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 –


              • FWIW looking at your photo again, I have discovered that the cable end of LiPo batteries give off a lot of magentic interference and now mount my batteries with the cable end as far away from the compass as possible. I suspect you have enough distance for this not to matter, but FYI.

                • Sorry to barge in and this has probably been discusses a thousand times 'somewhere' but do you think it's advantageous to put copper foil tape on the bottom of a gps case? I have the typical black round plastic gps case on a mast. Would copper tape on the bottom be a good idea? Seems a but less messy that copper foil on all the wires. Thoughts? Thanks 

                  • copper base helps a bit. but what helps way better is to use properly filtered 5V voltage feed, from a BEC separate from the one that feeds flight controller. when i rerouted power and stopped using 5V from the COM port where GPS was connected to quality of data has improved tremendously, as well as speed of sats lock. 

                  • So I've always been suspicious of this since I'm pretty sure every GPS has a ground plane anyway. I think the EMF interference is a field rather than unidirectional, so you'll be missing some of the radiation this way. That's why I think identifying the sources and shielding them is more effective.

                    But Cala's experience shows that it still works pretty well!

                  • I put cooper under gps on my last build, It's changed from 10-12 sats to 18-20 sats :O and I don't need a tall mast, only a second floor over the Pix, I connected the cooper to the pix with a ground wire.

              • Sweet! Glad you got it sorted.

                I think this kind of story shows just how vunerable GPS's really are and just how much the FC is using it. I had no idea when I first got into this. I'm also amazed how much difference shielding makes - its so much more convient than distance!

          • Could try connecting to ublox ucenter and doing a cold restart, then let it run for a while (30min?). I've had that help on big deviations.

            What hdop and # sats are you getting?

            • I'm not sure of the HDOP, that is prob in the log, but I usually have 10-13 sats within 10 seconds. Andy, I'm glad yours improved. I will try that and have results soon, too. Thanks for your suggestions.

          • I agree that 1.3Ghz could be wreaking havoc BUT having just been through this myself I think another highly likely option is the camera and video cable - neither are shielded and on my mini quad they were completely killing the GPS (vtx had no impact but that was on 5.8Ghz). I have what looks like the identical camera and I believe it leaks a lot of RF interference. Likewise the cable. Wrap both in copper tape and and that should make things a lot better. I would not advise putting the GPS above the camera for this reason - you would be better off moving it to the back. If you look at a fat shark camera setup the cables are always screened.

            See here:


            • Just a follow-up on this. Finally got to properly test my camera/cable screening solution (copper tape) and the difference is night and day! Before I was rarely getting a lock after many minutes and even if I did it was 4 sats high HDOP. Afterwards I was getting a lock in < 30s with 10 sats and HDOP 0.8 on an LEA-6H. YMMV as my camera is VERY close to the GPS unit (0.5 cm) but FYI.

This reply was deleted.


Gremsy liked Gremsy's profile
Mar 12
DIY Robocars via Twitter
RT @chr1sa: Donkeycar 4.4 released with tons of new features, including path learning (useful with GPS outdoors), better Web and Lidar supp…
Nov 27, 2022
DIY Robocars via Twitter
RT @NXP: We are already biting our nails in anticipation of the #NXPCupEMEA challenge! 😉 Did you know there are great cash prizes to be won…
Nov 24, 2022
DIY Robocars via Twitter
RT @gclue_akira: レースまであと3日。今回のコースは激ムズかも。あと一歩 #jetracer
Nov 24, 2022
DIY Robocars via Twitter
UC Berkeley's DIY robocar program
Nov 24, 2022
DIY Robocars via Twitter
RT @chr1sa: The next @DIYRobocars autonomous car race at @circuitlaunch will be on Sat, Dec 10. Thrills, spills and a Brazilian BBQ. Fun…
Nov 24, 2022
DIY Robocars via Twitter
RT @arthiak_tc: Donkey car platform ... Still training uses behavioral cloning #TCXpo #diyrobocar @OttawaAVGroup
Nov 20, 2022
DIY Robocars via Twitter
RT @emurmur77: Points for style. @donkeycar racing in @diyrobocars at @UCSDJacobs thanks @chr1sa for taking the video.…
Nov 20, 2022
DIY Robocars via Twitter
RT @SmallpixelCar: Going to @diyrobocars race at @UCSDJacobs
Nov 8, 2022
DIY Robocars via Twitter
RT @SmallpixelCar: Race @diyrobocars at @UCSDJacobs thanks @chr1sa for taking the video.
Nov 8, 2022
DIY Robocars via Twitter
RT @PiWarsRobotics: Presenting: the Hacky Racers Robotic Racing Series in collaboration with #PiWars. Find out more and register your inter…
Oct 23, 2022
DIY Robocars via Twitter
RT @Hacky_Racers: There will be three classes at this event: A4, A2, and Hacky Racer! A4 and A2 are based around UK paper sizing and existi…
Oct 23, 2022
DIY Robocars via Twitter
Oct 23, 2022
DIY Robocars via Twitter
Oct 19, 2022
DIY Robocars via Twitter
Oct 18, 2022
DIY Robocars via Twitter
RT @NeaveEng: Calling all UK based folks interested in @diyrobocars, @f1tenth, @donkey_car, and similar robot racing competitions! @hacky_r…
Oct 13, 2022