Self-calibration method of the bias of a space electrostatic accelerometer

The high precision spaceelectrostatic accelerometer is an instrument tomeasure the non-gravitational forces acting on aspacecraft. It is one of the key payloads for satellite gravitymeasurements and space fundamental physics experiments. Themeasurement error of the accelerometer directly affects the precision of gravity field recovery for the earth. This paperanalyzes the sources of the bias according to the operating principle and structural constitution of the spaceelectrostatic accelerometer.Models of bias due to the asymmetry of the displacement sensing system, including the mechanical sensor head and thecapacitance sensing circuit, and the asymmetry of the feedback control actuator circuit are described separately. According to the twomodels, a method of bias self-calibration by using only the accelerometer data is proposed, based on the feedback voltage data of the accelerometer before and after modulating the DC biasing voltage (Vb) applied on its test mass. Two types of accelerometer biases are evaluated separately using in-orbitmeasurement data of a spaceelectrostatic accelerometer. Based on the preliminaryanalysis, the bias of the accelerometer onboard of an experiment satellite is evaluated to be around 10−4 m/s2, about 4 orders of magnitude greater than the noise limit. Finally, considering the two asymmetries, a comprehensive biasmodel isanalyzed. A modified method to directly calibrate the accelerometer comprehensive bias is proposed.

Source: Review of Scientific Instruments - November 9, 2016 Category: Physics Authors: Shao-Bo Qu, Xiao-Mei Xia, Yan-Zheng Bai, Shu-Chao Wu and Ze-Bing Zhou Source Type: research