Magnetometers are widely used for measuring the Earth's magnetic field, in geophysical surveys, to detect magnetic anomalies of various types, and to determine the dipole moment of magnetic materials. In an aircraft's attitude and heading reference system, they are commonly used as a heading reference.

What is a magnetometer and how does it work?

A magnetometer is a device used to measure the magnetic field, particularly with respect to its magnetic strength and orientation. A popular example of a magnetometer would be the compass, which is used to measure the direction of an ambient magnetic field (i.e. in this case, the earth's magnetic field).

How do phone magnetometers work?

A system called Pulse uses the magnetic field sensor, or magnetometer, for the compass app in iPhones and Android phones, to receive messages in the form of a varying magnetic field produced by a nearby electromagnet.