EKF check error on a APM (not a pixhawk)

From the WIKI:
EKF / DCM Check Failsafe
Copter 3.2 adds a DCM heading check and an EKF (Extended Kalman Filter - Pixhawk only) check to catch flyaways caused by a bad heading estimate…

I received two errors simultaneously in my log. ERR: EKF_CHECK-2 and EKF_CHECK-0

Pixhawk only?
I take it it means roughly the same on the APM ie. lost gps lock.

Yes? No?


Copter 3.2 you need set AHRS_EKF_USE = 1.

Can you share log file?

I am having problems because the WIKI does not match actual data in the mission planner. The parameter “AHRS_EKF_USE” does not exist in my version. Here is a photo of a search for EKF:

here is my log file:
2016-11-09 15-46-46.log (4.0 MB)
and bin file:
2016-11-09 15-46-46.bin (1.7 MB)

bump? I made another flight. In that flight I completed “Auto Trim” and “Auto Tune”. I engaged RTL and my quad began to fly away in the opposite direction of “home” that should have be established when I armed the quad (correct?)

I brought the quad back and tried RTL again and it took off in the same direction it had on the first try.

When I attempt to review the log (I have very little experience with this!) I see several EKF errors. I am VERY nervous about putting my expensive 650 class into the air for fear it will fly off as some people have reported with EKF errors.

I have read here: http://ardupilot.org/copter/docs/ekf-inav-failsafe.html
and looks like the developers have put alot of work into this system but what some of the docs say is I don’t have this feature on ArduCopter V3.2.1 (36b405fb) loaded on an APM 3.1

Please help as I would like to fly and enjoy my quad.


I am pretty sure that APM cant run EKF (Enhanced Kalman Filter). It has to use the DCM (Direction Cosine Matrix) filter

Thanks Sky,
So to the short of it, what do you think is causing this error? Do I need a new GPS module? Have magnetic interference? The Kaltman filters incorporate so many sub systems in coordination with each other I am not sure how to track down the root of this fault.

Have you checked the basic things, such as does your heading, attitude and GPS location look correct in the ground station as you change the direction and attitude of the aircraft ? It is best to check all this with the aircraft outside away from buildings, even if that means moving your desktop outside!