Figure 2.

Shown is a rotation around an arbitrary axis to align the $z_{\mathrm{LCP}}$ axis with the $z_{\mathrm{LTP}}$ axis. The axes of the LTP are shown in green, the axes of the LCP are shown in magenta, and the arbitrary axis $r_{{\mathrm{h}}_0}$ and the rotation angle ${\theta }_{\mathrm{h}}$ with grey.