Gradiometer and magnetometer integration by using a pair of fundamental mode orthogonal fluxgate sensor heads

A novel method for constructing an integrated gradiometer and magnetometer is proposed based on Fundamental mode Orthogonal Fluxgate (FM-OFG) operation. The new method is an extension from the recently presented FM-OFG gradiometer (3 mm diameter, 30 mm length) where the signal subtraction is made at the sensor head level, in which the capability of suppressing the response to uniform magnetic fields can be enhanced by adjusting the dc-bias current in one of the heads. In the new method for integrated sensor construction, the summation of both sensor head outputs is used for the magnetometer operation and the subtraction of them is used for the gradiometer operation.