Capacitive detection scheme for space accelerometers applications

This paper presents the design and performance of an ultra-sensitive positi on sensor dedicated to future space accelerometers. The electromechanical t ransducer is based on a capacitive scheme and aims at detecting the motion of a proof-mass in an electrostatic accelerometer. A new design called "are a variation capacitance" is investigated to minimize back-action forces exe rted on the proof mass. The resolution of that position sensor is a few ten ths of picometer in the 0-1 Hz bandwidth. The position is digitized with a sigma-delta converter to feed the control laws of the accelerometer. (C) 19 99 Elsevier Science S.A. All rights reserved.