Actuation to sensing crosstalk investigation in the inertial sensor front-end electronics of the laser interferometer space antenna pathfinder satellite

Abstract

Abstract The inertial sensor (IS) front-end electronic (FEE) is considered to be one of the most critical designs in the laser interferometer space antenna (LISA) and LISA pathfinder (LPF) satellite. The actuation to sensing crosstalk in the IS FEE could deteriorate the IS test mass (TM) sensing information, thus affect the TM control and the mission performance critical estimation of the TM net electrostatic charge level. By detailed modeling, we find that the crosstalk is most likely caused by the capacitance variation at the output stage of the actuation circuit due to the applied actuation signal. Different types of capacitors were tested in the prototype sensing and actuation circuit and the sensing performance for different actuation signals were measured. The measurement results show that the crosstalk in our prototype circuit can be made negligible, but not fully avoided since the capacitors are not absolutely constant when the actuation signal is applied. Compared to the use of other types of capacitors, the use of polyphenylene sulphide (PPS), polyester (PET) and C0G type capacitors can achieve better performance with crosstalk level far below the limit.