If the direct cosine matrix for the transformation from xyz to x^{′} y^{ ′} z^{′} is the same as it was in Example 4.5,
[ Q] = \begin{bmatrix} 0.64050 & 0.75319 & -0.15038 \\ 0.76736 & – 0.63531 & 0.086824 \\ -0.030154 & -0.17101 & -0.98481 \end{bmatrix}
find the angles α , β and γ of the yaw, pitch, and roll sequence
Use Algorithm 4.4.
Step 1:
\alpha=\tan^{-1}\!\!\frac{Q_{12}}{Q_{11}}=\tan^{-1}\!\left(\frac{0.75319}{0.64050}\right)
Since both the numerator and the denominator are positive, α must lie in the first quadrant. Thus ,
\tan^{-1}\left({\frac{0.75319}{0.64050}}\right)=\tan^{-1}1.1759=49.62°
Step 2:
\beta=\sin^{-1}(-Q_{13})=\sin^{-1}[-(-0.15038)]=\sin^{-1}(0.15038)=8.649°
Step 3:
\gamma=\tan^{-1}\!\!{\frac{Q_{23}}{Q_{33}}}=\tan^{-1}\left({\frac{0.086824}{-0.98481}}\right)
The numerator is positive and the denominator is negative, so γ lies in the second quadrant,
\tan^{-1}\left({\frac{0.086824}{-0.98481}}\right)=\tan^{-1}\left(-0.088163\right)=-5.0383^{\circ}\Rightarrow γ = 174.96°