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EKF 2 Multiple sensors fall over and recovery

(John) #1

Hi, I am trying to fully understand something with the EKF 2 and multiple sensor redundancy like in the Pixhawk or the Cube/ other controllers with multiple IMUs as I have seen a lot of chatter on this since the cube bulletin and the changes added to PR.

Iv got my head around the EKF failsafe and that is as I understand it a failure it can’t recover from and there are no others it goes into landing mode but this is the last resort as I see it and not normal behaviour .

With regards to having multiple IMUs this is where I am still not fully clear.

As standard the cube for instance sets the EK2_IMU_MASK to 3 so this means there are 2 EKF2 Cores running in parallel, one using IMU1 and the other IMU2, if one fails then it can switch to the other EKF as I read it.

If you set the mask to 1 this means there is only one EKF core and its using IMU1, my question is can the EKF still change IMUs with in the core and not triggering EKF switch or failsafe with or without having multiple cores running ?

Further to this If your using either single EKF or duel EKF’s does it have the ability to switch to the unused 1 or 2 unused IMU/‘s depending on the mask setting but not actually change the whole EKF core ?

What I’m trying to understand is, Does the EKF2 and or 3 have access to all of the addition sensors when only one instance is running like a voting system of the best data with all the available sensors with in the whole single process running if that makes sense.

(John) #2

I guess it’s tumbleweed on this one :frowning: