Artifacts - Investigation and Ground-Truth Data Collection for Re-Calculation of Gravity-based Artifacts within BCG Signals

The ballistocardiography (BCG) method shows promise for health monitoring on Earth and in space, but faces challenges in signal interpretation. ISS experiment "Wireless Compose 2" identified gravity-induced artifacts in BCG data. Upcoming experiments aim to clarify BCG signals in microgravity, potentially improving accuracy.

The ballistocardiography (BCG) method offers great potential, both for terrestrial (digital health) and extraterrestrial  applications (health monitoring and primary prevention for astronauts).

Despite numerous research projects, there is still a fundamental uncertainty in characterizing the BCG signals, making interpretation extremely difficult. As part of our recently conducted ISS experiment "Wireless Compose 2" (ISS EXP 67/68), it was noticed that the movements caused by the heart and propagated to the body surface cause the sensor to roll and pitch so that under the influence of earth's gravity, acceleration artifacts appear on the BCG data. These can lead to misinterpretations.

In µg environment, due to the lack of influence of gravity per se, these artifacts should not form. Therefore, in this parabolic flight experiment, reference measurements under µg will be performed to be able to derive models of the actual morphology of the BCG signal at the body surface (without artifacts).

This measurement campaign in a µg environment is essential for further BCG research and serves the following goals:

• Enable basic research in the field of BCG measurement to be able to understand and describe the origin of the artifacts
• Further derivation of models to describe the actual (artifact-free) morphology of the BCG signal at the surface of the body
• Further derivation of methods to compensate for artifact formation by recomputing the gravitational acceleration
• The signal processing chain for the automated analysis of the BCG signals from the AuRelia project will be evaluated as a secondary result.

The experiment itself is embedded in the DLR project AuRelia, in which an autonomous and reliable BCG sensor system for future long-term missions is being developed. The sensor system itself is used in this experiment to collect the data.

The results of this experiment benefit all BCG-related research. Data quality will significantly improve for newly acquired measurements, and both new and old data will profit from better interpretability of the BCG signals.