Astronaut Motion Measurement System (AMMS)

In order to study astronaut biomechanics on ISS, a system is needed which can accurately measure the position of various parts of the human body relative to the subject¿s workspace with minimal intrusion on the subject and the environment. As with all spaceborne vehicles, ISS has strict restrictions on the electromagnetic environment, as well as mass and power. Disturbances to the crew are also to be avoided, particularly in this case, as disturbing the crew might well affect the data. The proposed Astronaut Motion Measurement System (AMMS) uses a series of small ultrasonic transmitters and receivers to measure the position and motion of astronauts within ISS without disturbing the visual, electromagnetic, or auditory environments. These measurements are accomplished by detecting the time of flight of an ultrasonic pulse between known base transceiver locations and transceivers worn by the astronaut. These transceivers are small and unrestrictive, making AMMS ideal for collecting long-term motion data without causing discomfort to the subject or producing erroneous data because the measurement device was cumbersome. Using AMMS, measurements of position can be taken with millimeter-level accuracy at sample rates in the 30Hz range (sample rate and accuracy are dependent on local environment size).