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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Throttle failsafe is what happens when you lose the receiver signal.

Low Battery failsafe is for the loss of power


I mean Throttle Failsafe when the receiver loses power only or lose signal receiver in issue for 3.1-rc2?

I'm sorry I don't understand what you are asking.

If the receiver looses the signal the PPM encoder will drop the Throttle channel to the Throttle Failsafe value indicating that the signal has been lost. 

The APM will respond by executing a Throtttle Failsafe sequence of either returning to the launch point or continuing with a mission.

Thanks Randy!

But, when upgrade to 3.1rc2 do we need entire procedure to do, as on 3.01? Or just to preflash?

thanks Randy for your immediate reply. let me check that again.



     Only when the radio loses power.  If it loses signal then the receiver itself will correctly pull down the throttle channel but when the receiver loses power then it's up to the ppm encoder to pull the throttle channel lower.  At the moment the ppm encoder always thinks that channel 3 is throttle so it'll pull that channel low.  If you've however remapped channel 3 so that it's roll, pitch or yaw in AC then when the receiver loses power instead of entering failsafe it will start spinning, rolling or pitching!


    You should just be able to upload the firmware.  I don't believe there will be any need to re-do all the setup.


    Yes, you're right.  The PID output isn't implemented for everything you can tune using ch6.  I was aware of that but so few people use the PID output that I think you're the first person to notice!  Feel free to stick an issue in the issues list.  I'm not sure if few people use it because it's not really useful or because they just don't know about it.  If it's not useful then I'd prefer to remove that feature 'cuz unnecessary features just lead to confusion and code bloat.

Has anyone use the gimbal function for brushless gimabls? How is this done?


is acro mode changes are in 3.1rc2 ? 

Randy, thank you for the rappid answer.

Because I'm surching since 6 month, during 4 hours test flights the reason for great variations (3m) in AltHold

I used this PID's in the log.

Below you can see how it is possible to find strange influences.

In the first diagram the red Line is BarAlt the blue Line Rate Roll/Pitch P.

With P=0.1 the Altitude starts oscillating shortly after increasing.

In the second Diagramm we can see why. Red is Rate Roll/Pitch P, reen Value P and Blue the Value I, which starts to oscillate.

The result of this analizes was to reduce Rate Roll/Pitch I and not P.

This result was only possible with knowing the exact Point of increasing The Gain.


So my quad has been flying great for probably 20+ flight now.  Flew it once yesterday and it flew great.  landed to put a fresh battery in.  Took back off and it was wobbling back and forth like the PID's weren't set up.  Any ideas?  didn't change anything but a fresh pack (same kind and size)  Hooked it up to the computer and all the settings are the same. 

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