EKF variance stops the compass

[Alejandro Hernández]

Hello,

I'm testing the ArduCopter master branch of diydrones/ardupilot. I have several problems with EKF. Sometimes appears the failsafe "EKF variance", but the drone is on the floor without moving. I have read this documentation[1] but I think is outdated, because now EKF is force in ArduCopter and the parameter AHRS_EKF_USE is deprecated. I have change the parameter EKF_CHECK_THRESH to 0, 1 or 0,8 but I always have the same result. I can't use the GPS modes like GUIDED or AUTO.

I'm using HMC5843 compass, When I used this compass with the DCM all works fine, but now when the failsafe EKF variance appears the compass stop working (at least in APM Planner) because I can calibrate the compass and I have debugged the code and the values are received.

Anyone can explain how EKF is working or how I can configure my drone to use GPS mode?

Thanks in advance.

[1] http://copter.ardupilot.com/wiki/configuration/ekf-inav-failsafe/

[Víctor MV]

This is related to #2026 and #1989 and produced (that's what we have concluded so far) by a miss-configured set of parameters for EKF (this started happening after the changes in master to adopt EKF by default in copter).

We are using these parameters. Any chance we can get some help fine tune them?

[Víctor MV]

For completion, falling back to DCM (forcing it in the code) fixes this sudden changes.

[iiapoxii]

How can I use this? I am having  this problem with a Pixhawk and 3DR GPS/Compass combo and cant figure out why its not working. I would like to use your parameters if you think it will fix it!!!