted at 2017-4-5 07:42
Hi,

I too did have the erratic flying problem. This is because with attitude evaluation failure, orientation is messed up. (think of being drunk - your brain can think 'walk straight' but you can't). Atti just means GPS is off in this case. To fly straight, the flight controller needs attitude information from the IMU and compass and if these are not functioning properly, then the craft flies erratically.

Mike-the-cat,

Please see the next post

DJI Natalia Posted at 2017-4-7 04:24
I hear from our engineers.
According to the flight records, the compass was interfered. It might be caused by the environment you calibrated it or flew it.
Please try to calibrate it in an open place without the interference and fly it again to see whether the error appears frequently or not.

DJI-Natalia,

OK...GOOD NEWS for this issue.  Its a bit of a story BUT I'm hoping this will help others that have the same two issues.

I  contacted Multicopter Warehouse which is a DJI authorized dealer AND a tier 1 DJI repair center and I spoke to one of the owners, and he had  the same two issue and what he told me to do is to stick my P4P into the freezer for 20 min. (less the battery) then do an IMU immediately after,  then recalibrate the compass and this should take care of it.

I  decided to take my P4P up into the mountains in a wide open area and to  the IMU and Compass calibration.  I put the quad in the bed of my truck, then drove up, temp was about 32F (0C) and was able to do an IMU &  compass recal.  On the compass....I did "the dance" instead of just twisting the quad around.
AS OF NOW AND AFTER 5 FLIGHTS, NO.....& I mean NO issues and the quad flies as straight as the day I got it.

DJI-Natalia,  thank you so much for looking into this for me and IF I have any more issues on this, I will contact DJI customer support and get it in for repair.

The pic below is AFTER I rrcalibrated everything.  ALSO, I  took some screen shots of BEFORE and AFTER of the IMU and Compass  screens on the DJI Go APP.

ProQuad Posted at 2017-4-8 18:19
Mike-the-cat,

Please see the next post

ProQuad,

First, congratulations on solving the issue. You must be one happy guy now...

You don' really have to stick the quad in the freezer! As you found out, the main thing is that the IMU must be COOL when the cal is done. Oftentimes, people say they REPEATEDLY performed calibration. They fail to note that that is pointless as the electronics would have already heated up.

Second, - thanks for acknowledging my earlier post. I've alerted Ed about this issue and I think the next thing is for DJI programmers to fix the misleading 'Compass' or 'GPS' error messages that are red herrings.

Enjoy your bird!

Mike-the-cat Posted at 2017-4-8 20:22
ProQuad,

First, congratulations on solving the issue. You must be one happy guy now...

Mike-the-cat,
I really didn't want to stick it in the freezer...seems a bit silly to me AND as it is in a warmer environment, it could get condensation with-in it...even though it was argued that, that would not happen.

I agree with you as far as letting Ed know and the DJI team to try and resolve this issue somehow.  Thanks again for letting him know.  I also found out since I posted this, that the owner of Multicopter Warehouse has it in with DJI and some of there big wigs...He also lets them know some issues as they pop up.  Thanks for all your input and if we see this again coming up in the forum, we will both know what to do/say.

ProQuad Posted at 2017-4-9 09:07
Mike-the-cat,
I really didn't want to stick it in the freezer...seems a bit silly to me AND as it is in a warmer environment, it could get condensation with-in it...even though it was argued that, that would not happen.

Great post!

My own IMU problem hasn't recurred so fingers crossed. Looking back, it was pretty scary that the bird seemed to take on a crazy personality when the IMU was faulty.. It took me awhile to regain confidence ..

Happy flying again and appreciate your flagging the issue with your contacts...