ArduCopter 3.0 is ready for widespread use.  To make the transition easier, this time we are asking people to voluntarily upgrade from 2.9.1b for the next month or so before we make 3.0 the default firmware downloaded by the mission planner.  The new version can be found in the Mission Planner's Beta firmware's link,, GitHub and the new Downloads Area.

Warning #1: A bug was found in the FENCE in which if you lost GPS it could lean at extreme angles as it tried to maintain an invalid position.  This is fixed in AC3.0.1-rc1.

Warning #2: This release has not been fully tested on Traditional Helicopters

Warning #3: GPS glitches can cause sudden and aggressive position changes while in loiter mode.  You may wish to reduce the WPNAV_ACCEL to 100 and Loiter PID to 0.2 (from 1.0) to reduce aggressiveness.

Improvements over 2.9.1b include:

  • Inertial Navigation for Loiter and Auto meaning much more accurate control (Randy,Leonard,JonathanC)
  • 3D navigation controller follows straight lines in all dimensions between waypoints (Leonard,Randy)

         WPNAV_SPEED, WPNAV_SPEED_UP, WPNAV_SPEED_DN, WPNAV_ACCEL allows configuring speeds and acceleration during missions

  • "compassmot" to compensate for interference on compass from the pdb, motors, ESCs and battery.  (Randy,JonathanC) (Set-up video here)
  • Safety improvements:
    • simple Tin Can shaped Geo Fence
    • pre-arm checks to ensure all calibration has been performed before arming (can be disabled by setting ARMING_CHECK to zero).  (video description here)
    • GPS failsafe - switches to LAND if GPS is lost for 5 seconds
    • stability patch improvements to stop rapid climbs in very overpowered or overtuned copters
  • Circle mode improvements including "panorama" when CIRCLE_RADIUS set to zero (Randy,Leonard)
  • SONAR_GAIN parameter added to allow better tuning of sonar surface tracking
  • CH8 auxiliary switch (same features as CH7)
  • works on PX4 (some minor features still not available) (Tridge,PatH)

How to upgrade:

1. Make sure you are using Mission Planner 1.2.59 or newer.

2. Click on the MissionPlanner's Firmware screen and click the "Beta Firmwares" link on the bottom right.  The version numbers should update to "ArduCopter-3.0.1rc2", then click the appropriate frame icon and it should upgrade as per usual.

3. Reduce the Loiter and Alt Hold PIDs if you have modified them from the defaults.  The modified PID values for the 3dr frame can be seen in the image below.

Note: Nav parameters have been combined with Loiter so do not be concerned if you can't find them.

4. If you purchased an APM prior to March of 2013, update your PPM encoder to the latest firmware.

5. Try out the new version in stabilize mode first, then alt-hold, then loiter and finally RTL and Auto.

Special Thanks to MarcoDaveC and the rest of the beta testers for putting their copters at risk during the extended testing period.  Some of their videos can be found hereherehereherehere and here.  Thanks also to MichaelO for the MP changes required for this release.

All feedback welcome.  Please put your questions, comments (good and bad!) below.  

Added by Craig:

Please watch Randy's videos on setting up and flying APM-Copter 3.0 before you go flying.  They are excellent!

3DR Quad Set-Up Suggestions
AC 3.0 "Live" Compass Calibration
AC 3.0 CompassMot Setup      
AC 3.0 Pre-Arm Checks            
AC 3.0 Fence                               
AC 3.0 Maiden Flight Checks   

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Sure no problem.  Here are the ESCs Im using and they are running stock firmware...

NO, no need to do any more I think Randy and I have found and fixed the problem!!!!

Thanks Marco and Andre for supplying me with those logs. Basically we had a float being converted to an int in the PID library that was causing the problems. When this got differentiated it was producing a spike every time it stepped up or down. The simon K esc's are fast enough for that to show through as a small oscillation. This oscillation is then messing up the inertial navigation solution because it is effectively shaking the apm back and forth.

Test again when Randy releases 3.0!!!

Thanks again everybody who talked to me about this and helped with logs and ideas!!!!

Ok just to confirm do you still need my IMU logs and video or not anymore?

@Andre: are you still getting high compassmot values? I was using the same SS ESC's as you but have now changed to some SimonK flashed Turnigy 20A UBEC ( and my compassmot dropped from 150+% to 35%, I just changed the ESC's

After I moved my compass up by 5cm and changed my dome bolts to nylon ones my compassmot value went from 54% down to 8%.

My ESCs are located out on the arms towards the motors so I dont think they interfere that much with the compass.

Where are you ESCs placed?

Hi Indre, i've seen that a couple times during 3.0 testing. We have not enough reports to be sure, but we think that it is a gyro initializations problem perhaps because of a moving copter after battery connection.

It is very possible that the gyro offsets did adjust automatically during flight, there is a function to do that. This explain that it was ok when you did land.

Try to keep your copter stable after battery connection during about 10 seconds, if the problem never reproduce like this then we'll have one more report confirming a gyro init problem at power on because of moves.


Hi Darrell,

It really isn't worth worrying about this right now. Randy is hoping to release the next version very soon. That version will fix a known but that is messing up yaw.

So I would suggest that you wait until you load that code and see if you still have the same problem.

If you do then I would post another log here with MOTORS turned on.

No, I think we are all good.

If you can test the new version when it comes out and tell me if that fixes the problem that would be great! (especially if you tell me it does)

Perfect, works for me!  I'll be waiting in anticipation for it...

Are we looking at another RC or will the next release be the official one?

I think it will be the official one but that is up to Randy. He is working his but off now he is back from holiday to make sure everything is working as it should.

I have had this resetting of level happen twice with 2.9.1.  Both times during a flight.  One almost caused a fly away.  Would resetting gyro offsets actually cause this?  Aren't the accelerometers what the system uses to determine level?

I've seen several unexplained issues related to fly aways in these forums that sound related to this problem. 

Does 3.0 also reset any offsets in flight?  I'm sure there must be a good reason to do it, but on the surface it seems like a bad idea to reset any of the offsets in flight.  The auto-learn function in the mag is a great example of why this is not good...


Hi Leonard,

It sounds like you have figured out the SimonK issue by now.... having tested over 50 flights trying to tune SimonK's with the very responsive GemFan wood props (and 880kv motors) has been extremely challenging because of the wobbles. The best solution that I have come up with to date involves lowering Rate "I" for both pitch and roll to 51% of the "P" instead of the defualt 66%. My current settings with a stock 3dr quad frame, 880K motors, GemFan wood props (12X4) and 600MHZ SimonK's is:


P-  .15

I-   .076

D-  .005

With these settings I have rock solid loiter (with SimonK wobbles here and there) with the default "P" of 1.0.

Thanks for all of the very hard work!


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