Semiglobal state observers for nonlinear analytic discrete-time systems

This paper presents an improved version of a semiglobal state observer for nonlinear analytic discrete-time systems, proposed by the authors in a recent work . The method is based on the Taylor approximation of the inverse of the system observability map. In this work the performances of the improved observer are compared with those of the old version, both from a theoretical point of view, by presenting the semiglobal convergence theorems for both observers, and from a practical point of view, through computer simulation.