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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Hi TheMightyThor. The graph image Christian is comparing cannot be compared since they are in different scales. The one on top has higher zoom and resolution than the one bellow. I don't know if a rescale to same resolution wouldn't show iddentical results.

ok thank you very much!!

Rui is right, I will create an image with correct scaling when I'm at home.

Thor, In my opinion THR_Mid is not affecting the Alt_hold controller and is used only for stabilise. It does only influence Alt_hold when your stick position is outside the 40-60% deadband, due to a wrong THR_Mid setting. So if you fly stabilise with 60%(61%) stick, the Althold controller will interpret that as climb request. You fly with 45% stick, so that should not be the issue.

But as I mentioned before your THR_Accel PIDs are to high. P default is 0.75 and I default is 1.5. In past Randy gave us advice to lower these values if copter is climbing. Please try that. Also Rate R/P "I" back to 0.1. If your copter is underpowered then only increase "P" (as you did already)

Regards Christian

thanks Christian, i dont remember it being that way in 3.0.1. infact this same aircraft, in a slightly different form, use to hold altitude very well before RC7. i will go thru the settings today, adjust where you mention and take it out flying to see the results. thanks for all your help, it is appreciated

I didn't test that but in some cases you can get a division by zero error in calculation. So if you still want to try that than use numbers closer to 0 such as 0.01 or 0.1.

Regards Christian

Hi Christian. Well, today I tryed it with a value of 3, because if I leave it with 1 or 2 it still gets accumulating error. It's weird tough, in previous versions where mixing did not exist, baro seemed to take care of business relativelly well. With mixing I get some type of hicups when trying to maintain altitude, and if I leave it to 0, then error starts to build and the longer I fly, the greater the error gets, wich causes my bird to jump to the sky after about 4min, if I switch in to alt hold. With a value of 3 I get the hicups but alt keeps within 1mt .

Hi again,

now new comparison:


so now we have nearly same range of ~1.9 units.

baro is similar.

Rui and Thor,

Did you try decreasing THR_ACCEL_P to 0.75 and THR_ACCEL_I to 1.5 or lower?

I lowered already to 0.65 and 1.3.

I'll try it. I can only fly during lunch time during the week :] (wich is a shame since you're having no wind / blue sky weather)



If  you want to compare the baro altitude and the GPS altitude yiu have to compare CTUN-BarAlt and GPS-RelAlt


I know. Unfortunately Thors Log doesn't provide GPS data, maybe log wasn't enabled, so there was no other chance. We don't want to compare gps with baro. I'd like to show the difference between my and Thor's baro. As you can see the value is jumping up and down in a higher frequency than my baro does.

Like noise on osciloscope.

I tried the changes you suggested and it didnt work out very well so i reloaded my saved parameters and will try it again tomorrow. i wish i knew the correlation between ALT HOLD hover speed and stabilize hover mode. i've had it do alt hold a number of times in 3.0.1 to my liking but not in RC7. My XAircraft fly great today on just default numbers in 3.0.1. i am beginning to wonder if these walkera parts just cant handle the APM Board. it so erratic

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