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I believe it is prudent to perform an IMU Calibration after performing a firmware update.  This issue has been discussed on Inspire 1 and the Phantom 2 forums. I know Tahoe Ed (a DJI representative) personnally agrees and has stated in these forums that this is his standard practice as well.  You can search for his posts. Questions for Tahoe Ed and DJI Autumn - What is DJI's official position on the need for IMU Calibration after a firmware update?  If it is prudent to perform an IMU calibration after a firmware update, why is the IMU Calibration procedure not included in the Phantom 3 Professional (or Advanced) User Manual or in the firmware update instructions?  The "Check IMU" and "IMU Calibration" options in the DJI Pilot app settings Menu are not even listed or described in the P3 User Manual.  Why? Here is my procedure for performing an IMU Calibration (this is a repeat of info I have provided in responses to other forum posts) To perform an IMU calibration, the P3 and the remote controller (RC) must be turned on with the DJI Pilot app running on the Apple IOS device, which is connected with a Lightning cable to the RC's USB port.  (An Android device and appropriate USB cable can also be used - but I only have experience with Apple IOS devices.) From the DJI Pilot app main menu screen, select Camera.  There are several ways to get to the correct settings menu - the fastest is to select the "Mode" button in the upper left (to right of home symbol).  This will bring up the "MC Settings" screen. Use your finger to scroll to the bottom of the MC Settings screen to reveal the "Sensors" menu item.  Select "Sensors" menu item.  Scroll to the bottom of the Sensors menu screen to reveal "Check IMU" and "IMU Calibration" choices. Caution: Before starting an IMU Calibration, the P3 should be "cold" (i.e., not recently flown) and must be sitting on a firm, level surface with no vibrations, other electronics, magnets (e.g., stereo speakers) or metal nearby (this includes rebar in your concrete driveway).  I use a perfectly level ceramic floor tile in my family room. Also, you must not touch, bump or move the P3 during the IMU calibration and you should minimize/avoid any floor vibrations (people walking nearby, doors slamming, spouse vacuuming in next room, etc.). Start the IMU Calibration, click through the message and warning screens.  The IMU Calibration takes 3-10 minutes - there is a status bar that will eventually go to 100% - it may take a minute or two before it changes from 0%.  Ensure you get an IMU Calibration complete message. I also recommend doing a Gimbal Auto Calibration immediately after the IMU Calibration is finished with the P3 still sitting on the same level surface.  This should correct any tilted horizons you may be seeing in your videos.

2015-5-13 00:16

you need a level surface.  I use my iphone level and put it on the floor (hardwoods) til I find a spot that is zero level.  Then put my phantom there and proceed to calibrate.  A little tip for you guys.

Thanks for the great instructions.

Now that I have done an IMU Calibration I get a IMU Warming Up message when I power up my P3A. I didn't get this before. Anything I can do to make it go away?

josepsamora@gma Posted at 2015-5-15 11:50
Thanks for the great instructions.

Now that I have done an IMU Calibration I get a IMU Warming Up  ...

l thought this was normal, mine does it every time l switch it on

CapitAn Posted at 2015-5-15 11:56
l thought this was normal, mine does it every time l switch it on

How long does it usually last for you?

l would say about a minute, which is a long time when you have a battery that is good for 20.

Worked for  me First flight...

I thought it only had to be away metal etc when doing the compass calibration. Does the same apply for the IMU also? I have a level 1/4 aluminum plate I was going to use.

Upgraded the firmware and re calibrated Imu.  It now takes 5-10mins to warm up.  I tried to recalibrate early in the morning when it was cooler but the calibration button is greyed out and won't initiate.  Any clues?

Neville Posted at 2015-6-2 07:58
Upgraded the firmware and re calibrated Imu.  It now takes 5-10mins to warm up.  I tried to recalibr ...

Try performing another IMU calibration immediately after powering up the P3.  Some others have suggested putting the P3 in front of an A/C unit or in the refrigerator to get it extra cold before starting IMU calibration.  I typically see the "IMU warming up" message for 30-60 seconds after first power on.  

Just chill your phantom on an air conditioning vent before IMU cal and there will be no warming up time.

1) Do the props need to be on for the IMU calibration?
2) I have recently updated to the latest firmware, and I am also having a slight tilted horizon problem. I've tried the gimbal calibration, but still have the tilted horizon problem. So, it sounds like I need to do the IMU calibration, but I'm afraid to do that fearing I might start getting the IMU warm up message at startup that I'm not getting now. Should I still do it?

playab0yyy Posted at 2015-6-7 03:37
1) Do the props need to be on for the IMU calibration?
2) I have recently updated to the latest firm ...

Want to calibrate your IMU cold... some even put it in the refrigerator to make sure it's cold... I don't think you need the props on but you will want a level place to set the craft when you calibrate. Power up the RC and App then the craft... As soon as you can calibrate the IMU... Took me about 25 mins or so. Then calibrate the gimble. I had to do the gimble twice. All works now . From what I have read you will want to calibrate your IMU and gimble after every firmware update.

Spankybear Posted at 2015-6-7 06:32
Want to calibrate your IMU cold... some even put it in the refrigerator to make sure it's cold... I ...

Thanks. I just did it (with props off). My P3 was room temp. (probably around 72 degrees). It only took maybe 3-5 minutes. It was quick. I wonder why some are taking longer than others to complete the IMU calibration. Also, I notice now when I start the P3, it says "Warming up" for about 25 seconds before it's ready to fly. Didn't do that before.

Mine hadn't flown as it was brand new... Maybe this has something to do with the time... Don't know. I just know it worked

I installed the new firmware and had difficulties with the IMU calibration.  Waited till after dark and left the P3 on the rear deck for an hour to cool off.  then turned it on, completed the Imu calibration and now I have no moe problems.  Went flying yesterday and by the time I completed the compas calibration, walked back to check the gps map position the Imu was ready to go.  Had the green ready to fly and off I went.  Much better now.  Does anyone know the reasoning behind this and if calibrating in a cooler position will affect navigation.

laddy@grandecom Posted at 2015-5-25 11:00
I thought it only had to be away metal etc when doing the compass calibration. Does the same apply f ...

Aluminum will not bother it in my experience.  

ntfa@sbcglobal. Posted at 2015-5-13 01:34
you need a level surface.  I use my iphone level and put it on the floor (hardwoods) til I find a sp ...

iPhone level?  

Is this an app?

msjh Posted at 2015-6-11 12:30
iPhone level?  

Is this an app?

Is a function of the iPhone  compass app.

Gustave Posted at 2015-6-11 15:54
Is a function of the iPhone  compass app.

Thank you!  Very helpful.

Using a table in the lounge and that level marker and a couple of handkerchiefs have got the table level.  Now to calibrate.

josepsamora@gma Posted at 2015-5-15 11:50
Thanks for the great instructions.

Now that I have done an IMU Calibration I get a IMU Warming Up  ...

its normal you should wait to finish

It seems most everyone that has done a IMU recalibration now suffers with the "IMU warming up" delay!  Never had that problem till I also did it. I redid it when cold, it cut the time down somewhat now, but I still have to wait about 1-2 min!

Ladies and Gentlemen, Bisexuals, Transvestites, Gay or otherwise,  Your making a big deal out of IMU Calibration and it is very simple if you follow the procedure as outlined in the beginning of this discussion.  As long as you get the 100% at the end of the calibration, your good to go, so quit worrying about keeping it cool or being stupid with the cold thing everyone is posting. It is the outcome your after.  If you do the calibration without having flown the P3P or P3A then your good to go, which simply means, do the calibrations before you go flying, so quit worrying.  Just do the calibration before you go to fly.  It is that simple, so quit making a Mountain out of a Mole Hill for those that understand the term.  Guess I am showing my age of 62.

combatvet71@gma Posted at 2015-6-29 08:28
Ladies and Gentlemen, Bisexuals, Transvestites, Gay or otherwise,  Your making a big deal out of IMU ...

Understand the good intentions of your post, however chilling the P3 prior to performing an IMU isn't overkill and neither is ensuring you have it on a level surface.  

With the current 1.2.6 firmware release for the P3 Pro, if you perform an IMU calibration with the P3 electronics already warm (from a previous flight) or even when the P3 is at an ambient temperature of 70-80 F, you can successfully complete the IMU calibration. However, every time thereafter that you start the P3 up for the first flight of the day, you may experience delays of 2-5 minutes with the message "IMU is Warming Up" displayed on the top line of the DJ Pilot App.  This 2-5 minute IMU Warming Up delay can be eliminated, in most cases, by reducing the P3 electronics temperature 20 degrees or more below ambient temperature and then performing an immediate IMU calibration.  

Yeah you definitely want to perform the IMU when it is cold, and the instant you turn it on, not after a recent flight.  Otherwise 2 mins of "warming up" can get a little frustrating each time you power up.

This is a good tutorial and explanation:

looks like IMU cal should be done ONLY when the ESC is complaining about it...

Why needs to do it after the firmware upgrade.  DONT think the IMU cal file data is overwritten during the porcess.

Firmware usually BIN files that upgrades the system except the existing DATA file...

Does the P3 complained re IMU after the upgrade ?  I dont see any steps that needs to recal the IMU afrterwards..

I think many people able to fly their p3 flawlessly after the upgrade w/o IMU recal..

and MOST of the P3 after upgrade has issues coz of IMU recal they did after upgrade... then they BLAME the firmware...

I just hope the DJI can backup/restore IMU cal or other settings thru the Pilot app.

Just to add to the debate. I now have over 80 flights , over 10 hours flight time. I am running p3p with 1.1.9 I have never calibrated either the compass or the imu. Start up flags error messages for under a minute, camera drops and points down fo about 30 seconds. After a minute all comes up safe and ready to go. I do not fly often in built up areas well, maybe three times, or over water, except once to get a shot From 500 ft of a 1 mile suspension bridge.. All locations within 60 miles of home. Why calibrate?
RayH

rhutty@gmail.co Posted at 2015-6-29 14:16
Just to add to the debate. I now have over 80 flights , over 10 hours flight time. I am running p3p  ...

Likewise, I have only ever calibrated the compass and then only when needed,  Ihave never touched anything else.  all firmware updates done,  and dozens upon dozens of long and high flights without any issues before during or after flights with very fast startup times.  

What  EVERYONE on this thread needs to learn is stop fixing things that are not broken.

57 flights, never touched the IMU or gimbal--only the compass for first flight and one or two other times when app said I needed to.  I also check the values before flying.

I calibrated the compass prior to my first flight in Brisbane, Eastern coast of Australia.  Have 70+ flights, 10 hrs and over 100kms and all ok.  I even flew in Broome which is in Western Australia, Western coast of Australia.  Think it is about 3000 kms west of Brisbane.  Same for IMU (had to recalibrate when cool) and gimbal.  

I agree, if it's not broken don't fix it.

Best to check your launch site with a small magnetic compass prior to take off to ensure you don't have interference (from magnetic rock, steel etc).  This may be the cause of many 'fly always'. Wave the compass close to the ground and make sure it points consistently north.  Bad sites may cause a deflection from north.  If this happens change sites, ie move 10 meters or so and check again.
Nifty

I calibrate on a billiards table. Works perfect.

josepsamora@gma Posted at 2015-5-14 22:50
Thanks for the great instructions.

Now that I have done an IMU Calibration I get a IMU Warming Up  ...

That would indicate that it wasn't COLD.  Do it when it is cold and the warmup will be only seconds.

laddy@grandecom Posted at 2015-5-24 22:00
I thought it only had to be away metal etc when doing the compass calibration. Does the same apply f ...

This is correct.  Compass calibration deals with magnetics, etc.  IMU deals with inertial movements and holding level.  After doing the IMU, do a gimbal calibration while you have it on a level surface.  I don't mean flat, I mean LEVEL!  Not the same.

I have the 1.4.010 fw in my p3p. Yesterday, for the first time I had a IMU warning at the power on. It disappeared only after an IMU check. For the next 5 times I flew, I had ever the same warning. Normally the message disapperas after one or two mins... This noon I decided for a re calibration. I put the quad in the freezer (+3c°) for 45 mins and I did the job according the outline at the beginning of this thread. Everything worked fine and now the quad starts up very fast, without errors.

Thank you all

If you look at the IMU stats, and it shows the correct accel numbers when flat, when 90 degrees, etc, is it necessary to re-calibrate?

Alternatively, a quick and dirty check for whether calibration should be done is to put it on a level surface and inspect those numbers.. if they are right, I don't see the need?

ntfa@sbcglobal. Posted at 2015-5-13 03:34
you need a level surface.  I use my iphone level and put it on the floor (hardwoods) til I find a sp ...

Just a hint.  My Son is a professional builder so frowned on me when he saw me using my phone as a level. His suggestion is for those without a professional level is to do this.  Some good phone apps allow the level to be calibrated,  so go down to your local hardware store, a good one builders use and use the best and most expensive level you can find and set it on a level surface,  then calibrate the phone on that same surface. Walk around and test various surfaces until you see the phone giving results as close to the pro level as you can.   I tried this myself at home using his professional level worth a heck of lot of money and found the results to be quite good.

lastorri Posted at 2015-10-14 01:49
I have the 1.4.010 fw in my p3p. Yesterday, for the first time I had a IMU warning at the power on.  ...

Your Freezer is at +3C?
You could probably drink your ice-cream with a straw!
;)

Yeah, 0*C is freezing. It was a balmy +3*C here in the Capital, today!

Ah, so I went for a SpYder rYde. ;-)

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