Compensation of Crosstalk in Three-Axial Induction Magnetometers

A method for the compensation of crosstalk in three-axial induction magnetometers is developed theoretically and verified experimentally. The compensation is based on deriving crosstalk-free magnetometer outputs from a system of equations describing the magnetometer total outputs as a function of the applied field, the parameters of the magnetometer coils, and the crosstalk factors for the applied and secondary magnetic fluxes. Processing the total outputs of an experimental magnetometer has demonstrated an effective reduction of the crosstalk: it has been reduced below 0.5% in the whole magnetometer bandwidth, including the frequencies near resonance, where the crosstalk is especially strong (20%). In comparison, the reduction of the crosstalk by applying magnetic feedback is much less effective: the crosstalk has been reduced down to 6% at resonance, remained unchanged at low and high frequencies, and even increased just below resonance. Moreover, magnetic feedback flattens the frequency response and significantly reduces the magnetometer selectivity, which can be advantageous in many applications. Employing magnetic feedback also increases the magnetometer complexity and its power consumption.