So I want to build a new project automated car for the moment using only compas as a test but I'm not sure what to trust more the HMC.. or the GPS compas ? I tested the HMC5883L and if I do vibrations or rapidly tilts the data is not accurate it's like jumping around and if I use that module close to motors it may be affected by the magnetic field.
About the GPS compas im not sure how it's working It use the satellites to define the direction or it got a inside magnetometer?
So what should I use? Personally I vote for the GPS but not sure, never had big experience with it.