Design of three-dimensional guidance law based on extended state observer for hit-to-kill interceptors

In this paper an Extended State Observer (ESO) based guidance law is proposed for hit-to-kill interceptors in the three-dimensional high-speed engagement. An approximate miss distance formula is given in this scenario. The nonlinear uncertainties and unknown target maneuvering are regarded as total disturbances of the kinematics, which are estimated by the ESO. With the estimation results as the compensation, the method of feedback linearization is adopted and the nonlinear kinematics is decoupled into two one-order subsystems. For each of the subsystems, a proportional controller is designed as the fictitious guidance command. The effectiveness of the ESO in estimation of the total disturbances and the performance of the guidance law are demonstrated through simulation.