PN guidance law identification using multi-model adaptive estimation

The intercepting missile guidance behavior identification problem in missile active defense application is investigated, and a Proportional Navigation (PN) guidance law multi-model identification method is proposed, which can estimate the intercepting missile's accelerations and guidance constants. The observability of the systems is analyzed using the nonlinear system observability theory. Under the assumption of the intercepting missile with PN guidance law, the necessary and sufficient condition of the guidance system observability is derived. Compared with the previous research, the actuator saturation of the intercepting missile due to eliminating the initial aiming errors is considered in the proposed method. Thus, under both the intercepting missile's actuator saturation and unsaturation situations, the guidance law can be estimated accurately. Additionally, different from the previous research in which guidance constants of PN guidance law were assumed to be known, the proposed method treats the guidance constants as a state of the guidance system needed to be estimated. The simulations demonstrate that the proposed method outperforms the pure PN guidance law identification Kalman filtering.