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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It looks like you will need to set it to 690 to not get any altitude rise when switching from Stabilize to AltHold.

Let me know how you go.

Good luck!


i dont understand ... when i set it lower ie 580,600,650 and then as an extreme 500 it always rose..

should it not have descended if it was set to a lower value than 690?

Hi Thorsten, Nice copter!!!

The autotune picks gains that result the the fastest possible response without overshoot. Assuming you have got a good autotune, you should keep the Rate pids (you can increase the I term if you like it high), but you can reduce the Stab P term, just don't make it bigger.

You should get slightly improved endurance with lower Stab P but it is a trade off between performance and endurance. You may also find that endurance starts to suffer if you go too low and the control becomes sloppy. However, the Autotune Rate parameters will be the best values for endurance simply because they tend to be softer than our manual tunes anyway and you probably don't want to push any lower.

I just test it is very perfect.

It seems to me that you have to re-setup the battery monitor and batt failsafe after updating between these release codes.  A little odd but easy enough to do, try that out.

The mid throttle setting is the throttle output when you have your throttle at half throttle. In your case you want your half throttle (500) to be 690.

In the extreme case where you set Mid Throttle to 500 you will need to move your throttle to 69% to hover. Then when you switch to Alt Hold you will be asking for an increase in altitude.

If you set the Mid Throttle to 690 you will have a throttle setting of 50% and you should not get an increase in altitude.

This my log test it.


Hi Leonard,

flight time is usually between 33 and 35 min (37 min was the maximum in loiter, 33 min was 23 min auto mode followed by 10 min loiter). I made some changes and reduced some weight so I don't have exact numbers now. But I will make an endurance comparison between the old parameters and the autotune ones and report. 

Thanks again,



Thanks for the info! I'll give it a try.


Cool, I will be interested to hear the results!!!

Thanks Leonard!



You didn't mention how long this autotune will take? how much battery you need in order to perform this?

hope that helps.

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