A MAGNETOMETER

摘要

A magnetometer (100) for measuring an external magnetic field has at least one core (102), two excitation coils (106a), (106b), and a pick-up coil (104). The at least one core (102) has a magnetoresistance property measurable in response to the external magnetic field (111). Each excitation coil (106a), (106b) is near or around opposite ends of the core (102) or near or around a respective core. The excitation coils (106a), (106b) are configured to be driven by an alternating current to partially saturate a magnetisation of the core during part of the AC cycle. The pick-up coil (104) is near or around at least a portion of the core (102) and the excitation coils (106a), (106b). The pick-up coil (104) is configured to carry a signal induced at least in the presence of the external magnetic field (111). The induced signal is measurable in response to the external magnetic field (111).