GPS Glitch is not resulting in EKF failsafe


We were flying Hexacopter. Suddenly we observed rapid changes in number of satellites and hdop value.

We expected EKF failsafe to be engaged and vehicle should land. But it didn’t happened because only velocity variance crossed the limit of 0.8 but position variance didn’t crossed 0.8. And according to EKF failsafe logic, which requires two of velocity, position and compass variance to cross the 0.8.

We are able to recover by manually changing the mode to AltHold.

We would like to know a way to make sure EKF failsafe engages. We were thinking of reducing EK2_POS_I_GATE to 3 sigma. Is this correct direction ?