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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     So you've correctly guessed that the major issue is compass interference.  When you run compassmot it should print the interference as a percentage of the earth's mag field right at the end but in any case, I've used excel to graph the mag field vs throttle and it looks like it's at least 200%. This is very likely what's causing the copter to immediately fly in the wrong direction aggressively when loiter is engaged.

     You can see in the graph below that the mag field is moving from 300 at the start (a normal value) to zero and then up to nearly 500.  I think the interference is too high for the compassmot to be able to correct for it so it would be best to move the APM away from sources of interference and then re-do both the live and compassmot calibration.

Re the "dive" when you enter loiter.  I think what's happened is just that the copter was moving up very rapidly when Loiter was engaged (see red altitude line above).  The target altitude is in green and you can see that the copter continues up past the target, then falls back down to the target.  This drop is what you're seeing.  If you enter Loiter a little more gently you shouldn't see this.

Couldn't hurt I guess.

The thing that doesn't make sense is that I know that people can successfully use the 3dr radio when flying missions which is very CPU intensive.  It doesn't make sense that it would only not work for you.  It also can't be quad vs hexacopter related because as Craig says earlier in the thread, they cpu requirements are almost identical.  The few extra multiplies to calculate the extra two motor outputs is a drop in the bucket.

Of course you know that you can't use telemetry and have your copter connected to your computer with the usb port at the same time right?  the telemetry won't work in that configuration but that should be the case whether you are armed or disarmed.

You've tried pushing the "Enable Telemetry" button on the Initial Setup > Optional Hardware > OSD screen?

I'm at a loss as to what the issue is.


No, I have never used super simple mode.  I can actually see when it happens, the copter kind of twitches, then forward/reverse becomes right/right/left.



Does this happen 10m away from the takeoff point? The dataflash log would have allowed me to check for that easily...

We added the ground plane for the GPS since we were having frequent GPS glitches.  It added about 10dB gain and greatly reduced our GPS glitch occurrences, but not completely.

How are you measuring a 10 db gain value?  

Hello Randy,

Iv'e been flying my quad for a month now with no problems, running several missions and RTLs with no problems, until this morning. just bought a new batt and wondering how much flight time I would get. after retuning with the new heavier batt. I flew it outside test the copters flying attitude, love it still solid, then switch to loiter. it was solid and steady. after about 5 mins of hovering in loiter it suddenly went down, and tumbled upside down on the grass. good thing nothing is damaged.

attached is my log, and if you have the chance, can find out what happened. thank you very much.



There has been a lot of talk about the compass lately. Here are some of my findings and test results with 2.9 and 3.0 firmware.

Please look at this post and give the community some input.


It would be much easier to analyize if you would post a dataflash log.

Please have a look here:

and here

The instructions are excellent.  It sounds like a mechanical or electrical failure. See if you can do the analysis your self because it would be great if we could get more people analyzing logs and helping other users.


Hi James .. 

I have purchased the external HMC5983 Module .. I was wanting to know How you were getting on with your one .. is it worth me learning how to add the changes to the code to use the later mag? ..I guess when the new firmware comes out ..I would have to alter the code in that version too ..(unless they include the 5983 code in the next update)..there is more connections on the later board ..which one goes where ? 

thanks reuben

When I did the compassmot thing it said 26%?

Ill try the high alt loiter again after I level out and see what happens.  Loiter is pretty solid near the ground.  Wanders a little bit from time to time but not bad. 

How do I make the RTL move faster?  Its really slow when kicked into RTL mode. (I could walk faster)

Can anyone tell me, if when connected to mission planner by usb and with 8 sat count and hdop of 1.3 should the icon of the quad in MP be stationary as if it were loitering. My icon wanders around by 30m odd and my loiter is rubbish also. Ive done all correct setup and seem to have all figures within ranges. Ive got an APM 2 with 3.0.1 and Mediatek with latest firmware on it also.

Not tried any loiter tuning yet, dont really want to try several flights to no avail due to bad GPS or something. It is doing a severe high speed toilet bowl maneuver around 30m diameter.

Any help would be much appreciated


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