Development and analysis of the numerical criterion for the degree of observability of state variables in nonlinear systems

This paper is concerned with the problem of development and analysis of numerical criteria for the degree of observability in nonlinear systems. The disadvantages of existing criteria of observability and controllability were introduced. A numerical criterion for the degree of observability of each state variable was developed in nonlinear systems by utilizing the representation of nonlinear models in the State Dependent Coefficient form. The application of the novel criterion was demonstrated for the analysis of the degree of observability of inertial navigation system errors by the simulation with experimental data.