Identification and compensation of quadratic terms of a space electrostatic accelerometer

Yun Ma,1,2 Yan-Zheng Bai,1,a) Hong-Yin Li,1 Ze-Bing Zhou,1,b) and Zheng Zhou1
1MOE Key Laboratory of Fundamental Physical Quantities Measurements, Hubei Key Laboratory of Gravitation and Quantum Physics, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
2School of Automation, Huazhong University of Science and Technology, Wuhan 430074,
People’s Republic of China

(Received 13 June 2018; accepted 10 October 2018; published online 5 November 2018)

The ultra-sensitive space electrostatic accelerometers have been successfully employed in the Earth’s gravity field recovery missions and the space gravitational experiments. Since the accelerometer output in the measurement bandwidth can be influenced by the orbital high-frequency disturbances due to the second-order nonlinearity effects, the relevant quadratic term must be accurately compensated to guarantee the accuracy of the electrostatic accelerometer. In this paper, three sources of the quadratic term are studied and formulated. They are the offset of the test mass in the housing due to the bias of the capacitive position transducer, the asymmetry of the electrode area, and the asymmetry of the actuation electronics. Two feasible compensation methods and an identification means are proposed. Compensation is achieved by adjusting the test mass actual working position or the asymmetry factor of the feedback actuation voltage. Identification is conducted by applying a periodic high frequency signal on the electrodes. Finally, the proposed methods are demonstrated, in view of future space applications, by suspending the accelerometer test mass on a torsion pendulum. 

Published by AIP Publishing.

https://doi.org/10.1063/1.5044477