On-orbit performance of high accuracy inertial grade MEMS accelerometer

Accelerometers play a pivotal role in spacecraft navigation, particularly in rendezvous and docking missions, by estimating incremental velocity with precision. This paper presents the on-board performance of an inertial-grade three-axes MEMS accelerometer package that measured the linear acceleration of the spacecraft over its background structural vibration input. Utilizing Hybrid Micro Circuits (HMC) technology for packaging, each axis integrates two in-house fabricated MEMS sensor chips, catering to both fine and coarse range measurements. The paper discusses on the observation of an onboard bias in the output of accelerometer and the reasons for the same and proposes mitigation strategies for future missions. Additionally, the feasibility of leveraging MEMS accelerometers for spacecraft platform vibration measurement is explored. The accelerometer practically achieved exceptional inertial performance with ± 2 µg Noise Equivalent Acceleration (NEA) with a ± 15 mg operating range and an overall accuracy of 10 µg for the fine range sensor. For the coarse range sensor, ± 30 µg NEA is attained with a ± 500 mg operating range and an overall accuracy of 100 µg. This onboard experiment affirms the capability of MEMS accelerometers to assist rendezvous and docking applications in future.