Before revision:  For the in-motion alignment, however, the two filters still need the assistance of the analytical / optimization-based in-motion alignment methods at the very start to avoid extremely large attitude errors, although they possess much larger convergence region than the traditional EKF does  .
After revision:  For the in-motion alignment, however, the two filters still need the assistance of the analytical / optimization-based in-motion alignment methods at the very start to avoid extremely large attitude errors, although they possess much larger convergence region than the traditional EKF does , although they still require the aid of attitude initialization so as to avoid large initial attitude errors .