Noise analysis of QFA servo circuit for gravity gradiometer
LEI Li-Ming1, SHU Qing2, YANG Ye1, CHENG Guan-De1
1. Tianjin Navigation Instrument Research Institute, Tianjin 300131, China;
2. China Aero Geophysical Survey & Remote Sensing Center for Land And Resources, Beijing 100083, China
High resolution accelerometer is a kernel sensor for gravity gradiometer measurement.The QFA is mostly used in this measurement at present,so the requirement of noise performance is very strict.Therefore,a new type low-noise QFA preamplifier is put forward to detect differential capacitor based on constant AC voltage stimulation.On such a basis,the integral servo circuit is designed in combination with the parameters of QFA and servo circuit calibration.The quantitative analysis of the noise influence of servo circuit has been done,the noise contribution of the circuit to the QFA servo system is approximately 1.0×10-10 g/√Hz(0.5Hz) at 0.5Hz.This can satisfy the needs of gravity gradiometer measurement above 10E resolution.
雷立铭, 舒晴, 杨晔, 程关德. 重力梯度仪用石英挠性加速度计伺服线路噪声分析[J]. 物探与化探, 2015, 39(S1): 22-27.
LEI Li-Ming, SHU Qing, YANG Ye, CHENG Guan-De. Noise analysis of QFA servo circuit for gravity gradiometer. Geophysical and Geochemical Exploration, 2015, 39(S1): 22-27.