Output-only observer/Kalman filter identification (O3KID).

This paper presents output-only observer/Kalman filter identification (O³KID), an effective method for the identification of the dynamic model of a structure and its underlying modal parameters using only output time histories measured on the field. The method is suitable for structural health monitoring based on modal parameters, in particular, for those civil infrastructures whose excitation is random in nature and in the way that it is applied to the structure (e.g., wind and traffic) and therefore is difficult to measure. O³KID is based on a linear-time-invariant state-space model and is derived from an established and successful approach for input-output system identification, known as observer/Kalman filter identification. The paper rigorously proves the applicability of the approach to the output-only case, presents the resulting new algorithms, and demonstrates them via examples on both numerical and experimental data. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]