Application of structured total least squares for system identification

The following identification problem is considered: minimize the ℓ₂ norm of the difference between a given time series and an approximating one under the constraint that the approximating time series is a trajectory of a linear time invariant system of a fixed complexity. The complexity is measured by the input dimension and the maximum lag. The problem is known as the global total least squares and alternatively can be viewed as maximum likelihood identification in the errors-in-variables setup. Multiple time series and latent variables can be considered in the same setting. The identification problem is related to the structured total least squares problem. The paper presents an efficient software package that implements the theory in practice. The proposed method and software are tested on data sets from the database for the identification of systems DAISY.