ZUPT-aided strapdown integration of world-frame acceleration

Double-integrates world-frame linear acceleration to velocity and position, applying a zero-velocity update (ZUPT) at each stance sample: the integrated velocity is de-drifted so that it returns to zero at every stance sample (linear de-drifting within each swing), which bounds the per-stride integration drift.

Usage

strapdownIntegrate(accel_world, sampling_rate, stance)

Arguments

accel_world

Numeric matrix (n x 3) of gravity-free acceleration in the world frame (m/s^2), e.g. from removeGravity() rotated into world axes.

sampling_rate

Sampling rate in Hz.

stance

Logical vector of length n, TRUE at stance samples (from detectStanceZUPT()).

Value

A list with numeric matrices velocity and position (each n x 3).

References

Mariani B, Hoskovec C, Rochat S, Bula C, Penders J, Aminian K (2010). "3D gait assessment in young and elderly subjects using foot-worn inertial sensors." J Biomech 43(15):2999-3006.

See also

detectStanceZUPT(), footImuGait().