A Space Inertial Sensor Ground Evaluation System for Non-Sensitive Axis Based on Torsion Pendulum

Abstract

The inertial sensor is the key measurement payload of the technology verification satellite of China’s space gravitational wave detection mission-Taiji Project, which uses capacitive sensors to sense the acceleration disturbance of the test mass under the influence of non-conservative forces in the frequency range of 10 mHz~1 Hz. It is necessary to perform a ground performance evaluation and estimate the working state of the payload in orbit. However, due to the influence of the earth’s gravity and seismic noise, it is impossible to directly evaluate the resolution level of the non-sensitive axis when testing with high-voltage levitation, which leads to incomplete evaluation of the performance of the inertial sensor. In order to implement this part of the test, the sensitive structure is designed and a torsion pendulum facility for performance testing is developed. The experimental results show that the measurement resolution of the non-sensitive axis of the inertial sensor can reach 9.5 × 10−7 m/s2/Hz1/2 under the existing ground environmental conditions and is mainly influenced by the seismic noise during the system measurement. If the inertial sensor enters orbit, the measurement resolution can achieve 3.96 × 10−9 m/s2/Hz1/2, which meets the requirements of the technology verification satellite for a non-sensitive axis. This proposed system also provides a reasonable method for the comprehensive evaluation of inertial sensors in the future.

Robust Control Allocation for Space Inertial Sensor under Test Mass Release Phase with Overcritical Conditions

“…The success of these missions has greatly encouraged more scholars to research drag-free control systems. The space inertial sensor (SIS) [ 8 , 9 , 10 , 11 ] is one of the key payloads of drag-free spacecraft, which consists of a test mass as an inertial reference and a set of electrodes acting as capacitive sensors and electrostatic actuators. During the launch and the following orbital transfer phase, the test mass is locked inside the electrode house by the caging and vent mechanism (CVM).…”

Hardware design of electrostatic levitation accelerometer control system

“…The Institute of Physics in Lanzhou mainly focuses on the processing of electrostatic levitation accelerometer inspection quality, the design, and manufacture of vacuum devices and electronic design, and has achieved many research results and participated in the development of the electrostatic levitation accelerometer used in the "Taiji Project" of the Chinese Academy of Sciences. The first experimental satellite of the Taiji Project, Taiji-1, was successfully launched in 2019, and the resolution of the electrostatic levitation accelerometer onboard was measured to reach 10 gHz -1/2 [8] .…”

Using DWS Optical Readout to Improve the Sensitivity of Torsion Pendulum

“…Finding and studying gravitational waves in the middle-and low-frequency regions is the ultimate objective [21,22]. After years of research, the first phase of the mission was completed, and the experimental satellite was successfully launched in 2019 at a very low cost and in a short amount of time, successfully verifying key technologies such as the inertial sensor, laser interferometer, and drag-free satellite platform [23][24][25].…”