For the magnetometer inside the phone the speaker is considered hard iron. Good thing about hard iron bias is that it can be easily corrected. Hard iron distortion is always additive to the to the earth’s magnetic field.Is there a model for the current-induced magnetometer bias?
Speciﬁcally, a model for the current-induced magnetometer bias as a function of the throttle command is established. Based on this model, an adaptive estimator is developed that determines the model parameters in realtime.What are the disadvantages of using a magnetometer?
There is one problem though, magnetometers are prone to distortion. The magnetic field used for determining the heading is the earth’s magnetic field. In addition to earth’s, there are additional magnetic fields which cause interference.What is interinterference with magnetometers?
Interference can be caused by ferromagnetic material or equipment in the magnetometers vicinity. If the magnetic field is permanent it is called “hard iron”. For example a mobile phone has a speaker. The speaker is permanently attached to the phone.