Time scaling for observer design with linearizable error dynamics

In this paper, we consider the problem of observer design for dynamical systems with scalar output by linearization of the error dynamics via coordinate change, output injection, and time scaling. We present necessary and sufficient conditions which guarantee the existence of a coordinate change and output-dependent time scaling, such that in the new coordinates and with respect to the new time the system has linear error dynamics. (C) 2003 Elsevier Ltd. All rights reserved.