It seems that GPS and IMU are not aligned in ESKF

[cheerss]

Thanks for you great work first, though I may find some potential problems. For the ESKF algorithm for GPS+IMU:

GPS uses the ENU frame, whose z-axis is aligned with gravity. While IMU only aligns with gravity (z-axis). Is it ok that the x- and y-axis are not aligned with ENU?

I run the code and yield good results, so i am not sure if I miss something important. Hope for your reply.

Many thanks again~