Tracking kinematic chains has many uses from healthcare to virtual reality. Inertial measurement units, IMUs, are well-recognised for their body tracking capabilities, however, existing solutions rely on gravity and often magnetic fields for drift correction. As humanity's presence in space increases, systems that don't rely on gravity or magnetism are required. We aim to demonstrate the viability of IMU body tracking in a microgravity environment by showing that gravity and magnetism are not necessary for correcting gyroscope-based dead-reckoning drift. We aim to build and evaluate an end-to-end solution accomplishing this. A novel algorithm is developed that compensates for drift using local accelerations alone, without needing gravity or magnetism. Custom PCB sensor, IMU, nodes are created and combined into a body-sensor-network to implement the algorithm and the system is evaluated to determine its strengths and weaknesses. Dead-reckoning alone is accurate to within 1 degree for 30s. The drift correction solution can correct large drifts in yaw within 4 seconds of lateral accelerations to within 3.3 degrees RMSE. Correction accuracy when drift-free and under motion is 1.1 degrees RSME. We demonstrate that gyroscopic drift can be compensated for in a kinematic chain by making use of local acceleration information and often-discarded centripetal and tangential acceleration information, even in the absence of gravitational and magnetic fields. Therefore, IMU body tracking is a viable technology for use in microgravity environments.

翻译：运动链跟踪在医疗健康到虚拟现实等多个领域具有广泛应用。惯性测量单元（IMU）以其人体跟踪能力著称，但现有解决方案依赖重力及磁场进行漂移校正。随着人类在太空活动日益增加，亟需不依赖重力或磁场的跟踪系统。我们旨在证明在微重力环境下，IMU人体跟踪的可行性，说明重力和磁场并非校正陀螺仪航位推算漂移的必要条件。我们设计并评估了一套端到端解决方案：提出一种新型算法，仅利用局部加速度补偿漂移，无需依赖重力或磁场。通过定制PCB传感器节点构建IMU体感网络实现该算法，并评估系统优劣。纯航位推算在30秒内精度达1度以内；漂移校正方案可在4秒内利用横向加速度将偏航角大幅漂移校正至均方根误差3.3度以内；无漂移状态下运动时的校正精度为均方根误差1.1度。我们证明，即使在没有重力和磁场的条件下，通过利用局部加速度信息以及常被忽略的向心加速度和切向加速度，运动链中陀螺仪漂移仍可被有效补偿。因此，IMU人体跟踪技术完全可应用于微重力环境。