Jamie Hellmich Posted at 2015-1-8 11:25
Good deal, I know EXACTLY how you must be feeling.  I can't wait until tomorrow afternoon to work on ...

Hi Jamie, did you have any luck fixing the yaw drift? I've been dealing with the same problem. Did your phantom always drift to the same direction regardless of whether you were yawing left or right?

marco_britt.hot Posted at 2015-2-16 06:28
Hi Jamie, did you have any luck fixing the yaw drift? I've been dealing with the same problem. Did ...

Yes, and I fixed it by shimming up the right side and the rear with business cards with trial and error method.  Leveling my Phantom did no good.

As noted in my posts in this thread, along with photos, the NAZA module in my Phantom is quite a bit out of level compared to the rest of the craft, and commensurate to leveling it with the way I shimmed it up.

My next step, if I ever get around to it or feel the need to do so, would be to remove the module and re-affix it on a plane (level) with the aircraft to see if that corrects the drift.

Without going back to look at my posts or pulling out my notes, I think I wound up shimming the rear up 3 cards and the right side 16 additional cards.  Therefore, the aircraft was 1/4" to 3/8" out of level when IMU calibrated, but it worked.

My posts also explain the directions of drift etc...  Good luck, just take your time in whatever method you go with, and take good notes.

Rats, I guess tomorrow I'll open mine up. There are some things I want to check anyway.

marco_britt.hot Posted at 2015-2-16 06:28
Hi Jamie, did you have any luck fixing the yaw drift? I've been dealing with the same problem. Did ...

As far as the  temperature notice, I wound up cooling the aircraft with a fan blowing into the empty battery bay.  Sometimes I still got the error, I would then close Assistant, shut off and re-power the Phantom, re-open Assistant, and a message would tell me "calibration in progress" (or something like that) and the calibration would resume.  Or ingore it.

Do you have to have the GPS cable hooked up when doing the IMU advanced calibration?  I just don't want the top influencing my leveling if possible.

jdlucas@embarqm Posted at 2015-2-28 21:26
Do you have to have the GPS cable hooked up when doing the IMU advanced calibration?  I just don't w ...

The only thing I have heard about not having the GPS connected, is that the motors won't start.  The calibration is not associated with GPS, so I would say you are okay.  But I have not tried it before.

I assume you have a drift during yaw turns.  I am curious as to what method of leveling you are using, and what your outcome might be.

Jamie, I do have drifting when I yaw.. As far as I can tell its about 6-10 ft  left when I yaw left and right when I yaw right. As for rear or front it's not much.  I really don't know if I had this much drifting before my first advanced calibration or not but I'm sure I didn't have this much!

As for my leveling method, I used my kitchen counter top which appeared to be pretty level with a 2 ft level.  I then calibrated a phone app (bullseye type)  to the counter top.  Now that's a pretty bad standard but the best I had at the time.  I then placed a piece of glass cross all four motors, leveled and calibrated.  

I have a background in machining so I have ordered 3 precision circular (bullseye) levels.  I hate doing things twice and at my age I lost patience long ago.  IMO Long levels have their place, but on a large flat uneven surface they might miss a low spot where you place your bird's skids, so a circular level used in close proximity to where you set your skids may be the best if you are not going to remove the top.

I've read  every page here and think everyone has resolved this yaw/drift.  I hope it works for me.  When I receive my levels I plan to make sure the IMU unit is level as others have done and also compare to my motors with the glass.  Ultimately I will calibrate to the IMU unit though and try it out.  I will also post my results as I rarely contribute tothis forum but only take.

thanks lucas, looking forward to your results.

gnixon2015 Posted at 2015-3-1 00:23
thanks lucas, looking forward to your results.

Hey guys, I recently moded my P2V+ to replace the original gimbal & camera with a GP4 + H4-3D gimbal.
Before that my P2V+ was working fine, but after this, I started noticing what seems to be the behavior mentioned in this thread (yaw drift), on top of that the phantom sometimes doesn't even hold its altitude position, it moves slowly up & down.
I did multiple advanced IMU calibrations, for one of them I even opened the shell and made sure the imu was level, and it seemed to be, although it's difficult to tell considering there's a 'bump' on top of the naza module.
Do you guys have any idea what to do next?

vico36, see this thread:
http://forum.dji.com/forum.php?m ... tid=4343&page=1

mike@singerscre Posted at 2015-3-2 00:21
vico36, see this thread:
http://forum.dji.com/forum.php?mod=viewthread&tid=4343&page=1

Yep I did see this thread, that's why I made sure the naza module was level before doing yet another advanced IMU calib, but mine also seems to have troubles holding its altitude, do you think this could be caused by an IMU not calibrated correctly?
btw didn't you just link the thread we're on? :O

vico36, per the DJI manual, the IMU measures altitude. So, it could be related.

vico36 Posted at 2015-3-2 00:33
Yep I did see this thread, that's why I made sure the naza module was level before doing yet anoth ...

Here is a video I took with my phone showing the phantom's behavior, 99% of the time in that video I didn't touch the throttle, it loses/regains altitude on its own...sometimes it's almost going to touch the ground like at the end of the video where I had to give it full throttle to make sure it didn't touch the ground.
When I made it roll on itself, it yaws a bit at the same time in some random direction

I found out what was causing my drift. I upgraded my phantom 2 compass to the new anti static compass took it out and did the compass calibration and everything worked flew great. took it inside hooked it up to the computer and it wouldn't let me do a basic calibration so I did advanced IMU calibration went out and it drifted all over the place. I checked the table and found it wasn't level so I got out a lever and got the table as level as I could calibrated the IMU again but it was to dark to fly and the last few day it was to windy to fly today it was good so I took it out but it still drifted so as I was hooking it up to the computer I notice it wasn't level I got the old landing gear out and they're about 1/2 inch shorter then the new one with the compass   


Put the old one back on re-calibrated everything and it fly like it did when I first got it.

awesome tony, thanks for sharing man!

I was looking for the anti-static compass on Amazon for the phantom 2 and it was $21.00 then I saw one for $19.00 so I bought it not seeing it was the one for the vision plus and it's about 1/2 inch taller then the stock gear and that was causing the drift so I took it off and put the old landing gear back on.
I was wondering if I get the landing gear for the vision plus and replace the other gear so they are both the same length will it work?

Cory and Jamie,

I wanted to thank you guys for all of your work on this issue. I must have missed your original post while I was studying and learning. My Phantom 2 Vision + v3 was working perfectly, have flown over 100 missions now, no real issues at all. Updated some apps while continuing to read thousands of posts. Came across one by Tahoe_Ed about doing the "advanced IMU calibration" and based on his apparent knowledge of the Phantom and his employment with DJI, decided to do it. I want to do everything as perfectly as I can. What a mistake I made! I'm kicking myself in the _ss for missing this thread before I hit that damned button! My Phantom is ridiculously off.

Thanks to all of the work the two of you have done, at least I've got a likely solution and a better understanding of the problem. I guess I'll be spending the day "shimming".

Again, thanks guys. Without guys like you, guys like me would be dead in the water.

Jerry

Okay Fella's here's what I did. A hybrid of what you guys have done. I was hoping I wouldn't have to open the shell again. I want to avoid removing the screws over and over again. Wasn't sure whether it would work without leveling the IMU itself but thought I'd give it a shot.

Found the most level surface I could find to put the Phantom on.
Got 4 plastic spacers from an old flat screen TV mount kit that fit perfectly over the motor studs
Took apart a picture frame that had a 10" x 13" pane of glass in it. (Standard size, I think)
Put the spacers over the studs
Laid the glass across the 4 spacers
Took a 2' straight level and leveled from front to back, side to side and then across all posts
I used standard business cards and started shimming
It took (looking from the rear at the battery: RR-5, RF-5, LR-1, LF-3 to get level in every position
Ran the advanced IMU calibration

Just got my first chance to fly (wind and temperature has been terrible here), hardly any wind this morning but cold. Hovered in place, no jumping around at all, did near perfect rotations, yawed correctly. Flew like a dream, better than when new. We'll see how it does with some more flight time but I'm extremely pleased at this point. May get a few more flights in today but the wind could get iffy.

Thanks again guys for all of your work! Would have never figured it out by myself.

Jerry

Pmcdn2014 Posted at 2015-1-7 12:03
When I had my vision I experienced yaw drift.  I agree, it's very annoying.  I reset the compass and ...

Your link seems dead.  Please verify.

I cal'ed my IMU after the 3.12 update. Flew it without cal'ing the compass and it flew fine. Yaw drift was about 3 feet. Cal'ed my compass today and flew it and the yaw is about a foot. Go figure. That is the best it been since it was new.

Jato,

Did you do the advanced IMU cal or the basic? Just curious, I'm still messing with mine.

Jerry

jtrjr@yahoo.com Posted at 2015-3-23 22:52
Okay Fella's here's what I did. A hybrid of what you guys have done. I was hoping I wouldn't have to ...

Good deal, glad you got it straightened out.  It's too bad that we feel the need to mess with things that already work well.  I guess it's a guy thing.  Lesson learned on that one eh?

Jamie Posted at 2015-3-24 07:08
Good deal, glad you got it straightened out.  It's too bad that we feel the need to mess with thin ...

Yes, lesson learned! (At least until I want to try something else...)

Thanks,

Jerry

jtrjr@yahoo.com Posted at 2015-3-24 03:12
Jato,

Did you do the advanced IMU cal or the basic? Just curious, I'm still messing with mine.

I did a full cal. But what I found tonight is it says pretty still if I yaw counter clockwize, but drifts about 3 feet when I go clockwise.

JATO Posted at 2015-3-24 09:46
I did a full cal. But what I found tonight is it says pretty still if I yaw counter clockwize, but  ...

Did you do the compass dance after the cal? I had the same issue but it resolved itself after the dance.

Jerry

Yeah but I going to cal it again tomorrow.

New to the forum and wanted to thank everyone for the thread. After reading the full thread I think a sheet of glass across the 4 motors and a bull’s-eye spirit level will do the job the best as it’s the motors that drive the Phantom and they are the most important thing to be level.

As for the IMU being level inside I don’t think this will mater as long as the motors are level. Even if the IMU is a mile off and you get motors level and calibrate the IMU.  It will set its self to the same level (ie 0 0 0 0) as the motors, all should be fine. I would think this is how DJi would do it so they don’t have to set the IMU perfectly level with the body.

Again thanks for the info.

Jamie Hellmich Posted at 2015-1-9 05:36
Okay Cory, here is what I have come up with.

I took the cover off the Phantom, and the IMU is way o ...

WOW.  You put in a lot of work on this.  I guess I am looking for a solution for us simpler folks.  My P2V+ horizon is not quit level.  It is off just enough to be annoying.  It yaw around, not on the center of the phantom but forward a bit closer to the front of the lens.

How do you suggest I get a level horizon, WITHOUT taking the camera apart (as most people suggest and give links to a youtube)?

Thanks

This post saved me. Thank you. I calibrated the IMU last night and didn't realize my desk wasn't completely flat. This morning's flight almost turned into a nightmare as I was flying in close quarters. Re-calibrated on a perfectly flat floor and I was back to spinning on a dime. Advice to other users, DON'T re-calibrate your IMU unless you really need to.

finlaywells@hot Posted at 2015-3-26 06:29
New to the forum and wanted to thank everyone for the thread. After reading the full thread I think  ...

I concur with using the motors to get it level.  I tried it both ways and got the same results so I would say the odds are pretty good that using the motors only method will most likely work fine.

I still wonder how it gets 'uncalibrated' to begin with since from the start I've always used my large heavy desk (which is level) to do updates and since it worked fine out of the box it seemed to get worse after a couple of months.  So the changes either happen because it is just a normal progression in the electronics of the IMU, possible hard landings or crashes causes changes, or the updates themselves are causing it to go out of calibration for some odd reasons.

I have heard that DJI engineers are constantly 'tweaking'  with the coding to help with stability, avoid flyaways, and changing flight characteristics like the update that lowered the maximum rate of descent in GPS mode to help out the idiots who try to descend quickly in place and get caught up in the vortex problem.  So it's possible some changes may affect the yaw calibration.

I see they've come up with a better compass now they should come up with a better GPS unit that receives both US and Russian satellites like my Note 4 phone that locks on to 12-15 satellites within a minute or two while the Phantom has trouble getting 6 in 5 minutes (trees around my property might slow that process down in the Phantom).  But it's all a matter of cost and keeping the retail price down low enough to sell and still make a profit.  I'd be willing to pay another $100 for a better GPS and compass when you consider that with a GoPro, Flytrex, and FPV equipment you're talking about a $2,500 investment.
EDITED TO ADD:  Almost forgot...A special thanks to all you guys who figured out the problem and different ways of correcting it.

Hi guys, great thread - read it start to finish as I am having similar issues to what everyone here has experienced - the only problem is I am still having them!

I've recalibrated on a perfectly flat surface and I'm still getting drift in all directions.

The only thing I have left to try is replacing my aftermarket landing gear with the original, but I don't see how that could help? Although, in typing that I have just realised how it could ...
Because I have higher landing gear my compass doesn't sit where it does on the stock landing gear - it's sitting at a slight angle ... could this be my problem.

It's late now, but I'll try that in the morning.

Hey Everyone;

I have a Phantom 2V+ Ver3 that I purchased in late December. I don't remember how it reacted when yawing when it was still "just out of the box" as I was learning, nervous, excited ... well, you get it.

Just after buying it, I did perform a firmware upgrade, poke at all the setting and perform an advanced IMU cali. The yaw-drift has been there ever since AND becuase I don't remember exactly how it acted out of the box, I can't confirm whether it was happening before the IMU calibration. My drift is to the rear, left) when yawing in position.

However, since finding this forum thread (after reading a LOT of other threads), I tried this over the weekend and it really helped. I think I need to fine tune it a little more but the wind was also a factor yesterday during my tests.

I want to send a HUGE thank you to Cory and Jamie for originally starting, investigating and apparently solving this issue! You guys really do deserve some serious good karma for your work!

With regards to the various methods mentioned here, I believe that there are only two methods that will work 100% and those are: 1) the trial-and-error method of shimming the struts OR 2) opening the top and placing a spirit level on the IMU.

It seems that the entire issue comes down the the "levelness" of the IMU when performing a calibration, isn't it?

If the IMU is mounted with 2-sided tape and it's level can vary from drone to drone, then there really is no correlation between the prop shafts and the level of the IMU, so leveling based on the prop shafts shouldn't do anything - right? Or, am I missing something here?

Anyway, I think that a spirit bubble level on the IMU would be the definitive way to take care of this but I really don't want to open the drone. I've got the yaw-drift to almost disappear with the trial-and-error method of shimming the struts and I'm so relieved. This IS my first rodeo with a higher-end drone.

Thanks again to everyone for sticking with this thread and working this through.

andydunlop@gmai Posted at 2015-4-3 05:11
Hi guys, great thread - read it start to finish as I am having similar issues to what everyone here  ...

Andy,

Sorry to hear that you're still having issues. Hey, looking at your photo, that appears to be a magnetic level. Just my two cents but I wouldn't be using anything magnetic during the advanced cal.

Jerry

OMG!!! I've been searching for months on a fix for my Tarot 680 pro. I recently rebuilt a broken phantom, and was having the same EXACT problem as my hex. So I started searching around and found this thread... now I'm wondering if my hex needs to be shimmied too to fix the yaw drift.

I haven't tried this for my phantom yet, but it sounds like it should work! Will check back in once i've done some testing!

jimdaway@gmail. Posted at 2015-4-6 21:40
Hey Everyone;

I have a Phantom 2V+ Ver3 that I purchased in late December. I don't remember how it  ...

Glad it was of help to you.  I did the process once, months ago, and all is still good.

If your bird flies well and spins/yaw turns in place with no drift, stay away from IMU calibration unless the Assistant software calls for a need to do so.

jimdaway@gmail. Posted at 2015-4-6 21:40
Hey Everyone;

I have a Phantom 2V+ Ver3 that I purchased in late December. I don't remember how it  ...

Jim, I'm with you on the IMU, but I think if it is on the same level as the prop shafts, using them as a leveling point should work out. My Phantom 2 seems to be doing good. I thought I had some drift (horizontal, no yaw) but checked it out the other day. Just let it hover for several minutes in one spot and it stayed withing a 2 foot area....it was pretty calm too.BTW...very good post. Kudos to all that contributed.

Jamie Posted at 2015-4-11 09:27
This thread is about drifting occurring during a hover when using yaw input to spin the aircraft in ...

Ok, sorry. I was referring more to the method used to correct it.

i have the same problem
http://forum.dji.com/forum.php?m ... mp;page=1#pid110446
i m going to try your solutions
let's hope

anyway recalibration imu = problems

i crashed just after an imu calibration and destroyed camera and gimbal... 650€
i think dji shoud fix this

cory@movecost.c Posted at 2015-1-8 10:24
OK so after calibrating the IMU with a stack of papers under the front definitely produced some resu ...

Mc cool down is an error. Just click on it and keep going.

cory@movecost.c Posted at 2015-1-9 00:13
Looks more like a rear drift to me. So I would shim up the front with 10 sheets of paper and redo th ...

Can you help me? Look at tath