Identifiability of nonlinear systems: A geometric approach

The parameter identifiability problem of deterministic nonlinear control systems is studied. The relations between nonlinear observability, nonlinear functional expansions, uniqueness theorem of nonlinear realization theory and identifiability are investigated. By using these relations, necessary and sufficient conditions of identifiability are obtained for the first time. These results provide an insight to the identifiability problem of nonlinear systems.