=& \dot{\psi}
    \end{eqnarray}
</p>
<p>and the state equations are</p>
<p>
    \begin{eqnarray}
    \nonumber \dot{{\rm x}}_1 &=& v_{\rm T} \cos \left( \psi + \alpha_{\rm T} \right) \\
    \nonumber \dot{{\rm x}}_2 &=& v_{\rm T} \sin \left( \psi + \alpha_{\rm T} \right) \\
    \nonumber \dot{{\rm x}}_3 &=& \dot{\psi} \\
    \nonumber \dot{{\rm x}}_4 &=& \frac{F_{x,{\rm F}} \cos \left( \alpha_{\rm T} - \delta_{\rm F} \right) + F_{x,{\rm R}} \cos \left( \alpha_{\rm T} -\delta_{\rm R} \right) + F_{y,{\rm F}}