Algorithm 1 RFU method with comprehensive metrics.
Require:${\mathit{\omega }}_{\mathbf{1}},{\mathit{\omega }}_{\mathbf{2}},{\mathit{a}}_{\mathbf{1}},{\mathit{a}}_{\mathbf{2}},{\mathit{m}}_{\mathbf{1}},{\mathit{m}}_{\mathbf{2}},{\mathit{j}}_{\mathbf{1}},{\mathit{j}}_{\mathbf{2}},q_{s_1}^{g_1},q_{s_2}^{g_2}$
Ensure:$k_{mag},k_{acc},q_{corr}$
1:	initialize $k_{mag},k_{acc}$
2:	while $sliding$ $windows$ do
3:	calculating the magnetometer measurement-based correction quaternion $q_{mag}$ using Equation (7)
4:	calculating the accelerometer measurement-based correction quaternion $q_{acc}$ using Equation (6)
5:	fusing $q_{mag}$ and $q_{acc}$ using Equation (8)
6:	calculating the main axis’ projections in the reference frame $\left[g_1\right]$ using Equation (9)
7:	forming the cost function as $f_i(k_{mag},k_{acc})=\parallel {\left[{\mathit{j}}_{\mathbf{1}}\right]}_{{\mathit{g}}_{\mathbf{1}}}-{\left[{\mathit{j}}_{\mathbf{2}}\right]}_{{\mathit{g}}_{\mathbf{1}}}\parallel$, and solving it using L-M method.
8:	end while