• The horizontal and vertical position variance errors are thrown when the EKF and GPS or other sensors do not agree.

    The most common time when this error is thrown is when flying in moderate to strong wind with a pitot tube. Adjust the parameter AHRS_WIND_MAX to help with this error.  I chose 15 as the value which is on the higher end of wind (33mph).

    Other parameters to adjust to help this are EKF_GLITCH_ACCEL and EKF_GLITCH_RAD which control how large of a GPS error the autopilot will see before throwing it out.

    You can find all these parameters and their full description here:

    Complete Parameter List — Plane documentation
  • Did you ever find out what this was? I get it quite a lot, and the craft is pretty twitchy all the time. How do I turn off *all* the EKF stuff? (I'm on 3.4rc1).
  • I found the solution. Switch off EKF and, for the latest arduplane, switch of EKF #2 as well. I also switch off using compass. It's actually not the correct way, but it's the only way I have peace on my screen.

    A real shame not more information is available.
    • I have this message too...did yours also come with "twitches" on althold / poshold as well?

      How did you turn it off btw - which parameters did you set?

  • MR60

    Welcome to the club of unknown, unexplained EKF variance errors.

    I got myself in the last arduplane flight : EKF velocity variance error and another EKF position (horiz) variance error. No clue where to look at.

    So it seems we are severely lacking documentation about EKF errors, troubleshooting and interpretation.

    I think, if I'm not mistaken that Paul Riseborough is the dev in charge of EKF development. Having no way to reach out to him, let's hope he reads this thread and provides us with some info & education...

  • I'm not an expert but I'm installing a Pixhawk to a copter and somethings I saw that perhaps are usefull. I updated the Mission planner to Beta one because it has a EKF status flags that's looks usefull and notice that warning appears but, when I solved my compass problem the flag change to green and the warning still appears on the hud time to time, perhaps a MP issue? Another thing, I have to repeat many times calibration until compass works well, until that, I saw the two errors; if the int compass is inconsistent with the orientation of the external one, you have error compass variance,, be shure that your ext compass is well oriented. 

    level your airplane and check if it is level on the hud or repeat acc calibration too;

    good luck.

    • My point is this:

      Some (or maybe many) of the error messages are extremely hard to understand. They may make sense to the developers, and are "techy" style, but for us, normal users, the don't make sense at all.

      Like Matt mentioned, "Error pos vert variance" or mine "Error compass variance". The message I got at least indicates something wrong with the compass, but I have no clue what it is, where it comes from and how to solve. "Error pos vert variance" is even worse. Not a clue where to look, not a clue where it comes from and when you try to find any information on the error message, nothing.

      It makes trouble shooting very hard. I do realize we work with open source software, and we should be happy many people work very hard on all of this, but some kind of trouble shooting guide with all messages would be very helpful.


      • Had the some problem with error compass variance still havent fixed. How did it go for you guys?

  • With Pixhawk or APM?

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