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!

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  • Randy,
    Is a repeatable 'error compass variance' condition pose any issue for a ekf system? May it produce any side effects like non smooth mvement at loiter or circle or will system revert to a stable compass and ignore one with a variance?
    • Developer


      I think it could lead to the EKF not using the compass so it could be serious.  I've heard from Rob as well that he often sees this on his TradHeli but it's not clear if his frame is the issue or if the EKF is being too strict about the compass quality.  I suspect it's the latter.  If you've got a dataflash log I think we should ask PaulR to have a look and we may need to adjust the EKF's strictness.

      • 3702711037?profile=originalone more question on same topic that I had for quite some time.

        if we have an internal and an external (in the GPS unit) compasses, which one is which in the parameters?

        I just applied copper foil to the bottom of the AUAV case and same copper foil on top of X8R unit that is right under the FC case and ran compass recalibration, in the same spot where I did it before.

        Compass offsets always change a ton after each calibration and it always somewhat puzzled me, how can it be so?

        look at prior and post results. Obviously an external compass should not have been affected, as nothing was changed on the drone or wires around it. Yet both compasses show new offsets, with first compass showing major change and second just a bit of it.

        So, is it a COMPASS_OFS2_% set of parameters that applies to the GPS based compass?

        BTW, even after this foil around FC and X8R it still pops up same compass variance error when I move drone around by hand.

        as I fly it a lot in the simple mode I can say it is reliable and does not ever confuse its rotation/location, so compass data quality should be quite adequate but I am not sure which data set it uses.

      • also, if it helps anything - here is a parameters file.

      • HI,

        here is the shortest log with this issue, it occurs 3/4 into the circle mode flight, I definitely saw it on the MP screen.

        Not sure where in the log itself this message can be seen but it has happened, and this flight was done right after I recalibrated compasses.

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      • I see this on both my vehicles as i have 2 compasses on both. I did motor compass interference calibration but not sure if it helped anything.

        I will try to post a log tomorrow. I saw this message today repeatedly after getting new compass calibration done, during circle mode at specific position only MP would flash this message. So i have suspected exactly same issue you just spoke about.

        Also, is there a list or xls of all messages with their codes? My taranis has voice files, i think, for messages with code id up to 122 or so, and i noticed some messages are not in the list now, like geofence, ekf, and this compass variance.
  • Just tested 3.3rc7. My problem is that as soon as I arm the copter I got "EKF variance" on apmplanner and I cannot use any GPS mode. Everything working fine under 3.2.1

    • Developer


      Thanks for giving it a try.  Could you set the LOG_BITMASK so that it's logged while disarmed and then attach a dataflash log?

      • Randy,

        here is 2 dataflash log one and two.

        I did not gave enough throtle to take off so the copter stayed on the ground the all time. I switched to alt hold then loiter that triggered an error then back to alt hold stabilize and disarmed.

        Let me know if you need anything else



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    • I just flashed one of my multi rotors with 3.3r7 and I have no bad behaviors..  I previously had instability in the Z axis, In stable mode, I have to work the stick to maintain altitude, and in alt hold, it was either rising or descending until i overrode with the stick.

      Now with r7  it seems solid both in stab, and in alt hold.  I am not getting pre-arm messages or any kind of EKF or variance warnings either.

      I don't get good gps lock in my back yard so I wasn't able to try any GPS modes.  (High voltage power lines very nearby  seem to mess with GPS, not sure why)

      Description of my multi rotor:

      This multirotor is a quad F-750 with 6s and low KV pancake motors, using an early Pixhawk. I use a 433 immersion  EZUHF receiver with Taranis and a 1.258 Video link (400mw), 3DR radios, Tarot 2D, GoPro hero3 black.  Also i use a minim OSD for pilot feedback on conditions.

      on the ground station I use a DIY repeater to turn 1.258 into 5.8 for video to my fat sharks and 7 inch monitor with built in receiver and DVR.  I use Mission Planner and feel blessed for all the work being done to make all this stuff work.  It is being done by individuals for no monitory gain..

      To the Dev's. Thanks and keep up the great work!

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