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Trajectory tracking and estimation of hypersonic glide vehicles (HGVs) is a very challenging issue in the defense systems. Insufficient knowledge about the HGV and inaccurate dynamic models for the accelerating HGV are the main challenges in this regard. In the present study, an integrated nonlinear Markov acceleration model is established to formulate the nonlinear dynamic characteristics of HGVs. Since the aerodynamic accelerations of the HGV are dominant and the corresponding aerodynamic coefficients are unknown, a statistics-based aerodynamic model is proposed. The proposed aerodynamic model is capable of providing primary information of the aerodynamic characteristics even without knowing the configuration of the HGV. Then, considering the maneuver mode of the vehicle, the iterative extended Kalman filter (IEKF) is applied to track the trajectory of the HGV by using the proposed model. Obtained results from the numerical simulation for the equilibrium glide mode and skip maneuver mode indicate that the proposed model can effectively improve the velocity estimation accuracy by about 40%-50% and acceleration estimation accuracy by about 20%-50% in the given examples.

This paper derives a new terminal homing guidance law for missiles to intercept noncooperative maneuvering targets subject to the constraint of terminal line-of-sight angle. The new guidance law avoids abrupt and large changes in guidance commands, while allows the control gains to be determined analytically or chosed loosely to ease the design of guidance law. This is achieved by combining the advantages of sliding mode, prescribed performance, and inertial delay controllers. The prescribed performance controller is designed by a new two-phased prescribed performance function with an improved continuous dynamic property, which drives the predefined state error-based sliding mode variable to a small residual set around zero. The inertial delay controller is adopted to suppress the system uncertainty. Thus, the new guidance law yields continuous guidance commands over the entire terminal homing phase while eliminating abrupt and large changes in the initial phase, resulting from the initial state errors in the prescribed performance function. The newly proposed guidance law improves the prescribed performance control that dominates the gains of the proposed guidance law. Theoretical analyses and numerical simulations are conducted to verify the robustness and preciseness of the proposed guidance law.