A new approach to state observation of nonlinear systems with delayed output

This paper presents a new approach for the construction of a state
observer for nonlinear systems when the output measurements are available
for computations after a non negligible time delay. The proposed observer
consists of a chain of observation algorithms that reconstruct the system
state at different delayed time instants (chain observer). Conditions are
given that ensure global exponential convergence to zero of the
observation error, whatever is the delay in the measurements. The
implementation of the observer is easy and computer simulations show its
effectiveness. Although only the case of systems with only one input and
one output is treated in the paper, the extension of the approach to
systems with multiple inputs and outputs does not present difficulties.