Magnetic Calibration System With Interference Compensation

TL;DR

This paper presents a new calibration method for dc-precise magnetometers that effectively compensates for magnetic interference in laboratory environments, achieving high accuracy with minimal external disturbance effects.

Contribution

A novel calibration approach using a reference magnetometer and specific procedures to mitigate magnetic interference in low-field magnetometry.

Findings

Achieved a standard deviation of 91 ppm in gain calibration.

Demonstrated an overall uncertainty of 0.1%.

Effective interference compensation shortly after coil energization.

Abstract

This paper describes a novel method for calibrating dc-precise magnetometers in the low field range (100 uT), which gives acceptable results even in laboratory conditions with significant magnetic interference. By introducing a closely mounted reference magnetometer and a specific calibration procedure, it is possible to compensate for the external magnetic field disturbances caused, e.g., by the local transportation operated with dc power supplies. The field compensation occurs only shortly after the calibrating coils are energized. In this case, the leakage of the coil's magnetic flux to the reference sensor due to the cancellation of the time-varying compensating field was negligible. When using 60 cm coils and reference sensor in 2.5 m distance, we were able to calculate magnetometer gains with a standard deviation of 91 ppm. We show that an overall uncertainty of 0.1% can be achieved.