Outputs analysis and dual immersion method for chaotic systems

When secure data transmission is implemented through chaotic systems, the choice of the output is a preliminary problem. In this paper, the quality of the transmitted information is analysed with respect to the observability concept, for each potential output. More-over, in order to overcome observability loss, a dual immersion technique is proposed.The use of high order sliding mode observer on a well known Lorenz system, allows to highlight the well founded of the proposed analysis and method.