Reference frames aligned along magnetic axes?

Goodmorning,
I would like to have a clarification regarding the several reference frames. Is the local or global reference frame aligned along the magnetic axes? If “no”, is there any way to get the fixed local reference frame rotation relative to the magnetic axes?

My goal is to use a common global reference system for a drone and ground vehicle. Since I am only interested in orientation and work outdoors, I opted for magnetic axes.

Thank you,
Gennaro Scarati