ArduCopter 3.0.1 has been released and is now available in the Mission Planner,, GitHub and the new Downloads Area.

Warning #1: Compass calibration and reducing interference is far more important than with 2.9.1b

Warning #2: GPS glitches can cause sudden and aggressive position changes while in loiter mode.  You may wish to reduce the Loiter PID P to 0.5 (from 1.0) to reduce aggressiveness (see image below of where this gain can be found in mission planner).

Warning #3: optical flow is not supported but will be back in the next release (AC-3.0.2 or AC-3.1.0).

Warning #4: loiter turns does not maintain altitude.  This bug will be fixed in AC-3.0.2.

Warning #5: This release has only been lightly tested on Traditional Helicopters.

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 (get it here)

2. Click on the MissionPlanner's Hardware, Install Firmware screen.  The version numbers should appear as "ArduCopter-3.0.1", 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. Although not directly related to this release, if you purchased an APM prior to March of 2013, update your PPM encoder to the latest firmware (instructions here).

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

Numerous How-To videos are available:

Special Thanks to MarcoDaveC and the large number of testers on the pre-release thread who put 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.

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I just wanted to give my own feedback on the new firmware 3.0.1.

I flashed my APM2.5 yesterday with 3.0.1 (just the Flash + radio calibration. The rest of the settings were still there (2.9.1).

I flew my quad (F450) + 5.8Ghz FPV

GPS lock (9sat)

ACC calibrated

compass calibrated (next to my notebook indoors) (like in the youtube video shown)



At first there were some strange hick ups. The copter suddenly twitched 30° left and right. I was in panic and landed. I switched it off and on.

This time the twitching was gone.

Today the same happened again. Just the first time I had lift off. After a reboot there was nothing twitching.


PH worked fine. After some flying time PH still worked fine, but switching to LOITER made the copter slowly land. I had to switch back to PH/Stabilize.

Same did happen in ALT hold just minutes later on the same + second lipo.


RTL worked fine yesterday. Copter went up and flew home.

Today the copter flew up and flew home, but very, very slowly (yes, there was some wind but I guess the copter keeps a certain speed not angle)


PH + Flying:

Usually I select PH and then fly around. This way whenever I panic I just stop steering and the copter holds Position.

Today the copter hold PH perfectly, but steering was nearly impossible. The copter moved so slowly even on full Nick. Switching to stabalize made a huge difference.

Are these bugs or did I forget to finetune settings?

Has anybody got a link to the the version 2.9.1b hex file? 

I've been clicking through almost every directory here but can't find it:

The stable directory contains only the latest stable.

Its a lot easier if you post the dataflash log when asking for advice. Otherwise, its almost impossible to answer.

#2 sounds like THR_MID - logs would confirm.

Hi, First and most importantly.  THANK YOU DEVS for all the great work.  I've seen a huge improvement in my Hexa-C's flight and stability since upgrading to 3.0.1.


I do however have an issue I would like someone to review and help me with.


1.  I do not think my sonar is working when I switch to ALT HOLD. I've attached logs for your review.  Am I right that it's not working?


2.  Where exactly do I go to see vibration issues with my motors?  How do I call up all 6 motors to monitor for vibrations.


3. Still trying to determine PID settings for LOITER.


Logs attached.  I'm open to suggestions. 



Hi John,

With 4s setup, 13.2volts battery failsafe is what I use. This means 3.3v per cell; perfectly fine to me...

I am not certainly sure if 4s set up would be better for you. I just made a suggestion so you check that option. But when you move to 4s from 3s, you must try a different prop (smaller one).

If you use the same prop on 4s as you use on 3s, and don't change the throttle output (needs to be lowered), you would probably be pulling more amp thus reduced flight time.

Finding the most efficient setup requires some trial & error...

I prefer to use higher voltage on my heavy platforms. I believe that higher voltage has some advantages over lower voltage setup.

To get vibration information you need to turn on IMU logs and go for a flight.

Hi Randy and crew-

Testing 3.0.1 now has been really great - random yaw gone, loiter spot on, sonar is perfect (mounted hanging off arm, away from prop, battery, and esc), RTL a thing of beauty.

Last night I fired up the LED strips and ran some midnight missions (full moon, clear skies - it is an absolute awe inspiring thing to watch this fly thru the stars - almost a religious experience for me!). The first mission was a simple back and forth thing-

It was perfect except for one thing - it flew the leg from 6 to 7 backwards, all others it yawed to face next wp. I got this result  It was the same with WP_YAW_BEHAVIOR set to 1 or 2, it only picked on this leg to fly backwards.

I then ran a longer mission and it flew backwards on 6 to 7 and on 9 to 10.   The missions all were flawless except for this repeatable goofiness.  Wassup??

Thanks again!



Hi Olivier,

Thank you for your time and help me to avoid a new crash in the future.

I attached a picture before crash of my octo with the gimbal, At the beginning when I build my copter always I have use the default PID values and lowered the rate P to 0.096 because I use low KV motors as show in the mission planner, and after checking the logs the ROLL IN vs ROLL was good and the copter was flying well so I don't modify anymore the PID values.

I have two questions:

What values must I change to avoid this again?

What do you think about the gimbal design? What must I change to avoid this vibrations? (maybe the mount plate is too soft)



Rick it sounds like you have some mis-conceptions about how the fence works.  It will only land if you either A) Tell it to or B) The APM cannot control the vehicle and is about to crash.

Randy has a great video explaining the fence here:

And the full instructions are here:

I was reading the GPS failsafe code. If you have GPS failsafe enabled, it would land if you were in a guided mode - that makes sense. Then it does this:

    // land if circular fence is enabled
if((fence.get_enabled_fences() & AC_FENCE_TYPE_CIRCLE) != 0) {

So I guess I could enable the fence and turn off the GPS failsafe...

That bug crashed my y6.....

in 3rc5

Quite often when I descend while in loiter, the copter will shoot off to the side. Everything is working otherwise very well. I'm not using compassmot compensation with this copter as it is light/low current and I am getting adequate performance without it.

I have attached a log, where towards the end of the flight I descended from 400ft while in loiter. I was giving slight forward pitch input as it was descending and about halfway down the copter started to move backwards and to the right, so I flipped out of loiter, and continued my descent in alt hold mode.


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