  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.
