Estimation of Angular Deviations in Precise Magnetometers

Abstract

Capabilities for calibrations of angular deviations of sensor triplets in precise magnetometers were evaluated in a 2.5 m, triaxial Helmholtz coil facility. The coil system is located in a magnetically quiet environment at SANSA Space Science in Hermanus, South Africa. The angular calibration results obtained from the “thin-shell” calibration procedure were compared with direct measurements on a nonmagnetic tilting/rotational platform. One-year expanded uncertainty of angular deviation calibrations is estimated as 6 × 10−2 degrees of arc; 3 × 10−4 degrees coil orthogonality is possible when doing a numerical recalibration and correction on a short-term basis. In addition, an approach for obtaining body-to-sensor angular calibrations is presented, allowing for speed-up of the calibrations and possibly increasing their accuracy and repeatability by avoiding alignment to the coils with a laser beam and leveling.