Algorithm 4. Dominant axis extraction(ω(n), m(n))

Compute ${\sigma }_{\omega x}\left(n\right), {\sigma }_{\omega y}\left(n\right), {\sigma }_{\omega z}\left(n\right), {\sigma }_{mx}\left(n\right), {\sigma }_{my}\left(n\right), {\sigma }_{mz}\left(n\right)$

For each axis

If signal is periodic For all axes of gyro and mag

$d{r_{axis}}_{\omega }$ = ${{\sigma }_{axis}}_{\omega }/\left|2\times {f_{\omega }}_{axis}- f_a\right|$

$d{r_{axis}}_m$ = ${{\sigma }_{axis}}_m/\left|2\times {f_m}_{axis}- f_a\right|$

Else

$dr=0$

Return (max ($d{r}_{\omega }$), max ($d{r}_m$))