Observer design for nonlinear systems with multi-rate sampled outputs - Application to attitude estimation

The present paper proposes an observer for a class of nonlinear systems with multi-rate sampled outputs. Each output can have irregular and aperiodic sampling rate independent of the others. This work extends previous studies on high gain observer to permit the estimation of multi-rated output systems. The stability is proved by using a Lyapunov approach, providing that the sampling rates of each outputs are respectively smaller than their associated upper bound. The observer is then applied to the attitude estimation problem.