xest(1,k) = xest(1,k-1) + dt*Vc*cos(phi) - dt*Vc/L*tan(alpha)*(a*sin(phi)+b*cos(phi));
    xest(2,k) = xest(2,k-1) + dt*Vc*sin(phi) + dt*Vc/L*tan(alpha)*(a*cos(phi)-b*sin(phi));
    xest(3,k) = phi + dt*Vc/L*tan(alpha);
...
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    A(1,1)=??; A(1,2)=??; A(1,3)=??;
    A(2,1)=??; A(2,2)=??; A(2,3)=??; 
    A(3,1)=??; A(3,2)=??; A(3,3)=??;
...
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    A(1,1)=1; A(1,2)=0; A(1,3)= Vc*dt*(-1)* (sin(phi) + tan(alpha)/L*(a*cos(phi)-b*sin(phi)));
    A(2,1)=0; A(2,2)=1; A(2,3)=Vc*dt*(cos(phi) - tan(alpha)/L*(a*sin(phi)+b*cos(phi))); 
    A(3,1)=0; A(3,2)=0; A(3,3)=1;
    Pest = ??;