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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  • I think the M8N's can vary a LOT. I had one that indicated a great sat count and low hdop and yet performed baddy. I got another one that seemed MUCH better. But I agree the huge sat count and low hdop does not seem to translate into much greater positioning. Tridge mentioned it's not just sat count it's other calculations it does regarding the trajectory that the gps does that is equally important.  For me the biggest improvement was the time it takes to get a good count. That is much better. 

    sorry.... OT again

    • My one(s) are from, two months to arrive in Brasil....but...

      Already tested with AC3.3-rc8 , more than 20 batteries....with no problems....

      Rock solid, no drift , I can "drink a coffee" when in poshold mode.


      I "had" another one(s) from another brand, .... hummm..... I threw in the trash, after 2 crashes...I spent mode then 200 hundred dollars to fix my multi... no make sense....


      Like cars....some of them are really cheap... but.....

      • yes, i agree , i also have a M8N from CSG Shop, works absolutely perfect here in Germany.I also have the new one M8T large from Drotek (the big one) and a XL M8N from Drotek , both also works perfect. every time more as 17 SAT and HDOP below 0.8 !

        • @Pit do you mind sharing a copy of your M8N parameters from ublox ucenter software ? 

          How to:

          You need to save it as .txt

          Open ublox ucenter , menu tools -> GNSS Configuration -> GNSS to file 


          • hello manuel

            thanks, yes, when i´m back from my Travel i will do it. 

          • Developer


            Marco's M8N parameters can now be found here in github.

            • Randy, just to let you know that using Marco's config file did the trick !!!

              That or the change of GPS_TYPE to Ublox. I did those two at the same time, so I dont know for sure which made my quad fly well again

              Thank you!

            • Thank you Randy

              If I'm not able to 'save' my GPS unit by loading these parameters from another unit, what's the next step ? 

              I mean, I've only changed a few parameters within ublox ucenter software, how can that make a gps useless :|

        • @Pit. +1 here for M8N from CSG shop. I have 6 differents large M8N on different multirotors. They are really good here in east cost of Australia.

          And the "new" improved ground plane incorporated (see photo) looks like a good way to isolate a it the electrical noise from "below".

          All my M8N are mounted much higher than the main "platform" where electrical noise is common. I do add a sandwitch aluminium/copper plate under the GPS. The M8N are located about 15 to 18 centimeters away (above) from main noise sources. They *all* are powered with *clean power (read: Not switching one) This is much better than ferrite filter. Never had a GPS glitch so far in any of the six aircraft. Could it be purely coincidental? :-)


          • hee henri, no i think its not a coincidental. look, its my copter with the large CSG GPS. Works fine and i have 3 UBEC for powering the PIX. I think a clean construction its importend. U are right! 

            Today i will make a test with RC9





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