Gravisensing

Gravisensing is the process of sensing and interpreting gravity-related signals to determine orientation, motion, and gravity-field properties. In practice, gravisensing uses data from gravity-sensitive sensors such as accelerometers and gravimeters, often within a larger inertial measurement framework that includes gyroscopes and magnetometers, to estimate the direction and magnitude of the Earth's gravity vector while separating gravitational acceleration from other body accelerations. In geophysics and space science, gravisensing also refers to methods that measure the local gravity field and its spatial variations to infer subsurface structure or mass redistribution.

In mobile and robotic contexts, gravisensing typically focuses on deriving a stable gravity vector from inertial sensor data and fusing with other sensors to provide reliable orientation and motion tracking. Applications include screen orientation, indoor navigation, augmented and virtual reality, drone stabilization, and autonomous robotics. In geodesy and space missions, gravity measurements support gravity-field mapping and orbit determination, including time-variable gravity observations from satellite missions.

Key challenges include distinguishing gravity from dynamic accelerations, sensor bias, noise, and drift, as well as calibration in varying environments. Common solutions rely on Kalman or complementary filters and multi-sensor fusion to maintain a robust gravity estimate.

Advances in MEMS sensors and algorithmic fusion continue to expand gravisensing capabilities in consumer devices, vehicles, and scientific instrumentation. See also gravimetry, gravity gradiometry, inertial navigation, gravimetric surveys.