Abstract. The goal of magnetic observatories is to measure and provide a vector magnetic field in a geodetic coordinate system. For that purpose, instrument set-up and calibration are crucial. In particular, the scale factor and orientation of a vector magnetometer may affect the magnetic field measurement. Here, we highlight the baseline concept and demonstrate that it is essential for data quality control. We show how the baselines can highlight a possible calibration error. We also provide a calibration method based on high-frequency "absolute measurements". This method determines a transformation matrix for correcting variometer data suffering from scale factor and orientation errors. We finally present a practical case where recovered data have been successfully compared to those coming from a reference magnetometer.

Abstract. Absolute magnetic measurements are of great importance in magnetic observatories. They allow not only instrument calibration but also data quality checking. They require the vertical and the geographic or true north as reference directions, usually determined by means of a level and by pointing an azimuth mark, respectively. We present here a novel system able to measure the direction of the magnetic field and of the vertical and true north. A design of a north seeker is proposed taking into account sensor bias as well as misalignment errors. Different methods are derived from this model and measurement results are presented. A measurement test at high latitude is also shown.

Abstract. Absolute magnetic measurements are of great importance in magnetic observatories. They allow not only instrument calibration but also data quality checking. They require the Vertical and the geographic North as reference directions, usually determined by means of a level and by pointing an azimuth mark respectively. We present here a novel system able to measure the direction of the magnetic field, of the Vertical and True-North. A design of a North-seeker is proposed taking into account sensor bias as well as misalignment errors. Different methods are derived from this model and measurement results are presented. A measurement test at high latitude is also shown.

No abstract

Abstract. The goal of magnetic observatories is to measure and provide vector magnetic field in a geodetic coordinate system. For that purpose, instrument setup and calibration are crucial. In particular, scale factor and orientation of vector magnetometer may affect the magnetic field measurement. We remember here the concept of baseline and demonstrate that they are primordial for data quality control. We show how they can highlight a possible calibration error. We also provide a calibration method based on high frequency absolute measurement. This method determines a transformation matrix for correcting variometer data suffering from scale factor and orientation errors. We finally present a practical case whose recovered data have been successfully compared to those coming from a reference magnetometer.