State-space parametrizations of multivariable linear systems using tridiagonal matrix forms

Tridiagonal parametrizations of linear state-space models are proposed for multivariable system identification. The parametrizations are surjective, i.e. all systems up to a given order can be described. The parametrization is based on the fact that any real square matrix is similar to a real tridiagonal form as well as a compact tridiagonal form. These parametrizations has significantly fewer parameters compared to a full parametrization of the state-space matrices.