Generalized Guidance Formulation for Impact Angle Interception with Physical Constraints

This paper proposes an optimal impact angle control guidance law for homing missiles with a narrow field-of-view of the seekers. As groundwork for designing a guidance law, we first present a general guidance structure that can achieve any terminal constraint of the line-of-sight rate based on the optimal control theory. We configure the desired profile of the line-of-sight rate using a saturation function whose exact form is determined to satisfy the required boundary conditions. By combining the line-of-sight rate profile with the optimal guidance structure, we develop a guidance law that achieves an impact angle interception with the field-of-view constraint. Herein, as the entire guidance structure is derived based on exact kinematics without any approximation, the proposed law ensures the accurate impact angle interception for various engagement scenarios. This precise consideration of the engagement kinematics also accurately ensures the energy optimality of preventing the excessive use of control inputs when homing. To evaluate the performance of the proposed method, numerical simulations with various engagement scenarios are conducted, and the results demonstrate that the proposed law allows missiles to accurately intercept their targets with the desired impact angles and without violating the prescribed field-of-view constraint.

Multi-agent cooperative multi-model adaptive guidance law

ABSTRACT A multi-agent engagement scenario is considered in which a high-value aircraft launches two defenders to intercept two homing missiles aimed at the aircraft. Under the assumption that all aircrafts have first-order linear dynamic characteristics, a combined multiple-mode adaptive estimation (MMAE) and a two-way cooperative optimal guidance law are proposed for the target–defenders team. Considering the full cooperation of the target and both the two defenders, the two-way cooperative strategies provide the analytical expressions for their optimal control input, enabling the target–defenders team to intercept the missiles with minimal control effort. To successfully intercept the missiles, MMAE is used to identify the guidance laws adopted by the missiles and estimate their states. The simulation results show that the target cooperating with the defenders to perform lure manoeuvres for the missiles can improve the guidance performance of the defenders as well as reduce the control effort of the defenders for intercepting the missiles.

Direct impact angle control guidance for passive homing missiles

A guidance problem for impact angle control applicable to a missile equipped with a passive seeker is investigated. The proposed guidance law based on the sliding mode control consists of the proportional navigation guidance term with a varying navigation constant and the additional biased term which is a function of the novel sliding surface. The guidance law directly uses the impact angle error but does not require any range information to be estimated by the additional filter loop of the passive seeker. The asymmetric limit of the passive seeker’s field-of-view is also taken into account, which is not violated by introducing a continuous switching function. The finite time convergence properties are analyzed, and nonlinear simulations are performed to investigate the effectiveness of the proposed guidance law.

An observer-based continuous adaptive sliding mode guidance against chattering for homing missiles

A novel observer-based continuous adaptive sliding mode guidance (OCASMG) is proposed for homing missiles. First, a new sliding mode guidance law is derived from the nonlinear dynamics describing the pursuit situation of a missile and a target in the two-dimensional space, where a continuous adaptive function is introduced to overcome the chattering problem in sliding mode. Second, to improve the accuracy of target interception, a new nonlinear extended state observer (NESO) is presented to estimate target acceleration and compensate for the sliding mode guidance law. The stability of observer-based closed-loop system is proved by Lyapunov theory. Finally, simulations are conducted on the nonlinear longitudinal missile model and results demonstrate the effectiveness of proposed method.