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 totally understand what you are saying, it's just that with 5-10m accuracy, you could easily spend a lot of  time being RTL, but if you don't have enough space, it's better than hitting a hard object or getting stuck in a tree. And that really the point I am trying  to make, is that be careful when setting the fence as it might just end up triggering all the time.

Maybe I have just been looking at it as a safety feature. My concern is that GPS glitches and accuracy become a factor as soon as you get into a small radius.

As for notification, my Pocket GCS keeps me up to date on what's happening. It would be interesting to have a custom_mode message in MAVLink that indicates its a fence breach. It could even just be transitory mode ie. the HeartBeat message transmits a FenceBreach mode and then changes to RTL/Land mode afterwards i.e.. FenceBreach mode is essentially loiter for 3 to 5 seconds, then RTL?


I think I found the problem with my guided mode. My compass offsets are large. I tried to calibrate in different places and several times I can't make it within the -150 to 150 range. I always get like 201, lowest was 196

Trying to perform compassmot, per instructions I have connected USB and started MP. I click Terminal and hit return 3 times, type setup compassmot, nothing happens. I would not expect anything to happen as per instructions, I never clicked connect. What is supposed to happen here? I am powering the quads main power first, then connecting USB. I am using the 3DR power cable.


Well everything was the Baro sensor noise. When i used foam over it, quad flies as a humming bird.

RTL, loiter and auto are in a word perfect. I'm in doubt if i upgrade to 3.0.1 if i lose the perfect flying quad :-)

Thanks to all developers for that 3.+ version.

Got it figured out, the instructions I was following explicitly say not to connect, which is wrong. under Dynamic Compensation For EMF Induced Magnetometer Deflection, which says not to connect. Weird.

Don't follow those instructions. Use:

So many versions of instructions in so many places.


Hi Randy,
Could you take a look at the log file when you find the time?
I hope you will be able to determine the source of this issue or able of pointing me in the right direction.

Thank you

Logs are attached


Noticed something strange today with my hex copter. When the sun went behind a cloud the Hex climbed about 2m and when the sun came out it decended about 2m. This happened several times but otherwise was stable.

Oliver and I have been kicking this around too and certainly a telemetric notification could be good in any case.

But for those without, the 360 degree yaw is an interesting option, you could do that during the 5 seconds before the RTL.

Probably if you resumed control you would want the copter to complete the 360 degree yaw before it returned control to you.

In any case I think that should just be a user imposable parameter option and likely not the default one so a user would actually have to put it in on purpose.

And I definitely know about GPS drift, but with our new GPS this is already a reduced problem and with a little forthcoming tweaking, perhaps better still.

And since we are already relying on the RTL to return it to where we want and it is already subject to the same GPS drift it doesn't seem that the fence would compound this.

In any case, there are many places where a smaller fence can serve a variety of purposes even with appropriate cautions.


     It could be one of two things:

  • temperature change in the air caused the air pressure to change (although the baro is already temperature compensated)
  • more likely it's the light hitting the baro.  We've discovered this effect within the past two months (maybe a bit less).  If light hits the barometer at just the right angle it can cause a jump in altitude of up to 17m (in our tests).  Normally it's a much smaller effect than that but it's still there.  The solution is to put some black electrical tape on the APM2.x case around where you see the pink foam peeking through the case.

Hi Randy ..

I,m looking for some info on this...

 I have noticed that the leds;s are very close to the baro unit this could be affecting readings too ? One thing i have noticed after doing the same test on all three of my APM2.5 and and APM2   that just sitting on the bench ..the altitude rises within 2 mins to over 3.0 m .. seems temperature plays a big part when i first started the test ..temp was reported at 20 Celsius and altitude was 0.15cm then as temp rose ( i guess the unit warms up a bit when powered up perhaps heat from the leds)? the altitude got higher and higher ..So we take off from home then when we want to land later the copter does not know the correct height land??? what are your guys thoughts on this (board / componet temp and altitude rise issue)..cheer R

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