First author. Removing reaction-wheel interference in the frequency domain by targeting its fundamental and harmonic signatures, with CASSIOPE/Swarm-Echo data as the case study.
Missions focused on space weather require magnetic field measurements. Satellite subsystems can emit their own magnetic field, interfering with the data. One such subsystem is the reaction wheel, commonly used for attitude control. The CASSIOPE/Swarm-Echo satellite is a clear example, where time-varying reaction wheel noise overlays the target geophysical signals. Typically Ness gradiometry is used: the difference between two vector magnetometers at different distances from the spacecraft gives an estimate of the noise, which can then be subtracted. With shorter booms the sensors experience a more complex multi-pole noise source, which needs additional signal processing to mitigate. We explore analyzing the signal in the frequency domain, targeting and removing the fundamental and harmonic signatures of the reaction wheels. We present our findings using data collected from the CASSIOPE/Swarm-Echo satellite as a case study.