GESO based robust optimal guidance

In this work, formulation of a robust optimal guidance law for tactical missiles in end game scenario is proposed. Using the linearized missile target engagement model, an LQR based guidance law is designed to minimize the miss distance. Implementation of the guidance law, however, needs availability of system states as well as target acceleration. Since the latter represents an unmatched uncertainty, many conventional approaches are not applicable for its estimation. In this work, the issue is addresses by employing the recently proposed Generalized Extended State Observer (GESO) approach. Apart from providing an estimate of target acceleration, the GESO also provides the estimates of the states enabling implementation and robustification of the LQR based guidance law. Simulations are carried out by employing the proposed guidance law to the nonlinear two-dimensional missile-target engagement model in presence of highly maneuvering target and the results are presented. Further, performance comparison is carried out with classical Proportional Navigation (PN) guidance to demonstrate the efficacy of the proposed formulation.