Electrostatic gravity gradiometer design for the future mission

Z. Zhu^a, Z.B. Zhou^a,b,*, L. Cai^b, Y.Z. Bai^a, J. Luo^a

^aKey Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education, School of Physics, Huazhong University of Science

and Technology, Wuhan 430074, China

^bInstitute of Geophysics, Huazhong University of Science and Technology, Wuhan 430074, China

Received 7 January 2013; received in revised form 30 January 2013; accepted 31 January 2013

Available online 8 February 2013

Abstract

Satellite gravity gradiometry has been applied in GOCE mission to obtain higher harmonics of the Earth’s gravity mapping. In-orbit results showed that the precision of GOCE gradiometry achieved a level of 10–20 mE/Hz1/2 in the bandwidth of 38–100 mHz, and the major error source came from the intrinsic noise of the core sensor electrostatic accelerometer. Two schemes for improving sensitivity of such accelerometer are presented by optimizing the parameters to reduce the dynamic range and choosing the heavier proof mass to suppress the thermal noise limited by the discharging gold wire. As a result, an accelerometer with a better resolution of 6.6* 10^{- 13}m/s2/Hz1/2 could be developed, and then a precision of 3 mE/Hz^1/2, corresponding to a spatial resolution of about 78 km half wavelength, is achievable for the future satellite gradiometric mission.

Crown copyright 2013 Published by Elsevier Ltd. on behalf of COSPAR. All rights reserved.

Keywords: Satellite gravity gradiometry; Future mission; Electrostatic gravity gradiometer; Electrostatic accelerometer