Arm prevented by GPS and AHRS differ by x.xx m error message

Has anybody with two GPSes (DroTek and Reach for me) seen pre-arm error messages in 3.6-RC1 “GPS and AHRS differ by x.xx m”? I saw one mention in another post that it may be the new GPS blending function. In my case, the second GPS isn’t used for navigation since GPS_AUTO_SWITCH=0, but perhaps its possible that the blending function isn’t accounting for the switch setting?

I was able to clear it once by redoing a accel calibration.

Anybody know why this message started showing up and how to work around it?

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Typically it will be caused by a GPS position error, or moving the aircraft between boot time and arming when the aircraft was booted and could not obtain satisfactory GPS position information. The solution is to shut down the flight systems, reboot it, and don’t move the aircraft by hand to let the AHRS and GPS sync.

Thanks for the reply! I’ll give that a try. It must take longer to settle in 3.6.

There was an issue having to do with vertical height being accounted for in the arming check, which will cause you issues unless GPS is your reference source for height data (not the default). This was fixed recently, and should vastly reduce the number of arming failures you see. This will be included in the next Copter 3.6 beta.