Copter-3.3 beta testing

Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.

Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.

Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).

Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station.  Video description is here.  The bug is fixed in Copter-3.3.1 so we recommend upgrading.

Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting.  HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features

Copter-3.3.1 is available through the mission planner.  The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.

Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.

Changes from 3.3:

1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff

2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)

Changes from 3.3-rc11:

1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent

Changes from 3.3-rc10:

1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF

Changes from 3.3-rc9
1) EKF improvements:
    a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
    a) fix INS3_USE parameter eeprom location
    b) fix SToRM32 serial protocol driver to work with recent versions
    c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
    d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
    a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
    b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
    c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
    d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
    e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)

Thanks for your testing!

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


                  • Developer

                    Hi Andre,

                    That second log looks like a bad tune.

                    Could you send me an autotune log with the AGGR set to 0.05 (you currently have it very high)

                    Also, I would suggest that you set RC_Feel to 25.

                    I am sorry but I can't even begin to guess how the taranis might be making a difference. However, I can see you have a bad tune.

              • Thanks Leonardt, I´ll follow your hint after the Rain stops:-)

                But how it could be possible the the Copter flies well with the Futaba/Jeti Transmitter and with the Taranis I've the strange behavior?

  • Rate Loiter and Throttle Rate settings disabled on my MP screen with rc7

    By the way, what is the "FF" settings on Rate( Roll Pitch Yaw) ?


    • Developer


      Ah yes, thanks for the reminder.  It's because we renamed those parameters between AC3.2.1 and AC3.3.  I'll ask MichaelO (and other GCSs to update the names on their side).  thanks!

      • You are welcome Randy.

        What is the meaning of "FF" Settings? Force Feedback? :)

        • Developer


          That's "feed-forward".  It's probably better explained on wikipedia but it's used to reduce the reaction time in the control loops.

  • Hi Guys,

    Can anyone help me out?  I still have three different Pixhawks (Original 3DR) with various setups that all error on arming.  Any advice would be MUCH appreciated!!!

    I have recalibrated, loaded new firmware, erased the board, checked GPS (Reconfigured with uCenter), set all params to default etc., disconnected all external equipment, loaded custom code so I can check what is causing the fault but I get stuck at bad position estimate.

    So far I have noticed that all of my boards report the following (which seems to be different from the working systems out there):

    EKF1> PN, PE both = 0

    EKF2>Ratio = 50 (Not moving)

    EKF2>MX, MY,MZ all = 0

    I am guessing that this is what is leading to some of the innovations in EKF3 also being 0 (IVN, INE, IVD).

    All of the RAW IMU, MAG data seems OK to me.  Even the FFT graphs in MP seem to show no problems but I am not sure what the sample rates should be, so I am guessing.

    GPS is LEA-6H 3DR model.

    I have been tyring to figure this out on my own but would really appreciate some guidance.  Attached is a log using the latest build and Quad sitting on the ground, not moving but refusing to arm without reporting EKF Error and going into failsafe.

    On 3.2.1 all of my machines are fine.  I realise that this is Beta firmware but I thought it might be helpful to see some info from a non working system.  I am pretty sure that there are no hardware related issues but either I have stuffed up some settings on three different configurations or there is a problem with 3.3 and my gear that is different to everyone else's.

    I realise this build is very beta and I am not complaining, just trying to offer some more data to the Dev's and also trying to learn how to fix this issue at the same time!

    2015-07-03 11-23-59 EKF Error Lockout.bin

    • Developer


      From a look at the GPS messages the number of satellites is quite low - it peaks at 9 but spends a significant amount of time at 6.  I guess this is the cause of the bad position message.

      • Thanks for the reply.  Much appreciated as is all of the work you guys do.

        I will try again with more sats and let you know.

        Is it normal to get the EKF Failsafe with low Sat count/High PDOP? I seem to get this on all my machines and once triggered the EFK error will not go away even with 10-12 satellites before arming.

  • Hello,

    I noticed my minimosd quit displaying data once I upgraded to 3.3 on my tricopter.  I'm running version R800 minimosd extra.  I'm assuming there is some incompatibility now.  Which version of software should I be using with the minimosd to work with 3.3 software on my pixhawk.

    Thank you

This reply was deleted.


Hiroki Tanaka liked Hiroki Tanaka's profile
Oct 13
Derrick Davies liked lisa TDrones's profile
Sep 23