Observer design for satellite angular rate estimation using the state-dependent riccati equation method

The problem of estimating the angular rate of a satellite is considered. A nonlinear observer based on the state-dependent Riccati equation method is proposed. A sufficient stability condition for the convergence of the estimation error is presented. This condition is related to a state-dependent algebraic Riccati equation. The Riccati equation is derived by transforming nonlinear error dynamics into a Lipschitz nonlinearity. Observer gains are obtained from this state-dependent algebraic Riccati equation. Numerical simulations are presented to demonstrate the proposed method.