Improved eigensystem realization algorithm and its application on ocean platforms

Based on the matrix mapping theory, an improved eigensystem realization algorithm (ERA), called C/ERA, is proposed in this paper. It rebuilds a Hankel matrix by replacing all elements of each anti-subdiagonal with the arithmetic average of the elements along the anti-subdiagonal, and introduces the concept of using the Frobenius norm (L2-norm) to control the iterations number after implementing the SVD algorithm by the ERA method. With the data associated with a 5-DOF mass-spring-dashpot system and jacket-type platform under impact loading, it is demonstrated that C/ERA has a better capacity of de-noising, and a higher accuracy for low-order modes, and can identify more high-order modes than the ERA method.