APM:Plane 3.0.3 released


The ardupilot development team is proud to announce the release of version 3.0.3 of APM:Plane. This release contains some important bug fixes for all supported boards.

The key bug fixes in this release are:
  • fixed handling of filter divergence in the EKF filter
  • fixed a glide slope calculation bug when entering AUTO mode

The EKF fixes are the main focus of this release. During testing of APM:Plane with the AHRS_EKF_USE enabled it was found that under some circumstances the EKF could diverge, resulting in loss of attitude estimate. Unless the pilot quickly took control in MANUAL this could result in the aircraft crashing.

The fix for this problem was in several parts. The main fix was to prevent the divergence, but as a precaution against future bugs of this type additional numerical checks were added to allow the EKF to automatically reset in flight when the internal state shows large gyro bias changes, which are the first sign of something going wrong in the filter. If this happens again the EKF will automatically disable itself for 10 seconds, allowing APM:Plane to fall back to the old DCM code. The EKF will then reset itself using initial state based on the DCM state. The aircraft will report the failure using the AHRS health bit in the SYS_STATUS MAVLink message.

The default EKF tuning parameters were also updated based on a number of user supplied flight logs to increase the robustness of the filter.

The second bug fixed in this release relates to the glide slope calculation when the aircraft enters AUTO mode for the first time when at an altitude above the altitude of the first waypoint in the mission. The starting point for the glide slope was incorrectly calculated using the home altitude, which resulted in the aircraft descending below the first waypoint altitude before climbing again. In some circumstances this could lead to a crash due to local terrain.

Many thanks to everyone who tested this release. Special thanks to Dellarb for reporting the glide slope bug and to Paul Riseborough for all his work on the EKF code over the last few weeks.

Happy flying!

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  • Connection issue solved. Set both parameters to 0, then it started working.They were set at 2.

    I guess defolt value changed in this FW , and never paid attantion as it was working fine before.

    Thank you.

  • I crashed my plane two days ago because a problem that reminds me to one that is described in this post, although I was flying with APM 2.5 (not Pixhawk). Firmware ArduPlane 3.0.2

    I don't really know why my plane became to pitch down while I was flying in FBWA until it crashed. I didn't notice that odd behaviour until it was too late so I could not react so quickly to change it to Manual mode to save my air plane.

    Checking my log I can see that there is a problem with Alt_error. I took off in FBWA without problems. Then I changed to RTL and changed Alt from 100 to 300 m AGL while I put my FPV googles. After that I changed again to FBWA and then my plane started to lose altitude, first in an smooth way but finally very steeply (that was when I worried and the crash happened).

    I don't know what else I can check.


  • Both units have solid green light , so they see each other. when I try to connect red light blinking green stays on.

    I did not change or checked  BRD_SER1_RTSCTS and BRD_SER2_RTSCTS, it was working fine just today on 3.0.2 I will check them shortly ,so they must have deffolt values. Powering air unit from separate BEC and I dont have RTS and CTC pins connected.

  • Developer

    Hi Rostislav,

    That is strange, I use RFD900 myself.

    What are the lights doing on the RFD900 when it doesn't work? How are you powering the RFD900? What setting do you have for BRD_SER1_RTSCTS and BRD_SER2_RTSCTS ?

    Cheers, Tridge

  • Andrew, 

    Since I upgraded to 3.0.3 I can't connect to PH via telemetry.

    I',m using RFD900 modems , havent had anyissues connecting to the board on 2.78, 3.00,.3.01, 3.0.2 FWs.

    Downgraded to 2.78 and it's working again . Pins for flow conrol are not connected.

  • I will get the logs tonight and post it.

  • Hello Andrew,

    I am powering the pixhawk with a 3DR power module and the planes BEC from the ESC is in channel 3. What is the definition of a brown out? Is it serious?

  • Developer

    Hi Christiaan,

    Rebooting at 50% throttle sounds like a brownout. How are you powering the Pixhawk? If you can post some logs then I could look at the power status messages and see if anything shows up.

    Also is it advisable to tune the PID's (manual) while flying?

    You can, but you should only try it if you have someone else to operate the GCS, as taking your eyes off the plane is a bad idea. I'd also suggest you look at the new autotune mode.

    Cheers, Tridge

  • Developer

    Awesome, thanks Tridge!

  • Hello, I uploaded this new firmware yesterday on my pixhawk and when I do tests to increase the throttle and let the motor spin(which prop on) the pixhawk reboots at around 50% throttle, why would this be? Also is it advisable to tune the PID's (manual) while flying?

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