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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Dataflash logs are always enabled.


Dataflash logs (the logs onboard)can be enabled or disabled via the cli or by changing the parameter, I think it is called LOGBITMASK, if I remember correctly. depending on the value changes which logs are recorded, the value zero disabled all of them which takes a load off the processor.

this page will explain enabling and disabling them, some are not turned on by default.



It looks like they may have fixed this, at least it sounds like it could have been what was happening.  if you read the git-version.txt from here.

this seems like it could have been what was happening.  still I want to fly the stable version for a while and see if it happens.

And so thats exactly why logs are useful - because most people mean the 3.0.1 code when they say latest, or they're explicit about running the 'trunk' code. The dataflash log allows us to quickly see what version of code is running, check for the obvious errors - rather than having to pull teeth.

But then we get the patronising response - so I'll take that as my cue to bow out. Its no wonder there are few folks willing to help out.

I apologize if I came off as patronizing, I did not mean to be. as I said I did not have the dataflash logs enabled when this happened so I cannot post them. I have them enabled now, if it happens again I will post them.


Hi Elvin Yes those numbers are normal ..I take it this info was from a log when you were in gps mode or just hovering in one place?

Today i connect external mag under gps module, now compassmot is fixed to 6% !

For the hexa 550 i think the battery over the frame very near at the main board (some one ) cause magnetical interference , so i put the sensor more far possible

( i have see a video some time ago but i do not find the link now, it is about vislero battery)


So with your rig behaving in an unexpected manner you decided to deliberately fly it that close to your wife and child

Hi Reuben,

To be honest, I have not seen any difference after adding the code to enable the temp compensation. If I had the time I would do some testing with a hair dryer and super cold spray to try and see the effect of temp change with and without the compensation enabled. If you have done it before and are comfortable making changes to the code then by all means do so but I wouldn't go to the trouble if you have not done it before. I use a custom version of the code anyway so am already committed to re-adding my changes every time a new update comes out (not too big a job with the right comparison/merge tools such as 'Win Merge')

Hi James 

Thanks for the reply I guess its best to just connect it the same as the one 3dr sell ..and leave out temp code changes until there has been more RnD into its benifits or its included into the Later Firmware ....

Maybe Randy could chirp in here and advise whether this is being considered.

Regards Reuben

Surely if you own and fly a multi-copter, you can determine the thrust direction of a prop?!


Quick question: my Quad descends almost exactly at the set speeds. However, my Octo simply does not want to go down. It will go down, but as a snail on a threadmill going backwards. I've tried a variety of settings: Throttle Accel, Throttle Rate P & D. Do not know what it is. Alt-hold is just fine. 

I admit that I did not do the compass mot on this, nor did I look at vibrations. That is also the reason that I did not include a log file as I don't want to waste your time looking at it, however, a brief reply with some ideas would be appreciated.

Alex P.

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