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 certainly compiles once you have changed HAL_BOARD to HAL_BOARD_APM1.

However, I keep on getting problems with verification of the firmware after upload on my APM1.  I would really like to hear if you have the same problems.



There were two versions of the APM1.x. The APM1.0 basically had the Atmel 1280 except for some end of the line production that had the Atmel 2560 installed. The APM1.4 has the Atmel 2560 which has sufficient memory for the Arducopter code. The APM1.0 with the Atmel 1280 does not have enough memory for the present code. Which version do you have?


TCIII ArduRover2 Developer

Yes, if I enable oscillate the buzzer beeps but it does it all the time low battery event or not, it has always been plugged into the same output. Maybe this is wrong.

I want the beeping (on/off/on/off) only when there is a low battery event but at the moment after a low battery event it just emits a constant tone, sorry if I'm not making myself clear.

Hi Peter,

I had a look and it seems to me like you had a mechanical or electrical failure.  You'll see right around line 13210, that your Roll starts to diverge really badly from the Roll In.  I believe this is the start of the event, and is most likely caused by a Mech/Elec failure.  Your Pitch control also failed at the same time, but I didn't show that for simplicity.

After that point, you are correct that the Throttle Out drops down while you had the Throttle In raised, but that is actually being caused by the Angle Boost function pulling down the Throttle Output while the copter is actually upside-down (due to control failure).  

It looks like your copter did 2 flips in the air?

Yes I thought very unlikely a software p

@ Bernard & Gerrie,

I have a APM 1.4 and I'm able to upload the 3.1-rc5 code without any issues using Arduino...

But it's even more unlikely to be hardware.  ;)  Very strange.

I'm sure they'll keep looking into this, but it's a very hard to solve problem.  Do you have another board you could try?

No, that's clear now thanks.

So, which port do you have the beeper plugged into?  Should be AN5, IIRC.

Thanks for the clarification. 

This is really interesting. I think I may have a APM1.0 with an Amtel 2560.  I will check now when I get home.   I always thought I bought the 1.0 but I was suprised to see 2560 on the MCU.

What would the implications be?  Are there major differences between APM1.x and APM1.0 with Amtel 2560?


Yes I have several. One I'm getting ready to upgrade from 3.0.1 to rc5 on my octo. I just upgraded the quad that was having the surging problem and on the first 2 flights of rc5 it didn't show the problem. On the octo I run virtually the same equipment (just more spread out) and have never seen this problem. With the power of the octo I think it would be tricky to land if it did start doing that. Even on the quad it's tricky to land if it really starts surging frequently. I will upgrade the Octo today to rc5.

Strange thing is when it happens, I usually just fly around in stable for less than a minute watching it surge here and there and then it seems to go away and then I switch to alt-hold and never see the problem again. Sometimes I land and replug the battery. I just can't see any pattern to it which is why I sent the logs so maybe something shows up there to clue us in.

@Andre, Gerrie,

Thanks for your quick reply, I have an APM 1.4 board.  I' ll try it and I' ll let you know.


I like the arm/prop spin.  :-)

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