Observer design for continuous-time dynamical systems

We review the main design techniques of state observer for continuous-time dynamical systems, namely algorithms which reconstruct online full information a process on basis partially measured data. Starting from necessary conditions existence such asymptotic observers, we classify available methods depending detectability/observability assumptions they require. show how each class relies transforming system dynamics in particular normal form allows an observer, and observability condition guarantees invertibility its associated transformation convergence observer. Finally, some implementation aspects open problems are briefly discussed.