FREQUENCY-DOMAIN STATE-SPACE SYSTEM-IDENTIFICATION

This paper presents an algorithm for identifying state-space models of linear systems from frequency response data. A matrix-fraction descri ption of the transfer function is employed to curve-fit the frequency response data, using the least-squares method. The parameters of the m atrix-fraction representation are then used to construct the Markov pa rameters of the system. Finally, state-space models are obtained throu gh the Eigensystem Realization Algorithm using the Markov parameters. The main advantage of this approach is that the curve-fitting and the Markov-parameter-construction are linear problems which avoid the diff iculties of non-linear optimization of other approaches. Another advan tage is that it avoids windowing distortions associated with other fre quency domain methods.