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


          Ah ok good.  At least some of these are "known issues" and all related to the log analysis tools rather than the logs themselves.  We have a fix for the Log Analyser but it needs to be tested and then the MP will need to pickup the change.  I'm not too familiar with Kev's log analyser tool but I suspect it needs changes as well to deal with AC3.3 log file format changes.

          The size of the logs is temporary. We've increased the IMU logging to 400hz for beta testing.  For the official release we will reduce that to 50hz and the logs will be 4x ~ 8x smaller (the IMU data is a large percentage of the total log size).

  • I think we should take this EKF dude behind the wood shed for a little talk.... lol

    • LOL !
    • Thanks for the replies.  Now I know what to focus on I will try a newer GPS model (when it arrives) and see what happens. 

      Richard, I am not complaining about the code and I understand it is Beta software.   I have been working on this on my own and am not just putting stuff up every time  I get stuck (which, until now, has both been rare and I have been able to fix). 

      That being said,  I thought the idea of beta testing is to both get reports of good results and bad ones.  I don't have a wood shed but I am happy to have a talk as long as you have something useful to to say that will help me out!!   I don't mind being told that I am doing something stupid if it fixes my problem.  So far all of the advice has been informative and constructive while helping me to narrow down possible causes.

      • Developer

        I think Richard is just kidding around and he's picking up on my weariness re the EKF.  The EKF is a fine piece of software but is more complicated than the older DCM/inertial nav and is proving a challenge to get exactly right and there's still some learning we need to do in the wider dev team in how it's acts.

        Definitely appreciate both good and bad reports re AC3.3 and we're close to the finale so we should expect it to perform very well at this point.

  • Hi Randy,

    Thanks for the info, I really appreciate the effort.  I have another GPS on order and will see if that make the difference.

    I have also previously tried replacing all of the GPS cabling and running the system removed from the frame (to get away from interference)

    All of my GPS units are 3DR LEA-6H with the original config on two and one of them I have reloaded the config a few times. When plugged into uCentre they all seem to work correctly with no problems.

    My next question would be, should I be able to fly in STAB or ALTHOLD without the EKFG Error?  Do I need a full 3D position fix every time I fly?

    Thanks again for the reply and it gives me more insight than I could obtain on my own but I have learnt a lot about the code etc in the process.  I am constantly in awe of the work you guys do and hopefully, one day I can actually be able to contribute something useful!

    • Developer


      You don't need a full 3D lock if you're only flying in stabilize or AltHold.  Ideally bad or missing GPS data shouldn't affect the attitude estimates but I'll ask PaulR to confirm.  If bad/missing GPS does affect the attitude then it's something we should fix.

  • I'm using rc7 and it's almost all fine, i have only troubles when i try to start without GPS signal in mode stabilize.

    The led is flashing blue then when the motors are startet the led starts flashing yellow/red. The copter then doesen't fly very good and it's also possible it's losing level.

    is this a known issue ?

    • I have had this happening since 3.3.2 came out.  I think randy said that EKF is using GPS to determine position even though GPS is not used in Stabilize mode.

      The copter flies fine except you may not have a good home position.

      Doesn't always happen but sometimes.

    • No. Can you attach a log?

This reply was deleted.


DIY Robocars via Twitter
RT @DanielChiaJH: @a1k0n @diyrobocars @circuitlaunch And here's the final showdown! Video courtesy of @chr1sa I think I was a little faste…
7 hours ago
DIY Robocars via Twitter
RT @DanielChiaJH: @a1k0n @armand_dpl @SmallpixelCar @diyrobocars @circuitlaunch I use @foxglovedev Foxglove Studio for my visualization nee…
7 hours ago
DIY Robocars via Twitter
7 hours ago
DIY Robocars via Twitter
RT @a1k0n: @DanielChiaJH @diyrobocars @circuitlaunch Here's my car's view of that race. About 8.4 second lap times for laps 2 and 3... both…
DIY Robocars via Twitter
RT @DanielChiaJH: Great racing against @a1k0n today at @diyrobocars! Pretty cool to both break sun-9s at the track today I think I got very…
DIY Robocars via Twitter
Broadcasting the @circuitlaunch race live now at Races begin around 2:00pm PT
DIY Robocars via Twitter
RT @a1k0n: ran a huge number of hyperparameter tuning experiments yesterday; now I can train a new policy, far with better quality, in 15 m…
DIY Robocars via Twitter
RT @a1k0n: Did I get rid of hand-tuned parameters? Yes. Am I still hand-tuning more parameters? Also yes. I have a few knobs to address the…
Sep 26
DIY Robocars via Twitter
RT @a1k0n: I'm not going to spoil it, but (after charging the battery) this works way better than it has any right to. The car is now faste…
Sep 26
DIY Robocars via Twitter
RT @a1k0n: Decided to just see what happens if I run the sim-trained neural net on the car, with some safety rails around max throttle slew…
Sep 26
DIY Robocars via Twitter
Sep 24
DIY Robocars via Twitter
RT @SmallpixelCar: @a1k0n @diyrobocars I learned from this. This is my speed profile. Looks like I am too conservative on the right side of…
Sep 24
DIY Robocars via Twitter
RT @a1k0n: @SmallpixelCar @diyrobocars Dot color is speed; brighter is faster. Yeah, it has less room to explore in the tighter part, and t…
Sep 24
DIY Robocars via Twitter
RT @a1k0n: I'm gonna try to do proper offline reinforcement learning for @diyrobocars and throw away all my manual parameter tuning for the…
Sep 23
DIY Robocars via Twitter
RT @circuitlaunch: DIY Robocars & Brazilian BBQ - Sat 10/1. Our track combines hairpin curves with an intersection for max danger. Take tha…
Sep 22
DIY Robocars via Twitter
RT @SmallpixelCar: Had an great test today on @RAMS_RC_Club track. However the car starts to drift at 40mph. Some experts recommended to ch…
Sep 11