Influence of sensor noise levels on magnetometer calibration parameters

Magnetometers are prime instruments of scientific spacecraft targeting the space plasma environments of solar system bodies. Despite extensive ground calibration efforts, regular inflight calibration activities of these magnetometers have shown to be crucial to maintain necessary data quality levels over time. Classically, 12 parameters influence the calibration: 3 gain values, 6 angles defining magnetic sensor orientations, and 3 zero level offsets that correspond to instrument outputs in vanishing ambient fields. Particularly in low fields, accurate choice of offset levels are of utmost importance. To achieve this, measurements of Alfvénic fluctuations in the solar wind are typically used. We investigate the influence of sensor noise levels on the accuracy of different calibration parameters, particularly on the offsets, using THEMIS/ARTEMIS magnetic field measurements.